Search

Brown marmorated stink bug (Halyomorpha halys Stål) is an invasive agricultural pest that causes severe damage to many crops. To determine potential associations between H. halys feeding damage, Fusarium infection, and mycotoxin contamination in field corn, a field survey was conducted in eight counties in Virginia. Results indicated an association between H. halys feeding damage and fumonisin contamination. Subsequent field experiments in Delaware, Maryland, and Virginia examined the ability of H. halys to increase Fusarium verticillioides (Sacc.) Nirenberg infection and fumonisin concentrations in corn. At the milk stage, H. halys (0 or 4 adults) and Fusarium (with or without F. verticillioides inoculum) treatments were applied to bagged ears in a two by two factorial randomized complete block design with 12 replicates. H. halys treatments increased levels of feeding damage (P < 0.0001) and Fusarium infection (P = 0.0380). Interaction between H. halys and Fusarium treatments influenced severity of infection (P = 0.0018) and fumonisin concentrations (P = 0.0360). Results suggest H. halys has the ability to increase both Fusarium infection and fumonisin concentrations in field corn. Further studies are needed to understand mechanisms by which H. halys increases fumonisin and to develop management strategies to mitigate impacts of H. halys on field corn in the region.

A 2-yr study in cotton (Gossypium hirsutum L.) was conducted to determine the abundance and species composition of thrips (Thysanoptera: Thripidae) on different plant parts throughout the season in Alabama, Georgia, North Carolina, South Carolina, and Virginia. Plant parts sampled included seedlings, terminals with two expanded leaves, leaves from the upper, middle, and lower sections of the canopy, white flowers, and medium-sized bolls. Adult thrips were significantly more abundant on seedlings and flowers in 2014, and on flowers followed by seedlings and leaves from the middle canopy in 2015. Immature thrips were significantly more abundant on seedlings, followed by flowers in 2014, and on seedlings followed by leaves from the lower canopy and flowers in 2015. Across locations and plant parts, thrips consisted of Frankliniella tritici (Fitch) (46.8%), Frankliniella fusca Hinds (23.5%), Frankliniella occidentalis (Pergande) (17.1%), Neohydatothrips variabilis (Beach) (7.4%), Thrips tabaci (Lindeman) (1.8%), and other species (3.4%). Frankliniella fusca represented 86.7% of all thrips on seedlings, while F. tritici was more abundant on terminals (51.6%), squares (57.5%), and flowers (75.1%). Across all leaf positions, F. fusca was the most abundant species (28.8%), followed by F. tritici (19.2%), N. variabilis (18.8%), F. occidentalis (12.9%), and T. tabaci (5.2%), as well as other species (15.0%). As neonicotinoid insecticides remain a primary tool to manage seedling infestations of F. fusca, our data indicate that mid- to late-season applications of neonicotinoid insecticides targeting other insect pests will intensify selection pressure for resistance on F. fusca, the primary pest of seedling cotton.

Cereal leaf beetle, Oulema melanopus L., is a pest of small grains and the literature conflicts on whether it is more abundant in sparse or dense stands of wheat. Our objectives were to determine the impact of stand denseness on cereal leaf beetle abundance and to investigate the regional dispersion of cereal leaf beetles across North Carolina and Virginia. One-hundred twenty fields were sampled across North Carolina and Virginia during 2011 for stand denseness, and cereal leaf beetle eggs, larvae, and adults. Two small-plot wheat experiments were planted in North Carolina using a low and a high seeding rate. Main plots were split, with one receiving a single nitrogen application and one receiving two. Egg density, but not larva or adult density, was positively correlated with stand denseness in the regional survey. Furthermore, regional spatial patterns of aggregation were noted for both stand denseness and egg number. In the small-plot experiments, seeding rate influenced stand denseness, but not nitrogen application. In one experiment, egg densities per unit area were higher in denser wheat, while in the other experiment, egg densities per tiller were lower in denser wheat. Larvae were not influenced by any factor. Overall, there were more cereal leaf beetle eggs in denser wheat stands. Previous observations that sparse stands of wheat are more prone to cereal leaf beetle infestation can be attributed to the fact that sparser stands have fewer tillers, which increases the cereal leaf beetle to tiller ratio compared with denser stands.

