ARS | Publication request: BIOASSAY TO EVALUATE FORMULATIONS OF ENTOMOPATHOGENS IN THE FIELD.

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: November 14, 1997
Publication Date: N/A

Technical Abstract: This paper is a review of various bioassay techniques used to determine formulations that are optimal for enhancing and extending the residual activity of biopesticides. It is very important to develop laboratory and greenhouse assays that accurately reflect what may happen under field conditions so that treatment numbers may be reduced for expensive and time-consuming field tests. We have developed artificial rainfall and solar stability assays based on commercially available equipment. A track-type spray chamber is used to apply field quantities of formulation onto plants. This chamber can then also be used to simulate rainfall. We apply approximately 5 cm rain in about 1 hr. Alternatively, sprayed plants can be placed under a xenon- based light source that accurately produces, quantitatively and qualitatively, energy along the solar spectrum. Amount of exposure depends on the biopesticide used. An insect-based bioassay is then used to assess residual activity after exposure to one or both environmental factors. Once acceptable formulations are identified, field assays are done using standard techniques. These techniques have been used to assess formulations of bacteria, viruses and chemical pesticides on corn, cabbage, beans, and cotton.