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The broad mite, Polyphagotarsonemus latus (Banks) (Acari: Tarsonemidae) is a highly significant pest in tropical and subtropical regions, with a wide host range that encompasses over 60 plant families. In particular, it can be a major and economically damaging pest on pepper plants, causing significant losses to the crop. The life table parameters of P. latus were determined under laboratory conditions to evaluate the susceptible and resistant cultivars of greenhouse pepper among 14 pepper cultivars, including Selva, Clavesol, Kamus, Chidem, Sympathy, Sven, Kamro, Lumos, Caoba, Bellisa, Sunset, Atlantic D90, Atlantic G50, and Atlantic P5001. The total pre-adult period was significantly different on the pepper cultivars tested, in which the shortest and longest duration was recorded on Atlantic P5001 (5.02 days) and Atlantic G50 (5.94 days), respectively. Adult longevity and total life span had significant differences among pepper cultivars, in which the longest durations were observed on Kamus (21.02 and 26.36 days, respectively). The population growth parameters, including the gross reproductive rate (GRR), net reproductive rate (R 0), intrinsic rate of increase (r), finite rate of increase (λ), and mean generation time (T), as well as the fecundity of the broad mite exhibited significant differences among the cultivars tested. Specifically, the maximum and minimum values of the intrinsic rate of increase (r) were observed in Lomus (0.319 day−1) and Sunset (0.242 day−1), respectively. The gross reproductive rate (28.33 eggs/individual) and net reproductive rate (27.18 eggs/individual) in the Kamus cultivar were significantly higher than those in the other cultivars. Our results indicated that among the pepper cultivars, Sunset, Sympathy, Chidem, and Clavesol were more resistant to P. latus compared with the others. [Display omitted] • Polyphagotarsonemus latus is one of the serious pests of greenhouse pepper. • Antibiosis resistance of 14 cultivars of greenhouse pepper was investigated. • A significant difference was observed in the development and population growth of P. latus on different cultivars. • The highest and lowest population growth of P. latus were obtained on the Lomus and Sunset cultivars, respectively. • Resistant pepper cultivars could be used for the control of the broad mite. [ABSTRACT FROM AUTHOR]

While wildlife damages are a relatively small part of crop insurance claims in the United States, reported damages from wildlife are growing and producers are concerned this issue is getting worse. Wildlife agencies advocate for hunting as a control to wildlife damages to crops but to our knowledge, no study has econometrically explored if hunting could reduce crop damage. Therefore, we analyze if county-level white-tailed deer (Odocoileus virginianus) harvest and other factors like habitat and field fragmentation are associated with corn and soybean acres being indemnified due to wildlife damages in Tennessee. We estimate a fractional probit model using crop insurance data to measure crop damages and a county-level white-tailed deer harvest dataset. We find a higher coverage level of a policy increases the likelihood of both corn and soybean acres being indemnified due to wildlife damage. We also find white-tailed deer harvest during the period post-harvest in the previous crop year (November through January) slightly decreases the likelihood of a claim being made due to wildlife damage for corn but was not found to mitigate losses to soybeans. The whitetail hunting season appears to align better with corn production to reduce crop losses than with soybeans. This study will be useful for wildlife and crop agencies in state and federal governments to develop policies to more effectively utilize hunting to reduce crop insurance claims from wildlife damages. • Crop insurance claims due to wildlife damage are up. • Hunting is advocated on ways to reduce damage. • Deer harvest reduced corn insurance claims. • Deer harvest did no impact soybean damages. [ABSTRACT FROM AUTHOR]

Rapeseed (Brassica napus L.) is the third most important oil crop worldwide and it has a high demand for its industrial characteristics that make it suitable for human consumption and production of biofuels. The main yield losses of the crop are produce by blackleg, caused by Leptosphaeria maculans (Desmaz.) Ces. and of Not. [Anamorph Phoma lingam (Tode ex Fr.) Desmaz]. In this context, 469 inbred lines (ILs) of the INTA-EEA Paraná breeding program were phenotypic characterized for its resistance to Blackleg by artificial inoculations with a local isolation. From the initial 469 ILs, a total of 59 (13%) were identified as phenotypically resistant and were characterized by molecular makers associated to resistant genes (Rlm1, Lepr3, Rpg3Dun, and Rlm4) with the aim to identify lines carrying different resistance genes to be selected as parental lines in the development of new resistant genotypes. Moreover, the resistant ILs were characterized for its agronomics performance, including yield; percentage of oil; and content of fatty acids, over two crop seasons (2018 and 2019). A Generalized Procrustes Analysis was conducted to correlate all the traits evaluated and identify elite lines. From the 59 resistants ILs, four lines were selected based on their high performances and multiple resistant gene combinations, as started lines to develop a pyramiding gene strategy. The selection of these elite lines to combine traditional breeding and gene-pyramiding based on MAS in our breeding program is a useful strategy to develop superior rapeseed genotypes. • Blackleg or stem canker is the main disease affecting yield in rapeseed. • Screened 59 resistant ILs from 459 ILs based on its responses to blackleg. • The R gene distribution and ILs agronomic performance were evaluated. • New resistant genes (L. maculans) were identified by molecular markers. [ABSTRACT FROM AUTHOR]

Corn consumption by birds is a costly problem in North America, yet growers have limited effective options for managing crop losses. Most research has focused on reducing bird conflicts in ripening corn fields, however, growers also report damage to newly-planted corn seeds and seedlings. We conducted a study of corn losses caused by birds on newly planted and emerging corn seedlings within fields in eastern and northern New York State during 2016–2018. A 97-day corn hybrid was selected with a typical insecticide and fungicide seed treatment package from Dairyland (DS 9791RA) in order to minimize other possible confounding variables. Each trial field (n = 5 in 2016; n = 16 in 2017; n = 20 in 2018) included a split-plot design on 2.02 ha (5 acres). Corn seed on half of each trial field 1.01 ha (2.5 acres) was treated with Avipel Shield (anthraquinone, AQ) and the other half was left untreated. Results from these field trials showed that the seed treatment with AQ reduced corn pulling by birds (primarily American crows) and increased plant populations during all 3 years. However, corn silage yield was similar between control and treatment blocks in trial fields, and was not impacted by seed treatment with AQ. Still growers believed the added repellent cost was justified to maintain high corn plant counts in spring and have at least the potential for better yields at harvest. • Corn-pulling by birds in spring is an important issue for farmers in New York State. • Avipel Shield containing anthraquinone significantly increased corn plant populations. • Corn silage yield was similar between control and treatment blocks at harvest. • Cost of seed treatment with Avipel Shield repellent was not excessive ($18.48/ha). • Growers believed the added cost was justified despite no differences in yield. [ABSTRACT FROM AUTHOR]

Root-knot nematodes are severe soil-borne pathogens that cause great damage to vegetable crops and economic losses all over the world annually. Therefore, there is an urgent need to seek novel nematicides or biological control agents. In this study, a bacterium strain, the Bacillus subtilis strain Bs-1, was obtained from rhizospheric soil, and had strong nematicidal effects and caused egg hatching inhibition and repellence of Meloidogyne incognita. Nematicidal activity was evaluated according to fermentation assays, and the mortality rate of second-stage juveniles (J2s) to the Bs-1 fermentation treatment was 100%. The results of ovicidal experiments indicated that fermentation of the strain Bs-1 also had a strong effect on decreasing the egg hatching rate. In both pot and field experiments, Bs-1 fermentation was able to significantly reduce root galls and promote the growth of cucumber. A repellence test of Bs-1 fermentation showed that a majority of J2s were obviously repelled by the Bs-1 fermentation and supernatant, but were attracted by cucumber root extracts. The gas chromatography-mass spectrometry (GC-MS) results showed that the volatile organic components (VOCs) produced by the strain Bs-1 were complex and diverse, such as ketones, acids, alkyls, sulfide and heterocyclic compounds and so on. These results revealed that the B. subtilis strain Bs-1 provides strong suppression against M. incognita and could be used as a potential biological control agent to suppress M. incognita. • A novel isolate Bacillus subtilis strain Bs-1 came from rhizosphere soil. • Strain Bs-1 performed repellence of J2s of M. incognita and hatching inhibition efficiency. • Strain Bs-1 has high biological control effect on root-knot nematodes. [ABSTRACT FROM AUTHOR]

