- Author: Elizabeth E Grafton-Cardwell
A meeting was held in Visalia on June 17 on the subject of protecting citrus fruit against egg-laying by Fuller rose beetle. Fuller rose beetle is extremely difficult to kill- the adults are built like tanks, live forever, and can go weeks without feeding. Foliar applications of Sevin, Actara and Kryocide work the best to kill adults, but no insecticide treatment kills all of them. The larvae are underground so they are difficult to treat. The eggs have a thick outer shell that protects them from insecticides and they are tucked under the button of the fruit. Because foliar insecticides are not very effective, the best line of defense against the pest is preventing it from ever reaching the trees. To accomplish this, a two step approach is the best strategy. First, skirt prune the trees up at least 24" so the branches don't touch the ground. This forces the flightless beetles to climb the trunk to get to the leaves. The next step is to block them from climbing the trunk by applying Brigade WSB in a thick band around the trunk. (See our web site for more details on how to build a spray wand to treat tree trunks http://ucanr.edu/sites/KACCitrusEntomology/Home/Fuller_Rose_Beetle_384/Management_36/) The Brigade repels the beetles and if they cross it, paralyzes them. The best treatment is the 0.5 lb AI/acre rate. The current 2ee allows only one treatment of this rate. CCQC hopes to obtain a 24c special registration, in the near future, that allows two treatments of this rate. The Brigade lasts 12-16 weeks and so a treatment applied in June and one in September will protect the trees from more than 90% of the beetle emergence. Foliar treatments could also be applied to provide a further level of protection. Research is underway to study the efficacy of these methods and to develop a post harvest treatments to replace Methyl Bromide fumigation, which is no longer allowed in Korea.