California agricultural officials will release hundreds of tiny, stinger-less wasps this month to combat the fruit- and leaf-eating light-brown apple moth, in a move to find alternatives to aerial pesticide spraying.
The California Department of Food and Agriculture will deploy the wasps, no bigger than a grain of rice, in San Luis Obispo and Sacramento counties and may expand the program to other counties with more serious infestations. The wasps lay their eggs inside light-brown apple moth eggs, where they incubate until the larvae emerge and kill the developing moths.
"These tiny wasps are harmless to people and pets, but they have a big appetite for the eggs of light-brown apple moths," said California Agriculture Secretary Karen Ross. She added that the "integrated pest management approach" minimizes detrimental effects.
The new, nontoxic approach comes after environmental groups took issue with the agency in 2007. The agency attempted to eradicate apple moths in Monterrey and Santa Cruz by quarantining crops and spraying a pheromone mixture without first conducting an environmental impact report. Hundreds of people reported falling ill, and environmental groups successfully fought the method in court. Since then, the agency has moved from trying to eradicate the species to controlling its population, but critics say the moth was never a threat in the first place.
"Using wasps may be a preferable solution in a situation where crops are going to be devastated," said Nan Wishner of California Health Initiative, "but the insect hasn’t been a threat."
A 2010 state environmental impact report confirms that there have been "no published studies of crop damages," but Steve Lyle, a spokesman for the Department of Food and Agriculture, said the apple moth has "caused a small amount of damage to California crops and plants and may have the potential to cause much more." The agency’s preventive measures stem from apple moth infestations that damaged crops in Australia, where the moth originates, and New Zealand.
Though the apple moth’s population in California is small, Lyle said, the agency is working to keep it under control. "If we waited for damage, it would be too late," Lyle said. "The hope is that there is never much damage."