Fiji leaf gall has been a major disease in the Australian sugarcane industry, causing extensive crop losses in the 1970–1990 period. The disease has been managed via a number of measures including varietal resistance, disease-free plant sources, termination of heavily-infested crops, quarantine and rogueing of disease stools. These measures have been highly effective and reduced detected disease incidence to zero in several districts. Over 32,000 crop inspections have been undertaken since the last known diseased crop was sighted in the Central Queensland region. All disease inspection data were collated and analysed for this region, with modelling undertaken to determine the probability of the disease being present but remaining undetected. These analyses suggest that it is very highly unlikely to be present; a proposal is made therefore to declare 'area freedom from Fiji leaf gall' for the Central Queensland region. •. FLG has caused extensive crop and financial losses within the Australian industry. •. It is over 25 years since the disease has been detected in Central Queensland. •. Over 32,000 crop inspections failed to detect the disease. •. Probability modelling suggests FLG is extremely unlikely to be present in CQ. •. We suggest 'area freedom' be declared for Central Queensland. [ABSTRACT FROM AUTHOR]

Abstract Cassava brown streak disease (CBSD) and cassava mosaic disease (CMD) are two viral diseases that cause severe yield losses in cassava of up to 100%, thereby persistently threatening food and income security in sub-Saharan Africa. For effective management of these diseases, there is a critical need to develop and deploy varieties with dual resistance to CBSD and CMD. In this study, we determined the response of advanced breeding lines to field infection by cassava brown streak viruses (CBSVs) and cassava mosaic begomoviruses (CMBs). This aim helped in identifying superior clones for downstream breeding. In total, 220 cassava clones, three in uniform yield trials (UYTs) and 217 in a crossing block trial (CBT), were evaluated for virus and disease resistance. Field data were collected on disease incidence and severity. To detect and quantify CBSVs, 448 and 128 leaf samples from CBSD symptomatic and symptomless plants were analyzed by reverse transcription PCR and real-time quantitative PCR, respectively. In addition, 93 leaf samples from CMD symptomatic plants in the CBT were analyzed by conventional PCR using CMB species-specific primers. In the CBT, 124 (57%) cassava clones did not express CMD symptoms. Of the affected plants, 44 (55%) had single African cassava mosaic virus infection. Single Cassava brown streak virus (CBSV) infections were more prevalent (81.6%) in CBT clones than single Ugandan cassava brown streak virus (UCBSV) infection (3.2%). Of the three advanced clones in the UYT, NAROCASS 1 and NAROCASS 2 had significantly lower (P < 0.05) CBSD severity, incidence, and CBSV load than MH04/0300. In the UYT, only 22% of samples tested had CBSVs, and all showed a negative result for CMBs. The low disease incidence, severity, and viral load associated with NAROCASS 1 and NAROCASS 2 is evidence of their tolerance to both CBSD and CMD. Therefore, these two cassava clones should be utilized in CBSD and CMD management in Uganda, including their utilization as progenitors in further virus resistance breeding. Highlights • Host plant resistance is essential for management of cassava mosaic disease (CMD) and cassava brown streak disease (CBSD). • Disease evaluation based on symptoms need to be augmented with molecular tools for better disease assessment. • Cassava brown streak virus is the most prevalent virus causing CBSD in Uganda. [ABSTRACT FROM AUTHOR]

Abstract Water rots are a group of important potato tuber rot diseases such as pink rot, Phytophthora tuber rot, and leak caused by the oomycete pathogens Phytophthora erythroseptica , P. nicotianae, and Pythium ultimum , respectively. If not managed, these diseases either alone or in combination, can cause severe yield loss and substantial reductions in quality. Growers continue to rely on fungicides for water rot management in the field and during post-harvest storage. Previous and ongoing breeding attempts have failed to identify and develop commercially acceptable potato cultivars resistant to all three diseases. This is mainly due to the complex, expensive, and time-consuming methodologies required to screen for susceptibility to water rot pathogens. Currently, potato genotypes are assessed for susceptibility to individual water rot pathogens which is labor intensive. Considerable savings in time and effort would be realized if potato genotypes could be evaluated for susceptibility to one water rot pathogen and then statistical analysis applied to determine the probability of the reaction of a genotype to the other rot pathogens. A proportional odds model was fitted to examine the risk of genotype screening outcome (ordinal) to understand the relationships among water rot causing oomycetes in potato. Compared to P. erythroseptica , P. ultimum infected genotypes having susceptibility risk was high (2.6) versus other cultivar susceptibility categories. Potato genotypes screened for P. nicotianae have a significant susceptibility risk decreased by 38% when compared to P. erythroseptica. Highlights • Proportion odds model is used to model ordinal outcome. • Risk of potato genotype screening outcome was used to understand the relationship between water rot pathogens. • Compared to Phytophthora erythroseptica , Pythium ultimum infected genotypes have high susceptibility risk. [ABSTRACT FROM AUTHOR]

Abstract We conducted no-choice cage and field infestation studies to determine if the fruit of kiwifruit (Actinidia chinensis var. deliciosa , 'Hayward' [green-fleshed], and Actinidia chinensis var. chinensis , 'Zesy002' [gold-fleshed]) are hosts for three invasive tephritid fruit fly species that may enter New Zealand or other kiwifruit growing areas. For cage studies, punctured and unpunctured (intact) fruits of green and gold kiwifruit were exposed to gravid female flies of Bactrocera dorsalis (Hendel) (Oriental fruit fly), Zeugodacus cucurbitae (Coquillet) (melon fly), or Ceratitis capitata (Wiedemann) (Mediterranean fruit fly), in screen cages outdoors for 24 h, and then held on sand in the laboratory for three weeks for pupal development and adult emergence. Unpunctured green kiwifruit produced an average of 1.3, 0.0 and 48.8 puparia per kg of fruit for B. dorsalis , Z. cucurbitae and C. capitata , respectively. Unpunctured gold kiwifruit produced an average of 54.7, 6.1 and 0.0 puparia per kg of fruit for B. dorsalis , Z. cucurbitae and C. capitata , respectively. For comparison, unpunctured papaya, a preferred host for all three species, produced 492–795 puparia per kg of fruit across all species. These results indicate that kiwifruit is a poor ovipositional host for B. dorsalis, Z. cucurbitae and C. capitata. When kiwifruit were punctured to facilitate oviposition, the number of puparia per kg fruit increased significantly compared with those on unpunctured fruit for B. dorsalis, but not for Z. cucurbitae or C. capitata , indicating that kiwifruit is a poor developmental host for these two species. For all fruit fly species, the average weight of individual puparia recovered from green and gold kiwifruit was roughly 50% of the weight of puparia recovered from papaya. Field infestation of kiwifruit suspended from papaya trees resulted in no infestation of green kiwifruit and very low infestation of gold kiwifruit by B. dorsalis , and no infestation in either cultivar by Z. cucurbitae under natural conditions. Overall, kiwifruit is a poor host for B. dorsalis , Z. cucurbitae and C. capitata. This information will help inform decisions about quarantine restrictions and potential crop loss in the event of incursions of these fruit flies into New Zealand or other kiwifruit producing countries. Graphical abstract Mean number of Mediterranean fruit fly (Medfly), melon fly and oriental fruit fly pupae emerging per kilogram of punctured (P) or unpunctured (U) 'Hayward' (green-fleshed), 'Zesy002' (gold-fleshed) kiwifruit and papaya. Image 1 Highlights • New pest incursions can cause a regulatory or quarantine response and interrupt trade. • A Mediterranean fruit fly, oriental fruit fly or melon fly incursion into New Zealand could threaten kiwifruit exports. • Host status studies were conducted in Hawaii with New Zealand kiwifruit. • Gold-fleshed and green-fleshed kiwifruit were poor hosts for these three fruit flies. • Pro-active development of quarantine treatments could prevent interruptions in trade during pest incursions. [ABSTRACT FROM AUTHOR]

Enhanced nutritional programs have been applied by growers in an attempt to reverse crop losses caused by huanglongbing (HLB), despite the limited evidence available on their effects on HLB progress and damage mitigation in symptomatic sweet orange trees. Therefore, a long-term trial was set up in a 10-year-old 'Hamlin' sweet orange orchard to verify the effects of an additional supply of calcium and magnesium on HLB incidence, severity progress, and symptomatic tree yield. The trial had four treatments in four randomized blocks (ammonium nitrate or calcium nitrate, with or without magnesium sulfate). In each plot and treatment, 30 trees with ∼33.7% of canopy with HLB symptoms (HLB severity) were selected in November 2012 (group 1 trees), and 20 trees with ∼5.2% HLB severity were selected in March 2014 (group 2 trees). Additionally, 20 asymptomatic trees were selected in each plot and treatment. Those selected trees were individually harvested every year. HLB incidence, HLB severity, and yield of individual trees and of total area were assessed from 2012 to 2018. There were no significant effects of calcium and/or magnesium inputs on the reduction of HLB incidence progress (increased from 18.3 to 53.8%) or on HLB severity progress (increased from 33.7 to 60.7% for group 1 and from 5.2 to 61.3% for group 2). In all plots, symptomatic trees never recovered their yield to the same yield of asymptomatic trees, producing 60 and 48% less for groups 1 and 2, respectively, at the end of the trial. The total plot yield also declined over time. [Display omitted] • HLB incidence and severity were not reduced by additional supply of calcium and magnesium. • No effect on yield of HLB-symptomatic trees was observed with additional supply of calcium and magnesium. • Additional supply of calcium and magnesium did not enhanced total plot yield over 5 years. [ABSTRACT FROM AUTHOR]

