University of California Integrated Pest Management Advisor Emily Symmes said there are some additions to San Jose scale guidelines, specifically to help growers make decisions. “With San Jose scale, we have some dormant monitoring guidelines and some treatment thresholds, or decision support tools, that allow you to look for presence of the pest as well as presence of natural enemies,” Symmes said. “What this actually is is a sequential sample where the total number of samples we take are maxed out at 100 but if you can make a decision earlier along the way, you don’t have to take the maximum number of samples.”
Symmes says this has led to the development of a tool that makes it very clear for growers. “What’s been developed recently is basically a decision tree,” Symmes said. “You collect your samples and count the number of infested spurs and it makes it very clear. For example, if you have seen one to three then you either take more samples or stop and make a decision. It takes you through this process in a very clean, step-by-step pattern.”
Feedback revealed that the sequential sampling may have been a little confusing to navigate for some. Symmes said this decision tree should alleviate the confusion. You can find the tool online at SacValleyOrchards.com.