Pesticide use in California agriculture with information on pest control advisors

Pesticides support crop production, enhancing global food security, but
are associated with serious environmental and health risks. Factors that
promote overuse of pesticides are therefore of great concern. Pest control
advisors (PCAs) are agricultural professionals who scout fields for pests
and may recommend pesticide applications. We test two hypotheses regarding
the influence of PCAs on pesticide use by California farmers, contrasting
four groups: independent PCAs, sales PCAs, farm-staff PCAs, and farmer
PCAs. The long-discussed conflict of interest hypothesis posits that sales
commissions earned by PCAs who work for agricultural chemical retailers
(“sales PCAs”) incentivize pesticide use; it predicts elevated use of all
pesticides by farmers advised by sales PCAs. The risk aversion hypothesis
posits that the risk of damaging pest outbreaks incentivizes pesticide
use; it predicts elevated pesticide use when targeting pests that can
exhibit outbreaks (arthropods and plant pathogens) but not when targeting
non-outbreak pests (weeds). We assembled a dataset of pesticide use on
nearly 600,000 crop-years grown in California from 2012 to 2021 by farmers
advised by different types of PCAs. Our analysis provides little to no
support for the conflict of interest hypothesis; farmers advised by sales
PCAs used slightly fewer pesticides than farmers advised by independent
PCAs (who receive no sales commission). Instead, our analysis reveals
pesticide use consistent with the risk aversion hypothesis, with elevated
use of pesticides by one group of PCAs (farm-staff) when managing
arthropods and pathogens, but not when managing weeds. Risk aversion,
rather than sales commissions, may be shaping pesticide use in California.