Pest description and crop damage Adults are dark and shiny with upturned labial palps characteristic of the family Gelechiidae. Adults range in size to about 0.5 inch long. When disturbed, they make short, darting flights and suddenly hide at the base of vegetation or under clumps of soil. The larvae are about 0.5 inch long and have rusty, red-brown, or slightly pinkish body segments, with a deep tan head capsule.
These insects feed on grass crowns, killing the plant outright or severely stunting growth. They feed on the root system and often burrow into the base of the stem. Damage first appears as individual dead tillers, progressing to destruction of the plant during August to November. This pest is found in eastern Oregon, Washington, and Idaho.
Biology and life history Larvae feed in spring and pupate on the soil surface in late April or early May. Adults emerge 2 weeks later, in mid-May through June and sometimes into July. Eggs are laid on the host plant in clumps of 5 to 25 in early June through July. Eggs hatch in about 5 to 10 days. Larvae feed into the fall, diapause until the next spring, and then resume feeding again for a month or so until they mature and pupate. There is one generation per year.
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