Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Aspects of the biology of Hyssopus pallidus (Hymenoptera: Eulophidae), a parasitoid of the codling moth (Lepidoptera: Olethreutidae).

Abstract

Hyssopus pallidus is a gregarious ectoparasitoid that attacks 2nd-instar to prepupal Cydia pomonella. Host attack includes initial probing, host paralysis, oviposition from 2 to 30 eggs per host, nondestructive host feeding, and brood guarding. The development rate of the immature stages increased with temperature, with a life cycle minimum threshold of 10°C and a maximum threshold of 30-35°C. Female development time from oviposition to adult emergence decreased from 39 days at 15°C to 12 days at 30°C. Female longevity decreased from 115 days at 15°C to 40 days at 30°C, and was significantly increased by provision of honey, but not by host feeding. Lifetime fecundity was estimated to be 172 eggs, with a female-biased progeny sex ratio of 0.58 males and 13.02 females per host. The presence of a 1st female guarding her brood did not prevent or influence the level of superparasitism by a 2nd female; experienced females were less likely to superparasitize than naive females, and superparasitism was most frequent among broods 24 h old. The host specificity of H. pallidus was tested using no-choice tests with 5 common orchard Microlepidoptera. It successfully attacked and developed on 100% of C. pomonella larvae and 60% of Argyrotaenia citrana larvae. It paralysed but did not oviposit on 20% of Pandemis pyrusana larvae, and it did not attack Choristoneura rosaceana or Amyelois transitella.