California Oak Moths

Killer wasps fighting hungry moths: the organic pest-control ...

In an attempt to curb an invasive moth infestation, the California Department of Food and Agriculture (CDFA) will release stingerless wasps to organically control the population and protect crops in Sacramento and San Luis Obispo counties.

The light brown apple moth (LBAM), originating in Australia but now also widespread throughout the United Kingdom, New Zealand, Ireland and New Caledonia, was first reported in California in 2007. According to a United States Department of Agriculture description of the LBAM, the species affects “over 1,000 plant species and more than 250 fruits and vegetables,” including cypress, redwood and oak trees, as well as grapes, nectarines and cherries.

Cal Poly horticulture and crop science assistant professor Michael Costello, said due to other pests that already affect grapes and fruits in California, the state worries about the effect of this species of moth.

“We already have two grape moth pests that are pretty closely related,” Costello said. “If it were just a grape thing, we could just deal with it. But (because) it feeds on lots of different fruit plants, we get a little worried.”

Steve Lyle, the director of public affairs for CDFA, said “the objective of all CDFA pest management programs is to stop the pest before it causes damage.”

In order to do this, the release of the wasps will be part of an integrated pest management (IPM) program, intended to not only suppress the effects of invasive pests, but also, suppress environmental effects.

Assistant professor David Headrick, who also works in the horticulture and crop science department and helped advise the secretary of the CDFA “regarding appropriate measures for (LBAM) eradication (and) control,” said the tiny, microscopic wasp, called a Trichogramma platneri, “seeks out” the eggs of LBAM and “insert(s its) own egg;” thus, the wasps help kill the moths biologically instead of using pesticides. Headrick said the wasp also is indigenous to California so it is already incorporated into the ecosystem.

“If we can deploy a native wasp to attack the LBAM populations, and hopefully, maintain them at non-economic levels, then to me that is a reasonable, responsible and environmentally-appropriate approach,” Headrick said. “Invasive species impact all of us and it’s important that we evaluate each one and make good decisions about what to do. Not doing anything is not a good approach.

Bulletin - California Agricultural Experiment Station

Bionomics of the California oak moth

Manual of tree and shrub insects, a general account of the more important or common insects attacking shade and forest trees and shrubs and woody ornamentals

Proceedings of the annual meeting

California Insects