Aphids Inflicting Huge Losses on Organic Farms
Organic farmers in Ventura County stand to lose millions of dollars in crops this year because of the worst outbreak of aphids in a decade.
Growers, who blame the outbreak on drought conditions, say that crops most endangered by the insect are organically grown lettuce, broccoli, cabbage and celery.
“In the mountains, all the vegetation is dry up there, so they come after our crop in stronger numbers,” said organic farmer Dean Walsh. “This is the worst year we’ve had in 10 years.”
Up and down the central coast, organic farmers are trying to exterminate armies of the tiny, winged insects. They say they are severely hampered, however, because--unlike other farmers--they do not use pesticides.
“We’ve had an aphid problem like we’ve never seen in our lives,” said Mary Ann Sprinkle, a spokeswoman for the Carpinteria chapter of California Certified Organic Farmers. “Aphids are on things I’ve never seen them on before.”
There is only a small contingent of organic farmers in Ventura County. Fourteen farmers till 1,200 acres, producing between $10 million and $15 million of vegetables and fruit, growers estimate.
Without organic solutions to the aphid outbreak, “you’re looking at a multimillion-dollar loss for the county,” said Bob Scowcroft, executive director of the California Certified Organic Farmers, which represents 630 growers.
While other farmers can spray chemicals to rid their produce of the pest, organic farmers say they are almost powerless to prevent the damage aphids can wreak. They are turning to nontoxic methods to kill the irksome insects: soapy water, and other bugs.
Organic farmers have been spraying their fields with soapy water by hand to wash aphids off their crops. They also have introduced ladybugs and lacewings, which feed on aphids, into their fields to reduce the aphid population.
Walsh runs the largest organic farm in Ventura County, a 540-acre ranch in Camarillo, and a 280-acre farm near Lompoc in Santa Barbara County. His farm ships about 1 million cartons of organic vegetables to domestic markets each year.
The green bugs suck vegetables dry, ruining produce that is ready for market. Even vegetables believed to be clean of bugs have made their way to supermarket stands, only to be found sprinkled with aphids.
About 10% to 15% of Walsh’s green vegetables were lost to hungry aphids last month when 15 acres were infested, he said. Harvested crops had to be dumped after supermarkets discovered the insect and rejected the produce.
While organic farmers blame lack of rain for the aphid outbreak, county agriculture officials refrain from attributing the outbreak only to the drought. They say the bugs are returning as part of a seasonal reproductive cycle, but admit the population is unusually large this year.
Phil Phillips, a pest management specialist with the University of California farm adviser’s office in Ventura, said lack of rain has broken down the resistance of crops to predatory insects such as aphids. Moreover, plant physiology changes during periods of drought and actually makes them more tasty to their enemies, he said.
“The plant, when it’s under stress, produces more proteins in the plant sap. In doing that, it produces a more nutritious meal,” Phillips said. Hungry aphids see it as “akin to eating filet mignon as opposed to hamburger.”
Aphids leave tell-tale signs of their feasting, Phillips said. After the bug has sucked a plant dry, its leaves curl under or wrinkle.
The only spray organic farmers can use is a soapy insecticide that dries out aphids, but it has only a “mediocre” deterrent effect, Phillips said.
Recently, organic farmers have begun planting other crops to divert aphids away from commercially grown vegetables. They are planting alfalfa, mint and marigold flowers, Walsh said.
Meanwhile, the Walsh farm is bracing itself for another attack on the cucumber and tomato harvest next month, Walsh said.
“Before there were farmers, there were aphids,” he said. “We’re always preparing for them.”
Agriculture officials say the most common signs of aphid infestation are:
* Aphids that are visible on the skin or outer leaves of vegetables or fruits.
* Wrinkled, curling or deformed leaves that indicate aphids have been sucking the juices out of the plant.
* Discoloration, such as small yellow specks, particularly on the outer leaves of cabbage.
* A sticky, filmy residue on the outer leaves and skin.
Produce that does have aphids can still be eaten, growers said. They add that a thorough rinse of the vegetable usually gets rid of the bugs.