Dangerous new moth detected in California coastal areas

The light brown apple moth (LBAM) was first detected in the Bay area in late February and has since been trapped in Central Coast and Bay area counties.

This is a serious pest and quarantine areas have been established in Alameda, Contra Costa, San Francisco, Marin, and Santa Clara counties, covering 182 square miles. Quarantine areas are expected soon for San Mateo, Santa Cruz (Soquel area), and Monterey (Prunedale, Royal Oaks area) counties.

This quarantine will “prohibit the movement of all nursery stock and host fruits and vegetables from the quarantine region unless it is certified as free from the pest by an agricultural official.”

The LBAM (Epiphyas postvittana) is a tortricid leafroller moth similar to Pandemis moth, orange tortrix, and fruittree learoller which already occur in the Central Coast. It is a native of Australia but also occurs in New Zealand, New Caledonia, Hawaii, the United Kingdom, and Ireland.

The larvae and moth are most similar to Pandemis moth in appearance. There is a pheromone lure available for trapping the adult male moth for monitoring purposes.

More than 250 hosts for the LBAM have been documented. Almost all major fruit and vegetable crops can be infested and many ornamentals.

On fruit trees, the most significant damage is surface fruit feeding, resulting in scarring similar to the other leafrollers. Internal damage to fruit can also occur, but it is much less common. The larvae can enter apple and pear fruits through the calyx.

Internal damage has also been noted as a problem with apricots, peaches, and walnuts. Leaf feeding damage is of lesser significance in tree crops. The overwintering larvae may bore out buds in late winter similar to eyespotted budmoth.

Other leafrollers have been effectively controlled through a combination of biological controls, cultural controls (thinning of fruit clusters), and the proper selection and timing of pesticide applications (both conventional and organically-acceptable) that control the pest without injuring beneficial parasites and predators.

However, additional control measures for this pest may be needed on crops that currently receive few insecticide sprays, such as apricots and cherries, because the LBAM has multiple (3-4) generations per year.

The LBAM also requires excellent spray coverage because it rolls leaves or hides in clusters of fruit. The other major problem will be that certain markets will not accept commodities from the quarantine areas or possibly the whole state. Florida has already imposed a quarantine on all California nursery stock.

The timing and efficacy of insecticide sprays in California have not been researched due to the recent arrival of the pest. Australian sources indicate most spray materials effective for codling moth control will control LBAM.

The official California Department of Food and Agriculture web site is http://www.cdfa.ca.gov/phpps/pdep/lbam_main.htm.

This site has descriptions of LBAM and quarantine maps. Internet web searches for “light brown apple moth” will give you a lot of other information from Australia and the United Kingdom.

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