the aphidiine parasitoids (hym., braconidae) attacking the pest aphids on various pome and stone fruit trees in different parts of iranwere studied. a total of 13 species belonging to seven genera of aphid parasitoids were identified in association with 17 aphid species on 10 different species of fruit trees. sixty nine tritrophic associations were detected from the studied area of which 25 ass...

Abstract To improve exclusion systems for fruit trees, insect nets of various types were evaluated their permeability to different beneficial and pest species, under laboratory field conditions. Pests studied the apple maggot, Rhagoletis pomonella (Diptera: Tephritidae) spotted wing drosophila, Drosophila suzukii Drosophilidae). Beneficials Aphidoletes aphidimyza Cecidomyiidae), Aphidius matric...

Abstract Drought events have the potential to mediate tri-trophic interactions. Changes in plant quality influence herbivore performance, which affects prey availability and for natural enemies. Parasitoid wasps are particularly vulnerable these changes since their development is inextricably linked that of prey. However, we know little about indirect effects water limitation on parasitoid espe...

A series of bioassays were conducted to determine the relative toxicities and residual activities of insecticides labeled for use in blueberry (Vaccinium corymbosum L.) on natural enemies, to identify products with low toxicity or short duration effects on biological control agents. In total, 14 insecticides were evaluated using treated petri dishes and four commercially available natural enemi...

Relationships between agents in multitrophic systems are complex and very specific. Insect-transmitted plant viruses are completely dependent on the behaviour and distribution patterns of their vectors. The presence of natural enemies may directly affect aphid behaviour and spread of plant viruses, as the escape response of aphids might cause a potential risk for virus dispersal. The spatio-tem...

Heritable symbionts are common in insects with many contributing to host defence. Hamiltonella defensa is a facultative, bacterial symbiont of the pea aphid, Acyrthosiphon pisum that provides protection against the endoparasitoid wasp Aphidius ervi Protection levels vary among strains of H. defensa that are differentially infected by bacteriophages named APSEs. By contrast, little is known abou...

The role of volatile stimuli in the host-searching behaviour of the two parasitoid species Lysiphlebus testaceipes Cresson and Aphidius colemani Viereck (Hymenoptera: Braconidae) was studied in relation to the host Aphis gossypii Glover (Homoptera: Aphididae) on cucumber plants, Cucumis sativa L. (Cucurbitaceae). Experiments were carried out in the laboratory in a wind tunnel, exposing individu...

Parasitoid host selection behaviour has been extensively studied in experimentally simplified tritrophic systems formed by one single food chain (one plant, one herbivore and one parasitoid species). The "Mother knows best" hypothesis predicts that the preference for a plant-host complex should be positively correlated with plant quality for offspring performance. We studied the host selection ...

Ecologically important traits of insects are often affected by facultative bacterial endosymbionts. This is best studied in the pea aphid Acyrthosiphon pisum, which is frequently infected by one or more of eight facultative symbiont species. Many of these symbiont species have been shown to provide one ecological benefit, but we have little understanding of the range of effects that a single st...

1049-9644/$ see front matter 2010 Elsevier Inc. A doi:10.1016/j.biocontrol.2010.05.013 * Corresponding author. E-mail address: [email protected] (J. Silve Ants frequently protect honeydew-excreting hemipterans from their natural enemies in exchange for food, and these interactions can have a negative impact on biological control. Invasive ant species, such as the Argentine ant, Linepithe...