Reducing Pesticide Application Rates by Elucidating the Pesticide Dose-Transfer ProcessEPA Grant Number: R823100 (R821171)
Title: Reducing Pesticide Application Rates by Elucidating the Pesticide Dose-Transfer Process
Investigators: Hall, Franklin R. , Chapple, A. C. , Downer, Roger A. , Ebert, Timothy A. , Hislop, E. C. , Taylor, R.A. J. , Wolf, T. M.
Institution: The Ohio State University
EPA Project Officer: Manty, Dale
Project Period: July 1, 1995 through June 1, 1997
Project Amount: $202,691
RFA: Exploratory Research - Environmental Biology (1995) RFA Text | Recipients Lists
Research Category: Biology/Life Sciences , Health , Ecosystems
Description:The objective of this project is to understand how agrochemical deposit structure influences toxin efficacy. The focus is on improving the dose transfer process for biological insecticides used against lepidopterous pests. Cypermethrin will be used as a "standard" for comparison of results. The test plant is cabbage with a target insect Trichoplusia ni. Once the methodology has been worked out, other pests will be tested to assess the generality of the results.
Assessment of deposit structure will be done using SEM for examining the within-deposit structure. This will provide some measure for assessing the biological effect of deposit topology. Factors like evenness of coverage, wet versus dry, and film versus particle are all important factors influencing the dose transfer process which require further elucidation for understanding and predicting optimal presentation characteristics. The deposit structure on a leaf surface will be examined using a mixture design model. This methodology will reflect the relationship between the variables (droplet size, droplet number, concentration of AI in the fluid) which interact multiplicatively and always result in a total applied dose. Previously, ANOVA models were used, but such models are inappropriate. Preliminary results suggest that the interactions are very complex. The main effects of AI concentration and the effect of droplet size are both greater than the effect of droplet number. However, the interaction terms between these factors have a greater impact on the biological effect than any factor by itself.
Results from these experiments will be validated in a track room where a double nozzle system developed by LPCAT will be used to apply a range of droplet sizes to plants. This intermediate phase will help bridge the gap between results from the laboratory to the field. Finally, a computer simulation model will be used to examine the theoretical reasons for the lab and field results. The ultimate goal is to improve efficacy of existing biological insecticides by understanding placement and formulation criteria for optimal dose transfer. This will reduce application rates, and reduce environmental contamination.