Apple moth may interfere with plant shipments Califonia Farm Bureau Federation
California Weather Forecasts Ag Alert: Apple moth may interfere with plant shipments

Apple moth may interfere with plant shipments

Issue Date: May 9, 2007

By Ron Miller

Nurseries in Santa Cruz and San Mateo counties fear the loss of the huge Mother's Day markets as a result of an eight-county infestation of light brown apple moths.

In order for a shipment of nursery stock, cut flowers and plant materials to be permitted from nurseries located within 1.5 miles of moth trapping sites, it must be visually inspected and certified as free of the pest. Outside the 1.5-mile area, host item production facilities must be inspected once, and if pest free a certificate will be issued permitting shipments.

The federal order also requires survey trapping, nursery treatment applications and precautionary production practices within quarantine areas. The U.S. Department of Agriculture's Animal and Plant Health Inspection Service (APHIS) and the California Department of Food and Agriculture (CDFA) continue to work together in implementing these activities.

"Growers in counties with the light brown apple moth are not only concerned about possible loss of foreign markets, they also must have their produce inspected to ship to farmers' markets outside their counties," said Rayne Thompson, director of horticultural crop policy for the California Farm Bureau Federation. "Ag commissioners in those counties are focusing their personnel on the needed inspections."

The main infestation of the insect is now centered in the Soquel region of Santa Cruz County where nearly 85 percent of the light brown apple moths have been found in traps. Two wholesale nurseries and the regions surrounding them are where most of the insects have turned up so far. Statewide, nearly 1,800 of the moths have been trapped.

There were unconfirmed reports on Monday that moths were trapped within 1.5 miles of two nurseries in Half Moon Bay. Thus far the insect has been found in eight Bay Area counties, while there are traps set in 38 counties. The exotic insect found the San Francisco Bay area communities feasts on more than 250 different agricultural crops.

"The insect feeds on every crop we grow in Santa Cruz County except cattle and redwoods," said Jess Brown, executive director of the Santa Cruz Farm Bureau.

The current theory is that the light brown apple moth somehow was introduced into Santa Cruz County near the nurseries, said Larry Hawkins, spokesman for the animal and plant health and inspection service in Sacramento.

"No one suspected it was there and undetected insects were taken to Bay Area locations on nursery shipments," he said.

APHIS has issued a two-tiered quarantine, which restricts movements of certain items such as nursery stock, cut flowers and greenery from the eight California counties where moths have been trapped. A similar quarantine exists for the entire state of Hawaii where the light brown apple moth has existed since the late 1800s.

A technical working group of scientists from the United States and New Zealand will meet this month to develop a plan to deal with the light brown apple moth and determine whether the pest can be eradicated, rather than just be contained. Both USDA and CDFA officials expressed hope that the insect can be eradicated.

While all farmers are concerned about the pest, organic farmers have expressed special concerns about what any attempt to eliminate the insects may do to their businesses.

Hawkins reported that there are pesticides certified for organic use such as Spinosad and BT which are effective against the light brown apple moth.

"Santa Cruz County is a leader in organic farming and there are farms located throughout the county," said Brown. "The current finds of the insect are in an urban region. They are about 7 miles as the crow flies from the major apple and strawberry growing regions of the county."

Strawberries are currently being harvested in Santa Cruz and Monterey counties and various bush berry crops will soon start. Government officials are scrambling to find inspectors to check and certify that farms do not have the light brown apple moth.

The list of regulated items on the federal order is somewhat all encompassing. Included are: nursery stock, cut flowers, garlands, wreaths or greenery of any plants, trees and bushes including cut Christmas trees, green waste, fruits and vegetables, hay, straw, fodder, plant litter, bulk herbs and spices, and any other products, articles or means of conveyance of any character whatsoever when it is determined by an inspector that they may present a hazard of spread of light brown apple moth.

The cost of inspections may be passed on to the customers of the wholesale nurseries.

"This pest has not been found in San Diego County, but our nursery growers have had to have inspections for the sudden oak death pathogen, and they have been able to pass the cost along to their customers," said Eric Larson, executive director of the San Diego County Farm Bureau. "Nurseries in other states have accepted that added cost is what it takes to do business with California nurseries."

The light brown apple moth is native to Australia and over the years it has made its way to New Zealand, the United Kingdom, other Pacific islands and Hawaii. It passes through three generations annually and has no winter resting stage. There is considerable overlap in generations. Eggs are laid in clusters on leaves of fruit, and the larvae cause damage to both foliage and fruit. Superficial damage is common in apple varieties, but internal damage is less common although a young larva may enter apples, pears or citrus. The pest destroys, stunts, or deforms young seedlings and spoils the appearance of ornamental plants. It feeds on more than 250 different species including occasionally Douglas fir trees.

The larvae are up to 25-mm long and pale to medium green in color. The adults are difficult to see, as they are light brown in color and only about 10-mm long. They like to roost on the underside of leaves and are not capable to flying long distances. They usually don't fly more than 400 feet, but when attached to plant leaves can be transported great distances.

CDFA spokesman Steve Lyle said a retired University of California, Berkeley entomologist first discovered the pest in California. That happened in February. Laboratories have since confirmed the identity of bug.

"He like many other retired entomologists continues to collect and examine insects. He found this one in his backyard, identified it and then alerted us."

Hawkins said that thus far other countires have not banned California products.

"Canada and Mexico have asked permission to send inspectors to observe how the matter is being handled, and that permission has been granted," he said.

(Ron Miller is a reporter for Ag Alert. He may be contacted at

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