Bertha armyworm (Mamestra configurata)
Spotted cutworm (Xestia c-nigrum)
Variegated cutworm (Peridroma saucia)
Pest description and crop damage Several species of cutworm, including the spotted cutworm and the variegated cutworm, may be in orchards at various times. Larvae are caterpillars that vary in color from dirty white to greenish or pinkish grey. Mature caterpillars may reach 1 to 2 inches long. Depending on species, they may overwinter as pupae or mature larvae in the soil or groundcover. Weeds are the preferred source of food for these larvae, and eggs typically are laid on weeds around the trees. Early in the spring, cutworm species may climb up trees at night and excavate out the developing buds and/or chew ragged holes out of new leaves, particularly those near the base of the tree. The adults are rather nondescript moths ranging in color from gray to brown with unique patterns of spots and bars on their wings.
Pest monitoring In the early spring around bud swell and throughout spring, scout fruit trees for signs of bud or leaf damage, particularly if the orchard or fruit trees have a history of cutworm damage. Confirm cutworm damage by scouting for the caterpillars at night with a flashlight.
Control weeds, grasses, and debris in the orchard that provide cover. Weed management prevents initial infestations of cutworms and eliminates natural ladders to lower limbs of the fruit tree. When practical, use a flashlight to find and hand-pick cutworm larvae in the lower canopy or groundcover at night. Caterpillars can be trapped by tying plastic wrap tightly around the base of branches and trunk, then applying sticky adhesive or a similar sticky material to the plastic wrap. Remove these wraps in the autumn.
Chemical applications target the overwintering caterpillars that seek to feed on green tree tissue before their normal weed host emerges. Later in the season, these applications target the young actively-feeding caterpillars as the older and mature caterpillars tend to be more tolerant of pesticides.
Management-chemical control: HOME USE
- azadirachtin (neem extract)-Some formulations are OMRI-listed for organic use.
- Beauveria bassiana-Some formulations are OMRI-listed for organic use.
- carbaryl-Highly toxic to bees.
- esfenvalerate-Highly toxic to bees.
- gamma-cyhalothrin-Highly toxic to bees.
- insecticidal soap-Not recommended for use on yellow-skin nectarine varieties. Some formulations are OMRI-listed for organic use.
- kaolin clay-Repels some insect pests when applied as a spray to leaves, stems, and fruit. OMRI-listed for organic use.
- lambda-cyhalothrin-Highly toxic to bees.
- permethrin-Peach only. Highly toxic to bees.
- pyrethrins-Some formulations are OMRI-listed for organic use.
- spinosad-Highly toxic to bees. Some formulations are OMRI-listed for organic use.
- zeta-cypermethrin-Highly toxic to bees.
Management-chemical control: COMMERCIAL USE
Dormant and delayed-dormant sprays
- chlorpyrifos (Lorsban Advanced) at 1.5 to 4 pints/a + horticultural mineral oil (rates vary; check product label). REI 4 days.
Spring and summer sprays
- methoxyfenozide (Intrepid 2F) at 10 to 16 fl oz/a. REI 4 hr. PHI 7 days.
- Entrust 80W at 1.25 to 2.5 oz/a. REI 4 hr. PHI 1 day. OMRI-listed for organic use.
- Success 2F at 4 to 8 fl oz/a. REI 4 hr. PHI 1 day. May act slowly.