Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

The parasitoid complex of three noctuids (Lep.) in a northern Florida cropping system: seasonal occurrence, parasitization, alternate hosts, and influence of host-habitat.

Abstract

Parasites of Trichoplusia ni Hb., Pseudoplusia includens (Wlk.) Heliothis virescens (F.) and other Lepidoptera were characterised in a model (3.2 ha in extent) of a cropping system in north Florida (including tobacco, soyabeans and 18 other crops) not treated with chemical pesticides. The study lasted for 2 years and samples were taken weekly. The results are presented in some detail. The main larval parasites of T. ni were Litomastix truncatella (Dalm.), Meteorus autographae Mues. and Voria ruralis (Fall.). The main egg parasites were Trichogramma spp. Parasitism of the eggs and larvae ranged from 0 to 55% and from 0 to 100%, respectively, on crucifers and was generally highest during the spring and autumn. Parasitism of the immature stages of Trichoplusia ni was highest on tomato crops. Parasitism of P. includens by the parasite complex was high but eggs laid in soyabeans were seldom attacked. Eggs of H. virescens were seldom parasitised on tobacco but were frequently attacked on tomato and okra. Generally, more than 50% of the larvae of H. virescens on tobacco were parasitised, usually by Cardiochiles nigriceps Vier.; this parasite was seldom collected from other plants.