Lolium rigidum Gaud. is the most prevalent and damaging grass weed of winter cereals in Spain. L. rigidum infestations are frequently treated with herbicides and, consequently, populations have evolved resistance. In 2012–2013 a random survey was conducted across cereal cropping areas of the Castilla-León and Cataluña regions to establish the distribution and frequency of herbicide resistance in L. rigidum populations to chlortoluron (Photosystem II inhibitor), chlorsulfuron (Acetolactate synthase inhibitor) and diclofop-methyl (Acetyl CoA Carboxylase inhibitor), commonly used herbicides for L. rigidum control in Spain. The results of this survey were compared with the results of a previous survey conducted in 2000–02. Resistance to PSII and ALS-inhibiting herbicides was common: 51% and 92% of the accessions collected from Castilla-León and Cataluña respectively were resistant to chlortoluron, while 75% of accessions from both regions were resistant to chlorsulfuron. Resistance to ACCase was more widespread in Cataluña, where 83% of accessions were classified as resistant, than in Castilla-León where 74% of the populations were still classified as susceptible to diclofop-methyl. These results show that resistance levels to all three herbicides had increased in Castilla-León since 2000 and to chlortoluron and chlorsulfuron in Cataluña. The accessions were also treated with the double dose (2X) of each herbicide. The percentage of L. rigidum that now exhibits multiple herbicide resistance has increased considerably, especially in Cataluña where 75% of the accessions were resistant to multiple herbicides, therefore herbicide sustainability and resistance management present a great challenge. [ABSTRACT FROM AUTHOR]

We report the results of one of the most comprehensive surveys on feral swine ( Sus scrofa ) damage and control in 11 US states (Alabama, Arkansas, California, Florida, Georgia, Louisiana, Mississippi, Missouri, North Carolina, South Carolina and Texas). The survey was distributed by the USDA National Agricultural Statistical Service in the summer of 2015 to a sample of producers of corn ( Zea mays ), soybeans ( Glycine max ), wheat ( Triticum ), rice ( Oryza sativa ), peanuts ( Arachis hypogaea ), and sorghum ( Sorghum bicolor ) in the 11-state region. Producers that failed to respond to the initial mailing received multiple follow-up phone calls in an attempt to minimize non-response bias, and a total of 4377 responses were obtained. Findings indicate that damage can be substantial. The highest yield loss estimates occur in peanut and corn production in the Southeast and Texas. Control efforts are common, and producers incur considerable costs from shooting and trapping efforts. Extrapolating crop damage estimates to the state-level in 10 states with reportable damage yields an estimated crop loss of $190 million. Though large, this number likely represents only a small fraction of the total damage by feral swine in the 10 states because it only includes crop damage to six crops. We hope findings from this survey will help guide control efforts and research, as well as serve as a benchmark against which the effectiveness of future control efforts can be measured. [ABSTRACT FROM AUTHOR]

Bird damage is a common and costly problem for fruit producers, who try to limit damage by using management techniques. This analysis used survey data from producers in five U.S. states to estimate bird damage to sweet cherry ( Prunus avium ) crops with and without the use of bird management. A partial equilibrium model was applied to the data to estimate the change in the marginal cost of production resulting from disuse of bird management. The model incorporates both decreased yield and elimination of management costs. A welfare analysis was conducted with short and long run supply elasticities derived from time-series data using geometric distributed lags. With no bird management, total surplus in the United States decreases by about $185 to $238 million in the short run and $21 to $29 million in the long run, indicating that bird management has a large impact on cherry production and associated market outcomes, including price and consumption. [ABSTRACT FROM AUTHOR]

Attract-and-kill is a possible alternative to the conventional control of Mediterranean fruit fly (medfly), Ceratitis capitata Wiedemann (Diptera: Tephritidae) with bait or cover sprays of organophosphate insecticides. In this study, we determined if an attract-and-kill device (MagMED ® ) could be applied alone at the recommended rate (80 devices/ha), or needed to be combined with other conventional control tactics to suppress medfly in deciduous fruit orchards (apple, nectarine, peach, pear, plum). We also determined if attract-and-kill had any detrimental effects on naturally occurring beneficial insects. Based on an acceptable level of crop loss of 2–5% (the level of crop loss growers can tolerate), attract-and-kill suppressed medfly and reduced crop loss below the acceptable level in orchards with additional controls. Attract-and-kill was most effective when combined with either bait spraying, cover spraying or both. Combining attract-and-kill with cover sprays of fenthion resulted in a drop in crop loss of apples from 2.5% to 0.5%. By combining attract-and-kill with weekly bait sprays and two cover spray applications, crop loss fell from 13.7% to 4.3% in peaches, from 6.3% to 5% in nectarines and from 6.3% to 3.7% in pears. Twice weekly bait spraying was the most effective technique at suppressing medfly, providing acceptable control when applied alone, which further improved by combining with attract-and-kill. By combining attract-and-kill with twice weekly bait spraying crop loss fell from 2% to 1% in nectarines and from 4% to 2% in apples. In laboratory trials, attract-and-kill devices killed 100% of brown lacewings ( Micromus tasmaniae Walker) and 94% of transverse ladybeetles ( Coccinella transversalis Fabricius) 24 h after contact. However, orchard samples suggest that it may not pose any significant negative impact on naturally occurring beneficials such as Neuroptera, Hymenoptera, Coleoptera, Thysanoptera and Syrphidae in the field. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine a statistical model described by regression equations as a tool for predicting the reduction in winter wheat yields as a function of the degree of pathogenic damage to the flag leaf and first leaf under the flag leaf at the stage of full heading, at growing sites with varied conditions. The study was carried out in the years 2007–2009, at two locations in the Wielkopolska region of Poland. The research was based on one-factor experiment on winter wheat, variety Tonacja. The method is based on the adaptation of the procedure of comparing of parallelism and separation for regression equations. These results indicated that expressing the yield as a function of the degree of infection by pathogens by means of a single regression equation is a process that requires several stages, entailing comparison of the regression coefficients and, independently of that, comparison of the intercepts (distances between hyperplanes). Determination of regression equations may be used as a tool for determining yield reduction, but it requires the consideration of factors including habitat conditions, leaf type and location. The program package R (3.0.2) was used for the calculations. [ABSTRACT FROM AUTHOR]

Weeds are a hidden foe for crop plants, interfering with their functions and suppressing their growth and development. Yield losses of ∼34% are caused by weeds among the major crops, which are grown worldwide. These yield losses are higher than the losses caused by other pests in the crops. Sustainable weed management is needed in the wake of a huge decline in crop outputs due to weed pressure. A diversity in weed management tools ensures sustainable weed control and reduces chances of herbicide resistance development in weeds. Allelopathy as a tool, can be importantly used to combat the challenges of environmental pollution and herbicide resistance development. This review article provides a recent update regarding the practical application of allelopathy for weed control in agricultural systems. Several studies elaborate on the significance of allelopathy for weed management. Rye, sorghum, rice, sunflower, rape seed, and wheat have been documented as important allelopathic crops. These crops express their allelopathic potential by releasing allelochemicals which not only suppress weeds, but also promote underground microbial activities. Crop cultivars with allelopathic potentials can be grown to suppress weeds under field conditions. Further, several types of allelopathic plants can be intercropped with other crops to smother weeds. The use of allelopathic cover crops and mulches can reduce weed pressure in field crops. Rotating a routine crop with an allelopathic crop for one season is another method of allelopathic weed control. Importantly, plant breeding can be explored to improve the allelopathic potential of crop cultivars. In conclusion, allelopathy can be utilized for suppressing weeds in field crops. Allelopathy has a pertinent significance for ecological, sustainable, and integrated weed management systems. [ABSTRACT FROM AUTHOR]