Brown marmorated stink bug (

Evidence of practical resistance of Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) to Bt cotton in the United States is debatable, supported with occasional reports of boll damage in the field. Our objective was to provide both empirical and long-term observational evidence of practical resistance by linking both in-season and end-of-season measurements of H. zea damage to pyramided Bt cotton bolls and to provide Cry1Ac diet-based bioassay data in support of these damage estimates. In-season boll damage from H. zea was highly correlated to end-of-season damaged bolls. Across North Carolina, Bt cotton fields with end-of-season bolls damaged by H. zea increased during 2016 compared to previous years. Elevated damage was coupled with an increase in field sprays targeting H. zea during 2016, but not related to an increase in H. zea abundance. Bioassay data indicated that there was a range of Cry1Ac susceptibility across the southeastern United States. Given the range of susceptibility to Cry1Ac across the southeastern United States, it is probable that resistant populations are common. Since H. zea is resistant to cotton expressing pyramided Cry toxins, the adoption of new cotton varieties expressing Vip3Aa will be rapid. Efforts should be made to delay resistance of H. zea to the Vip3Aa toxin to avoid foliar insecticide use.

Traditional identification of thrips species based on morphology is difficult, laborious, and especially challenging for immature thrips. To support monitoring and management efforts of thrips as consistent and widespread pests of cotton (Gossypium hirsutum L.), a probe-based quantitative PCR (qPCR) assay with crude DNA extraction was developed to allow efficient and specific identification of the primary species of thrips infesting cotton. The assay was applied to identify over 5,000 specimens of thrips (including 3,366 immatures) collected on cotton seedlings from Alabama, Georgia, North Carolina, South Carolina, and Virginia in 2016. One half of all adult samples were examined by morphological identification, which provided a statistically equivalent species composition as the qPCR method. Frankliniella fusca (Hinds) (Thysanoptera: Thripidae) was the dominant species across all the locations (76.8-94.3% of adults and 81.6-98.0% of immatures), followed by Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) in Georgia, North Carolina, and Virginia (4.6-19% of adults and 1.7-17.3% of immatures) or Frankliniella tritici (Fitch) (Thysanoptera: Thripidae) in South Carolina (10.8% of adults and 7.8% of immatures). Thrips tabaci (Lindeman) (Thysanoptera: Thripidae) and Neohydatothrips variabilis (Beach) (Thysanoptera: Thripidae) were occasionally found among adults but were rarely present among immature thrips. These five species of thrips represented 98.2-100% of samples collected across the Southeast. The qPCR assay was demonstrated to be a valuable tool for large-scale monitoring of species composition of thrips at different life stages in cotton. The tool will contribute to a better understanding of thrips population structure in cotton and could assist with development and application of improved management strategies.

Currently there are several neonicotinoid insecticide seed treatments registered for use on soybean (Glycine max L.), with disparity in adoption rates in the eastern United States. A complex of seedling insect pests is found in mid-south soybean, but thrips are the primary early season pest of soybean in Virginia and North Carolina. Published knowledge regarding their impact on soybean yield is minimal, as is the impact of thrips on soybean yield; thrips species composition is also understudied. In 2008 through 2010, nine field experiments in Virginia and North Carolina were conducted to evaluate the impact on thrips population dynamics; the influence on yield of neonicotinoid seed treatments, imidacloprid and thiamethoxam, was reported from nine of these experiments. Moreover, thrips species abundance was recorded in three of these experiments. Both imidacloprid and thiamethoxam reduced thrips densities compared with untreated soybean. Thiamethoxam was more effective than imidacloprid in reducing adult thrips densities at 5 wk after planting. Adult densities peaked at 3 wk after planting, followed by larval densities, which peaked at 4 wk after planting. The most abundant thrips species was Frankliniella fusca (Hinds), followed by Neohydatothrips variabilis (Beach). Other common species included F. occidentalis (Pergande) and F. tritici (Fitch). In general, F. fusca was more common earlier in the season, while N. variabilis was more common later in the season. There were no significant differences in yield among any of the treatments or in the untreated controls. Although neonicotinoid insecticides reduced thrips abundance, data collected in these studies demonstrated that there was no positive yield response.

