Come by and visit UC ANR booth 1512 in Pavilion A if you would like to talk about citrus pest issues. Beth Grafton-Cardwell, Sara Scott and Jennifer Ruvalcaba will be there. We have pest damaged fruit and several beneficials to display including Tamarixia, the parasitic wasp that attacks Asian citrus psyllid.
A number of Tulare County PCAs have observed a very dark thrips infesting the calyx and areas of the rind where fruit touch in mandarins this year. Samples were collected and identified by Dr. Mark Hoddle (Dept of Entomology, UC Riverside) as western flower thrips. We don't normally consider this thrips a pest of the rind of citrus. However, in some cases, a circular scarring was associated with the thrips feeding on the rind of the fruit. It is likely this is a rare event, precipitated by freeze and drought conditions. Should growers treat for this thrips? This decision has to be made based on each individual situation. The thrips have likely already done the damage and will be difficult to control with insecticides because they are tucked away. In addition, they will readily move to flowers when they become available.
One of the requirements of the Fuller rose beetle program for shipping fruit to Korea is application of a foliar spray by Oct 15. I am in the process of testing various products for efficacy against Fuller rose beetle to find insecticides to recommend, in addition to Actara. While several other products (Kryocide, Lorsban Advanced, Sevin XLR) show good efficacy, they do not have MRLs established or the MRLs for Korea are substantially lower than the US. There are two products I tested that include the active ingredient in Actara - thiamethoxam: Agri-Flex 8.5 oz (thiamethoxam + abamectin) and Voliam Flexi 7 oz (thiamethoxam + chlorantraniliprole). These products could be used as the foliar FRB treatment, if used at a rate that provides a similar level of thiamethoxam.
Numerous questions have come up about combining the FRB Actara treatment with a gibberellin spray or a Copper-Lime-Zinc spray. This morning a test was conducted at Lindcove REC and Gibb was not found to alter pH. In contrast, the lime treatment raised the pH to an unacceptable level (from 7.5 to 12.2) and so should not be combined with Actara. Additional tests are underway to see if these treatments reduce the efficacy of Actara against FRB in the field.
The Tulare County Agricultural Commissioner's office is announcing that two additional Asian citrus psyllids (ACP) have been detected on traps north of Eckert Field near Strathmore and northeast of Ducor. The latest interceptions were confirmed by the California Department of Food and Agriculture (CDFA) this morning. Maps and current information will soon be available on the Agricultural Commissioner’s website: http://agcomm.co.tulare.ca.us/default/.
The Tulare County Ag Commissioners office announced to day that one Asian citrus psyllid on a trap card was found next to a commercial citrus grove southeast of Exeter. More news on that subject will follow as the area is delimited by CDFA.
The 5 mile quarantine areas around the Dinuba and Wasco ACP finds have now been officially established and can be viewed on the ACP Distribution Web Site: www.ucanr.edu/sites/acp.