Use Pesticides Wisely to Avoid Resistance
Thursday May 08, 2025
Repeated use of pesticides with the same mode-of-action used in the orchard can accelerate the development of insecticide resistance. WSU recommends that when you choose insecticides, keep track of which ones are being used so that you alternate materials with the different modes-of-action (shown in DAS) between generations.
Bt Applications for Leafrollers
Thursday May 08, 2025
Bacillus thuringiensis (Bt) is a bacterium that must be eaten by lepidopteran larvae (caterpillars) to be effective. Bt is a great material for leafroller control because it is specific and has little effect on natural enemies. However, it must be applied 2-3 times to be effective when leafroller populations are high. Experience has also shown that in the spring, the high temperatures need to be above 65°F for 3 or more days so that larvae have a chance to feed on it before sunlight breaks it down. DAS provides forecast temperatures for all stations in the "Weather Forecast" and in the "Show Data Grid" table so that you can decide whether or not to use Bt or other recommended chemicals.
Campylomma Bug
Thursday May 01, 2025
Campylomma can be a pest during the bloom period when it feeds on young developing fruit. However, it is a beneficial predaceous insect that is valuable in control of soft bodied insects (such as spider mites) throughout the rest of year. DAS predicts the phenology of Campylomma during the spring, but beating tray samples need to be taken before and during the spring bloom period to determine if Campylomma is present and whether treatment is necessary.
What is DAS?
A collaborative project between WSU Extension and WSU Agricultural Research Center.
WSU-DAS is a web-based platform designed to transfer time-sensitive information to decision makers in the tree fruit industry. It runs insect, disease, disorder, and horticultural models to estimate the current status of the issue and links that to appropriate management and pesticide recommendations.