ARSTRACT Experiments were conducted to evaluate the toxicity, feeding preference, repellency, and field efficacy associated with the organic insecticides azadirachtin, pyrethrins, and spinosad against two stink bug species, Acrosternum hilare, (Say) and Euschistus servus, (Say) (Hemiptera: Pentatomidae). Laboratory toxicity bioassays were conducted using treated green bean pods. The conventional pyrethroid λ-cyhalothrin was included for comparison. A. hilare, adults and nymphs were most susceptible to λ-cyhalothrin and to tank mixes of pyrethrins + spinosad. E. servus, adults were susceptible to λ-cyhalothrin, spinosad, and all tank mixes, whereas E. servus, nymphs were susceptible to λ-cyhalothrin only. Feeding preference tests were conducted using insecticide-treated tomatoes and counting the number of feeding stylet sheaths on fruit after 24 h. All tomatoes treated with either azadirachtin, pyrethrins, or tank mixes resulted in fewer numbers of stylet sheaths than the untreated control, whereas treatme...

Laboratory bioassays and field trials were conducted to evaluate the efficacy of selected organophosphate, pyrethroid, and neonicotinoid insecticides, as well as a chitin inhibitor, novaluron, against 2 common stink bug pests in Virginia, the green stink bug, Acrosternum hilare (Say), and the brown stink bug, Euschistus servus (Say). Green bean dip bioassays revealed differences in insecticide susceptibility between the 2 species. Acrosternum hilare adults were highly susceptible to all pyrethroids tested, the organophosphates except acephate, and the neonicotinoids except acetamiprid. Acrosternum hilare nymphs were also susceptible to all pyrethroids tested. In general, the neonicotinoids, dinotefuran and clothianidin, were toxic to A. hilare, whereas thiamethoxam and acetamiprid were toxic to E. servus. In field trials in soybean, the neonicotinoids, dinotefuran, imidacloprid, and thiamethoxam were efficacious at controlling stink bugs and, in general, performed comparably to the organophosphates and pyrethroids. These results indicate that neonicotinoid insecticides offer an alternative to growers for managing stink bugs that may fit with integrated pest management programs where conservation of natural enemies is a consideration.

Tomato spotted wilt virus (family Bunyaviridae, genus Tospovirus, TSWV), transmitted by many thrips species, is a devastating pathogen of peanut, Arachis hypogaea L. TSWV has become a serious problem in the Virginia/Carolina peanut-growing region of the United States. During 2002, TSWV was present in 47% of the North Carolina hectarage and caused a 5% yield reduction in Virginia. Factors influencing levels of TSWV in runner market-type peanut cultivars, which are primarily grown in Alabama, Flordia, Georgia, and Texas, have been integrated into an advisory to help those peanut growers reduce losses. An advisory based on the southeast runner market-type version is currently under development for virginia market-type peanut cultivars that are grown primarily in the Virginia/ Carolina region. A version based on preliminary field experiments was released in 2003. One factor used in both advisories relates to insecticide use to reduce the vector populations and disease incidence. This research elucidated the influence of insecticides on thrips populations, thrips plant injury, incidence of TSWV, and pod yield in virginia market-type peanut. Eight field trials from 2003 to 2005 were conducted at two locations. In-furrow application of aldicarb and phorate resulted in significant levels of thrips control, significant reductions in thrips injury to seedlings, reduced incidence of TSWV, and significant increases in pod yield. Foliar application of acephate after aldicarb or phorate applied in the seed furrow further reduced thrips plant injury and incidence of TSWV and improved yield. These findings will be used to improve the current virginia market-type TSWV advisory.

