Frass production by Heliothis zea (Boddie) larvae infected at varying mortality levels with Heliothis nuclear polyhedrosis virus (NPV) was determined and used to estimate the effect of the virus on larval food consumption. Treatment in the early stages was essential to substantially reduce food consumption. Reduction in food consumption was also directly related to NPV dosage. Food consumption by larvae surviving NPV treatment was not significantly different from the untreated larvae. Field tests indicated that NPV applications must be timed against 1st- or 2nd-stage larvae to achieve an appreciable mortality level and prevent infected larvae from reaching the damaging late developmental stages. Preliminary maximum treatment levels for use of Heliothis NPV for suppression of H. zea on soybean are presented.
Contributor Notes
1 Published with approval of the Director, Arkansas Agricultural Experiment Station. Use of a trade name does not imply endorsement or guarantee of the product of the exclusion of other products of similar nature.
2 This material is based in part upon work supported by the U. S. Department of Agriculture under Agreement No. 82-CRSR-2-1000. Any opinions, findings, and conclusions or recommendations expressed in this publication are those of the authors and do not necessarily reflect the view of the U. S. Department of Agriculture.