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Excess vegetative growth and irregular fruit-bearing are often undesirable in horticultural practice. However, the biological mechanisms underlying these traits in fruit trees are not fully understood. Here, we tested if growth vigour and susceptibility of apple and pear trees to alternate fruit-bearing are associated with vascular anatomy. We examined anatomical traits related to water transport and nutrient storage in young woody shoots and roots of 15 different scion/rootstock cultivars of apple and pear trees. In addition, soil and leaf water potentials were measured across a drought period. We found a positive correlation between the mean vessel diameter of roots and the annual shoot length. Vigorously growing trees also maintained less negative midday leaf water potential during drought. Furthermore, we observed a close negative correlation between the proportions of total parenchyma in the shoots and the alternate bearing index. Based on anatomical proxies, our results suggest that xylem transport efficiency of rootstocks is linked to growth vigour of both apple and pear trees, while limited carbohydrate storage capacity of scions may be associated with increased susceptibility to alternate bearing. These findings can be useful for the breeding of new cultivars of commercially important fruit trees.

The Malay apple is a fruit tree found in northeastern Brazil; little is known about the composition and properties of its fruit, which motivated the present study. Among natural antioxidants, anthocyanins are pigments responsible for the red and blue coloring of a wide range of food plants. There is a growing interest in their use by the pharmaceutical industry; however, their sensitivity to environmental factors means processing is required to ensure their stability. Spray‐drying has proved to be effective in this regard. The aim of this study was to dry Malay apple skin extract by two different methods (spray‐ and freeze‐drying) and analyze the physical and chemical properties, morphology, and bioactive compounds of the products obtained, in order to assess the preservation of the antioxidants and conduct a preliminary study on their possible encapsulation. The results indicated that it is possible to obtain a powder with low humidity and preserved biocharacteristics using freeze‐ and spray‐drying, with high yield. When compared to the freeze‐dried product, the spray‐drying conserved the bioactive compounds and provided smaller size distribution than that obtained by freeze‐drying. The results obtained by spray‐drying showed favorable for use in controlled release systems. PRACTICAL APPLICATIONS: This work had as practical applications the use of a local and almost industrially unexplored fruit, the Malay apple, as a product rich in anthocyanins and other bioactive compounds for use as food additive and with potential use in cosmetics, since the compounds obtained, anthocyanins, have proven antioxidant capacity. Bioactive compounds from the peel of the Malay apple were determined for the first time. The spray‐drying process maintains much of the bioactive characteristics of the Malay apple skin. The freeze‐drying process is more effective in preserving the properties of the skin of the Malay apple. The zeta potential of the Malay apple was determined for the first time.

We analysed records of spring phenological events (budding and flowering) of pear (Pyrus sp.) cultivar ‘Pingguoli’ at six sites in the Yanbian District of Jilin Province, northeast China across 58 years from 1953. The aims of this study were to test if the phenological timing in spring has changed due to the long-term change in surface air temperature and to see if the relationship between the phenological timing and the surface air temperature shows nonlinearity as suggested by a past study. We fitted a linear model of phenological timing as the sum of the effects of long-term temperature trends and year-to-year temperature fluctuations. The results showed that the acceleration of spring phenology can be attributed to the corresponding trends of increasing mean air temperature in spring. The relationship between air temperature and phenological timing was linear for budding, but it was nonlinear for flowering with a lower temperature sensitivity at higher air temperature.

BACKGROUND Malus domestica is the most widely cultivated fruit tree and is well known for its therapeutic value. Apple leaves are known to contain phenolic compounds but the nature of these has not been explored to the same extent as in apple fruit. A simple, rapid and sensitive ultra-performance liquid chromatography–diode array detection (UPLC-DAD) quantification method has been developed. Total polyphenol and flavonoid contents, as well as the antioxidant activity of golden and royal apple leaves were evaluated. RESULTS Four compounds, namely rutin, 3-hydroxyphloridzin, phloridzin and quercetin-3-O-arabinoside were identified by UPLC. The separation was achieved in less than 7 min. Total polyphenol and flavonoid contents were found to be slightly higher in apple golden variety than royal variety. The IC50 values determined by the DPPH assay were 49.94 µg mL−1 for golden apple leaves and 43.89 µg mL−1 for royal apple leaves. IC50 values determined by the ABTS assay were 47.10 and 66.53 µg mL−1 for golden and royal apple leaves, respectively. Antioxidant activity was determined as 24.45 and 21.15 mg ascorbic acid g−1 for golden and royal apple leaves, respectively, by using the FRAP assay. CONCLUSION This study showed that apple leaves (both varieties) contain considerable amounts of polyphenols and flavonoids and are also a promising source of phloridzin. © 2015 Society of Chemical Industry

Plant resistance strongly depends on plant characteristics that affect herbivore preference or performance. Different plant genotypes may express specific characteristics that lead to differential resistance to herbivores. Few studies have investigated these aspects for weevils, a particularly speciose taxon of insect herbivores, on fruit tree cultivars, which are vegetatively propagated. We studied the influence of apple cultivar on preference and performance of a fruit tree herbivore, the flower-feeding apple blossom weevil Anthonomus pomorum (Coleoptera: Curculionidae). We quantified field infestation of five different apple genotypes by the weevil at different collection dates as measure of preference, as well as the mass and emergence time of weevils developing on these cultivars as measures of performance. Infestation of apple flower buds by A. pomorum differed significantly between cultivars. The collection date affected the number of infested flowers in a cultivar-specific way. Weevil mass differed significantly between apple cultivars. The average mass of weevils from Ariwa, the cultivar producing the heaviest weevils, was 40% higher than the mass of weevils from Rewena, the cultivar producing the lightest weevils. Weevil emergence time from infested flowers differed significantly between cultivars. Weevils emerged earliest from cultivars Ariwa and Retina, at an intermediate time from Discovery and Florina, and latest from Rewena. The present study demonstrates that preference and performance of florivores feeding on fruit trees can strongly differ between apple cultivars representing specific tree genotypes. These differences may directly and indirectly affect herbivore and antagonist populations and can be considered for pest management.

The genetic diversity of Phytophthora spp. was investigated in potted ornamental and fruit tree species. A metabarcoding approach was used, based on a semi-nested PCR with Phytophthora genus-specific primers targeting the ITS1 region of the rDNA. More than 50 ITS1 sequence types representing at least 15 distinct Phytophthora taxa were detected. Nine had ITS sequences that grouped them in defined taxonomic groups (P. nicotianae, P. citrophthora, P. meadii, P. taxon Pgchlamydo, P. cinnamomi, P. parvispora, P. cambivora, P. niederhauserii and P. lateralis) whereas three phylotypes were associated to two or more taxa (P. citricola taxon E or III; P. pseudosyringae, P. ilicis or P. nemorosa; and P. cryptogea, P. erythroseptica, P. himalayensis or P. sp. ‘kelmania’) that can be challenging to resolve with ITS1 sequences alone. Three additional phylotypes were considered as representatives of novel Phytophthora taxa and defined as P. meadii-like, P. cinnamomi-like and P. niederhauserii-like. Furthermore, the analyses highlighted a very complex assemblage of Phytophthora taxa in ornamental nurseries within a limited geographic area and provided some indications of structure amongst populations of P. nicotianae (the most prevalent taxon) and other taxa. Data revealed new host–pathogen combinations, evidence of new species previously unreported in Italy (P. lateralis) or Europe (P. meadii) and phylotypes representative of species that remain to be taxonomically defined. Furthermore, the results reinforced the primary role of plant nurseries in favouring the introduction, dissemination and evolution of Phytophthora species.

