How to Manage Pests
UC Pest Management Guidelines
Scientific name: Cydia pomonella
(Reviewed 5/06, updated 4/09)
In this Guideline:
DESCRIPTION OF THE PEST
Larvae are white to pinkish caterpillars with brown to black heads. Adult moths have gray wings with a copper spot on each wing tip. After overwintering as mature larvae in silken cells under loose bark on the tree, moths emerge from March to May. Adults mate and lay eggs; larvae feed on small fruit. A second generation appears in June and often a third one in August, depending on temperatures.
Fruit feeding by the codling moth has resulted in a high percentage of unmarketable fruit in some orchards. Codling moth larvae usually tunnel all the way to the pits of fruit; extrusions of frass or excrement are often found at the entrance of the larval tunnels.
Codling moth is a pest in plums in the San Joaquin Valley that can be controlled with a single treatment timed using pheromone traps and degree-days.
An important egg and larval parasite is the braconid wasp, Ascogaster quadridentata. Natural enemies do help control codling moth but are unable to keep it below economic injury because it spends most of its larval stage inside the fruit, where it is protected from predators and parasites.
Remove abandoned or unsprayed apple, pear, plum, apricot, and walnut trees near the plum orchard.
Monitoring and Treatment Decisions Sunset temperatures
Calculate degree-days for codling moth in your location.
Learn to use degree-days to time insecticide applications.
Pheromone traps, degree-days (DD), and twilight temperatures are used to monitor codling moth activity. Soon after bud break or by March 15, place pheromone traps in your orchards to determine first moth emergence. See PHEROMONE TRAPS for more details and record results on a sampling form. The first biofix is the first date that moths are consistently found in traps and sunset temperatures have reached 62°F. To predict egg hatch, begin accumulating degree-days (DD) from the biofix, using a lower threshold of 50°F and an upper threshold of 88°F. Remove trapped insects from the trap bottom after you count and record information on the monitoring form .
Population levels of codling moth vary greatly from one area to another and from one variety of plums to another. If codling moth has caused damage in previous years, consider treating for this pest.
First generation egg hatch
Time the first spray for the beginning of egg hatch to kill emerging larvae 250-300 DD after the first biofix.
Second and third generation egg hatch
Use pheromone trap catches to detect an increase in flight activity around 1060 DD from the previous biofix, which signals the start of the next moth flight. If treatment is warranted, a single application is usually sufficient. Make this application when 250 DD have accumulated from the second or third biofix.
Take a fruit damage sample at harvest to assess the effectiveness of the current year's IPM program and to determine the needs of next year's program. See FRUIT EVALUATION AT HARVEST. Record results on a monitoring form .
UC IPM Pest Management Guidelines:
Insects and Mites
Acknowledgment for contributions to Insects and Mites:
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