Resistance ( R ) genes have been effectively deployed in preventing rice crop losses due to the fungus Magnaporthe oryzae . In the present study, we studied the interaction between 24 monogenetic lines, carrying at least one major R gene, Pia , Pib , Pii , Pik , Pik-h , Pik-m , Pik-p , Pik-s , Pish , Pit , Pita , Pita-2 , Piz , Piz-t , Pi1 , Piz-5 , Pi3 , Pi5 (t), Pi7 (t), Pi9 , Pi11 (t), Pi12 (t), Pi19 , or Pi20 , with 14 commonly found races (isolates) of M. oryzae . We demonstrated that the monogenic lines carrying Pi9 and Pita-2 provided broad spectrum resistance and their resistance frequencies were 92.9% and 78.6%, respectively. The races (isolates), IB33(FLN9), IE1(ZN13), IB1(ZN15), IC1(120), IE1K(TM2), IA1(ARB20112-114), IB49(unnamed), IH1(unnamed), ID1(ZN42), and IC17(ZN57) of M. oryzae were highly virulent to monogenic lines, and more than 50% of the isolates were pathogenic across all monogenic lines, respectively. Genetic diversity of 16 races (isolates), two as controls, of M. oryzae was verified by repetitive element palindrome polymerase chain reaction (Rep-PCR). Based on these data, a useful strategy of pyramiding blast R genes against pathogenic M. oryzae races was proposed. Eight rice germplasms were identified to carry more than two blast R genes with pathogenicity assays and R gene specific primers. These findings are important for breeding for improved blast resistance in the USA and worldwide. [ABSTRACT FROM AUTHOR]

For cost-effective control of a weed, it is essential to know about its economic threshold level in a specific crop. The yield response of maize ( Zea mays L.) to varying densities of the invasive weed Parthenium hysterophorus L. was tested during autumn seasons of two consecutive years 2012 and 2013. Increasing densities of P. hysterophorus (0, 5, 10, 15 and 20 plants m −2 ) increased P. hysterophorus dry weight up to 433% and relative competition index up to 145%. Corresponding increases in the uptake of N (up to 336%), P (up to 180%) and K (up to 295%) were also recorded. Maize plant height and number of grains per cob were reduced at parthenium weed densities beyond 10 plants per m 2 . Five or more parthenium weed plants per m 2 decreased grain yield, biological yield, 100-grain weight, grain weight per cob and harvest index of maize. Maize grain yield losses varied between 21 and 50% with P. hysterophorus density ranging from 5 to 20 plants m −2 . Maximum N, P, and K uptake by P. hysterophorus was 78.0, 9.0 and 64.0 kg ha −1 , respectively. The economic threshold of P. hysterophorus as determined by prediction model was 1.2 and 1.0 plants m −2 during year 2012 and 2013 indicating that parthenium weed in maize should be controlled at these density levels. [ABSTRACT FROM AUTHOR]

Among plant pathogenic organisms, fungi are a major reason for crop losses around the world and have a significant impact on yield and quality. Previous studies suggest that up to 42% yield loss caused by fungal diseases can be prevented by applying foliar fungicides to winter wheat. Local wheat production data on fungicide application, yield, and disease severity for four soft-red winter wheat cultivars (Magnolia, Terral LA841, Pioneer 25R47, Coker 9553) for two years (2011 and 2012) in three locations in Northeast Texas (Royse City, Howe, and Leonard) were analyzed to study the economics of one foliar fungicide (TebuStar ® 3.6L). A preventive application of the fungicide resulted in a relatively conservative 9.41% overall yield gain and a net return (from investing in tebuconazole) of $107.7/ha in 2012, which lead to an overall positive (two-year average) net returns of $52.09/ha. A probability analysis indicated that positive overall net returns are likely and that most of the cultivars considered have the potential to produce a yield gain necessary to at least break even with or exceed the cost of applying tebuconazole. [ABSTRACT FROM AUTHOR]

Botrytis cinerea is an important plant pathogen that can infect a wide range of hosts and cause serious losses in many crops. In Orchidaceae, gray mold is one of the main diseases caused by fungi, commonly associated to flower spots. Here, we described a new disease caused by B. cinerea on Maxillaria richi , an orchid native from Ecuador and marketed in Brazil. Samples of M. richii with unusual defoliation symptoms were observed in a greenhouse. The diseased material was used to isolate the pathogen. The morphological and molecular data revealed that the isolates belong to B. cinerea. The pathogenicity test confirmed that B. cinerea is the etiological agent of the defoliation. To our knowledge, this is the first report of B. cinerea causing basal leaf rot and defoliation on a member of Orchidaceae. • Botrytis cinerea is among the most important plant pathogens in the world. • B. cinerea cause distinct symptoms in orchids from several genera. • Unusual basal leaf rot and defoliation symptoms were observed in Maxillaria richii. • B. cinerea is the fungal pathogen that causes defoliation on M. richii. [ABSTRACT FROM AUTHOR]

Kochia [ Bassia scoparia (L.) A.J. Scott] is a problematic summer-annual tumbleweed that infests cropped and noncropped areas in the Great Plains of North America. Efficient seed dispersal, prolific seed production, and abiotic stress tolerance facilitate invasiveness of kochia, while both resource-limiting and non-resource-limiting interference aid in rapid colonization of disturbed areas. Resistance to up to four herbicide sites-of-action allow kochia to escape herbicidal control in several field crops and contribute to crop yield losses. Near-complete crop failure (>90% yield loss) has been reported due to kochia interference in corn (Zea mays L.), sorghum [ Sorghum bicolor (L.) Moench ssp. bicolor ], sugar beet (Beta vulgaris L.), and sunflower (Helianthus annuus L.). Mean reported yield losses due to kochia interference were greatest in grain corn (68%), followed by sorghum (62%), soybean [ Glycine max (L.) Merr.] (52%), sugar beet (46%), silage corn (40%), sunflower (23%), spring wheat (Triticum aestivum L.) (20%), spring canola (Brassica napus L.) (13%), field pea (Pisum sativum L.) (13%), and spring oat (Avena sativa L.) (7%). However, crop yield losses due to kochia interference depend on several factors, including kochia density, relative emergence timing, duration of interference, the environment, and potentially also fitness penalties caused by pleiotropic effects of herbicide resistance traits. This review provides a synthesis of the impact of kochia on farm operations, crop yield losses due to kochia interference, factors affecting kochia interference, and interference mechanisms. Together, this synthesis highlights the critical need for research identifying integrated strategies for kochia management, and their subsequent adoption by the farming community. • Multiple herbicide-resistant kochia is difficult to manage in several field crops. • Kochia exhibits both resource-dependent and resource-independent interference. • Kochia density, emergence timing, interference duration, and environment regulate crop yield losses. • Kochia can cause >90% yield loss in corn, sorghum, sugar beet and sunflower. • Mean yield losses: grain corn > sorghum > soybean > sugar beet > silage corn > sunflower > spring wheat > canola = pea > oat. [ABSTRACT FROM AUTHOR]

Abstract: Among the various sectors of the Brazilian economy, agriculture plays a prominent role, generating jobs and income for the country. However, the agricultural sector faces systematic annual losses due to pests and diseases. The damage caused by insect pests is one of the primary factors leading to the reduced production of major crops. The study presented here estimates the production losses of major crops caused by insects and the economic impact related to the direct damage caused by insects, to the purchase of insecticides, and to medical treatment for humans poisoned by insecticides. The results indicate that insect pests cause an average annual loss of 7.7% in production in Brazil, which is a reduction of approximately 25 million tons of food, fiber, and biofuels. The total annual economic losses reach approximately US$ 17.7 billion. These results are important for government policies in the agricultural sector, as well as indicate the need for updated data regarding the losses caused by insects in Brazil and the need for systematic monitoring of these losses. [Copyright &y& Elsevier]

Abstract: Quantifying the relationship between plant injury and yield loss is a critical component for decision making in integrated pest management (IPM). The effects of foliar injury during different growth stages of potato (Solanum tuberosum L.), caused by natural populations of the leafminer fly Liriomyza huidobrensis (Blanchard) on potato yield, and the economic injury level for potato varieties with different maturity times were studied in the Cañete valley on the central coast of Peru. Field experiments were carried out during the potato cropping season (July–November) in the years 2005, 2007 and 2008 using early, middle-late and late potato varieties. Insecticides with different control efficiencies or the use of varying numbers of insecticide applications obtained various levels of leafminer fly infestation intensities. Leafminer fly infestation caused foliar injury in all potato varieties resulting in yield losses, which varied, according to the seasonal adult flight activity in each year of evaluation, between 22% in 2007 (2508 adults/trap/season) and 51% in 2005 (3147 adults/trap/season). Foliar injury increased with the development and growth of the potato plant, with the highest injury registered at the end of the cropping period. Early varieties showed higher foliar injury and yield loss than late potato varieties with the exception of Maria Tambeña, which is considered partially resistant to leafminer fly infestation. Yield losses increased linearly by each percentage of foliar injury in all potato varieties. Critical point and multiple point models made it possible to identify the potato growth stage at which leafminer infestation had the greatest effect on yield. Pest infestation-crop loss relationships indicated that the accumulated foliar injury up to the growth stages of flowering and berry formation produced the highest yield losses in the different potato varieties. Economic injury levels varied according to control costs and commodity values in each potato variety (Desiree: 21–28%, Revolucion: 34–47%, Canchan: 31–40%, Maria Tambeña: 40–53%, Tomasa: 55–74%, and Yungay: 40–54% of foliar injury). Potato varieties can tolerate considerable levels of foliar injury by the leafminer fly before control measures are needed. The use of the economic injury levels is suggested as a decision support tool for managing the leafminer fly at reduced pest management costs. [Copyright &y& Elsevier]

