We are evaluating systemic insecticides for the management of current and newly emerging pests of California avocados. Studies are being conducted in commercial avocado groves, under normal agronomic practices. Trees are treated using a variety of techniques – soil application and trunk injection – to establish the methods that will provide the best uptake of insecticide for the protection of the trees. Our primary research focus is on the avocado thrips and the avocado lace bug although this work may have application to control of armored scales if one or more species were to establish in California. Despite its recent introduction, the avocado thrips is already an established pest of avocados in California. The avocado lace bug is a more recent introduction, and has not yet established widely within the avocado growing regions. Current management practices for avocado thrips are centered on the use of foliar insecticides. Several foliar treatments are available (Agri-Mek, Delegate, and Veratran D) for the control of avocado thrips. However, the number of products is limited, the mode of application can be difficult (helicopter use on steep hillsides, applications near urban regions), and there are risks of resistance development, particularly to Agri-Mek due to it also being used against persea mite during the summer. Systemic neonicotinoid insecticides are relatively easy to apply (via established sprinkler irrigation systems or by modern trunk injection systems), and have a mode of action that has not been in use for the management of avocado thrips. A new mode of action would substantially lower the resistance risk associated with Agri-Mek, and alleviate operational difficulties in the use of foliar treatments.