In developing management strategies for hemipteran pests in cotton (Gossypium hirsutum L.), it is important to understand the potential of plants to compensate for loss of the fruiting structures. Because of its northern latitude, Virginia has fewer available heat units relative to other cotton-producing states. Therefore, there may be limited opportunity for compensation relative to more southerly production areas. Previous work in Virginia demonstrated that cotton can sustain relatively high levels of first position square loss with no yield loss. This study evaluated the impact of a single event loss of 10–14-d-old bolls via mechanical removal on cotton lint yields with the premise that boll loss would have greater impact than square loss as less time and fewer heat units are available for compensation. Field experiments examining four levels of boll removal (0, 5,15 and 20%) were conducted in 2001,2002 and 2003. Each boll removal level was imposed at three different dates, beginning 2 wks after first flower and at 3- to 5-d intervals thereafter. Yields ranged from 1103–1422 in 2001, 909–1124 in 2002, and 843–1015 kg lint per ha in 2003. There were no significant differences in lint yields among the boll removal dates or removal levels. The results of our study showed that cotton in Virginia, which approaches the northernmost latitude for cotton production, is capable of sustaining losses as high as 20% of 10–14-d-old bolls at a single removal event without affecting lint yield. Results were consistent despite the wide variation in rainfall and temperatures during the 3 study years.

Management for twospotted spider mite, Tetranychus urticae Koch, populations in peanut, Arachis hypogaea L., relies on acaricides. The outcomes of acaricide applications are most predictable when complete information on their toxicity and specificity is available. Specifically, the degrees to which acaricides impact different stages of T. urticae and natural enemies combined determine the overall efficacy of an acaricide application. The objectives of this study were to determine stage-specific direct and residual efficacies of three acaricides (fenpropathrin, etoxazole, and propargite) against T. urticae, and the direct and residual toxicity of the acaricides to Orius insidiosus (Say) adults. Direct toxicity of acaricides to T. urticae was measured on peanut cuttings. All acaricide treatments caused significant mortality to a mixed stage population of T. urticae, and mortality did not differ among the acaricides 7 d after treatment. When toxicity to eggs was tested, the proportion of eggs that h...

The LAI-2000 Plant Canopy Analyzer provides a rapid estimate of leaf area index (LAI), but its accuracy and utility for estimating soybean [Glycine max (L.) Merr.] defoliation is unknown. This study evaluated minimum plot-size requirements for manually defoliated soybean experiments using the LAI-2000; compared LAI estimates using the LAI-2000 with directly determined values for 0, 33, 67, and 100% manual defoliation levels; and compared estimates between two LAI-2000 detector types having spectral sensitivity differences. The minimum plot size for obtaining accurate indirect estimates of LAI in defoliated canopies (0.89-m height) with 0.38-m row centers is six rows by 2.28 m and with 0.91-m row centers and a canopy height of 0.81 m is four rows by 2 m plus an additional 1-m defoliated area at the ends of the two middle rows. Indirect measurements of LAI with the wide-blue detector, which is included on newer LAI-2000 units, were statistically greater than directly determined values in 10 of 12 comparisons. Measurements with the narrow-blue detector were the same as directly determined values in three of five comparisons in 1998 and 1999 but were statistically greater in 11 of 12 comparisons in 2000. Estimates with the wide-blue detector were 9 and 2% greater than those with the narrow-blue detector in 1999 and 2000, respectively.

The failure of glyphosate to control all weeds throughout the entire growing season has sometimes prompted growers to use herbicides other than glyphosate on glyphosate-resistant soybean. Field studies were conducted in 1999 and 2000 to investigate potential crop injury by several herbicides in glyphosate-resistant soybean and to determine the relationships between soybean maturity group, planting date, and herbicide treatment on soybean injury, leaf area index (LAI), and yield. Glyphosate-resistant soybean generally recovered from early-season herbicide injury and LAI reductions; however, some treatments reduced yield. Yield reductions were more common in double-crop soybean than in full-season soybean. In full-season soybean, most yield reductions occurred in the early-maturing ‘RT-386’ cultivar. These yield reductions may be attributed to reduced developmental periods associated with early-maturing cultivars and double-crop soybean that often lead to reduced vegetative growth and limited LAI. Reduction...

