Predator Determination and Efficiency on Heliothis virescens1 Eggs in Cotton Using 32 P 2

Abstract

Radioactive Heliothis virescens (F.) eggs were placed in an east Texas cotton field during 1977, and the following arthropods showed evidence of predation on the eggs: Solenopsis invicta Buren; Orius insidiosus (Say); Geocoris punctipes (Say); Geocoris uliginosus (Say); Pseudatomoscelis seriatus (Reuter); Hippodamia convergens Guérin-Méneville; Cycloneda sanguinea (L.); Coleomegilla maculata (De Geer); Scymnus loewii Mulsant; Heliothis spp. larvae; Phidippus spp.; Peucetia viridans (Hentz); Oxyopes salticus Hentz; and Misumenops spp. These and other unidentified predators and parasites were a dominant factor in the destruction of Heliothis spp. eggs throughout the growing season. The mean predation for eggs per 24-h exposure period ranged from 48–90% with a seasonal mean of 73%. Seasonal mean predation for exposures of 48 and 72 h were 87 and 93% respectively, with a single case of 100% predation following a 72 h exposure. Older (>24 h) Heliothis virescens eggs were found to have a higher likelihood of survival than younger eggs (< 24 h) found in the field at the same time. In addition, predation rates were reduced for as long as 48 h after the occurrence of rain.