Lithophane antennata and other fruitworm species
Pest description and crop damage Several species of green fruitworms can attack fruit trees. Adult fruitworm moths vary depending on the species but are generally large, with gray to reddish-brown wings, and are attracted to lights in the fall and spring. Immature larvae are similar to cutworms, with green bodies and heads. Mature larvae are green with white or cream longitudinal stripes. Green fruitworms can also be found feeding on a wide range of hosts such as willow, birch, alder, maple, and strawberry.
Green fruitworm larvae feed on flowers and leaves, occasionally tying them together with silk. When the larvae increase in size, they begin feeding on the fruit, starting inside the cluster and taking bites out of most fruit within the cluster. Badly damaged fruits drop, and damaged fruits that remain have large, russeted cavities.
Biology and life history Depending on species, the insect may overwinter as a pupa in the ground or as a fertilized female on the soil surface. In the spring, eggs are laid on the twigs, often before buds open. The eggs hatch at the pink stage, and young larvae feed on the flowers and leaves, and later on the leaves and fruit. When the larvae mature, they drop to the soil to pupate. Depending on species, they remain as pupae through the winter or emerge as adults in fall, mate, and the females overwinter.
Pest monitoring Examine fruit clusters shortly after fruit set for the small green larvae. They tend to occur in clumps, so thorough monitoring is required.
Birds often are seen eating green fruitworm larvae. Ground predators probably reduce pupal or adult overwintering populations. Some parasitic wasps are also important.
Adults can be collected in black-light traps. Hand-pick larvae when thinning fruit.
Management-chemical control: HOME USE
- azadirachtin (neem oil)-Products containing neem extract may be phytotoxic to some pear cultivars. Some formulations are OMRI-listed for organic use.
- bifenthrin-Highly toxic to bees.
- carbaryl-Highly toxic to bees.
- esfenvalerate-Highly toxic to bees.
- gamma-cyhalothrin-Highly toxic to bees.
- kaolin-Applied as a spray to leaves, stems, and fruit, it acts as a repellant to some insect pests. Some formulations are OMRI-listed for organic use.
- lambda-cyhalothrin-Highly toxic to bees.
- permethrin-Highly toxic to bees.
- pyrethrins-Highly toxic to bees. Some formulations are OMRI-listed for organic use.
- zeta-cypermethrin-Highly toxic to bees.
Management-chemical control: COMMERCIAL USE
- chlorantraniliprole (Altacor) at 2.5 to 4 oz/a. REI 4 hr. PHI 5 days. Do not exceed 9 oz/a per season.
- cyantraniliprole (Exirel) at 10 to 17 fl oz/a. REI 12 hr. PHI 3 days. Do not exceed three applications per season.
- thinning and tying. PHI 14 days. Do not exceed 14.4 oz/a per season. Labeled for use in WA only.