Abstract: Isolates of the fungus Fusarium oxysporum cause some of the most devastating plant diseases, leading to significant crop losses in both the greenhouse nursery and field environments. Because of this, tools that permit early pathogen detection are essential. This study develops such a tool. A specific primer set (FOX S and FOX R) and TaqMan probe (FOX TM) for F. oxysporum quantification were developed from an SCAR marker derived from RAPD-PCR. This system was used to monitor the presence of F. oxysporum in the substrate and the vegetative tissue of melon seedlings growing under greenhouse conditions. Detection and quantification data were obtained within 48 h with the new technique, compared to 5–6 days for the classical plate culture method, while also providing greater specificity and sensitivity. [Copyright &y& Elsevier]

Abstract: Yield loss to damage functions were established to determine multiple-pest economic injury levels (EILs) on Pusa Basmati 1 rice (Oryza sativa L.) at different crop growth stages through field and pot experiments in 2009 and 2010. The yield loss to damage functions were derived for two-pest combinations of leaf folder, Cnaphalocrocis medinalis Guenée, and stem borers, Scirpophaga incertulas (Walker) and Sesamia inferens (Walker), at reproductive crop stage during 2009 and for leaf folder and planthoppers, Nilaparvata lugens (Stål.) and Sogatella furcifera Horvath, at vegetative crop stage, and planthoppers and stem borers at reproductive stage during 2010. Single-species as well as multi-species EILs were determined. Across experiments, single-species EILs of leaf folder and stem borer ranged from 2.9–6.4% folded leaves and 1.9–3.0% whiteheads, respectively, while that of planthoppers varied between 5.5 and 7.3 hoppers per hill. Iso-loss equations, based on yield loss to damage functions, depicted various two-pest incidence combinations which resulted in economic damage. These joint incidence combinations showed that, although each pest was below its EIL, the combination of both pests inflicted economic damage. The multi-pest EILs can be useful to monitor simultaneous occurrence of two-pest species thereby helping to prevent yield losses. [Copyright &y& Elsevier]

Abstract: In sub-Saharan areas of Africa, cotton growers no longer cut the shoot tips from plants (topping), although manual topping was promoted at the start of the 20th century to improve yield and, surprisingly, to reduce pest incidence. In these areas, the bollworms Helicoverpa armigera Hübner, Earias spp., and Diparopsis watersi Rothschild are responsible for the majority of cotton yield losses, and the use of pyrethroids has resulted in resistance in field populations of H. armigera. In the face of these problems and given the scarcity of literature on the effects of topping on pest control, we assessed bollworm infestation levels in 12 trials comparing manual topping and non-topping cotton plots in Mali over a six-year period (2002, 2003, and 2005 to 2008). Topping was performed at the emergence of the 15th sympodial branch or at 10 days after the first flower opening. Our results showed no significant difference in seed cotton yields between topped and non-topped cotton. Bollworm infestations (all species) were always lower on topped cotton and 7 out of 12 trials showed significantly lower infestations on topped cotton. In plots of topped cotton, we recorded an average of 56% fewer H. armigera larvae, 68% fewer Earias spp. larvae, and 71% fewer D. watersi larvae with respectively 5, 4, and 3 out of 12 trials with significant differences in favor of topping and no significant difference in favor of non-topping. To our knowledge, our study is the first to report decreases in D. watersi larval infestation with cotton topping. Further studies are required to understand the mechanisms involved in these effects and to ensure that topping is economically attractive for farmers. [Copyright &y& Elsevier]

Abstract: Conservation biological control by means of ground cover offers an interesting alternative to chemical control of the twospotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae), a key pest of clementine mandarins. The aim of this study was to investigate whether this tactic could actually achieve significant reductions in crop losses caused by this pest. The three most common cover practices used in citrus in Spain were compared: wild cover, a cover of Festuca arundinacea Scherb. (Poaceae), and bare soil. The action threshold was more often exceeded in wild cover than in bare soil or F. arundinacea. When expenditures and revenues were balanced, the most favorable cover was F. arundinacea (between 44.4 and 74.5% cost reduction relative to the most expensive one). F. arundinacea as a cover crop is a conservation biological control strategy highly recommendable for clementine producers. Although its use did not reduce mite populations below the action threshold, the population decreases obtained made the adoption of this tactic a beneficial alternative both ecologically and economically. [Copyright &y& Elsevier]

Abstract: Populations of wild boar (Sus scrofa Linnaeus, 1758) and reports of crop damage by them have increased in Japan. In considering strategies for damage control, it is necessary to quantify both the environmental factors and the countermeasures affecting damage. We surveyed damage by wild boar in 1540 rice paddies on the Boso Peninsula. We obtained environmental factors by GIS: distance from forest edges, rivers and settlements; overground openness; and human population density. We recorded the weeding and fencing practices as countermeasures. We constructed cumulative logit models using Bayesian inference to predict damage and assessed the importance of the simultaneous evaluation of environmental factors and countermeasures by deviance information criteria. The best model incorporated both environmental factors and countermeasures, indicating that both are important for predicting damage. It showed that weeding around rice paddies, electric fencing and corrugated iron fencing were effective at reducing damage by wild boar. The risk of damage increased with lower values of distance from forest edges and rivers, overground openness, and human population density, and with higher values of distance from roads. These environmental factors allowed us to identify high-risk cropland where countermeasures could be introduced to reduce damage. [Copyright &y& Elsevier]

Abstract: Tomato spotted wilt virus causes tomato spotted wilt (TSW), a disease that results in economic losses on several crops including tobacco in the southeastern United States. The effect of imidacloprid (IMD) applied as a pre-transplant soil drench alone, in combination with acibenzolar-S-methyl (ASM), or followed by a foliar application of ASM immediately after transplanting on TSW incidence and severity on tobacco was quantified in studies conducted in North Carolina from 2006 to 2008. Pre-transplant IMD application in combination with ASM provided the greatest reduction in TSW incidence and severity; however other treatments provided economically efficacious controls when TSW incidence was <30% in a field. From these results, TSW incidence was classified as Low (<10%), Moderate (11–20%), High (21–30%), or Very High (>30%), classes corresponding to different control recommendations, and subsequently used for modeling temporal TSW progress in a field. The temporal progress of TSW was modeled with data collected from 23 tobacco fields in North Carolina from 2006 to 2008. Cumulative degree-days (DD) and the average class of TSW incidence observed in a field for 5 seasons before the one that data were collected were significant variables (P < 0.05) for explaining the temporal progress of TSW incidence. DD based on four temperature thresholds (10.5, 18.0, 20.0, and 26.0 °C) were investigated, resulting in four models. Models were validated with data collected in 2009 and the model in which DD were calculated based on the threshold of 10.5 °C had a higher predictability (R 2 = 0.70) than the other three models. The 26 °C DD model had the poorest predictability (R 2 = 0.33). These models are currently being validated in North Carolina and the other flue-cured production states of the southeast United States as a tool for implementing disease control recommendations. [Copyright &y& Elsevier]

Abstract: A long-term study was conducted between 2000 and 2009 to characterize the incidence, progress and causal agents of cucumber vine decline in Oman. A survey in 175 different greenhouses showed that disease incidence levels range from 0 to 50%, with the highest levels of mortality being in the hotter seasons. Detailed temporal disease increase data from 24 different greenhouses showed mortality progress consists of two phases. The first phase is characterized by attack of young seedlings (<3 weeks old), resulting in damping-off disease. The second phase was characterized by re-appearance of symptoms and plant death (vine decline) during the fruit setting period, 35–50 days after transplanting. Isolations from 148 declining adult cucumber plants yielded Pythium aphanidermatum (80%), Pythium spinosum (13%), Fusarium equiseti (12%), Fusarium solani (8%), Rhizoctonia solani (5%) and one isolate each of Trichoderma hamatum and Bionectria sp. P. aphanidermatum, P. spinosum, R. solani and F. solani were found to be pathogenic on cucumber, with P. aphanidermatum being the most aggressive. This appears to be the first report of association of P. spinosum with vine decline in greenhouse cucumbers and the first report of the high susceptibility of adult cucumber plants to vine decline during the initial period of fruit setting. In addition, this is the first report of association of R. solani and F. solani with declining adult cucumber plants in Oman and the first report of the occurrence of T. hamatum and Bionectria species in the country. [ABSTRACT FROM AUTHOR]

