Jerry V. Cross

Components of male aggregation pheromone of strawberry blossom weevil, Anthonomus rubi herbst. (Coleoptera:Curculionidae).

The strawberry blossom weevil, Anthonomus rubi, is a major pest of strawberries in the United Kingdom and continental Europe. As part of a project to develop noninsecticidal control methods, the pheromone system of this species was investigated. Comparison of volatiles produced by field-collected, overwintering individuals of each sex led to identification of three male-specific compounds—(Z)-2-(3,3-dimethylcyclohexylidene)ethanol, (cis)-1-methyl-2-(1-methylethenyl)cyclobutaneethanol, and 2-(1-methylethenyl)5-methyl-4-hexen-1-ol (lavandulol)—in amounts of 6.1, 1.2, and 0.82 μg/day/male. The first two compounds are components of the aggregation pheromone of the boll weevil, Anthonomus grandis, grandlure II and grandlure I, respectively. Grandlure I was the (1R,2S)-(+) enantiomer and lavandulol was a single enantiomer, although the absolute configuration was not determined. Trace amounts of the other two grandlure components (Z)-(3,3-dimethylcyclohexylidene)acetaldehyde (grandlure III) and (E)-(3,3-dimethylcyclohexylidene)acetaldehyde (grandlure IV) were also detected. (E,E)-1-(1-Methylethyl)-4-methylene8-methyl-2,7-cyclo-decadiene (germacrene-D), a known volatile from strawberry plants, Fragaria ananassa, was collected in increased amounts in the presence of pheromone-producing weevils. Male weevils only produced pheromone on F. ananassaand not on scented mayweed, Matracaria recutita, or cowparsley, Anthriscus sylvestris, although these are known food sources. In field trials using various combinations of synthetic grandlures I, II, III, and IV and lavandulol, significantly more weevils were caught in traps baited with blends containing grandlure I and II and lavandulol than in those baited with blends without lavandulol or unbaited controls. Addition of grandlure III and IV had no significant effect on attractiveness. Horizontal sticky traps were found to be more effective than vertical sticky traps or standard boll weevil traps. In mid-season females predominated in the catches, but later more males than females were trapped.

Attraction of Male European Tarnished Plant Bug, Lygus rugulipennis to Components of the Female Sex Pheromone in the Field

Previous work showed that females of the European tarnished plant bug, Lygus rugulipennis Poppius (Heteroptera: Miridae), produced three chemicals, hexyl butyrate, (E)-2-hexenyl butyrate, and (E)-4-oxo-2-hexenal, and that these were suspected to be components of the female sex pheromone. In field experiments, traps baited with blends of these chemicals dispensed from polyethylene vials and sachets failed to catch significant numbers of males. Here, we report more recent field experiments in which the chemicals were released from glass microcapillary tubes. A blend of hexyl butyrate and (E)-4-oxo-2-hexenal was significantly attractive to male L. rugulipennis. In addition, whereas the mixture of all three components attracted fewer L. rugulipennis males, this tertiary blend captured significantly greater numbers of males of the congeneric species Lygus pratensis than the binary mixture. The possible reasons for the success of the microcapillaries compared with other dispensers are discussed.

Trapping Dasinuera mali (Diptera: Cecidomyiidae) in Apples

Abstract The midgeDasineura mali (Kieffer) (Diptera: Cecidomyiidae) is a significant pest of apples (Malus spp.), and the recent identification of the female sex pheromone is enabling new direct control tactics to be considered. Direct control using male suppression will require knowledge of the frequency of multiple mating, dispersal and colonization rates, and the efficiency of male removal. Males were able to mate up to five times, with a mean of 2.7 times when presented in a 10 female-to-1 male group, designed to simulate male suppression. Male catch in response to the pheromone loading was curvilinear over 4 orders of magnitude from 3 μg to 30 mg on rubber septa. Trapping using a high-dose pheromone lure was combined with oil-based traps similar to the inexpensive New Zealand “Lynfield trap” used for tephritid surveillance, to test male suppression in young orchard blocks at 500 traps per ha. Monitoring traps indicated 96% lower catch in the treated plots compared with control plots, over 137 d. However, a lack of shoot tip infestation in both treated and untreated plots indicated limited colonization and prevented an assessment of potential population suppression. Furthermore, a contribution to these results from communication disruption cannot be ruled out. Replicated transects of frequency of infested shoots from a mature orchard across the adjacent young block confirmed that colonization by ovipositing females was essentially limited to the first 30 m.

