California agriculture’s battle against the European Grapevine Moth (EGVM) is starting to look like the arcade game Hammerhead.
The government is the hammer and the bad guy pop-ups are a gaggle of menacing EGVM (Lobesia botrana). The state and federal exterminators are banging away, trying to smash the pest as they turn up in widely separated areas within the state’s 40 grape growing counties.
The more than 200 growers, packers, PCAs and others sardined into a conference room at the University of California Kearney Research Center at Parlier, Calif., left feeling like so many who play Hammerhead; the EGVM pop-ups are winning.
George Flagler and his son David farm grapes in Parlier and believe that while this particular pest can be devastating, it should be relatively easy to control with existing pest management practices for Lepidopterous/worm pests. UC entomologists agree.
“I am not worried about the bug. It is not a big deal. The big deal is the quarantine,” said David, who has farmed 30 years. His dad has 50 years in the business. “It is worse than the insect.”
“What the government should do is spray the whole area where the moths have been trapped and eradicate it now and get rid of the quarantines,” suggests George Flagler. He knows that is not going to happen soon with the entanglement of red tape a widespread eradication program like that requires.
If two or more EGVM are trapped within a certain area, the state and federal government slaps a quarantine over a wide area, extending over a 5 mile radius around the finds.
So far the state has quarantined almost 1,000 square miles in Napa, Sonoma, Mendocino and Solano counties in California’s premier wine grape growing region.
It has recently quarantined 96 square miles east of Fresno where six moths were trapped. Regulators say a similar quarantine likely will be slapped on the Snelling area of Merced County. A second or third moth find near the recent Monterey County EGVM find will net the Central Coast its first EGVM quarantine area.
No one will be surprised if more EGVM are trapped far from ground zero, the North Coast. Experts believe the invasive pest has been in the state for a couple of years at least, undetected because there were no traps out.
These quarantines come with variety of burdensome, expensive regulations from washing equipment and trucks going in and out of wineries; mandatory fumigation of table grapes; issues with transporting of cull fruit and even a federal stamp on fruit packed from within the quarantine area. This stamp is supposed to signify the fruit is clean, but also identifies it as being from a quarantined area.
This, according to Barry Bedwell, president of the California Grape and Tree Fruit League (CGTFL), could stigmatize fruit, resulting in lower prices than fruit from non-quarantine areas.
Organizations are trying to deflect marketing fallout from this insect, which has never been found in the U.S. until it was trapped in Napa Valley last fall.
“Everybody has a stake in this, and we want to work with the counties and others to make sure this does not get out of hand,” said Bedwell. “Farmers are smart. They are going to do all they can to keep it out of vineyards and orchards.”
Several customer countries are watching this crisis unfold to see how the federal and state governments handle it. Domestic customers also are concerned and the feds are negotiating with Oregon, a grape growing state that wants no part of EGVM, about movement of grapes and other commodities into that state.
Mexico has a long list of trade issues, many involving pest issues, but not all. Two years ago 5.5 million boxes of table grapes were shipped to Mexico from California. Last year it went down to 1.6 million because of new tariffs imposed by Mexico when the U.S. refused to allow Mexico trucks into the U.S.
“As we are dealing with the European Grapevine Moth, it is ironic that President Obama is meeting with Mexican President Calderon where the truck issues will likely be discussed and hopefully resolved. If it is, I can just hear someone say, ‘Oh, by the way about the insect…,” Bedwell bemoans.
Bedwell points out that so far only six moths have been trapped in a portion of Fresno County, while there have been more than 75,000 trapped in Napa County since the first one was identified last fall. Speculation is that the moth was brought into the premium wine growing region on smuggled plant material.
“Obviously, what we are finding are moths that have somehow hitchhiked out of Napa into the Central Valley and other areas,” said Bedwell. Napa and Fresno are 200 miles apart. What has been found in relatively small areas of Fresno County is not an infestation, he points out. “The quarantine does not cover Fresno County … only a small portion of it. That is important to let our customers know.”
Similar distances separate Merced and Monterey from the North Coast.
Robert Leavitt, director of the California Department of Food and Agriculture plant health divisions, said the state has 47,000 traps in all grape growing areas (40 counties).
The vast trapping program was ordered after late fall finds in Napa last year and the discovery that at least two Rutherford area vineyards had total crop losses attributed to breeding EGVM population. This worm pest feeds only on grapes in all stages of development.
Leavitt said it became obvious EGVM was established in Napa last fall. “We did not catch many moths then because they were just going into diapauses,” he said, adding that CDFA knew it had to initiate an aggressive trapping campaign to see if and where EGVM had spread elsewhere in California. At stake is California’s $3.9 billion grape industry and accessibility to major world and domestic markets where EGVM has not invaded for a wide array of California fresh fruit. It is primarily a pest in Europe and is widespread in Chile. However, it has not been detected in many parts of the world, including Australia, New Zealand, Canada and Peru.
Leavitt emphasized that the finds this spring outside of Napa do not mean that the moth is spreading. The trapping is to find out where it might pose an establishment threat so aggressive action like quarantines and stepped up farmer insect control programs can prevent it from becoming established outside the North Coast.