Three techniques for estimating wheat foliage defoliation by cereal leaf beetle, Oulema melanopus (L.), larvae were evaluated. The techniques were visual estimation, computer estimation with image capture through a flatbed scanner (Lanalyze), and a commercially available video computer image analysis system (CIAS). Both computer-assisted techniques exhibited high levels of repeatability. Both consistently produced errors of less than 3 percent, although each system exhibited different error patterns. The Lanalyze system tended to systematically underestimate actual defoliation of mock leaves, while the CIAS system tended to overestimate actual defoliation. Visual estimators exhibited greater variation among estimates and, on average, greater discrepancies from actual defoliation when compared with the computer assisted techniques. The experience of the observer had a bearing on the accuracy and consistency of visual estimates; more experienced observers had the best accuracy.

Cereal leaf beetle, Oulema melanopus L., can be effectively managed in southeastern U.S. wheat, Triticum aestivum L., with scouting and a single insecticide treatment, applied at the recommended economic threshold. However, many growers eschew this approach for a prophylactic treatment, often tank mixed with a nitrogen application before wheat growth stage 30. The efficacy of a prophylactic and an integrated pest management (IPM) approach was compared for 2 yr using small plot studies in North Carolina and regional surveys across North Carolina and Virginia. Economic analyses were performed, comparing the total cost of management of each approach using the regional survey data. From a cost perspective, the prophylactic approach was riskier, because when cereal leafbeetle densities were high, economic loss was also high. However, fields under the prophylactic approach did not exceed threshold as often as fields using IPM. Total cost of prophylactic management was also $20.72 less per hectare, giving this approach an economic advantage over IPM. The majority of fields under the IPM approach did not exceed the economic threshold. Hence, from an economic perspective, both the prophylactic and IPM approaches have advantages and disadvantages. This helps explains the partial, rather than complete, adoption of IPM by southeastern U.S. wheat growers. Cereal leaf beetle was spatially aggregated across the region in 2010, but not in 2011. As a result, from an economic standpoint, prophylaxis or IPM may have a better fit in localized areas of the region than others. Finally, because IPM adoption is favored when it has a strong economic advantage over alternative management approaches, more emphasis should be placed on research to reduce costs within the IPM approach.

Since its initial discovery in Allentown, PA, USA, the brown marmorated stink bug (BMSB), Halyomorpha halys (Heteroptera: Pentatomidae) has now officially has been detected in 38 states and the District of Columbia in the USA. Isolated populations also exist in Switzerland and Canada. This Asian species quickly became a major nuisance pest in the mid-Atlantic USA region due to its overwintering behavior of entering structures. BMSB has an extremely wide host range in both its native home and invaded countries where it feeds on numerous tree fruits, vegetables, field crops, ornamental plants, and native vegetation. In 2010, populations exploded causing severe crop losses to apples, peaches, sweet corn, peppers, tomatoes and row crops such as field corn and soybeans in several mid-Atlantic states. Damaging populations were detected in vineyards, small fruit and ornamentals. Researchers are collaborating to develop management solutions that will complement current integrated pest management programs. This article summarizes the current pest status and strategies being developed to manage BMSB in the USA. Published version

The brown marmorated stink bug, Halyomorpha halys (Stål) is an invasive insect in the Mid-Atlantic region that is spreading rapidly across the United States. In this article, the authors document the pest potential of this bug to vegetable crops based on their observations in the Mid-Atlantic United States thus far. Accepted for publication 20 April 2012. Published 23 May 2012.

The brown marmorated stink bug (BMSB), Halyomorpha halys (Stål), is an invasive pest from China that causes economic damage to field crops, vegetables, and tree fruit. Due to its destructive potential, applications of broad-spectrum insecticides have escalated. Researchers are trying to identify options for controlling BMSB that have less of a negative impact on non-target species. Chitin biosynthesis inhibitors are more selective than the commonly used pyrethroids and organophosphates. They are active on the larval stage of the insect and are reported as having sublethal effects such as reducing adult fecundity. In our studies, bioassays were completed with chitin biosynthesis inhibitors novaluron and diflubenzuron to evaluate the effectiveness of these insecticides on adult mortality, nymphal growth, adult fecundity, and egg hatch. Our data indicate that treatments of novaluron at 362.2 g ai/ha or diflubenzuron at 280.2 g ai/ha effectively controlled BMSB nymphs. However, the insecticides were not effective at reducing egg hatch, adult fecundity, or adult life span. If novaluron or diflubenzuron are used in agriculture for BMSB control, then the nymphal stage should be targeted. Accepted for publication 9 November 2012. Published 12 December 2012.