Arthropod pests of currant and gooseberry crops in the U.K.: their biology, management and future prospects

1 Approximately 10–12 species of Ribes plants are cultivated for fruit production, mainly blackcurrants, red‐ and whitecurrants and gooseberries. These crops are increasingly recognized as rich sources of vitamin C and anthocyanins, with production rising by 24% in Europe subsequent to 1998. To date, research into insect pests of Ribes has been fragmented, with little appreciation of how changes in climate and agronomic practices affect biology. 2 We review 12 key pests of currant and gooseberry crops in Northern Europe, with specific emphasis on their biology and current management options. These are blackcurrant leaf curling midge Dasineura tetensi, blackcurrant sawfly Nematus olfaciens, common gooseberry sawfly Nematus ribesii, European permanent currant aphid Aphis schneideri, redcurrant blister aphid Cryptomyzus ribis, currant–sowthistle aphid Hyperomyzus lactucae, European gooseberry aphid Aphis grossulariae, woolly vine scale Pulvinaria vitis, common green capsid Lygocoris pabulinus, winter moth Operophtera brumata, clear wing moth Synanthedon tipuliformis and blackcurrant gall mite Cecidophyopsis ribis. 3 It is anticipated that global climate change could lead to increases in the incidence of some aphids through increased overwintering survival and longer seasonal activity. Moreover, changes in management practices such as increased cropping densities (from 5400 ha−1 to 8700 ha−1) and machine harvesting could lead to pest outbreaks through optimal microhabitats and increased susceptibility to pest colonization. 4 Future management options are considered, focusing on integrated pest management approaches, including behaviour‐manipulating semiochemicals, predictive models, biocontrol and improved plant resistance through breeding.

Influence of commercial fungicides on the germination, growth and virulence of four species of entomopathogenic fungi

Abstract The influence of 15 commercially available fungicides on the germination, growth and virulence of Metarhizium anisopliae, Beauveria bassiana, Isaria fumosorosea, and Lecanillium longisporum was evaluated. The influence of the fungicides on conidial germination was dependant on the fungicide type and dose. Most fungicides retarded conidial germination of all the fungi tested at 10× and at the recommended rate of application, however, their toxicity declined at lower concentrations. Most of the fungicides inhibited mycelial growth of B. bassiana, whereas L. longisporum growth was unaffected. Only two and eight fungicides influenced mycelial growth of I. fumosorosea and M. anisopliae, respectively. None of the fungicides influenced the virulence of B. bassiana and L. longisporum, however, tolylfluanid and azoxystrobin reduced the virulence of M. anisopliae and I. fumosorosea, respectively. These studies clearly show that certain fungicides have the potential to inhibit germination of entomopathogenic fungi in vitro but appear to have little or no effect on their virulence against target insects.

Arthropod ecosystem services in apple orchards and their economic benefits

Apple is grown as a long‐term perennial crop and orchards provide relatively stable ecological habitats. Only a small proportion of the diverse fauna of arthropods that can inhabit the orchard ecosystem are important pests, the majority of species being minor pests, beneficial or benign. In this paper, the interacting ecosystem services provided by five contrasting naturally occurring arthropod groups in cool temperate apple orchards are reviewed, and their economic benefits broadly quantified. These are:The roles of bees and other insects in apple pollination increasing yields and fruit quality, the economic value of which may be significantly underestimated. Naturally occurring, pesticide‐resistant phytoseiid predatory mites and their role in regulating phytophagous mites. They eliminate the need for 1–2 acaricide sprays per annum and the risk of acaricide resistance. The earwig Forficula auricularia L. and its role in regulating several important apple pests. There is great variability in populations between orchards for reasons not fully understood. It is estimated that F. auricularia reduces insecticide applications by 2–3 per annum and reduces pest damage. Mutualism between the common black ant Lasius niger (L.) and important pest aphids, the roles of competitors, natural and artificial food sources, and ant exclusion in disrupting mutualism which can foster biocontrol of aphids by generalist predators so greatly reducing the need for sprays. Beneficial epigeic arthropods and their role in predating the soil dwelling life stages of insect pests. These contribute to the control of pest populations although the level of suppression is not consistent depending on several ecological factors.

The common black ant, Lasius niger (Hymenoptera: Formicidae), as a vector of the entomopathogen Lecanicillium longisporum to rosy apple aphid, Dysaphis plantaginea (Homoptera: Aphididae).

The potential for common black ant Lasius niger workers to vector conidia of the entomopathogenic fungus Lecanicillium longisporum to colonies of the rosy apple aphid Dysaphis plantaginea was assessed in laboratory and field experiments. Scanning electron microscope studies showed that L. niger workers which were artificially contaminated with L. longisporum conidia, carried conidia primarily on their tarsae but also on antennae and mandibles. Neither L. niger workers nor larvae were susceptible to infection with L. longisporum. Workers which were artificially contaminated with conidia of L. longisporum initiated infection in colonies of healthy D. plantaginea on apple. Mortality due to L. longisporum was recorded as 68.3, 30.8 and 3.7% of aphids under laboratory, semi-field and field conditions, respectively.