What makes the EGVM particularly insidious in the Central Valley is that quarantines involve a whole host of crops, not just grapes as is the case in the North Coast. It does cause major damage in non-grape crops, but it can survive on olives, plums, apricots, cherries and many other crops and ornamentals.
Virtually all of the crops within the quarantine areas are impacted by regulations. This involves inspections and regulations covering movement of not only fresh packed fruit, but culls and dehydrated fruit. All nursery stock is covered by quarantine rules. Growers must sign compliance agreements to say they will abide by quarantine rules.
“We need to control this bug and not put farmers out of business,” said Manual Cunha, president of the Nisei Farmers League.
Cunha grilled federal officials about various production and packing scenarios and how the quarantines would impact growers and packers. He got many vague answers.
The insect has been found in so many areas that federal, state and county officials are scrambling to cover all production situations within its quarantine regulations.
Leavitt said there will be no mandatory spray programs; however, government officials were encouraging growers to monitor and initiate aggressive control programs. There may be government-directed treatments of wild areas and abandoned vineyards that may host the pest.
Leavitt said it will take 18 months to prepare an environmental impact report on any government-directed eradication program, if it becomes necessary.
“We need to eradicate this pest immediately. We cannot wait two years,” said Cunha.
Tye Hafner, deputy Fresno County ag commissioner, believes the pest can be contained within quarantine areas. There are 800 growers within the one in Fresno County and with voluntary compliance to the quarantine rules and aggressive growers control programs, EGVM can be turned back and not get out of hand like it has in Napa.
Unfortunately, even if growers are successful by frequent trap data, government officials told growers quarantines would not be lifted until the pest has gone through its life cycle without any more finds. That could be at least for a season.
These Web sites provide extensive, detailed information about the pest and what state, federal and county governments are doing to bring it under control:
• Link to the UC IPM Web site: http://www.ipm.ucdavis.edu/EXOTIC/eurograpevinemoth.html
• Link to the California Department of Food and Agriculture Web site: http://www.cdfa.ca.gov/PHPPS/egvm/index.html
• Link to an extensive report from the EGVM Technical working group: http://www.aphis.usda.gov/plant_health/plant_pest_info/eg_moth/downloads/TWG-Report-2-10.pdf
• Link to Napa County's latest info on EGVM: http://cenapa.ucdavis.edu/newsletterfiles/newsletter2084.htm
UC IPM specialist Walt Bentley at Parlier, and his counterpart on the North Coast, Lucia Varela in Sonoma County, and others recently went to Chile where the EGVM was first detected in 2008. Varela is on the CDFA technical working group developing containment strategies for the state program. Varela, said Bentley, has developed much of the information about EGVM.
Damage from the EGVM looks similar to the raisin moth larvae. It looks like the mature berries have been peppered with shotgun pellets. Mold, particularly Botrytis, develops quickly in berries drilled by the worms.
It is similar in damage inflicted by many leafrollers.
There are three generations a year and EGVM feeds only on the grape flowers and bunches, not on leaves or other parts of the grapevine as do many other leafrollers. It overwinters in the bark, fence posts or abandoned vines where Bentley says it escapes control measure.
The same material used to control other leafroller and Lepidopterous pests are effective on EGVM.
Early season, it takes at least seven days for eggs to hatch. Later in the year, that drops to only three to six days when the weather warms.
Growers David and George Flagler believe, if established, EGVM would have overlapping generations, making it more challenging to monitor and time control.
“Some believe that when temperatures reach the upper 90s there will be some mortality. I do not agree,” said Bentley.
Bentley also believes DOV raisin vineyards with bunches hanging down and gable-trellised table grapes are particularly vulnerable, since bunches hang down from the vines and are openly exposed.
There are a host of larvicides and ovicides registered to control EGVM. Bentley recommends first use of Intrepid, an insect growth regulator with the longest residual.
Several Bt products (Dipel and Biobit) are available for organic growers.
Other products he said will also control EGVM are diamides Altacor and Belt; Sodium channel blocker; Avaunt; spinosyns Success, Entrust and Delegate; pyrethroids, Danitol, Baythroid, Brigade, Renounce and Tombstone Helios; carbamates Lannate, Sevin XLR and Sevin and organophosphate Imidan.
These products are segregated by modes of action to alert growers and PCAs to rotate chemistry to ward off resistance.
There is a newly registered pheromone mating disruption product. It is Isomate EGVM from Pacific Biocontrol Corp. from Vancouver, Wash. It is a double tube dispenser composed of a plastic tube filled with the pheromone solution. It looks like a pipe cleaner. It is tied to trellis wire.
The pheromone is the same as is being used in Delta traps to detect the EGVM. Government officials do not want growers in uninfested areas to use the pheromone-laced ties for mating disruption, since it would render the Delta traps useless and the government would lose the capability to detect moths with the government traps.
However, government officials in Parlier said Napa area growers are using the ties, since EGVM is well established there.
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