Abstract: A field experiment was conducted to investigate the impact of simulated rat damage on grain yield in irrigated lowland rice in An Giang province, in the Mekong Delta of Vietnam. Rat damage was simulated by making a 45° cut at the base of the rice tillers about 3–5 cm above the soil surface. 0% (control), 5%, 10%, 25% and 50% of the tillers were removed at the tillering (25 days after sowing, DAS), panicle initiation (43 DAS), flowering (72 DAS) and ripening (87 DAS) stages. The total number of mature tillers, immature tillers and percent filled grains, the weight of 1000 grains and grain yields were recorded. The rice crop completely compensated by increased tillering and yield for tillers damaged up to 50% at the tillering stage. However, the damage and yield loss were highly variable. The ability of the rice crop to compensate at later stages progressively reduced. The implications for managing rat damage to rice crops are (1) rodent control activities should be applied before 10% of tillers are damaged at the tillering stage, and (2) a well balanced nitrogen supply during the tillering stage could potentially assist the rice plants to better compensate for rat damage. [ABSTRACT FROM AUTHOR]

Abstract: Conflicts due to damage caused by wildlife pose serious threats to conservation. In addition, wildlife damage incurs severe economic loss to communities living in the close vicinity of the park, affecting the livelihoods and well-being of locals. While different studies have emphasised identification and quantification of crop damage problems, studies highlighting the means used for crop protection and their effectiveness are limited. This study aimed to examine the effectiveness of means used by communities to protect their crops against wildlife. 117 households were visited at two Buffer Zone villages of Bardia National Park, Nepal. Findings suggested that crop depredation by wildlife was a function of several factors, such as the distance of the farmland from the park, the size of the crop raiding animals and the frequency of attacks on the farmland, and the type of crops. Ten different means were identified by communities which were used regularly to prevent crop damage. Households combined both traditional and modern means to guard their crop against the wild animals. Means differed according to the animals as well as crops being protected. Among all these means, Machan (i.e. watch towers) combined with other means such as throwing flaming sticks and group shouting were the most effective and safest modes of crop guarding for all kinds of animals and crops. Trench and Bio-fencing were effective mostly for deer species. However, crop guarding was an intensive process and no means were able to completely prevent crop damage. Problem animals differed according to the villages and crops being damaged, which suggests that employment of single means would be ineffective. Site-specific management strategies and economic as well as technical support from funding organisations would be most useful to minimise crop loss. In addition information exchange and learning between farmers and the park management about different mitigating means could support and prepare farmers for improvement in the means. [Copyright &y& Elsevier]

Abstract: The ‘within-season’ module of the Weed Manager decision support system (DSS) predicts the effect of twelve UK arable weeds on winter wheat yields and profitability. The model and decision algorithm that underpin the DSS are described and their performance discussed. The model comprises: (i) seedling germination and emergence, (ii) early growth, (iii) phenological development, (iv) herbicide and cultivation effects and (v) crop yield loss. Crop and weed emergence are predicted from the timing and method of cultivation, species biology, and the weather. Wheat and weeds compete for resources, and yield losses are predicted from their relative leaf area at canopy closure. Herbicides and cultural control methods reduce weed green area index, improving crop yield. A decision algorithm identifies economically successful weed management strategies based on model output. The output of the Weed Manager model and decision algorithm was extensively validated by experts, who confirmed the predicted responses to herbicide application were sufficiently accurate for practical use. Limited independent data were also used in the validation. The development of the module required integrating novel and existing approaches for simulating weed seedling establishment, plant development and decision algorithm design. Combining these within Weed Manager created a framework suitable for commercial use. [Copyright &y& Elsevier]

Abstract: Ralstonia solanacearum (formerly Pseudomonas solanacearum) causes large losses in more than 200 different cultivated plant species. Banana and plantain “Moko” disease is caused by R. solanacearum race 2. Moko disease may cause 100% loss if prompt control measures are not applied. Although a number of investigations have been carried out, many ecological and epidemiological aspects of R. solanacearum race 2 are still unknown, particularly in the tropics. Bacteria dispersion occurs by infested tools, soil, water, insects, domestic animals and agricultural labourers. Alternative hosts have been described which may contribute to inoculum availability in crop fields. In banana crops, cable-ways are routinely used to transport fruit and materials inside plantations. In most humid tropical areas, drainage channels are made to evacuate excess soil water. It is thought that agricultural activities associated with drainage channels and cable-ways may play a role in bacteria dispersion but individual contributions have not yet been quantified. In this work we have used field-integrated information in geographical information systems (GIS)-based maps to evaluate Moko presence in the Urabá region of Colombia, during three different time periods. A previously described risk index (RI) and losses throughout the three periods were quantified. A regression model was developed to quantify the relationship between infested area and distance from every Moko focus to the nearest cable-way and drainage channels. Farms were grouped into four different profiles according to the RI. Parameters calculated using the regression model showed that 76% of Moko foci detected during the three time periods were associated with cable-ways used for transport of fruit and consumables. This finding has important implications for disease management since bacteria spread in these ways may be prevented by simple measures taken inside plantations. [Copyright &y& Elsevier]

Abstract: Beginning in the 1930s and continuing through the 1970s, rhesus macaques and patas monkeys were introduced to presumed secure locations, primarily coastal islets, in Puerto Rico. Escapes into the wild began almost immediately after introduction. Today the combined range of the two species covers approximately 600km2 of southwestern Puerto Rico, where serious conflicts with agricultural interests have resulted. The Puerto Rico Department of Agriculture surveyed about 90% of commercial farmers in the range of the monkeys to begin quantifying damage by monkeys and the associated economic losses during the years 2002–2006. During that time, total economic losses by commercial farmers to monkeys increased from $1.13 million USD to over $1.46 million per year. Of these amounts, the economic losses due to farmers avoiding monkey damage by switching from fruit and vegetable crops to less rewarding land use (primarily hay or pastureland) increased from $490,000 to $1.33 million per year. The losses reported from the survey represent only a portion of economic losses to the invasive monkeys. Subsistence and other smaller farms and agriculture were not included in the survey. We also discuss many other economic issues surrounding the impacts of the invasive monkeys, but for which sufficient data are not available for economic analyses. These include concerns such as destruction of native (especially endangered) wildlife, threat of disease spread, and property damage, all of which would also have to be considered to fully evaluate invasive monkey economic impacts in Puerto Rico. [Copyright &y& Elsevier]

Abstract: Weather factors are driving forces in plant disease development and differ between years and locations. Results from long-term fungicide field trials 1983–2007 and disease surveys 1988–2007 in winter wheat in southern Sweden were used to evaluate relationships between yield, the yield increase obtained by fungicide treatment, thousand grain weight (TGW), disease severity and disease incidence, and the independent variables air temperature and precipitation as monthly means. These two weather variables explained more than 50% of the variation between years regarding yield increase, TGW, LBDs (Leaf Blotch Diseases, including Septoria tritici blotch, Stagonospora nodorum blotch and tan spot), brown rust, yellow rust and eyespot, but less than 50% of the variation in yield and powdery mildew. Precipitation in May was the factor most consistently related to LBD disease intensity, and adding another two weather factors further improved the degree of explanation. Weather factors in the preceding growing season influenced growth stage, powdery mildew and brown rust. Mild winters and springs favoured the biotrophs such as powdery mildew, brown rust and yellow rust. Statistically significant correlations between incidence and severity were found for LBDs, brown rust and eyespot, but not for yellow rust and powdery mildew. Regression models with disease incidence as dependent variable generally had a higher degree of explanation and lower P-value than models with disease severity as dependent variable. Our results confirm that weather data can be successfully used in wheat disease prediction models. [Copyright &y& Elsevier]

Abstract: The panicle rice mite (PRM), Steneotarsonemus spinki Smiley, was reported in 2007 in the United States in greenhouses and/or field cultures of rice (Oryza sativa L.) in the states of Arkansas, Louisiana, New York, and Texas. PRM had not been reported in rice culture in the United States since the original type specimen was collected in Louisiana in association with a delphacid insect in the 1960s. PRM is the most important and destructive mite pest attacking the rice crop worldwide. It has been recognized as a pest of rice throughout the rice-growing regions of Asia since the 1970s. Historical reports of rice crop damage dating back to the 1930s also have been speculatively attributed to the PRM in India. In the late 1990s PRM was reported in Cuba, and quickly spread throughout the Caribbean and Central America. Rice crop losses of up to 90% in the Caribbean have been attributed to the PRM since first reported. The PRM attacks rice plants by feeding on the inside of the leaf sheath and developing grains. Damage associated with PRM infestations in rice includes plant sterility, partial panicle infertility, and grain malformation. However, it is difficult to characterize the damage caused solely by the PRM because the mite is commonly reported interacting with several rice plant pathogens including Sarocladium oryzae (Sawada) and Burkholderia glumae (Kurita and Tabei). The purpose of this article is to review the literature regarding the PRM in response to its re-discovery in the United States. We also summarize findings from countries where the PRM has historically been a significant pest of the rice crop. This article re-examines the taxonomic ranking of the PRM and includes a key to the USA species of Steneotarsonemus, its current distribution, damage to rice plants, its association with plant pathogens, host plant records, life history, survival under extreme temperature conditions, and current management strategies. Our hope is that this article will stimulate research on the biology and management of the PRM in the United States. [Copyright &y& Elsevier]

