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.
The second male flight has started in Kern and Tulare counties. It occurs 1100 degree days after the biofix of the first male flight. Temperature units are ahead of the 30 year average. See our web site for more information.
For citrus growers: The Citrus Pest and Disease Prevention Program (CPDPP) has created a very helpful web site called the "CPDPP Citrus Insider" to update growers on Asian citrus psyllid issues. It has news information, maps, quarantines and updates by region. Check it out and sign up for automatic updates. http://www.citrusinsider.org/
For homeowners: UC IPM updated their Asian citrus psyllid quick tip. It provides information for homeowners about the symptoms of the psyllid and disease, what to do if they think thay have the psyllid, and how to manage it in their yards. Great information to pass on to friends and relatives. The quick tip cards can be obtained from your local cooperative extension office or printed off of the web. http://www.ipm.ucdavis.edu/QT/asiancitruscard.html
California red scale: The biofix for California red scale was March 11-25 for various areas of the San Joaquin Valley and degree days have been accumulating ever since. Kern County is always warmest and has reached the 550 dd 1st crawler emergence point. The other counties will reach that mark in the next two weeks. It has been an exceptionally warm spring and so we are about 50 degree days ahead of the 30 year average.
See my web page for Monday updates. http://ucanr.edu/sites/KACCitrusEntomology/Home/California_Red_Scale/Degree_Days_885/
Citrus peelminer: The biofix for Tulare County was on April 22 and that starts the degree day accumulation clock. Remember that the first two generations of citrus peelminer attack noncitrus hosts such as willows, walnuts etc. It isn't until the third generation that the peelminer starts to attack pummelos and grapefruit. We will keep you informed as to when those flights are occurring.
See my web page for Monday updates. http://ucanr.edu/sites/KACCitrusEntomology/Home/Citrus_Peelminer/Degree_Day_Calculations/
On April 22 a field event was held at Lindcove with speakers Joseph Morse from UC Riverside and Jim Cranney from the California Citrus Quality Council. The issue discussed was how California citrus growers are going to prevent fruit from arriving in Korea with live Fuller rose beetle eggs, now that Korea is no longer going to fumigate citrus. Korea will reject citrus shipments if live Fuller rose beetle eggs are found. Speakers suggested that a systems approach that combines several strategies (a combination of skirt pruning, trunk treatments, foliar treatments, and/or post-harvest fumigation) may be necessary to accomplish the goal, since no single treatment provides complete control. The problems with pesticide treatments are that Fuller rose beetle adults emerge from the soil year round, they are difficult to kill with pesticides, and the pesticides must be reapplied to maintain their efficacy. The problems with the post harvest fumigants currently under study (phosphine and ethyl formate) are that they require extended periods of treatment and cold temperature to achieve a high level of kill of the eggs. Research is being conducted on all of these strategies and until it is completed, the best management strategy includes skirt pruning, trunk treatment starting in June, and a foliar spray 600 degree days prior to harvest. More information can be found at this web site, http://ucanr.edu/sites/KACCitrusEntomology/Home/Fuller_Rose_Beetle_384/Management_36/ that includes information on how to build a spray wand for trunk treatments.