Studies on soil persistence of some entomopathogens (wild-type and recombinant Baculoviruses) on some field crop pests

Abstract

Studies on the persistence of recombinant and wild-type nucleopoly­

hedroviruses (NVP) (Family: Baculoviride) were carried out on two !i agricultural pests from Order: Lepidoptera, Family: Noctuidae. These pests I are:

(1) The cotton bollworm Helicoverpa zea (Boddie) (also known as the

Icom earworm, and

lII

tomato

fruit worm) as an u•nportant pest of

rotten, com and tomato.

(2) The cabbage looper, Trichoplusia ni (Hubner) an important pest of

, abbage and crucifer family. J field and laboratory microcosm experiments were carried out (on

monthl intervals from 12-17 months, as one experiment every 2 months, for field :!experiments, and one experiment every 3 months for laboratory experikent) to study the effect and persistence of these viral formulations underenvironmental fuctors, e.g., ultraviolet (UV) radiation from sunlight, heat, hins (precipitation), drafting, and agricultural operations in the field II! (diskihg, harrowing and mowing). l 'Cotton (DPL 5409) was planted on June 1997, in Louisiana State

Unive sity Agricultural Center, Red River Station, near Bossier City, 'I USA.J' Then it was replanted once again in the same site in 1998 season. An isolated area was divided into 12 experimental plots, 4 plots were assiJed for each treatment as well as the control. The plots were arranged "' in a dridomized block design. 1 ,[Mixed populations of the cotton bollworm Helicoverpa zea

(Bodcfie) and the tobacco budworm Heliothis virescens (Fabricius) in "I cottoti field were sprayed five times during a growing season on August j and . September 1997 with a wild-type clone H. zea NVP virus