This study aimed to elucidate the relationship between plant hosts and root-colonizing fungi recovered from apple orchard soils that had been replanted over multiple generations. Functional relationships of three groups of filamentous fungi (Ceratobasidium sp., Cylindrocarpon-like group and Fusarium acuminatum) with apple rootstocks were evaluated in plant growth bioassays. The Cylindrocarpon-like group and Ceratobasidium sp. showed a relationship with the host plant varying from pathogenic to commensal through to mutualistic for the latter group, while that of F. acuminatum tended to be mutualistic. Seven fungal isolates of each group, which induced the highest plant growth in bioassays, were evaluated for auxin (IAA) and gibberellin (GA3 and GA4) production in culture filtrate. All isolates of F. acuminatum as well as most of those of the Ceratobasidium sp. and ylindrocarpon-like groups produced IAA in culture filtrate. IAA production was evaluated for additional isolates of endophytic fungal species from fruit tree orchards and the functionality of IAA was confirmed by growing in vitro micropropagated plantlets of apple rootstock on MS medium supplemented with fungal culture filtrate. Findings from his study may explain the difficulty in defining the recise role of diverse root-colonizing fungal populations in replant disease aetiology of fruit tree orchards. However, the results demonstrate the presence of a positive and widely available biotic component of the orchard soil biology that may be exploited for the benefit of tree growth and production.

Competing successfully for the best feeding sites is an important behavioral strategy but little is known about how feeding sites vary nutritionally within a fruit tree. To answer this question we tested how the nutritional value of a fruit is influenced by its ripeness and its height within the tree crown. A complementary objective was to assess the nutritional value of the midripe fruit, a food item rarely mentioned in the literature despite being exploited on a daily basis by many frugivores. We measured how the dry weight of pulp, water content, and concentration of macronutrients and condensed tannins varied within the tree crowns of 15 fruit species. Collections occurred early in the fruiting cycle, so as to assess the amount of food in the tree before its exploitation by primates. We found that (1) the upper crown produced fruit densities 4.2 times higher, and a fruit crop 4.8 times larger, than the lower crown of the same tree; (2) considering only midripe and ripe stages, upper-crown fruits contained 28.6% more dry pulp, 21.1% more water, and 13.5% more sugars per dry matter than lower-crown fruits of the same tree; (3) midripe fruits contained 80% of the concentrations of sugars of ripe fruits, making them a sweeter food item than one would expect from the intermediate color of their epidermis; (4) cellulose, hemicellulose, proteins, and ash proportionally decreased in concentration while dry pulp and sugars increased during ripening; and (5) ripe fruits were usually rare in the tree (

Sweet cherry is a self-incompatible fruit tree species in the Rosaceae. As other species in the family, sweet cherry exhibits S-RNase-based gametophytic self-incompatibility. This mechanism is genetically determined by the S-locus that encodes the pollen and pistil determinants, SFB and S-RNase, respectively. Several self-compatible sweet cherry genotypes have been described and most of them have mutations at the S-locus leading to self-compatibility. However, ‘Cristobalina’ sweet cherry is self-compatible due to a mutation in a pollen function modifier that is not linked to the S-locus. To investigate the physiology of self-compatibility in this cultivar, S-locus segregation in crosses involving ‘Cristobalina’ pollen, and pollen tube growth in self- and cross-pollinations, were studied. In the crosses with genotypes sharing only one S-haplotype, the non-self S-haplotype was inherited more frequently than the self S-haplotype. Pollen tube growth studies revealed that the time to travel the whole length of the style was longer for self-pollen tubes than for cross-pollen tubes. Together, these results suggest that ‘Cristobalina’ pollen tube growth is slower after self-pollination than after cross-pollination. This reproductive strategy would allow self-fertilisation in the absence of compatible pollen but would promote cross-fertilisation if cross-compatible pollen is available, a possible case of cryptic self-incompatibility. This bet-hedging strategy might be advantageous for an ecotype that is native to the mountains of the Spanish Mediterranean coast, in the geographical limits of the distribution of this species. ‘Cristobalina’ blooming takes place very early in the season when mating possibilities are scarce and, consequently, self-compatibility may be the only possibility for this genotype to produce offspring.

BACKGROUND The pear psylla, Cacopsylla bidens (Sulc), is one of the most damaging pests of commercial pear orchards in Israel. Psylla control is a major obstacle to efficient integrated pest management, necessitating research on cultivars with natural resistance to pear psylla. Recently, two pear accessions (Py.760-261 and Py.701-202) from the local Newe Ya'ar fruit tree live collection were identified as having apparent resistance to pear psylla. Our goal was to evaluate the resistance of these two accessions relative to the commercial cultivar Spadona Estiva, and to identify whether the resistance mechanisms in the former interfere with insect colonisation of the plant (antixenosis) or inhibit insect growth, development, reproduction and survival (antibiosis). RESULTS Settlement and development of C. bidens was evaluated under natural conditions (pear orchard), semi-natural conditions (potted plants), and on detached branches and leaves (laboratory). Our results indicate that the selection Py.760-261 is 10 times more resistant than Spadona while Py.701-202 is five times more resistant. CONCLUSIONS The resistance mechanism in both accessions appears to be antibiosis affecting nymph survival. These resistant accessions may be used as rootstock or as a source of resistant genes in breeding programmes. © 2013 Society of Chemical Industry

Sharka, a disease caused by plum pox virus (PPV), has a significant economic impact on fruit tree production. In this work, we analysed the effect of (2,1,3)-benzothiadiazole (BTH) and L-2-oxo-4-thiazolidine-carboxylic acid (OTC) on plant growth and virus content. OTC reduced sharka symptom, stimulated plant growth and alleviated PPV-induced oxidative stress, indicated by a lack of changes in some oxidative stress parameters. PPV infection reduced chloroplast electron transport efficiency. However, in the presence of BTH or OTC, no changes in the chlorophyll fluorescence parameters were observed. PPV produced an alteration in chloroplast ultrastructure, giving rise to a decrease in starch contents that was less dramatic in OTC-treated plants. Furthermore, PPV reduced the abundance of proteins associated with photosynthesis, carbohydrate and amino acid metabolism and photorespiration. These changes did not take place in OTC-treated plants, and increases in the expression of proteins related with the aforementioned processes, including ADP-glucose pyrophosphorylase, were produced, which correlated with the lower decrease in starch contents observed in PPV-infected plants treated with OTC. The results suggested that OTC treatment provides protection to the photosynthetic machinery and/or the chloroplast metabolism in PPV-infected peaches. Thus, OTC could have practical implications in agriculture in improving the vigour of different plant species as well as in immunizing plants against pathogens.

BACKGROUND: Iron (Fe) chlorosis is a serious problem affecting the yield and quality of numerous crops and fruit trees cultivated in alkaline/calcareous soils. This paper describes the efficiency of a new class of natural hetero-ligand Fe(III) chelates (Fe-NHL) to provide available Fe for chlorotic lemon trees grown in alkaline/calcareous soils. These chelates involve the participation in the reaction system of a partially humified lignin-based natural polymer and citric acid. RESULTS: First results showed that Fe-NHL was adsorbed on the soil matrix while maintaining available Fe for plants in alkaline/calcareous solution. The effects of using three different sources as Fe fertilisers were also compared: two Fe-NHL formulations (NHL1, containing 100% of Fe as Fe-NHL, and NHL2, containing 80% of Fe as Fe-NHL and 20% of Fe as Fe-ethylenediamine-N,N′-bis-(o-hydroxyphenylacetic) acid (Fe-EDDHA)) and Fe-EDDHA. Both Fe-NHL formulations increased fruit yield without negative effects on fruit quality in comparison with Fe-EDDHA. In the absence of the Fe-starter fraction (NHL1), trees seemed to optimise Fe assimilation and translocation from Fe-NHL, directing it to those parts of the plant more involved in development. CONCLUSION: The field assays confirmed that Fe-NHL-based fertilisers are able to provide Fe to chlorotic trees, with results comparable to Fe-EDDHA. Besides, this would imply a more sustainable and less expensive remediation than synthetic chelates. Copyright © 2012 Society of Chemical Industry

Local extinction or population decline of large frugivorous vertebrates as primary seed dispersers, caused by human disturbance and habitat change, might lead to dispersal limitation of many large-seeded fruit trees. However, it is not known whether or not scatter-hoarding rodents as secondary seed dispersers can help maintain natural regeneration (e.g. seed dispersal) of these frugivore-dispersed trees in the face of the functional reduction or loss of primary seed dispersers. In the present study, we investigated how scatter-hoarding rodents affect the fate of tagged seeds of a large-seeded fruit tree (Scleropyrum wallichianum Arnott, 1838, Santalaceae) from seed fall to seedling establishment in a heavily defaunated tropical forest in the Xishuangbanna region of Yunnan Province, in southwest China, in 2007 and 2008. Our results show that: (i) rodents removed nearly all S. wallichianum seeds in both years; (ii) a large proportion (2007, 75%; 2008, 67.5%) of the tagged seeds were cached individually in the surface soil or under leaf litters; (iii) dispersal distance of primary caches was further in 2007 (19.6 ± 14.6 m) than that in 2008 (14.1 ± 11.6 m), and distance increased as rodents recovered and moved seeds from primary caches into subsequent caching sites; and (iv) part of the cached seeds (2007, 3.2%; 2008, 2%) survived to the seedling stage each year. Our study suggests that by taking roles of both primary and secondary seed dispersers, scatter-hoarding rodents can play a significant role in maintaining seedling establishment of S. wallichianum, and are able to at least partly compensate for the loss of large frugivorous vertebrates in seed dispersal.