Field studies were conducted in Virginia cornfields from 1989 to 1991 to evaluate a preplant method for detecting damage to germinating corn seeds by multiple species of insect pests, including seedcorn maggots, Delia platura (Meigen); several species of wireworms in the genera Melanotus, Conoderus , and Aeolus ; and several species of white grubs in the genera Popillia, Cyclocephala, Cotinis , and Maladera . The method used consisted of evaluating feeding damage to com seeds in wire-mesh traps (i.e., baited wire traps) that were buried in cornfields for ≍2 wk before planting. In the 1989 study conducted in a cornfield with a large infestation of wireworms, a significantly greater proportion of com seeds exhibited feeding damage in the baited wire traps (38.3%) compared with corn seeds planted by hand at conventional plant spacings (i.e., simulated commercial plantings) (31.5%). Further evaluation in 47 cornfields in 1990 and 1991 revealed no significant difference between the proportion of damaged corn seeds in the baited wire traps (2.7%) and simulated commercial plantings (2.0%). A Significantly greater proportion of com seeds exhibited feeding damage in the commercial plantings (5.4%) compared with the baited wire traps; however, mean stand loss associated with insect feeding in the commercial plantings was only 0.4%, which was substantially less than the proportion of damaged com seeds in the haited wire traps. Significant linear regressions were obtained between the proportion of damaged seeds in the baited wire traps and the proportion of damaged seeds in the simulated commercial plantings, commercial plantings, and proportion of stand loss in the commercial plantings. However, the lack of economic stand loss in the commercial plantings and low regression coefficient of determination precluded the development of a baited wire trap damage threshold to predict stand loss in fields subsequently planted with corn.

A regression model was developed to predict the flight activity of Acrosternum hilare (Say) using data on the number of adults collected in a single black light trap located in Painter, VA, in the 18-yr period from 1990 to 2007. Eighteen initial weather variables, including cumulative precipitation over different time periods, mean monthly precipitation (PJA) and days below freezing (DFJA) from January to April, and mean monthly temperatures from December to April were tested in developing the regression model. Mixed (backward and forward) stepwise regression analysis showed that a two-variable model using PJA and DFJA was adequate for predicting the seasonal mean weekly number of A. hilare adults in the trap. Validation of the model using five independent black light trap data sets resulted in a strong correlation (r = 0.98) between observed and predicted mean weekly number of A. hilare adults caught in traps. Three peaks in flights of A. hilare adults were observed when mean trap catch was plotted over time for the 18-yr period. Peaks occurred at 319, 892, and 1,331 degree days (DD) from 1 January. Based on known developmental rates, the first peak was attributed to overwintered adults, the second to first-generation adults, and the third to a second generation of adults. This research suggests that A. hilare undergoes two complete generations in Virginia. Cumulative trap catch estimated from the 18-yr mean trap catch showed that 10, 50, and 90% of the total seasonal catch should occur by 153, 501, and 1,066 DD.

Experiments were conducted to evaluate the toxicity, feeding preference, repellency, and field efficacy associated with the organic insecticides azadirachtin, pyrethrins, and spinosad against two stink bug species, Acrosternum hilare (Say) and Euschistus servus (Say) (Hemiptera: Pentatomidae). Laboratory toxicity bioassays were conducted using treated green bean pods. The conventional pyrethroid lamda-cyhalothrin was included for comparison. A. hilare adults and nymphs were most susceptible to lamda-cyhalothrin and to tank mixes of pyrethrins + spinosad. E. servus adults were susceptible to lamda-cyhalothrin, spinosad, and all tank mixes, whereas E. servus nymphs were susceptible to lamda-cyhalothrin only. Feeding preference tests were conducted using insecticide-treated tomatoes and counting the number of feeding stylet sheaths on fruit after 24 h. All tomatoes treated with either azadirachtin, pyrethrins, or tank mixes resulted in fewer numbers of stylet sheaths than the untreated control, whereas treatment with spinosad alone did not. In filter paper repellency tests, both E. serous and A. hilare were repelled by pyrethrins and exhibited no response to azadirachtin. E. servus was attracted to spinosad in comparison with a water-treated control; however, A. hilare displayed no response. In field efficacy trials, each of the organic insecticides reduced the number of stink bugs in soybean, Glycine max (L.) Merr., for up to 2 d after treatment; however, none of the insecticides reduced stink bug damage to fruit in tomatoes even after multiple applications. Implications for organic growers and integrated pest management programs are discussed.

