Euphorine (Hymenoptera: Braconidae) Parasitism of the Tarnished Plant Bug (Heteroptera: Miridae) in Areas of Washington County, Mississippi Disturbed and Undisturbed by Agricultural Production

Abstract

Tarnished plant bugs (TPB), Lygus lineolaris (Palisot de Beauvois), were collected from wild host plants growing in weed fields undistrubed by agricultural practices, and from the same plant species found in disturbed areas adjacent to cotton fields in Washington County, MS during 1984 and 1985. Euphorine parasitism of TPB adults and nymphs collected in these 2 types of habitats was determined by dissection. For each year of the study period, parasitism of TPB collected from all host plant species sampled in weed fields peaked at 8 and 32% on 28 June 1984, and at 6 and 12% on 30 May 1985 for nymphs and adults, respectively. On these 2 dates parasitism of adult TPB found on all host plant species sampled in the weed fields was significantly higher (P ≤ 0.01) than parasitism of those TPB collected from the same plant species in areas adjacent to cotton fields. Parasitism of TPB in the undisturbed areas may have been sufficient to locally reduce TPB populations. However, undisturbed areas are uncommon in Washington County and the parasitoids are probably univoltine. Consequently, the impact of euphorine parasitoids on area-wide TPB populations was probably small.