The apple tree is known to have an isohydric behaviour, maintaining rather constant leaf water potential in soil with low water status and/or under high evaporative demand. However, little is known on the xylem water transport from roots to leaves from the two perspectives of efficiency and safety, and on its genetic variability. We analysed 16 traits related to hydraulic efficiency and safety, and anatomical traits in apple stems, and the relationships between them. Most variables were found heritable, and we investigated the determinism underlying their genetic control through a quantitative trait loci (QTL) analysis on 90 genotypes from the same progeny. Principal component analysis (PCA) revealed that all traits related to efficiency, whether hydraulic conductivity, vessel number and area or wood area, were included in the first PC, whereas the second PC included the safety variables, thus confirming the absence of trade-off between these two sets of traits. Our results demonstrated that clustered variables were characterized by common genomic regions. Together with previous results on the same progeny, our study substantiated that hydraulic efficiency traits co-localized with traits identified for tree growth and fruit production.

Apple chlorotic leaf spot virus (ACLSV), Apple stem pitting virus (ASPV), Apple stem grooving virus (ASGV) and Apple mosaic virus are economically important viruses infecting fruit tree species worldwide. To evaluate the occurrence of these pome fruit viruses in Latvia, a large-scale survey was carried out in 2007. Collected samples were tested for infection by DAS ELISA and multiplex RT-PCR. The accuracy of the detection of the viruses in multiplex RT-PCR was confirmed by sequencing amplified PCR fragments. The results showed a wide occurrence of viruses in apple and pear commercial orchards established from non-tested planting material. More than 89% of the tested apple trees and more than 60% of pear trees were infected with one or more pome fruit viruses. Analyses showed that the high occurrence of viruses in several apple cultivars is due to the propagation of infected clonal rootstocks and scions from infected mother trees. Sequence analyses targeting the 3′-terminal region of the tested viruses showed various degrees of genetic diversity within respective virus isolates. This is the first report of the occurrence of ACLSV, ASGV and ASPV in apple and pear trees in Latvia and demonstrates their genetic diversity in different host genotypes.

Megaplatypus mutatus (Chapuis) (Coleoptera: Curculionidae: Platypodinae) is an ambrosia beetle native to South America, but it has recently been introduced into Italy and represents a serious problem in commercial poplar and fruit tree plantations. Male M. mutatus emit a sex pheromone composed of (+)-6-methyl-5-hepten-2-ol [(+)-sulcatol], 6-methyl-5-hepten-2-one (sulcatone), and 3-pentanol. We performed three field trials of mating disruption of M. mutatus in hazelnut and poplar plantations in Argentina and Italy. To perform these tests, we made plastic pheromone reservoir-type dispensers for sulcatol, sulcatone, and 3-pentanol with zero-order kinetics that were deployed in the field during the female flight period. The number of galleries where mating took place was significantly higher in control than in treated areas, indicating that pheromone application had interfered with female behavior and male localization. Because damage reduction was >56% in both countries, these results demonstrate the potential for the strategy of pheromone-mediated mating disruption of M. mutatus in commercial poplar and hazelnut plantations. Also, our study provides the first evidence for successful pheromone-mediated mating disruption in a forest beetle.

Very few studies have attempted to disentangle the respective role of ontogeny and water stress on leaf photosynthetic attributes. The relative significance of both effects on photosynthetic attributes has been investigated in leaves of field-grown almond trees [Prunus dulcis (Mill.) D. A. Webb] during four growth cycles. Leaf ontogeny resulted in enhanced leaf dry weight per unit area (W a ), greater leaf dry-to-fresh weight ratio and lower N content per unit of leaf dry weight (N w ). Concomitantly, area-based maximum carboxylation rate (V cmax ), maximum electron transport rate (J max ), mesophyll conductance to CO 2 diffusion (gm)' and light-saturated net photosynthesis (A max ) declined in both well-watered and water-stressed almond leaves. Although g m and stomatal conductance (g s ) seemed to be co-ordinated, a much stronger coordination in response to ontogeny and prolonged water stress was observed between g m and the leaf photosynthetic capacity. Under unrestricted water supply, the leaf age-related decline of A max was equally driven by diffusional and biochemical limitations. Under restricted soil water availability, A max was mainly limited by g s and, to a lesser extent, by photosynthetic capacity and g m . When both ontogeny and water stress effects were combined, diffusional limitations was the main determinant of photosynthesis limitation, while stomatal and biochemical limitations contributed similarly.

In recent years, anthracnose has become a significant disease affecting avocado fruit in the state of Michoacan, Mexico, where it significantly reduces fruit quality and commercial yield. Anthracnose has been assumed to involve Colletotrichum gloeosporioides and C. acutatum as causal agents. However, because of the increasing incidence of anthracnose, a more precise identification of the Colletotrichum spp. involved in this disease has become desirable. During the years 2004–2007, avocado fruits of different sizes exhibiting brown-black and reddish spots on the pericarp and soft rot in the mesocarp, were gathered from orchards in nine counties. Fungal isolates were cultured on potato dextrose agar, and among these, 31 were selected for molecular, morphological and pathogenicity analyses. The molecular approaches used sequence typing of the internal transcribed spacer region and the partial nuclear large ribosomal subunit, allowing the unequivocal identification of C. gloeosporioides (71%), C. acutatum (16%) and C. boninense (13%). This last species has not been previously reported as being associated with anthracnose symptoms in avocado fruits anywhere in the world. Various morphological characteristics such as the size and shape of conidia were determined, as well as the conidial mass colour. Pathogenicity tests performed with all three species were conducted by inoculating healthy fruits. In each case, identical symptoms developed within 3 days of inoculation. Knowledge of the Colletotrichum populations in the Michoacan state, including the newly encountered avocado pathogen C. boninense, will facilitate further studies addressing the relationships between these Colletotrichum spp. and their avocado host.

Red scale, Aonidiella aurantii Maskell (Hemiptera: Diaspididae), has a contagious distribution among fruit and among trees largely due to the fact that most young settle on the same fruit as their mothers. The pattern of distribution and degree of dispersion of red scale within various sets of contiguous citrus trees in several orchards were recorded each autumn for 4 years. Changes in density and site occupancy within trees and within contiguous groups of trees were made to assess the strength of any link between populations and their dynamics on different trees. Aonidiella aurantii was found to have a very clumped distribution whereby trees with a level of scale infestation well above average for their block could be adjacent to trees with few or no detectable scale. However, patches of high density on a given tree usually did not recur for more than 2 years but were replaced with above average infestations on other trees. The stability of the red scale populations varied from block to block. Some blocks had few or no infested trees over the study period whereas others had widely fluctuating levels of infestation. Dispersion coefficients at 'within tree' and 'within block' levels were similar. Theoretical and statistical models of the relation of average scale levels to the percentage of fruit or trees infested were less precise than they are for other pests because of high variation of clumping intensity of scale within any block.

