Beginning in 1993, Florida’s citrus industry has been invaded by citrus leafminer (Phyllocnistis citrella Stainton, Lepidoptera: Gracillariidae), brown citrus aphid (Toxoptera citricida Kirkaldy, Homoptera: Aphididae), and the Asian citrus psylla (Diaphorina citri Kuwayama, Homoptera: Psyllidae). The source(s) of these pests remain unknown but other countries in the Caribbean, as well as Centra...

Performance of oleander aphid (Aphis nerii Boyer de Fonscolmbe) and large milkweed bug (Oncopeltus fasciatus Dallas) on 21 species of Asclepias was evaluated in a two-year field study. Season-long pest and beneficial insect population growth was monitored. Plant quality ratings also were obtained. Relative numbers of Monarch butterfly (Danaus plexippus (Linnaeus)) larvae were also recorded. All...

Aphids commonly harbour facultative bacterial endosymbionts and may benefit from their presence through increased resistance to parasitoids. This has been demonstrated for Hamiltonella defensa and Serratia symbiotica, while a third common endosymbiont, Regiella insecticola, did not provide such protection. However, this symbiont was recently detected in a highly resistant clone of the peach-pot...

Temperature variation is an important factor determining the outcomes of interspecific interactions, including those involving hosts and parasites. This can apply to variation in average temperature or to relatively short but intense bouts of extreme temperature. We investigated the effect of heat shock on the ability of aphids (Aphis fabae) harbouring protective facultative endosymbionts (Hami...

Aphid species feeding on lettuce occupy distinct feeding sites: the lettuce aphid Nasonovia ribisnigri prefers to feed on heart leaves, whereas the potato aphid Macrosiphum euphorbiae feeds only on outer leaves. The aphid parasitoid Aphelinus abdominalis, known to be able to regulate M. euphorbiae on many crops, has recently been indicated as a promising biocontrol candidate also for use agains...

PREMISE OF STUDY Although there is increasing recognition of the effects of plant intraspecific diversity on consumers, the mechanisms by which such effects cascade-up to higher trophic levels remain elusive. METHODS We evaluated the effects of plant (lima bean, Phaseolus lunatus) intraspecific diversity on a suite of insect herbivores (leaf-chewers, aphids, and seed-eating beetles) and their...

Increasing temperature and CO2 concentrations can alter tritrophic interactions in ecosystems, but the impact of increasingly severe drought on such interactions is not well understood. We examined the response of a wheat-aphid-parasitoid system to variation in water-deficit stress levels. Our results showed that arid area clones of the aphid, Sitobion avenae (Fabricius), tended to have longer ...

Decline in landscape complexity owing to agricultural intensification may affect biodiversity, food web complexity and associated ecological processes such as biological control, but such relationships are poorly understood. Here, we analysed food webs of cereal aphids, their primary parasitoids and hyperparasitoids in 18 agricultural landscapes differing in structural complexity (42-93% arable...

the grain aphid, sitobion avenae (hemiptera: aphididae) is one of the injuriously important pests of wheat and praon volucre (hymenoptera: braconidae) is one of its major parasitoids in iran. in this research, thermal requirements of the grain aphid and its parasitoid were evaluated at six constant temperatures (10, 15, 20, 25, 27.5 and 30 °c), 60 ± 5 % relative humidity and a photoperiodicity ...

This study aimed to evaluate the quality of the aphid Myzus persicae (Sulzer), Lipaphis erysimi (Kaltenbach) and Brevicoryne brassicae (L.) as hosts for the parasitoid Diaeretiella rapae (McIntosh). Parasitization by D. rapae was higher on M. persicae than on L. erysimi and B. brassicae. The time of development of D. rapae from egg to mummy or egg to adult male or female were shorter on M. pers...