How to Manage Pests
UC Pest Management Guidelines
Oriental Fruit Moth
Scientific Name: Grapholita molesta
(Reviewed 11/09, updated 11/09, pesticides updated 9/15, corrected 10/16)
In this Guideline:
Description of the Pest
Oriental fruit moth overwinters as a brown mature larva in bark cracks and in leaf litter. The small brown moths emerge in late February. Larvae are white to pink with a brown head capsule. There are five to six generations per year.
Oriental fruit moth is an occasional pest of young cherry trees grown near other hosts such as almonds or peaches. First and second generation larvae mine young, tender shoots, causing them to wilt and die.
Calculate degree-days for oriental fruit moth in your location.
Learn to use degree-days to time insecticide applications.
Oriental fruit moth rarely causes significant damage to cherry trees. Sprays are usually only required if shoot strikes are occurring on young trees that are near other sources of Oriental fruit moth (e.g. infested peach, nectarine, and almonds).
Adult Oriental fruit moth populations can be monitored and treatments timed (if necessary) with pheromone traps. They should be placed in orchards by February 15 in the northern or eastern quadrant of the tree, 6 to 7 feet high. Use three traps per orchard or varietal block less than 30 acres. Use one trap per 10 acres for 30- to 80-acre orchards and one trap per 20 acres for orchards larger than 80 acres. Monitor traps once a week. Replace pheromone lures according to manufacturer's directions and replace trap liners when dirty, or after counting and removing an accumulated total of 150 moths.
To determine optimum time to spray, accumulate degree-days beginning with the first male moth trapped from the second flight, which usually occurs in May. Use a lower threshold of 45°F and an upper threshold of 90°F. The optimum time to treat for Oriental fruit moth is 500 to 600 degree-days after the first trapped male in any flight.
UC IPM Pest Management Guidelines:
Insects and Mites
J. A. Grant, UC Cooperative Extension, San Joaquin County
Acknowledgment for contributions to Insects and Mites:J. Colyn, Mid-Valley Ag. Services
M. Devencenzi, Devencenzi Ag. Pest Mgmt. and Research
P. McKenzie, Mid-Valley Ag. Services