Management for twospotted spider mite, Tetranychus urticae Koch, populations in peanut, Arachis hypogaea L., relies on acaricides. The outcomes of acaricide applications are most predictable when complete information on their toxicity and specificity is available. Specifically, the degrees to which acaricides impact different stages of T. urticae and natural enemies combined determine the overall efficacy of an acaricide application. The objectives of this study were to determine stage-specific direct and residual efficacies of three acaricides (fenpropathrin, etoxazole, and propargite) against T. urticae, and the direct and residual toxicity of the acaricides to Orius insidiosus (Say) adults. Direct toxicity of acaricides to T. urticae was measured on peanut cuttings. All acaricide treatments caused significant mortality to a mixed stage population of T. urticae, and mortality did not differ among the acaricides 7 d after treatment. When toxicity to eggs was tested, the proportion of eggs that hatched for all acaricide treatments was significantly lower than the control, with etoxazole and propargite causing 100% mortality. Exposure to acaricide residues caused30% mortality of T. urticae adults 1 and 2 d after treatment and was not significantly different from the control. Fenpropathrin and propargite caused 100% mortality and etoxazole caused50% mortality of O. insidious adults after direct exposure to the acaricides. Residual toxicity of acaricides to O. insidiosus adults varied but remained toxic to O. insidiosus longer than to T. urticae. Fenpropathrin had the longest residual effect on O. insidiosus adults, causing95% mortality after 14 d; etoxazole and propargite caused30% mortality after 14 d.

Previous research indicates a correlation between leaf area index (LAI) and yield of full-season soybean [Glycine max (L.) Merrill], which is a single crop planted early in the season. Leaf area index values of at least 3.5-4.0 in the reproductive stages are required for maximum potential yield. It is unknown how yields of double-crop soybean, which is planted late into harvested small grain fields, respond to changes in leaf area index. We hypothesized that double-crop soybean would be more sensitive to defoliation than full-season soybean. This study used linear and linear plateau models to describe the yield response of full-season and double-crop soybean to reductions in leaf area index through manual defoliation, and evaluated the yield response of double-crop soybean to reductions in leaf area index through natural insect defoliation. From 15 manual defoliation experiments over 3 yr, significant linear decreases in yield occurred in both full-season and double-crop soybean when leaf area index values were below 3.5-4.0 by developmental stages R4 to R5, whereas yields usually reached a plateau at higher leaf area index levels. Average yield loss was 769 +/- 319 kg ha(-1) for each unit decrease in leaf area index below the plateau; average maximum yield was 3,484 +/- 735 kg ha(-1). From eight field experiments over 2 yr, insect defoliators had no effect on double-crop soybean yield; leaf area index levels were above 4.0 by the developmental stage when leaf area index estimates were taken (R3 to R6). Therefore, double-crop soybean that maintains leaf area index values above the 3.5-4.0 critical level by mid-reproductive developmental stages can tolerate defoliating pests.

