What is in this article?:
- The California citrus industry is working to keep Fuller rose beetle eggs out of Navel orange shipments exported next year to Korea.
Jim Cranney, California Citrus Quality Council president, works to find ways to keep Fuller rose beetle eggs from hitchhiking in California Navel orange shipments to Korea.
No crystal ball
Many of the mitigation measures needed to control FRB need to be in place before the season begins.
Given Korea’s previous efforts to eliminate blanket fumigation over the last two years, it creates uncertainty about its continued viability and the ability of USDA negotiators to maintain the fumigation.
The USDA Animal and Plant Health Inspection Service and Korean quarantine officials will negotiate the final terms of the issue this summer.
“We really need to take steps to control the pest in California,” Cranney said with urgency in this voice.
“No one has a crystal ball and we don’t know for sure how this issue will be resolved. From everything we have heard from APHIS, it will be a very heavy lift to maintain blanket fumigation in Korea.”
CCQC, researchers, government leaders, and other organizations are working hand-in-hand to develop effective FBR control techniques to ensure the California-Korea pipeline remains open.
There is not a single solution right now, Cranney says. The industry has a toolbox of methods to greatly reduce beetle and egg numbers.
“I think we have a good set of options in place,” Cranney said. “However right now, we cannot guarantee that any of these tools by themselves will eliminate every single insect or egg.” The tools are designed for implementation in Navel orange groves and packinghouses.
The adult FRB is a crawling insect, which moves from the soil into the tree wherever the two come in contact – low limbs touching the ground and the tree trunk. Once in the tree, the FRB adult lays its eggs under the calyx; the area where the stem attaches to the fruit.
FRBs feed along the citrus leaf margin creating sharp, ragged notches but cause no damage to the actual fruit.
The CCQC is collaborating with University of California entomologists Joseph Morse and Beth Grafton-Cardwell to find solutions to keep the insects out of the tree. Morse recommends skirt pruning branches to keep the limbs from touching the ground.
For FRBs which prefer to climb up the trunk, Morse’s solution is to apply the Brigade WSB, with the insecticide active ingredient bifenthrin, on the trunk using a wand sprayer to keeps the pesticide from reaching the fruit.
The problem though is the current product label maximum rate for Brigade WSB is two applications at one-quarter pound each (one-half pound annually); possibly not enough for an effective kill rate or enough applications to kill the adults during peak emergence from July through October.
The CCQC is working with FMC, the product manufacturer, and the California Department of Pesticide Regulation to increase the maximum label rate to four applications at the same rate (1-pound total annually). Morse says this rate offers improved FRB control.
Cranney says bifenthrin is highly effective against FRB adults, but is not 100-percent effective.
“Korea doesn’t want 95-percent control. Korea wants 99.9999-percent control. We don’t have 100 percent control of the Fuller rose beetle eggs with this method right now, but it is the best option currently available.”