Abstract: In order to evaluate the competitive ability (CA) of canola cultivars against wild mustard, two experiments were conducted at the Gorgan Institute in Iran during the 2005–2007 cropping seasons. The experimental factors were canola cultivars (1st year: Zarfam, Option500, Hayola330, Hayola401, Talayh, RGS003 and Sarigol; 2nd year: Zarfam, Hayola330, RGS003 and Option500) and weed density (1st year: control and 30plantsm−2; 2nd year: control, 4, 8 and 16plantsm−2). The result of the first year of experiment indicated that the grain yield and competitive indices differed significantly between the cultivars. Cultivar Zarfam showed a high ability to withstand competition (AWC=47%), high competitive indices (CI=1.79 and CI2 =10 1.83) and low grain yield in the weed-free plots (1729kgha−1). The cultivar Option500, a less competitive cultivar had the lowest ability to withstand competition (AWC=4%) and the lowest competitive indices (CI=0.09 and CI2 =0.11) amongst the cultivars. However, the cultivar Option500 showed more grain yield in the weed-free plots (2333kgha−1) than cultivar Zarfam. In the second year of the experiment, the result of the yield loss models showed that the lowest and highest yield loss belonged to cultivars Zarfam and Option500 (50 and 95% respectively). A comparison of different empirical models revealed that the empirical yield loss model based on weed relative leaf area was more reliable for predicting canola yield loss according to a high coefficient of determination (R 2 =0.99). The relative damage coefficient (q) of the weed relative leaf area model showed that wild mustard was more competitive than canola (q >1). [Copyright &y& Elsevier]

Abstract: The rice striped stem borer, Chilo suppressalis (Walker) (Lepidoptera: Pyralidae) is one of the most important rice pests worldwide. Rice is frequently grown in an intensive production system in areas adjacent to environmentally sensitive areas. Therefore, the use of insecticides is problematic and new techniques, including mating disruption, are being introduced. Due to the high cost of pheromones, it is essential to optimize the density of the pheromone dispensers. The main purpose of this research was to determine the minimal dosage and optimal dispenser distribution for effective mating disruption of C. suppressalis. To this end, we conducted a wide-area trial to test several dispenser densities, 31, 25 and 16 dispensers/ha during 3years. Results were compared with a standard mating disruption treatment (51 dispensers/ha) and a standard aerial chemical treatment with tebufenozide. Treatment efficacy was determined by pheromone trap catches and crop damage assessment. The release rate of the pheromone dispensers was also quantified. The results of these trials suggest that such treatments provide effective pest control even with reduced pheromone dispenser densities. Longer-lasting dispensers with lower residual load at the end of trials will greatly improve the efficacy of mating disruption for C. suppressalis. Moreover, an important consideration is that these newly tested dispenser densities imply a significant reduction in the cost of the treatment. These results are essential in order to expand the use of mating disruption in rice crop protection. [Copyright &y& Elsevier]

Abstract: Fungicides are routinely used to prevent yield losses in winter wheat in southern Sweden. Yield and 1000 grain weight (TGW) data from 432 trials in farmers'' fields were evaluated to review long-term yields (1977–2005) and control of eyespot and Leaf Blotch Diseases (LBDs, including Septoria tritici blotch, Stagonospora nodorum blotch and tan spot), powdery mildew, brown rust and yellow rust. Regression analyses revealed that control of LBDs explained 74% of the yield increase achieved by fungicide treatment at GS 45–61, followed by powdery mildew (20%), brown rust (5%) and yellow rust (1%). Yield of both untreated and fungicide-treated plots increased from approx. 6000 to 12 000kgha−1 over the period 1983–2005. Single eyespot treatment improved yield by ∼320kgha−1 yr−1 during the period 1977–2002, mainly due to occasional years with severe eyespot. Single leaf disease treatment at GS 45–61 increased mean yield by 10.3% or 810kgha−1 yr−1 (9.9% or 660kgha−1 yr−1 for 1983–1994 and 10.7% or 970kgha−1 yr−1 for 1995–2005) due to increased TGW and grain numbers, especially in high-yielding stands. Additional extra early treatment at GS 30–40 against LBDs increased yield by ∼250kgha−1 yr−1. Estimated variance in yield and TGW was higher between years than within years, while that in yield increase and plant diseases was lower between years than within. The results confirm potential and limits of fungicides and the need for supervised control strategies including factors affecting disease, yield and interactions. [Copyright &y& Elsevier]

Abstract: Consequences of the fungus Fusarium verticillioides (Sacc.) Nirenberg (synonym F. moniliforme Sheldon) (teleomorph, Gibberella moniliformis), colonizing kernels of maize, Zea mays L., may be plant disease and/or mycotoxin production. Plant disease may reduce crop production and mycotoxins may cause harmful, and often fatal, effects on humans and animals. The objective of the current experiments was to track migration of a F. verticillioides isolate transformed with foreign genes from inoculated to non-inoculated maize ears to determine the population flow of this fungus among maize plants under field conditions. Distribution patterns of F. verticillioides following artificial infections have been described within growing maize plants, but not among maize plants. Maize ears were inoculated through either the shuck or the silk channel at one of two stages of silk development, green or brown. The inoculum was a genetically transformed isolate, designated F. verticillioides PATg, carrying two foreign genes, one coding for hygromycin resistance (hygr) and the other for β-glucuronidase (GUS). The average expression of hygr was 66% and of GUS was 96% for mycelia emerging from kernels of ears inoculated with F. verticillioides. Mycelia resistant to hygromycin appeared in cultures of kernels from non-inoculated and water-inoculated ears, but only at ⩽3%. However, none of the mycelia stained positive for GUS in kernels originating from non-inoculated ears and only 7% of those from water-inoculated ears. Thus, dissemination of F. verticillioides PATg was minimal from plant to plant under field conditions existing in Georgia during the growing seasons of 2001, 2002, and 2003. Negligible F. verticillioides PATg was detected in a few ears inoculated with water through the silk during the green silk stage of development. Perhaps the mechanical injury during inoculation provided an entry site for the spores of F. verticillioides PATg dispersed by abiotic factors such as rain or wind. [Copyright &y& Elsevier]

Abstract: Four field trials were conducted over a two-year period at Exeter (2005, 2006), Harrow (2006) and Ridgetown (2006), Ontario to evaluate the tolerance of pinto and Small Red Mexican (SRM) beans to the pre-emergence application of dimethenamid-p at 693 and 1386gaiha−1, s-metolachlor at 1600 and 3200gaiha−1, pyroxasulfone at 209 and 418gaiha−1, imazethapyr at 75 and 150gaiha−1, linuron at 1125 and 2250gaiha−1, flumetsulam at 70 and 140gaiha−1 and cloransulam-methyl at 35 and 70gaiha−1. All treatments including the non-treated control were maintained weed free during the growing season. Dimethenamid-p and s-metolachlor, especially at high doses, caused up to 19% visual injury to pinto and SRM, but these injuries were transient and had no effect on maturity and yield. Pyroxasulfone and linuron caused as much as 33% visual injury and reduced plant height, shoot dry weight and yield by up to 29, 36 and 25%, respectively. Imazethapyr, flumetsulam and cloransulam-methyl caused less than 5% visual injury and had no adverse effect on plant height, shoot dry weight, seed moisture content and yields of pinto and SRM beans. Based on these results dimethenamid-p, s-metolachlor, imazethapyr, flumetsulam and cloransulam-methyl applied pre-emergence have potential for inclusion in a weed management program for pinto and SRM beans. However, pyroxasulfone and linuron, applied pre-emergence at the doses evaluated do not have an adequate margin of crop safety for use in pinto and SRM bean production. [Copyright &y& Elsevier]

