Projects Funded for Yanan Zheng


Positive Externalities of Pesticide Use: Cross-crop Benefits to Lygus Bug Management in San Joaquin Valley Cotton

Rachael Goodhue and Yanan Zheng


Specific Objectives of the Project:
• To utilize administrative data to identify whether pesticide applications made by alfalfa and safflower growers reduce pesticide applications made to nearby cotton fields in the San Joaquin Valley
• To construct a bio-economic model of lygus bug population development and migration to estimate the magnitude of any positive externality identified.

Summary of Results:
• Pesticide applications made by other growers to nearby fields of alfalfa, safflower and other host crops reduce pesticide applications to cotton fields.
• Pesticide applications made by a grower to nearby host crop fields of their own sometimes increase pesticide applications made by that grower to a cotton field.
• While the data do not enable us to determine the reasons for the latter, one possibility may be that some growers are more likely to apply pesticides.

The bio-economic model is still in development.