(2S,8Z)-2-Butyroxy-8-heptadecene: Major Component of the Sex Pheromone of Chrysanthemum Gall Midge, Rhopalomyia longicauda

The sex pheromone of the chrysanthemum gall midge, Rhopalomyia longicauda (Diptera: Cecidomyiidae), the most important insect pest in commercial plantations of chrysanthemum, Dendranthema morifolium (Ramat.) Tzvel., in China, was identified, synthesized, and field-tested. Volatile chemicals from virgin females and males were collected on Porapak in China and sent to the United Kingdom for analysis. Coupled gas chromatographic–electroantennographic detection (GC-EAG) analysis of volatile collections from females revealed two compounds that elicited responses from antennae of males. These compounds were not present in collections from males. The major EAG-active compound was identified as 2-butyroxy-8-heptadecene by gas chromatographic (GC) retention indices, mass spectra, in both electron impact and chemical ionization modes, hydrogenation, epoxidation, and derivatization with dimethyldisulfide. The lesser EAG-active compound was identified as the corresponding alcohol. The ratio of butyrate to alcohol in the collections was 1:0.26. Racemic (Z)-8-heptadecen-2-ol and the corresponding butyrate ester were synthesized from (Z)-7-hexadecenyl acetate, and the synthetic compounds found to have identical GC retention indices and mass spectra to those of the natural, female-specific components. Analysis of the volatile collections on an enantioselective cyclodextrin GC column showed the natural pheromone contained (2S,8Z)-2-butyroxy-8-heptadecene. Field tests showed that rubber septa containing racemic (Z)-2-butyroxy-8-heptadecene were attractive to R. longicauda males. The (naturally occurring) S-enantiomer was equally as attractive as the racemate, while the R-enantiomer was not attractive to males, and did not inhibit the activity of the S-enantiomer. The attractiveness of the butyrate was significantly reduced by the presence of even small amounts of the corresponding alcohol.

Fermentation for Disinfesting Fruit Waste From Drosophila Species (Diptera: Drosophilidae)

Abstract Economic losses in a range of fruit crops due to the Drosophila suzukii (Matsumura) have become severe. Removal and treatment of fruit waste, which may harbor D. suzukii, is a key step in preventing reinfestation of fruit production. Natural fermentation for disinfesting fruit wastes from D. suzukii was examined at ambient air temperatures of 12–20 °C. Soft and stone fruit wastes infested with eggs, larvae, and pupae of Drosophila melanogaster (Meigen) or D. suzukii were placed in sealed vessels containing fruit wastes, and samples were retrieved at intervals and tested for the emergence of adults. Mean temperatures of the fruit waste in the sealed vessels during fermentation were 15–23 °C. Fermentation for 3 d was effective in disinfesting waste from different life stages of D. suzukii. Treatment for 4 d also ensured that the waste was free of viable life stages of D. melanogaster, which could be used as an indicator species for disinfestation of waste from D. suzukii owing to its greater tolerance of fermentation. The O2 concentration of the headspace air in the vessels became undetectable after 13–16 h, with a corresponding increase in CO2 concentration, which exceeded 80% vol/vol. The resulting hypoxia and hypercapnia may explain the efficacy of the fermentation treatment in disinfesting the waste. Fermented fruit remained attractive to D. suzukii and retained its capacity to rear a life cycle. Covering or mixing fermented fruit with a sufficient depth (0.1 m) or volume (×9) of soil or coir prevented the reinfestation of treated waste.

Semiochemical-based pest insect management in strawberry and raspberry

Introduction: For many insect species, pheromones and host plant volatiles are of major importance in mate finding and host plant location. Therefore, there is potential for using these interactions to develop new strategies and effective control measures. The strawberry blossom weevil (Anthonomus rubi), the European tarnished plant bug (Lygus rugulipennis) and the raspberry beetle (Byturus tomentosus) cause large losses (10->80%) in both conventional and organic strawberry and raspberry production. We investigated whether the natural semiochemical mechanisms of these key pests can be exploited to develop effective traps for their management through mass trapping. Methods: Attractive traps and lures with host plant volatiles and pheromones were developed and combined into a “multitrap” for management of these pests simultaneously. These traps were deployed within and around the perimeters of the soft berry fields. Insect catches were evaluated according to species, habitat and environmental variables. Plant damage was also assessed. Results/Conclusion: For both crops it was possible to combine lures so that different targeted insect species were caught in the same trap simultaneously, but optimal insect traps in strawberry were not the same as in raspberry. Perimeter traps and multiple traps placed inside the plantations showed the potential to reduce pest numbers and subsequent fruit damage. In addition, bycatch of non-targeted invertebrate species were low. Thus, it is possible to develop new plant protection strategies by using these techniques. In this paper we will discuss the benefits and difficulties in using these techniques as part of integrated or organic pest management.