The persea mite, Oligonychus perseae Tuttle, Baker & Abbatiello (Acari: Tetranychidae), a pest of avocado, was first discovered in Israel in the autumn of 2001. It has since spread to most avocado growing areas in Israel. To establish an economic injury level (EIL), based on the percentage of leaf area damaged (PLAD), we conducted an extensive field study. For three consecutive seasons we created distinct pest infestation levels on the Hass avocado cv., by applying acaricides (spirodiclofen and abamectin) at 50, 100, and 250 mites per leaf levels, along with non-sprayed controls in a replicated block design. At harvest time we evaluated the level of leaf damage and fruit yields across treatments. In two out of the 3 years, trees sprayed at 50 and 100 mites per leaf levels had similar PLAD values, differing from trees treated at the 250 mites per leaf level and the non-treated control, the latter pair also being similar. Over the 3 years, mean yield attained at the two higher infestation levels was reduced by 20% in comparison to the mean yields recorded for plots sprayed at the lower thresholds. Accordingly, we suggest that scouts adopt an action threshold (AT) of 50-100 mites per leaf. Future research is needed to refine this AT. Mean annual cumulative mite days (CMDs) of the two higher levels was ca. 13500 ± 700 per leaf. Using the linear regression equation PLAD = 0.0009CMDs + 2.42, describing leaf damage as a function of CMDs, we estimated an EIL of ca. 15 PLAD.

In phytophagous insects, oviposition strategy is determined by complex trade-offs among many factors. The winter cherry bug, Acanthocoris sordidus Thunberg (Heteroptera: Coreidae), deposits its eggs not only on host plants, but also on non-host plants. Oviposition on non-host plants may cause higher nymph mortality, as nymphs may be unable to find their host plants during the second instar when the first feeding occurs. Therefore, we hypothesised that this uncommon oviposition strategy would be maintained by a trade-off between egg and nymphal mortality risks. To test this hypothesis, we conducted field surveys to compare egg mortality due to biotic (predation and parasitism) and abiotic factors on host plants vs. non-host plants. We also conducted a semi-field experiment to quantify the risk of nymphal mortality caused by oviposition on non-hosts during the second instar. In terms of mortality risk during the egg stage, a 2-year field survey revealed that oviposition on non-host plants resulted in higher survival of eggs than on host plants; this strategy was also particularly effective for avoiding attacks by ground-living arthropod predators. In terms of mortality risk during the nymphal stage, the semi-field experiment demonstrated that nymphs placed off host plants do risk being unable to reach host plants. However, the presence of conspecific adults on host plants increased the probability that nymphs reached host plants. Therefore, second instars may have evolved the ability to utilise chemical cues emitted by adults on host plants or by host plants fed by adults to reduce their risk of not reaching host plants. We concluded that oviposition on non-host plants by A. sordidus females could be maintained by the balance between the benefit of lower egg mortality and the cost of higher nymph mortality compared to oviposition on host plants.

A study to investigate the association of phytoplasmas with papaya dieback and citrus decline syndromes in Ethiopia was carried out between July 2009 and February 2010, with sampling performed in major papaya- and citrus-growing areas of the Rift Valley. Samples of plants with symptoms were collected from papaya, citrus and suspected phytoplasma weed hosts and crops in and around the papaya and citrus fields studied. Nested polymerase chain reaction (nested-PCR) was used for initial characterization, using primers that amplify regions of the 16S rRNA and secA genes, and results were then confirmed with rapid real-time group-specific LAMP (loop-mediated isothermal amplification) assays. The results identified the occurrence of a phytoplasma belonging to the stolbur (16SrXII-A) group in papaya plants showing dieback symptoms, whilst no phytoplasmas were found associated with citrus decline. These results contradict previous reports that a 16SrII phytoplasma was associated with both papaya dieback and citrus decline in Ethiopia, but correspond with the association of a 16SrXII phytoplasmas with Nivum-Haamir-Dieback of papaya in Israel and papaya dieback in Australia. No 16SrXII phytoplasmas were found in any of the weeds and potential alternative hosts studied, although 16SrII phytoplasmas were consistently found in Parthenium hysterophorus weed plants. These results indicate that a 16SrXII phytoplasma is associated with papaya dieback in Ethiopia, whilst the causal agent of citrus decline is not a phytoplasma and remains unidentified.

With 1 table Abstract The behaviour of 31 plum cultivars (Prunus salicina, Prunus cerasifera, P. domestica, P. cerasifera × P. salicina and P. salicina × P. armeniaca) against a Dideron-type isolate of Plum pox virus (PPV) (sharka) was evaluated in an insect-proof greenhouse, grafted onto ‘Adesoto’ diseased rootstocks, during three growing cycles. All plum cultivars showed the symptoms of sharka or were ELISA positive in at least one of the replications evaluated. However, the behaviour of cultivars was different. Most of the Japanese plums were very sensitive or sensitive, showing strong sharka symptoms and being ELISA positive. Only the Japanese plums ‘Black Star’, ‘Calita’, and ‘Laroda’ showed tolerance to PPV, with mild sharka symptoms and a very low percentage of infected plants. In addition, among the four P. cerasifera studied, ‘J9’ was very sensitive, ‘Kometa’ was sensitive, and ‘P16’and ‘P2980’ were tolerant to sharka. Finally, the inter-specific hybrids ‘J300’ and ‘Flavor Supreme’ were sensitive, and ‘Obilnaya’ was tolerant to the disease.

The effects of copper sprays on annual and polyetic progress of citrus canker, caused by Xanthomonas citri subsp. citri, in the presence of the Asian citrus leafminer (Phyllocnistis citrella), were evaluated in a study conducted in a commercial orchard in northwest Parana state, Brazil, where citrus canker is endemic. Nonlinear monomolecular, logistic and Gompertz models were fitted to monthly disease incidence data (proportion of leaves with symptoms) for each treatment for three seasons. The logistic model provided the best estimate of disease progress for all years and treatments evaluated and logistic parameter estimates were used to describe polyetic disease dynamics. Although citrus canker incidence increased during each of the seasons studied, it decreased over the whole study period, more so in copper-treated trees than in water-sprayed controls. Copper treatment reduced disease incidence compared with controls in every year, especially 2004–2005, when incidence was ca. 10-fold higher in controls than in treated plots (estimated asymptote values 0·82 and 0·07, respectively). Copper treatment also reduced estimated initial disease incidence and epidemic growth rates every year.

The cashew gummosis caused by the fungus Lasiodiplodia theobromae is one of the most important disease of cashew in the northeast of Brazil. The lack of studies about method of early detection, pathogen dissemination, host predisposition, mechanisms of attack and defence and efficient control measures assures this disease as a limiting factor as to growing of cashew under semi-arid conditions. Therefore, the characterization of spatial patterns of gummosis development under commercial orchards may provide important insights into the mechanisms involving in dissemination and disease progress of this disease, as well as in the understanding of dynamic of host, pathogen and environmental interactions for this pathossystem. This work aimed to characterize gummosis temporal and special dynamics in three commercial orchards of cashew clones of cashew with different levels of susceptibility by studying the special arrangement of diseased plants. Disease incidence and severity, quantified determined by a descriptive scale in clones BRS 226 (resistant), Embrapa 51 (slightly resistant) and Faga 11 (susceptible) in a commercial orchard located in Pio IX district (Piaui state, Brazil), were monitored and mapped. Data were collected within three blocks of 90 plants for each clone. Indices of dispersion were estimated to study the spatial dynamic. The dynamics and structure of gummosis foci were also analysed. As expected, data showed different degrees of gummosis incidence and severity for the three clones. Even under different levels of disease, a random dispersion pattern model of dispersion could be observed at the beginning of epidemic for all clones. However, as disease develops, a clustered model is likely to fit. The increase in disease incidence resulted from the increasing in both focus number and size.

The term 'transmissible small nuclear ribonucleic acids' (TsnRNAs) describes well characterised viroid RNA species that do not induce any disease syndromes in specific citrus hosts but rather act as regulatory genetic elements modifying tree performance. Twelve-year-old navel orange and 10-year-old Clementine mandarin trees on Carrizo citrange (Citrus sinensis x Poncirus trifoliata) rootstock treated with a mixture of three TsnRNAs (-Ia, syn. Citrus bent leaf viroid, +IIa, syn. Hop stunt viroid and + IIIb, syn. Citrus dwarfing viroid) were reduced in size by 33% and 43%, respectively. Clementine trees treated with a mixture of TsnRNA―Ia+IIa or ―Ia+IIIb also had reduced canopy volume (CV) (∼38 and 31%, respectively), whereas trees treated with TsnRNA―IIa+IIIb showed little effect. The effects of the double TsnRNA treatments ―Ia+IIa and ―Ia+IIIb on Clementine canopy size and commercial performance were comparable and in some cases superior to that of the triple TsnRNA mixture. The TsnRNA―Ia+IIa treatment had the most attractive commercial traits with increased production of Clementine fruit per CV (23.6%), more fruit with high commercial value (31.7%), and more fruit optimally distributed in the canopy (68% of fruit between 0.5 and 2.5 m). None of the TsnRNA treatments affected the growth of Carrizo rootstock seedlings after 8 years in the field. Navel orange and Clementine scions treated with the same triple TsnRNA mixture expressed different trunk and fruit production patterns although effects on CV were similar.