Abstract: Stemborers and Striga hermonthica co-exist in cereal fields in sub-Saharan Africa where together they cause crop damage that sometimes results in total crop loss. Striga alters both the chemistry and morphology of cereals and this may influence behaviour and performance of stemborers on the host plants. Studies were undertaken to compare the effects of various levels of Striga infestation of maize on oviposition preference and survival of Chilo partellus. Potted maize plants were exposed to different densities of Striga seeds (0, 1000, 2000 and 3000/pot) and subsequent effects on C. partellus oviposition evaluated in no-choice and choice-tests. In addition, larval arrestment, settlement, feeding, growth and development were assessed. Results showed that Striga infestation and plant height had non-significant influence on oviposition preference of C. partellus, except in 2-choice assays involving uninfested maize and one under high Striga infestation, in which case they preferred to oviposit on the latter. Similarly, Striga infestation had no influence on larval arrest and settlement. The larvae, however, consumed significantly more of the leaves and stems from uninfested than infested maize plants, with a progressive decline in the consumed proportions with increasing level of Striga infestation. Larval food assimilation was not influenced by Striga infestation, but larval period, percentage of pupation and growth rate were significantly higher on uninfested plants as compared to medium and high Striga infested plants. Possible reasons underlying these observations and their implications are discussed. [Copyright &y& Elsevier]

Abstract: A model relating Verticillium wilt assessment in early stages of eggplant growth to total crop losses is proposed, based on the results of 3 years experimentation. The model resulted from the integration of the area below the yield versus disease regression curve and the ordinates axis, represented losses, on axis Y from Y 0 to Y 100 which are the limits of % yield losses and leaf symptom index (LSI) on X-axis from X 0 to X 5 which are the limits of LSI. According to mathematical functions the following model is proposed:where n is the total number of plants counted, , where n 0, n 1, n 2, n 3, n 4 and n 5 are the numbers of plants belonging in each rank of the LSI, and the area A has limits 0–5. The algorithm obtained by the model is interpolated in the data of yield losses of each rank of the symptom index found in the experimental work, and the resultant number is the final estimation for future losses. The model has been validated with several results from other experiments and gave high accuracy () at least for the cultivars used in the experiments. [Copyright &y& Elsevier]

Abstract: Powdery mildew, caused by Erysiphe betae, is a major foliar disease of sugar beet in areas with dry and relatively warm weather, worldwide. Four fungicides—azoxystrobin, kresoxim-methyl, pyraclostrobin and trifloxystrobin—were evaluated, at three application doses (100, 150 and 200ga.i.ha−1), for control of the disease. Trifloxystrobin and kresoxim-methyl were the most effective with control efficacy values higher than 94% compared to the control treatment even when applied at the lowest application dose of 100ga.i.ha−1. Azoxystrobin and pyraclostrobin had poor to modest activity against the disease even at the highest application dose. Disease severity, in terms of area under the disease progress curve values, was significantly correlated with decreased root yield, while no significant correlation existed between disease severity and sugar content of the roots or sucrose yield. In addition, the efficacy of tank mixtures of each of the strobilurin fungicides applied at 100ga.i.ha−1 with either of two sterol demethylation-inhibiting fungicides, difenoconazole and cyproconazole applied at 62.5 and 25ga.i.ha−1, respectively, was evaluated. The mixtures of azoxystrobin and pyraclostrobin with either difenoconazole or cyproconazole provided better control efficacy compared to single applications of each mixture partner, while the tank mixtures of trifloxystrobin and kresoxim-methyl with either difenoconazole or cyproconazole provided better control efficacy compared to single applications of difenoconazole or cyproconazole and similar control efficacy compared to that obtained by single applications of the strobilurin fungicides. [Copyright &y& Elsevier]

Abstract: Sodium bicarbonate (SBC) effectively inhibited spore germination and germ tube elongation of Venturia inaequalis in vitro. SBC at 0.5%, 1%, and 2% inhibited spore germination by 59.0%, 96.4%, and 100%, respectively. In two orchard experiments to investigate the efficacy of SBC alone or in combination with a reduced dose of tebuconazole in inhibiting apple scab, applications of 1% SBC to trees at 10-d intervals significantly reduced disease incidence and severity on leaves and fruit compared to the water-treated control. In the first experiment, by the last assessment, the 1% SBC treatment had reduced the disease incidence on leaves to 29.6% compared with 62.6% in the water-treated control. The efficacy of 1% SBC was comparable with that of the label dose of tebuconazole on leaves and fruit. Combining 1% SBC with a reduced dose (10% of label dose) of tebuconazole did not improve the efficacy of 1% SBC alone. Treatments of 2% SBC were phytotoxic to leaves, but 1% SBC was neither phytotoxic to leaves nor did it adversely affect quality parameters of harvested fruit. [Copyright &y& Elsevier]

Abstract: Damage caused by wildlife to human economic activities represents a serious problem to conservation efforts. Conflict resolution efforts are particularly complex in Bolivian protected areas, which generally harbour human populations that settled there before the establishment of the protected area. We carried out a study that estimated wildlife damage to crops using paired exclosures and open (control) fields, in a protected area in Bolivia, that was primarily montane forest. We compared the performance (proportion of attacked plants and total crop yield) of three crop species within and outside of the exclosures. Simultaneously we recorded the wildlife species that visited crop fields by means of track plots, and identified their share in the damage events. Damage was significantly higher in control fields for two out of three crop species. Total yield was higher, though not significantly, in exclosures for all three crop species. Brown agouties (Dasyprocta variegata) was the most frequent wildlife species in crop fields and was responsible for some crop damage; however, collared peccaries (Tayassu tajacu) caused complete crop loss in two cases. We discuss our results from a broad management perspective and propose that conservation efforts, especially in Bolivia and other third world countries, should consider both applying methods to reduce wildlife damage and direct or indirect economic compensation. The latter could be achieved through the commercial use of non-threatened local wildlife species. [Copyright &y& Elsevier]

Abstract: A database created from insecticide control experiments conducted under the All-India Coordinated Rice Improvement Project from 1965 to 1992 was used to derive empirical estimates of yield losses caused by stem borers. Each unit percent damage due to white earhead damage had a much greater impact on rice yield in the irrigated ecosystem than did damage due to dead heart. White earhead damage occurs later in the season and results in direct loss of a yielding panicle, and thus, no compensation (or very little) is possible. The grain yield loss from the two phases, dead heart and white earhead damage to rice, is more than additive. Based on 770 experimental units from 28 years data, our projections for damage over rice ecosystems due to 1% dead heart or white earhead, or to both phases of stem borer damage are 2.5%, 4.0%, and 6.4% yield loss, respectively. In terms of grain production loss over ecosystems, 1% dead heart, or white earhead, or both phases of stem borer damage would be 108, 174 and 278kg/ha, respectively. In irrigated ecosystem, 1% dead heart resulted in 0.3% or 12kg/ha loss whereas, 1% white earhead caused 4.2% or 183kg/ha loss in grain yields; the loss due to 1% infestation in both phases of stem borer damage was 4.6% or 201kg/ha. In rainfed lowlands, for 1% dead heart or dead heart and white earhead caused 2.3% or 76kg/ha yield loss. Even at levels below the currently used economic threshold considerable losses can occur. This perception on losses assumes more importance because of the inadequate host-plant resistance to stem borer in rice. Although no insecticide gave total control of stem borer damage, many increased grain yields significantly. Emulsifiable concentrates of monocrotophos and chlorpyriphos appeared more economical for adoption by farmers as their application caused maximum mortality of larvae and unhatched eggs. Insecticide granules such as diazinon and carbofuran were equally efficient in preventing stem borer damage. [Copyright &y& Elsevier]

Abstract: Sitobion avenae is one of the most harmful cereal aphids in western Europe and it damages winter wheat in southern Sweden. Field experiments with insecticides were carried out (1977–2002) in farmers’ fields to evaluate the relationship between aphid density and crop yield and quality. A crop loss model is presented based on average annual yield loss in field experiments in high yielding varieties, 1995–2002, with low coefficients of variation. Aphid populations varied greatly between years and population peaks occurred at different crop stages. Less than 40% of the years since 1977 have been aphid years with more than 15 aphids/tiller on average. Peak values of aphids gave better regressions than aphid days. The economic injury level was found to be 7 aphids/tiller with a control cost of 300SEK/ha and a wheat price of 1SEK/kg. Volume weight and grain weight were only slightly affected by high aphid populations and the protein percentage was unaffected. The proposed crop loss model is a logistic curve: y=0.3826ln(x)−0.4108 ( p&#60;0.001; r 2=0.9799; DF=7) similar to a classic inverted S-shape with no damage under 4 aphids/ tiller. The model shows rapidly increasing damage from 4 to10 aphids/straw but much less damage/aphid at aphid levels from 15 to 40 aphids/tiller. Dynamic economic thresholds are proposed for different expected yield levels and different growth stages. Thus the economic threshold for high yielding wheat is 1 aphid/tiller at crop stage 59, 4 at crop stage 69 and 7 at crop stage 75. Economic injury levels and economic thresholds are important components of a cost-effective integrated pest management programme and are useful for decision-making in the application of pesticides. Understanding and appropriate use of economic decision levels in dealing with pests can increase profits and maintain environmental quality. [Copyright &y& Elsevier]