Abraham Havron

Selection for pesticide resistance in Aphytis. I : A. holoxanthus, a parasite of the Florida red scale

Field‐collected populations of Aphytis holoxanthus DeBach (Hymenoptera: Aphelinidae), a parasite of Chrysomphalus aonidum (L.) (Homoptera: Diaspididae), were tested for malathion and for azinphosmethyl tolerance, and selected for increased resistance. Initial tolerance for malathion was not significantly different between populations, and could not be significantly increased by 30 selection cycles. Two field populations showed relatively high levels of azinphosmethyl tolerance, which were further increased by selection to 24–48 times that of a susceptible laboratory population.

Release of Sphecophaga orientalis Donovan (Hymenoptera: Ichneumonidae: Cryptinae) in New Zealand as a possible ‘new association’ biocontrol agent for the adventive social wasps Vespula germanica (F.) and Vespula vulgaris (L.) (Hymenoptera: Vespidae: Vespinae).

The hornet (Vespa spp.) parasitoid Sphecophaga orientalis Donovan was imported into New Zealand from Israel as a possible ‘new association’ biological control agent for the adventive pestiferous social wasps Vespula germanica (F.) the German wasp, and V. vulgaris (L.) the common wasp. In quarantine, when adult wasps were absent, S. orientalis propagated prolifically on sealed brood of both species of wasp. In the field, parasitoid cocoons were formed in four of eight German wasp nests inoculated with the parasitoid, but there was no attack on 27 inoculated nests of the common wasp. Whether S. orientalis has established is unknown. If worker common wasps prevent attack or remove developing parasitoid larvae from cells, it is possible that parasitoids may be able to successfully attack the small nests constructed by queens in spring, before workers emerge. A major decline in wasp populations over the release period may have decreased the likelihood of establishment because of fewer small spring-founded nests available for attack.

Parasitization ofVespa orientalis nests bySphecophaga vesparum curtis in Southern Israel (Hymenoptera: Vespidae, Ichneumonidae)

Vespa orientalis F. (Hymenoptera: Vespidae), a major pest of apiculture, indirectly disrupts pollination of fruit and vegetable crops, and constitutes a public health menace. Control methods are imperfect, labor-intensive, and entail the use of medically and environmentally dangerous chemicals. A parasitic wasp,Sphecophaga vesparum Curtis (Hymenoptera: Vespidae), has been found to attack a large proportion (up to 100%) of observedV. orientalis nests in southern Israel. Within these nests, 2.5–95.1% of host cells were parasitized by three to seven individuals. Heavily parasitized nests showed considerable reductions in the proportion of queen cells.

Abstracts of papers presented at the 3rd conference on agricultural entomology

S OF PAPERS P R E S E N T E D AT THE 3rd C O N F E R E N C E ON A G R I C U L T U R A L ENTOMOLOGY