Leaves are the main photosynthetically active tissues in most plants. However, stems and fruits are also important for the overall carbon balance of the plant because of their contribution to fixation of the CO(2) released by respiration. Photosynthesis could not be possible without a complete set of photoprotection mechanisms, which include the ubiquitous violaxanthin (V) cycle and the taxonomically restricted lutein epoxide (Lx) cycle. In this work, we characterise carotenoid stoichiometry in photosynthetic stems and fruits of avocado in comparison with that of leaves and specifically whether Lx is present in these tissues and also whether it is involved in a light-driven cycle. Avocado was selected as model species to study whether both cycles were functional in non-foliar photosynthetic structures (stems and fruits). An unusual pigment composition was observed in avocado fruit, with a high content of cis-V and cis-Lx, suggesting a different photosynthetic function. In stems, both xanthophylls de-epoxidated upon illumination, but only V recovered in the dark, indicating the existence of a possible 'truncated' Lx cycle. Lx in fruits was de-epoxidated only when its pool was higher than a threshold of 30 mmol mol(-1) chlorophyll, indicating a high non-photoconvertible pool of Lx. We conclude that, at least in stems, the dynamic regulation of photosynthetic activity could also depend on the Lx cycle.

BACKGROUND: The efficacy of systemic applications of imidacloprid for the management of avocado thrips and avocado lace bug was determined in field trials. Following insecticide treatment by chemigation, leaves of appropriate age for each insect were sampled over a 6 month period and used for bioassays. Imidacloprid residues were measured by ELISA in leaves used for bioassays to determine concentrations of insecticide that were toxic to both pests. RESULTS: The uptake of imidacloprid into treated trees was extremely slow, peaking in the current year's leaf flush at only 8 ng cm−2 leaf tissue after 15 weeks. Avocado thrips mortality in bioassays with young flush leaves, the preferred feeding substrate for this insect, was minimal, indicating that imidacloprid concentrations were below threshold levels needed for effective control. Residues present in older leaves, which are preferred by the avocado lace bug, were higher than in young flush leaves, and provided good control of this pest. Probit analysis of bioassay data showed that the avocado lace bug (LC50 = 6.1 ng imidacloprid cm−2 leaf tissue) was more susceptible to imidacloprid than the avocado thrips (LC50 = 73 ng imidacloprid cm−2 leaf tissue). CONCLUSIONS: In spite of the slow uptake of imidacloprid into avocado trees, the levels of imidacloprid would be sufficient to control avocado lace bug infestations. In contrast, the slow uptake would be problematic for avocado thrips control because inadequate levels of insecticide accumulate in new flush foliage and would allow avocado thrips populations to build to levels that would subsequently damage developing avocado fruit. Copyright © 2010 Society of Chemical Industry

Leaf area expansion, thickness and inclination, gas exchange parameters and relative chlorophyll content were analysed in field-grown fig (Ficus carica L.) leaves over time, from emergence until after full leaf expansion (FLE). Ficus carica leaves showed a subtle change in shape during the early stages of development, and FLE was reached within ca. 30 days after emergence. Changes in leaf thickness and inclination after FLE demonstrated good adaptation to environmental conditions during summer in areas with a Mediterranean climate. Changes in gas exchange parameters and relative chlorophyll content showed that F. carica is a delayed-greening species, reaching maximum values 20 days after FLE. Correlation analysis of datasets collected during leaf expansion, confirmed dependence among structural and functional traits in F. carica. Pn was directly correlated with stomatal conductance (Gs), transpiration (E), leaf area (LA) and relative chlorophyll content up to FLE. The effect of pruning on leaf expansion, a cultural technique commonly applied in this fruit tree, was also evaluated. Although leaf development in pruned branches gave a significantly higher relative leaf area growth rate (RGR(l)) and higher LA than non-pruned branches, no significant differences were found in other morphological and physiological traits, indicating no pruning effect on leaf development. All studied morphological and physiological characteristics indicate that F. carica is well adapted to semiarid conditions. The delayed greening strategy of this species is discussed.

The study was performed on apple trees, ‘Golden Delicious' cv., which is a scab-susceptible cultivar. The phenolic content of apple fruit was determined in different parts of the peel. The phenolic compounds were analysed in the scab spot, in the tissue around the spot and in the healthy tissue. We determined the concentration of various phenolic compounds and related enzyme activities. Infection with the Venturia inaequalis fungus enhanced the metabolism of phenolic compounds at the scab spot, around the spot and in healthy peel. Compared with the healthy tissue and the tissue around the spot, the scab spot showed higher enzyme activity for all tested enzymes, except for dihydrochalcone 2′-O-glucosyltransferase, which had lower activity in the scab spot. In comparison to the healthy peel, the scab spot showed up to 3.4 times more hydroxycinnamic acids, up to 1.1 times more dihydrochalcones and up to 1.4 times more flavan-3-ols. In contrast, the healthy peel showed up to 1.6 times more flavonols than the scab spot.

Cloudy stain is a physiological disorder of the Japanese persimmon blemishing the skin and causing a great reduction of fruit quality, thus decreasing its commercial value. The stain starts at or just prior to the fruit colour-break stage, coinciding with the presence of cuticular cracks which increase cuticle water permeability and expose subepidermal cells to air and water, causing oxidation of polyphenol substances of large skin areas that turn almost black. The incidence of the disorder examined over four consecutive years in two growing areas of Spain revealed significant differences from year to year, between areas and even the tree face examined. The data consistently showed that cooler groves and fruit located on the northern face of the canopy were more prone to develop the stain. During the 4 years of the study, the average daily minimum temperature of a period of 15–25 days prior to the onset of staining followed the same order as the yearly staining rate, and accumulated hours below 13°C correlated significantly with the percentage of fruit starting the disorder. No relationship was found between the time-course of relative humidity (RH) and the onset of staining, but once the stain started the lower RH resulted in the lower percentage of affected fruit. Dew point, wind speed, rainfall and evapotranspiration did not correlate either with the onset of staining or with its incidence. Rind of cloudy-stained fruit had higher concentration of N, K, Mg and Fe and lower concentration of Ca than that of healthy fruit, but it is not the cause of the disorder. Accordingly, we conclude that cloudy stain of Japanese persimmon starts after a period of low temperature (≤ 13°C) and, afterwards, RH is responsible for its development and severity.

With 3 figures and 3 tables Abstract Previous studies have demonstrated that genotypes of PpACS1 and PpACS2 genes are associated with certain levels of ethylene production in Japanese pears (Pyrus pyrifolia Nakai). This study was undertaken to examine further the relationships of PpACS1 and PpACS2 genotypes and internal ethylene concentration (IEC) with fruit firmness/softening in both European (P. communis L.) and Japanese pears (P. pyrifolia Nakai). Our data showed that P. communis L. lacked genotypes ‘AB’/‘Ab’ and ‘aB’, for high and medium IEC respectively, irrespective of high levels of IEC found in the European pear cultivars/selections. PpACS1 and PpACS2 genotypes were related to IEC at 20 days after harvest (DAH) in P. pyrifolia Nakai but IEC did not have any significant relationship with fruit firmness at 50DAH in either P. communis L. or P. pyrifolia Nakai. Harvest firmness was a better predictor of postharvest firmness than IEC across both species and genotypes, explaining 46% of the variation in fruit firmness at 50DAH. We recommend breeding for higher harvest firmness within low ethylene cultivars in order to extend the shelf life/storage potential of Japanese pears.

The citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), is a worldwide pest ofcitrus crops and is responsible for proliferation ofcitrus bacterial canker,Xanthomonas axonopodis (Hasse) pv. citri (Gamma Proteobacteria: Xanthomonadaceae). We developed and evaluated an attracticide formulation, termed MalEx, for control of P. citrella. MalEx is a viscous paste with UV-protective properties that is dispensed as 50-ll droplets using custom-made calibrated pumps. A formulation containing 0.016% P. citrella pheromone [3:1 blend of (Z,Z,E)-7,11,13-hexadecatrienal and (Z,Z)-7,11-hexadecadienal] and 6% permethrin was found to suppress male response to pheromone in the field better than formulations containing 10· less pheromone. Although formulations without permethrin showed some suppression of male activity because of mating disruption, additionof6%permethrintotheformulationwasrequiredforoptimalefficacy.WhenMalEx,containing 0.016% pheromone and 6% permethrin, was applied at 3 000 point sources ha )1 , the application height did not influence efficacy of male P. citrella suppression within mature 4-m tall citrus trees. Decreasing the rate of MalEx from 3 000 to 1 500 droplets ha )1 reduced efficacy as measured by both male P. citrella activity and larval infestation. Although 4 500 droplets ha )1 did not result in statistically better efficacy than 3 000 droplets ha )1 , there was a noticeable trend for higher efficacy as droplet density increased. Continuous treatment of 0.5-ha blocks of citrus with MalEx over the course of 112 days reduced larval infestation of new flush, as compared with those in untreated control plots, by 3.6‐7.2· depending on droplet application density. In laboratory behavioral bioassays, the attractiveness of MalEx droplets to male P. citrella was drastically reduced after 21 days of field aging. However, our laboratory investigation confirmed that 100% of males contacting MalEx droplets, aged up to 35 days in the field, were killed within 24 h. Direct observation of male P. citrella behavior in thefield confirmed that attracted males made contact with droplets. Control of P. citrella with MalEx should reduce the number ofrequired broadspectrum sprays for leafminer management inbothfieldandcitrus nurserysettings.

White haze (WH), a manifestation of extensive colonization of anamorphic smut fungi of the genus Tilletiopsis on the surface of apple fruit, has recently been described as a new postharvest disorder of the cultivar Elstar. This study shows that these fungi can also affect apple fruit of different cultivars prior to harvest, and therefore seriously compromise the quality of the produce in Northern Italy. In order to identify the Tilletiopsis taxa involved in the induction of WH in this region, 48 isolates, mainly derived from fruit samples, were analysed by DNA sequencing of the internal transcribed spacer region. Six haplotypes were identified that could be assigned to three different phylogenetic lineages, the T. washingtonensis group, the T. pallescens group and the Entylomataceae. More than 40% of the isolates were classified as T. washingtonensis which had not previously been associated with WH. Furthermore, this is the first study that reports the occurrence of this species on field-grown fruit samples. The extensive overgrowth of apple fruit by Tilletiopsis spp., appearing erratically in the last decade, may be a consequence of moist weather conditions and novel cultural practices, such as the use of hail nets and the intensive application of foliar nutrients.

We investigated the influence of temperature and infestation sequence on interspecific competition between two fruit flies: an invasive (Bactrocera invadens Drew, Tsuruta '' White, (B) and a native (Ceratitis cosyra Walker, C) (both Diptera: Tephritidae) species. Mango fruits [Mangifera indica L. (Anacardiaceae)] were co-infested with larvae at different constant temperatures (15, 20, 25, and 30 °C) and relative humidity of 50 ± 8%, using different infestation sequences at each temperature (BC together; BC/CB 1, 2, and 3 days apart). There were significant effects of competition in most experimental treatments, resulting in reduced larval survival, pupal mass, and adult emergence for both species. At most of the infestation/temperature combinations, C. cosyra was clearly the inferior competitor. The only exception was at 20 °C when the outcome depended on the sequence of infestation: no C. cosyra survived when the sequence was BC, but more C. cosyra than B. invadens survived when it was CB. At 15 °C, all C. cosyra larvae died, while the development of B. invadens was prolonged and adult emergence reduced. We conclude that resource pre-emption and fluctuations in temperature in mango agroecosystems help to explain observed shifts in dominance between B. invadens and C. cosyra on mango in many parts of Africa. The small window of competitive superiority for C. cosyra at 20 °C and CB infestation sequence, together with other factors such as fecundity and alternative hosts, may allow for co-existence in some environments.

A novel, visually-attractive bait station was developed in Hawaii for application of insecticidal baits against oriental fruit fly, Bactrocera dorsalis (Hendel), melon fly, Bactrocera cucurbitae (Coquillett), and Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (all Diptera: Tephritidae). The bait station developed represents a supernormal visual stimulus of papaya foliage and takes advantage of the flies' strong response to the high light-reflecting properties of yellow color and of their need for shelter, while fully protecting the bait against rainfall. Field studies revealed that the behavioral response of female fruit flies, in particular C. capitata and B. cucurbitae, to yellow-painted bait stations sprayed with GF-120 NF Naturalyte Fruit Fly Bait was significantly enhanced compared with similarly sprayed bait stations that mimicked the green color of fully grown papaya leaves. Field studies conducted with B. cucurbitae indicated that the period of bait attractiveness can be extended for at least 1 week after bait application due to the rain-fastness properties of the bait stations and the use of a visually-attractive color. Our studies provide the behavioral basis for the development of improved attract-and-kill bait stations for fruit flies in Hawaii. These devices also provide a standardized way of evaluating bait spray formulations, thus allowing for proper comparisons over time, across species, and among geographical areas.

Field studies in the role of bumblebees (Bombus spp.) in fruit tree pollination In 1969, 1970, 1973, 1975, and 1976 comparative studies were made concerning the frequentation of blossoming fruit trees by bumblebees and honeybees. The study areas were in the Main-Spessart district. Bumblebees and honeybees show different daily activity. On warm days bumblebees chiefly fly in the evening and somewhat less frequently in the morning. On such days honeybees are most active at noon-time, when bublebees hardly are. On cool days honeybees stop visiting blossoms, whereas bumblebees only postpone their main activity to the afternoon. Only in exceptional cases honeybees and bumblebees are equally active throughout a day. Bumblebee queens and workers show the same daily activity. Bumblebee queens visit two to three times as many blossoms as honeybees in the same lapse of time. Big and small species indicate no difference concerning the quickness of visiting flowers. Bumblebee workers are somewhat slower than queens, but still quicker than honeybees. As far as morello cherries are concerned, bumblebees shift more often from tree to tree and are less constant on certain varieties than honeybees. The most abundant bumblebees ascertained in the study area on fruit tree blossoms were the three big species with short probosces: B. lapidarius, B. lucorum, and B. terrestris. In May 1973 workers of the species B. pratorum, and B. terrestris/lucorum could be seen in a greater number on blossoming apples and morello cherries. As bumblebees are less constant in visiting certain varieties and less sensitive to low temperatures they can become of economic importance to certain plantations and in certain years. In case that the use of bumblebee colonies for pollinating fruit trees is planned, the species B. terrestris, B. lucorum, B. lapidarius, B. pratorum and B. hypnorum and recommended. Zusammenfassung In den Jahren 1969, 1970, 1973, 1975 und 1976 wurde der Besuch von bluhenden Obstbaumen (Malus silvestris, Prunus avium, Prunus cerasus) durch Hummeln und Honigbienen vergleichend untersucht. Die Untersuchungsgebiete lagen im Main-Spessart-Kreis (Nordbayern). Die Aktivitatszeiten von Hummeln und Bienen erganzen einander. An warmen Tagen fliegen die Hummeln verstarkt in den Abendstunden und etwas weniger haufig in den Morgenstunden. Die Hauptaktivitat der Bienen fallt an solchen Tagen in die Mittagsstunden, in denen die Hummeln kaum aktiv sind. Bei kuhlem Wetter stellen die Bienen den Blutenbesuch ein, wahrend die Hummeln ihre Hauptaktivitat in die Nachmittagsstunden verlagern. Nur in Ausnahmefallen zeigen Hummeln und Honigbienen eine gleiche tages-zeitliche Aktivitat. In ihrer Aktivitatsverteilung stimmen Hummelarbeiterinnen und Hummelkoniginnen uberein. Hummelkoniginnen besuchen in der gleichen Zeiteinheit wie Bienen zwei- bis dreimal so viele Bluten. Grose und kleine Arten zeigen keine Unterschiede in der Schnelligkeit des Blutenbesuchs. Arbeiterinnen sind im Blutenbesuch langsamer als die Koniginnen, aber noch immer schneller als Honigbienen. Die Hummeln wechseln auf Sauerkirschen schneller von Baum zu Baum und sind weniger sortenstetig als Honigbienen. Als haufigste Hummeln (62,4–99,5%) auf bluhenden Obstbaumen wurden im Untersuchungsgebiet die drei grosen, kurzrusligen Arten B. lapidarius, B. lucorum und B. terrestris ermittelt. Im Mai 1973 konnten Arbeiterinnen der Arten B. pratorum und B. terrestris/lucorum in groserer Zahl auf Apfel- und Sauerkirschbluten beobachtet werden. Auf Grund ihrer geringeren Sortenstetigkeit und ihrer Unempfindlichkeit gegen niedrige Temperaturen konnen die Hummeln in bestimmten Jahren und in bestimmten Anpflanzungen wirtschaftliche Bedeutung erlangen. Fur einen eventuellen Einsatz von Hummelvolkern zur Obstbaumbestaubung werden die Arten B. terrestris, B. lucorum, B. lapidarius, B. pratorum und B. hypnorum vorgeschlagen.

