FRESNO, Calif. — When the European grapevine moth quarantine ended March 8 in Fresno County, growers, packers and shippers who grew or packed grapes from the zone were free of the strict protocols they had been following for more than a season.
At the same time, the U.S. Department of Agriculture let U.S. trading partners know of the successful pest-fighting effort, said Tye Hafner, Fresno County deputy agricultural commissioner.
“It should be business as usual for the growers, but the county is maintaining traps in the area just as a precaution to make sure we truly did eradicate it and we didn’t get a reinfestation,” Hafner said.
A handful of importing countries, including Australia, New Zealand, Mexico and Canada, had shut their borders to table grapes originating from within the quarantine area the past two seasons, he said.
The eradication declaration should allow grapes from those vineyards to move freely this season.
That’s good news, said George Matoian, salesman for Visalia Produce Sales Inc., Kingsburg, who had table grapes within the quarantine boundary.
“It’s a little bit of a headache for the grower to do the sampling prior to picking,” he said.
About 70% of Bravante Produce’s table grape acreage was inside the quarantine zone, which meant the firm had to follow strict pre-harvest protocols, said Ron Wikum, table grape category manager for the Reedley-based grower-shipper.
“We had to jump through hoops in terms of inspections, permits and bunch inspections,” he said.
“Other than that, we didn’t have a problem getting our grapes out of those vineyards.”
Trap catches totaling 11 European grapevine moths in spring 2010 set in motion a state and federal quarantine over about 96 square miles.
Bordered roughly by Sanger, Fowler, Selma, Kingsburg and Reedley, the area included about 2,800 acres of table grapes as well as stone fruit orchards and raisin and wine grape vineyards.
In California, grapes appear to be the preferred host of the grapevine moth, which is native to the Mediterranean, said Walt Bentley, a University of California Extension entomologist based at the Kearney Agricultural Research and Education Center near Parlier.
Scientific literature also cites several alternate hosts, including stone fruit, pomegranates, kiwifruit, gooseberries, blackberries and persimmons.
Because of when the moths were discovered and the quarantine imposed, stone fruit growers experienced the bulk of the early market disruptions, said Barry Bedwell, president of the California Grape and Tree Fruit League.
By the time the table grape harvest began, most of the snags had been worked out of the quarantine protocol and the system appeared to work fairly efficiently, he said.
As part of the grapevine moth quarantine, table grape growers had to follow an a
pproved integrated pest management program that timed pesticide applications with peak moth flights, Hafner said.
Vineyards also had to have one trap for every 5 acres, and the trapping had to be done by the county agricultural commissioner’s office.
Before harvest, growers had to call to schedule inspections. County inspectors checked each vineyard to make sure it was clear of moths as well as inspected 300 grape bunches for any signs of the pest.
Grapes from quarantined vineyards had to be kept separate, and boxes had to carry a “diamond 10” stamp identifying them as originating from a quarantine zone.
The only remnant of the infestation now is the intensive trapping program, for which the growers in the area pay.
Before the infestation, the county deployed 16 traps per square mile. Since the eradication, the rate is 25 traps per square mile, Hafner said.