Cooperative Extension Integrated Pest Management Advisor Kris Tollerup says the leaffooted bug, like many other pests, is sensitive to a certain degree of weather. Tollerup says if growers see winter temperatures drop into the high 20’s for some time they can expect less pressure from the pest in the following season.
UC IPM Website: Monitoring
Walk the orchard during the months of March and April to look for dropped nutlets (particularly on susceptible varieties), nuts with gummosis, and leaffooted bugs. Finding adult bugs is the best indication that a problem may arise, but the cryptic nature of these pests and their behavior of staying in the tops of trees makes this difficult to do. A more practical approach is to look for nuts with gummosis or egg masses on the sides of nuts. If gummosis exists, cut a cross-section across the damaged site to look for a puncture mark from the bug’s mouthparts to confirm that the gummosis is not due to physiological reasons.
The easiest monitoring method is to look for aborted nuts on the ground. However, basing treatments on gummosis and nut drop also means that there can be a 7-10 day lag time between when feeding takes place and when gummosis and nut drop occur – so the dispersing insects may have already moved to another block. Read more about leaffooted bug on the UC IPM website.