Results are given of field applications of 2 commercial Bacillus thuringiensis preparations for the control of the larvae of the winter moth Operophthera brumata and the summer fruit tree leaf roller Adoxophyes orana. Larvae of the summer generations were satisfactorily controlled by one of the preparations. The effect of both preparations on the larvae of the winter moth was still insufficient for practical use. Zusammenfassung Feldanwendungen von Bacillus thuringiensis-Praparaten zur Bekampfung der Larven des kleinen Frostspanners und des Apfelschalenwicklers Es wurde die Wirkung von zwei industriellen Bacillus thuringiensis-Praparaten auf die Larvalstadien des kleinen Frostspanners Operophthera brumata und des Apfelschalenwicklers Adoxophyes orana im Freiland untersucht. Beide Praparate wirkten auf die Larven des Frostspanners ungenugend. Dagegen fuhrte der Gebrauch von Dipel, einem der untersuchten Handelsprodukte, das auf einem kurzlich isolierten, sehr virulenten B. thuringiensis var. alesti Stamm basiert, zu guten Resultaten gegen die Sommergeneration von Adoxophyses orana.

Trials to control the fruit tree leaf roller Archips podana with pheromones The effectiveness and specificity of the pheromone mixtures of Adoxophyes orana and Archips podana was confirmed in trapping experiments in the field. In a 0,93 ha apple orchard near Bozen/Italy a trial was run to control Archips podana employing 40 traps with 1 mg of the pheromone mixture (cis- and trans-11-tetradecenylacetate 50: 50) in polyethylene capsules. Their attractancy lasted at least 7–8 weeks, being sufficient to cover one flight period. The fruit damage was reduced to 5,1%, untreated orchards suffering 20–30% attack. Zusammenfassung Die Wirksamkeit und weitgehende Spezifitat der fur Adoxophyes orana und Archips podana angegebenen Pheromonmischungen konnte in Feldversuchen bestatigt werden. In einer Apfelanlage von 0,93 ha bei Bozen wurden 40 Fallen mit Glycolfullung und je 1 mg der Mischung von cis- und trans-11-Tetradecenylacetat 50: 50 in Polyaethylenkapseln zur Bekampfung von Archips podana ausgebracht. Die Lockwirkung hielt mindestens 7–8 Wochen an und genugte zur Erfassung der Falter einer Flugperiode. Der Fruchtbefall wurde auf 5,1 % gesenkt gegenuber 20–30 % in unbehandelten Baumen.

Four lepidopterous species are gaining importance as pests of deciduous fruit trees in Central Province of Iran: Lyonetia clerckella L. (Lyonetiidae), not previously known as important fruit tree pest, is seriously damaging fruit trees in certain regions with cold climates at about 1000–2000 meters elevation. The larvae make irregular galleries on upper surface of the leaves, cutting secondary veins and causing leaf margins to burn. They overwinter as adults under the bark and produce 2–3 generations annually. Leucoptera scitella Zell. (Lyonetiidae) is most abundant in plains with long growing seasons. The larva causes a dark brown blotch on the upper surface of leaves. It is easily distinguished by its spindle shape and three characteristic protrusions on the third thoracic and first and second abdominal segments. There are 3–4 generations annually. Lythocoletis (Phyllonorycter) turanica Ger. (Gracillariidae) is the most abundant and destructive, particularly in areas with hot, dry summers. The larva feeds mostly on parenchyma of upper surface of leaves, leaving veins and upper cuticle. It overwinters as full grown larva in fallen leaves and produces up to 5 generations annually. Phyllonorycter blancardiella F. is closely related but its larva feeds on under surface of leaves. Zusammenfassung Vier Blattminierer als Obstbauschadlinge in Zentral-Iran 4 blattminierende Schadlingsarten erlangen im Zentral-Iran als Schadlinge von Obstbaumen Bedeutung: Lyonetia clerckella L. (Lyonetiidae), bisher als wichtiger Obstschadling noch unbekannt, verursacht Schaden hauptsachlich in kalteren Klimazonen von 1000-2000 m Hohe. Die Raupen stellen unregelmaβige Minengange im Gewebe der Blattoberseite her, wobei sie sekundare Blattadern durchschneiden und eine Braunung des Blartrandes verursachen. Sie uberwintern als Adulte unter der Rinde und haben 2–3 Generationen jahrlich. Leucoptera scitella Zell. (Lyonetiidae) tritt am starksten in Gebieten mit langer Vegetationszeit auf. Die Raupe stellt eine dunkelbraune Blase innerhalb der Blattoberflache her. Sie ist durch ihre spindelformige Gestalt sowie 3 charakteristische Vorsprunge am 3. Thorakal- sowie 1. und 2. Abdominalsegment leicht erkenntlich. Die Art bildet 3–4 Generationen jahrlich. Lythocoletis (Phyllonorycter) turanica Ger. (Gracillariidae) ist die haufigste und schadlichste der 4 Arten. Sie bevorzugt Gebiete mit heiβen, trockenen Sommern. Die Raupe friβit vornehmlich im Parenchym der Blattoberseite, wobei sie Epidermis und Adern verschont. Sie uberwintert voll erwachsen in abgefallenen Blattern und bringt es auf 5 Generationen jahrlich. Phyllonorycter blancardiella F. ist sehr nahe mit der vorigen Art verwandt, doch zer-storen ihre Raupen die Blattunterseite.

The effects of cuticular crack surface area and inoculum density on the infection of nectarine fruits by conidia of Monilinia laxa were studied using artificial inoculations with conidial suspensions and dry airborne conidia during the 2004 and 2005 seasons, respectively. Additionally, the effect of ambient humidity on fruit infection was evaluated in the 2005 experiment. An exploratory analysis indicated that (i) ambient humidity did not significantly explain the observed variability of data, but that (ii) the incidence of fruit infection increased both with increasing inoculum density and increasing surface area of cuticular cracks. The product of these two variables represented the inoculum dose in the cracks, and was used as a predictor of fruit infection in the model. Natural infection in the orchard was observed to increase throughout the season in both 2004 and 2005. The relationship between the probability of fruit infection by M. laxa and the artificially inoculated dose in the cuticular cracks was well described by a logistic regression model once natural inoculum density was taken into account (pseudo R2 = 65%). This function could be helpful for estimating the risk of fruit infection at harvest based on fruit size and natural inoculum density.

