Bcg. Scholz et al., AN EVALUATION OF SELECTIVE HELICOVERPA-ARMIGERA CONTROL OPTIONS IN SWEET CORN, Australian journal of experimental agriculture, 38(6), 1998, pp. 601-607
Helicoverpa armigera is a serious insect pest of sweet corn in Austral
ia and is becoming increasingly difficult to manage with conventional
chemical insecticides due to resistance problems. A number of alternat
ive H. armigera control options were evaluated in sweet corn and compa
red with deltamethrin and no action (control). The alternative tactics
evaluated were: heliothis nuclear polyhedrosis virus plus Trichogramm
a nr. brassicae releases; Bacillus thuringiensis; and Trichogramma alo
ne. The H. tea nuclear polyhedrosis virus + Trichogramma plots had the
lowest cob damage (6.0%), followed by the B. thuringiensis plots (12.
0%), Trichogramma alone plots (20.2%), control plots (23.2%) and delta
methrin plots (53.5%). There was no evidence to suggest that the Trich
ogramma nr. brassicae releases had any impact on H. armigera egg morta
lity. However, there was a large natural population of Trichogramma pr
etiosum in all plots. The application of deltamethrin reduced the acti
on of these wasps and predators, resulting in higher larval infestatio
n and significantly more cob damage. The findings indicate that the pa
thogens heliothis nuclear polyhedrosis virus and B. thuringiensis can
effectively control H. armigera when their action complements high nat
ural levels of egg parasitism, and that they have potential for use in
integrated pest management programs in sweet corn.