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Title: ACTIVITY AND PERSISTENCE OF THE NUCLEAR POLYHEDROSIS VIRUSES THE CELERY LOOPER (LEPIDOPTERA:NOCTUIDAE) WITH A FEEDING STIMULANT AND A STILBENE- DERIVED ENHANCER

Author
item Farrar, Robert
item RIDGWAY, RICHARD - RETIRED
item DIVELY, GALEN - UNIVERSITY OF MD

Submitted to: Journal of Entomological Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/22/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary: Commercial agriculture continues to rely heavily on chemical pesticides for insect pest control, despite problems with environmental contamination, worker exposure, and residues in agricultural products. Nuclear polyhedrosis viruses (NPVs) are naturally occurring viruses, each of which infects only a certain few species of insects or other arthropods. They are promising alternatives to pesticides for many important pests, especially caterpillars. The NPV of the celery looper (AfMNPV)is under commercial development as a biopesticide for the beet armyworm and several other major pests. However, it is difficult to obtain consistent levels of control with NPVs alone, particularly because sunlight can rapidly deactivate them. We tested two additives for AfMNPV, the fluorescent brightener Blankophor BBH and the feeding stimulant Coax in the greenhouse and small field plots. In the laboratory, Blankophor BBH enhances the potency of AfMNPV against the beet armyworm, while Coax increases ingestion of the virus by the pest. Both materials also protect NPVs from sunlight. We showed in the present study that both materials should also work in the field. Our results will aid in the development of effective and economical use patterns for NPVs in practical insect pest management programs. This can, in turn, reduce the use of chemical pesticides and problems of contamination, worker exposure, and residues.

Technical Abstract: The nuclear polyhedrosis virus of the celery looper, Anagrapha falcifera (Kirby) (AfMNPV), was evaluated with a nutrient-based feeding stimulant and a diaminostilbene disulfonic acid-derived enhancer against beet armyworm, Spodoptera exigua (Hubner), on collard, Brassica oleracea L. (Acephala group), cv. Vates. Tests included holding larvae on whole sprayed potted plants in the laboratory and bioassays of foliage collected from sprayed plants in the field. The feeding stimulant increased mortality in all tests. The enhancer increased virus-caused mortality in the bioassays of field-collected foliage but not in the test of potted plants. At the concentration tested in the field(0.25 to 0.5% of the spray), the enhancer may have acted as a feeding deterrent. Therefore, on the whole plants, where the larvae were free to move around, effects on feeding behavior may have reduced the effectiveness of the enhancer. In the bioassay of field collected foliage, larvae were confined on small pieces of foliage, and thus did not have the option of moving away from the enhancer.