We studied, under laboratory conditions, demographic parameters of adult Mediterranean fruit flies, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) (medfly), obtained from three sweet orange varieties, lemon, and bitter oranges. These data were combined with immature developmental rates and survival on the same hosts to estimate host-specific population parameters. Pairs of newly emerged adults from each citrus variety were held individually in transparent plastic cages, and females were allowed to oviposit in either red domes (artificial, pre-punctured plastic oviposition devices), or intact, whole citrus fruits. We found strong effects of larval host (citrus fruits) on adult longevity and fecundity. In all five citrus varieties, females did not manage to deposit eggs into fruit pulp. The proportion of eggs laid in either the flavedo or albedo area of the fruit peel differed depending on the citrus variety. In all cases except bitter oranges, females oviposited fewer eggs in citrus fruits than in the artificial oviposition substrates, suggesting that most citrus fruits cause a significant reduction in the reproductive potential of medflies. Negative correlations were found between fecundity and (a) the density of oil glands, and (b) the amount of essential oils in the flavedo area of citrus fruits. There was no correlation between fecundity and other fruit physical characteristics, such as resistance of fruit peel to pressure and thickness of the flavedo. Apparently, resistance of citrus fruits to medfly infestation is directly related to citrus essential oils. The intrinsic rate of increase (r) was higher in bitter oranges than in the three sweet orange varieties tested. A negative r was estimated for flies that developed and oviposited in lemons, indicating a tendency for population decrease in this host. The suitability of citrus fruits for medfly development and the practical implications of our findings for management of medflies in citrus orchards are discussed.

The long juvenile period of trees delays the breeding of new varieties. Flowering begins within 5–10 years in most cultivated forest trees under intensive management, but can take up to 40 years in some species and environmental conditions. To accelerate the breeding process several agrotechnical and biotechnical methods have been developed. Knowledge about genes controlling flower initiation in model plants like Arabidopsis thaliana, and identification of homologous genes in trees, have led to new possibilities for early-flower induction. Overexpression of MADS-box and other floral regulatory genes resulted in early flowering in some tree species and/or varieties. However, these methods have not yet been shown to enable the production of fertile, viable or normal gametes and progeny; developmental research towards these ends is therefore of high priority. A breeding scheme has been developed to use early flowering trees for the introduction of genes from wild species that would allow several backcrosses to occur in only a few years, and to produce at the end a non-transgenic improved variety. Research to develop practical early flowering methods could lead to several new methods for breeding and biotechnology.

33 Pag., 3 Tabl., 6 Fig. The definitive version is available at www.blackwell-synergy.com, Although pollination is essential for both seed and fruit set in most angiosperms, even after an adequate pollination, only a fraction of the flowers develop into fruits. The role played by floral traits on reproductive success is well known, but the possible influence of pistil traits has been overlooked, probably because of the difficulty of non-destructive pistil examination. The aim of this work was to examine the influence of several pistil traits on reproductive success in apricot (Prunus armeniaca). For this purpose, in a population of individually labelled flowers, the styles were cut off once the pollen tubes had reached the ovary but prior to the achievement of fertilisation. This approach allowed relating several morphological and physiological pistil parameters in the dissected styles and stigmas to the subsequent set or abscission of the corresponding ovary that remained in the plant. Under the same pollination conditions, the flowers that finally set a fruit show a larger stigmatic area and a higher number of pollen grains, pollen tubes growing along the style and xylem vessels surrounding the transmitting tissue than flowers that abscise before the establishment of fruit set. Furthermore, starch is present in the transmitting tissue of the style in all the flowers that develop into fruits but only in half of the flowers that abscise. The examined pistil traits established prior to fertilisation are related to flower fate, suggesting that the capacity of a flower to become a fruit could be preconditioned at anthesis., Financial support for this research was provided by Ministerio de Ciencia e Innovación-FEDER (Plan Nacional de Investigación Científica, Desarrollo e Innovación Tecnológica, project grants: AGL2006-13529-C02-00/AGR and AGL2007-60130/AGR) and by Grupo de Excelencia A-43 (Gobierno de Aragón).

Apple, Malusdomestica, is the most important fruit grown within the tem- perate zonobiome. It is attacked by both fruit-damaging and leaf-damaging lepidopteran pest insects, which require regular control such as the carpopha- gous codling moth, Cydia pomonella, or frequent control such as the phyllopha- gous apple leaf miner, Lyonetia clerkella. As many environmentally friendly pest control tactics are only effective at low levels of infestation, host plant resistance is a promising future component of integrated pest management systems, but knowledge is still lacking on such genetically based approaches against lepidopteran pests. The aim of the study was to identify molecular markers linked to C. pomonella and L. clerkella resistance or susceptibility in commercial apple as well as markers linked to selected fruit traits. The number of C. pomonella-infested fruits and the number of L. clerkella mines were quan- tified as measures of apple resistance or susceptibility to the studied moth spe- cies. Herbivore surveys on 160 apple genotypes, representing a segregating F1 cross of the apple cultivars 'Fiesta' and 'Discovery', were carried out during two consecutive years and at two sites in Switzerland. Broad-sense heritability was 29.9% (C. pomonella), 18.2% (L. clerkella), 21.9% (fruit number) and 16.6% (fruit diameter). A subsequent analysis identified a quantitative trait locus (QTL) associated to C. pomonella susceptibility on the Discovery linkage group 10. The closest marker to this QTL was the random amplified poly- morphic marker Z19-350. No significant QTL was identified for resistance to L. clerkella. A putative QTL associated to fruit number was identified on Fiesta linkage group 12. The presented QTL associated with C. pomonella susceptibil- ity and the putative QTL linked to fruit number may facilitate marker-assisted breeding of resistant apple cultivars with cropping traits desirable for optimal fruit production.

Most tropical fruit flies only lay into mature fruit, but a small number can also oviposit into unripe fruit. Little is known about the link between adult oviposition preference and offspring performance in such situations. In this study, we examine the influence of different ripening stages of two mango, Mangifera indica L. (Anacardiaceae), varieties on the preference and performance of the Oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), a fly known to be able to develop in unripe fruit. A series of laboratory-based choice and no-choice oviposition experiments and larval growth trials were carried out. The results demonstrated a general preference by B. dorsalis for mango variety Oakrong over variety Namdorkmai, but in most cases the single largest dependent variable influencing results was fruit ripening stage. Ripe and fully-ripe mangoes were most preferred for oviposition by B. dorsalis. In contrast, unripe mango was infrequently used by ovipositing females, particularly in choice trials. Consistent with the results of oviposition preference, ripe and fully-ripe mangoes were also best for offspring survival, with a higher percentage of larval survival to pupation and shorter development times in comparison to unripe mango. Changes in total soluble solids and pericarp toughness correlated with changing host use across the ripening stages. Regardless of the mango variety or ripeness stage, B. dorsalis had difficulty penetrating the pericarp of all fruits offered in experiments. Larval survival was also often poor in all experiments. We discuss the possibility that there may be differences in the ability of laboratory and wild flies to penetrate fruit for oviposition, or that in the field flies more regularly utilize natural fruit wounds as oviposition sites.

Prune dwarf virus (PDV), a pathogen of stone fruit trees worldwide, shows a great variability in its biological, serological and molecular properties. The coat protein sequences of ten PDV variants from different stone fruit tree species in Turkey were determined. The sequence for each variant was 657 nucleotides in length. The phylogenetic analyses of the sequences of the Turkish variants and of additional sequences of other PDV variants from international databases indicate the existence of four groups of PDV variants: one contains cherry variants that differs in group specific conserved amino acids; a second contains one apricot and cherry variants, most members of the group being Turkish variants; a third contains mixed variants from cherry, peach, plum trees and an almond tree; and a fourth contains only variants from almond trees. Based on their hosts, we propose the nomenclature of these groups as cherry I, cherry II, mixed and almond groups, respectively.

The developmental time and survival of immature stages of Neoseiulus californicus were studied at nine constant temperatures (12, 16, 24, 24, 28 32, 36, 38 and 40°C), 60-70% RH, and a photoperiod of 16 : 8 (L : D) h. The total mortality of immature N. californicus was lowest at 24°C (4.5%) and highest at 38°C (15.2%). The total developmental time decreased with increasing temperature between 12°C (18.38 days) and 32°C (2.98 days), and increased beyond 32°C. The relationship between the developmental rate and temperature was fitted by five nonlinear developmental rate models (Logan 6, Lactin 1, 2 and Briere 1, 2). The nonlinear shape of temperature development was best described by the Lactin 1 model (r 2 = 0.98). The developmental variation of each stage was well described by the three-parameter Weibull distribution model (r 2 = 0.91-0.93). The temperature-dependent developmental models of N. californicus developed in this study could be used to determine optimal temperature conditions for its mass rearing, to predict its seasonal population dynamics in fruit tree orchards or greenhouse crops, or to develop a population dynamics model of N. californicus.