We conducted field experiments in 1982 and 1983 in central Alabama to determine the effectiveness of CME 134, a new insect growth regulator with molt-inhibiting activity, on immature lepidopterous pests of soybeans including the soybean looper ( Pseudoplusia includens [Walker]), the corn earworm ( Heliothis zea [Boddie]), the green cloverworm ( Plathypena scabra [Fabr.]), and the velvetbean caterpillar ( Anticarsia gemmatalis Hubner). CME 134 was applied in doses of 16.5, 33.0, 66.0, 132.0, and 264.0 g (AI)/ha. CME 134-treated plots remained almost completely free of lepidopterous pests for at least 55 days after application in the 1982 tests, demonstrating high residual activity. Results of laboratory experiments suggested that residual activity was maintained through larvicidal activity of CME 134 residues on leaf surfaces. Dosage-mortality responses were determined for CME 134 against Heliothis zea larvae by continuous feeding on diet media in which the product was incorporated. LC50 values following 7 days of exposure were 21.9, 18.2, and 24.0 μg (AI)/ml diet medium for first-, third-, and fourth-instar larvae, respectively. LC50 values based on total larval + pupal mortality in insects initially exposed in the same three instars were 2.8, 2.2, and 3.7μg(AI)/ml medium, respectively. Dosage-mortality regressions for total larval + pupal mortality did not differ among instars. Early instars in general, died more rapidly than did later instars. Later instars died during the prepupal-to-pupal transformation.

Megacopta cribraria (F) (Hemiptera: Heteroptera: Plataspidae) was first discovered in North America in 9 counties in northeastern Georgia (USA) in October 2009. By the end of 2012, surveys conducted in Georgia and neighboring states confirmed that the insect had spread into 383 additional counties in the southeastern U.S., including the states of Alabama, Florida, Georgia, Mississippi, North Carolina, South Carolina, Tennessee and Virginia. It was reported from 33 species of plants representing 15 taxonomic families in these surveys, with 17 of those from the family Fabaceae (legumes). Kudzu (Pueraria montana Lour. [Merr.] variety lobata [Willd.] Maesen & S. Almeida) was the most frequently reported host. All life stages of the insect were observed only on kudzu and soybean (Glycine max [L.] Merrill) which, to date, are the only confirmed reproductive host plants of M. cribraria in its expanded North American range.

Soybeans, Braxton variety, were planted in 36-in. rows at the Brewton Experimental Farm, Brewton, Ala., in June. Treatment plots were four rows x 50 ft arranged in a randomized complete block design with four replications. Treatments were applied with a CO2 pressurized, hand carried sprayer delivering 14.7 gal/acre through three TX6 nozzles per row at 30 lb/in2 . Applications were made on 9 Sep. when combined velvetbean caterpillar (VBC) - green cloverworm (GCW) populations had reached economic threshold levels. Prespray evaluations were made on 9 Sep. by taking a 6-ft shake cloth sample from each plot. Postspray evaluations were made on 14 and 19 Sep. by taking two 6-ft samples per plot. Larvae were recorded as small (1st and 2nd instar), medium (3rd and 4th instar), and large (5th and 6th instar, prepupae). Treatment means for each size class per species and combined species totals were calculated. Numbers of small VBC and GWC larvae were combined because of the difficulty in distinguishing between the small larvae of these species in the field.

Soybeans were planted in 102 cm rows, at the Plant Breeding Unit near Tallassee, AL in May. Treatment plots were n rows x 15.2 m arranged in a randomized complete block design with 4 replications. Treatments were applied with a CO2-pressurized, hand carried sprayer delivering 15.4 1/ha through 3 TX6 nozzles per row at 40 psi. Applications were made on Aug 19, when soybean looper and podworm populations had reached economic threshold levels and again on Aug 31, when an influx of soybean loopers occurred. Evaluations were made by taking a 0.91 m shake cloth sample from each plot on Aug 19 (prespray), 24, 27, Sep 3 and 7.

Soybeans were planted in 40-inch rows at the Auburn University Plant Breeding Unit in east-central AL. Treatment plots (6 rows by 50 ft) were arranged in a randomized complete block design with 4 replicates. Treatments were applied on 6 Aug, when the number of H. zea larvae in the test field was ca. 1 per row ft. Applications were made with a CO2 pressurized backpack sprayer calibrated to deliver 13.68 gal/acre at 40 psi, through 3-TX4 hollow cone tip nozzles per row. All insect counts were made using the standard shake cloth technique. Two 6-ft samples were taken per plot, per sample date. A pretreatment sample was taken on 6 Aug. Posttreatment samples were taken on 9, 14, and 19 Aug, after which time the H. zea population declined in the test field.