For years, there’s been a lingering suspicion in agriculture: if your pest control adviser also sells pesticides, you might end up spraying more than you need. The idea that conflicts of interest lead to overusing pesticides has become common belief, and it’s influenced major policy decisions in California and around the world. However, this belief was arrived at without much data to support it. This study took a hard look at that idea using data from the California Pesticide Reporting (PUR) system, and the answer isn’t quite what people expect.

Across a wide range of crops and situations, growers working with sales-based PCAs did not use more pesticides overall than those working with independent advisers. In other words, the feared “conflict of interest” doesn’t show up as a simple increase in total spray volume.

What does change is the type of decisions being made. Growers advised by sales PCAs tend to lean a little more toward prevention. They are more likely to use products like adjuvants or plant growth regulators—inputs that don’t directly kill pests but help reduce the chances of something going wrong. It’s a more cautious, “cover your bases” approach.

On the flip side, growers working with independent PCAs tend to use slightly fewer pesticides overall, but they may be more willing to wait and respond if problems develop. The data suggest they are a bit more likely to use rescue treatments for insects, which hints at reacting to outbreaks rather than trying to prevent them in advance.

However, what was interesting, was that in-house PCAs tended to use more insecticides than the sales PCAs although this was still in the statistical ballpark with independent PCAs and farmers. The authors point to the risk aversion hypothesis as guiding the differences in pesticide use between these different types of PCAs.

So, the real story isn’t about sales pressure driving up pesticide use. It’s about how different advisers—and growers—manage risk. Some prefer to invest upfront to avoid surprises, while others are comfortable holding back and stepping in only when needed. As the authors state ” our analyses suggest […] fear (of pest outbreaks) rather than greed (the desire to earn greater sales commission that drives differences across groups of PCAs in pesticide.” This explains the push for seaweed or grower’s secret from some sales PCAs rather than pushing pesticides.

The takeaway for growers is straightforward. Who your PCA works for matters less than how you and your adviser think about risk. If the goal is to reduce unnecessary inputs, the conversation shouldn’t just be about products or incentives. It should focus on how much uncertainty you’re willing to tolerate, and how confident you are in your ability to monitor and respond in time.

In the end, pesticide use decisions look less like a sales problem and more like a risk management strategy playing out in the field. Everyone has an incentive to cover their berries.

Literature cited

Rosenheim, J. A. and Culshaw-Maurer, M. 2026. Conflicts of interest, risk aversion, and pesticide use in California agriculture. Journal of Pest Science 99:19. https://doi.org/10.1007/s10340-025-01999-8