Webworms


John Van Duyn, North Carolina State University, Entomology Extension Specialist

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Several species of webworms (Crambus Spp.) may occasionally be found feeding on seedling corn plants. Webworms overwinter as caterpillars in the soil and around grassy plants. They eat a wide variety of grasses. Webworms typically construct a silken tunnel in the soil, leading to the host plant. The short (1/4 to 1/2 inch long), hairy, usually spotted, and active caterpillars are most often found in or near the silken tunnel. Damage ranges from foliage feeding where leaves will show holes and ragged edges, to small seedlings being cut off, resembling cutworm damage.

Webworms can be found in most corn fields at very low levels but seldom pose an economic threat. Populations can be much higher when corn is planted after spring plowing of pasture or especially when sod is herbicide killed and planted with no-tillage methods. If necessary, webworms can be controlled with insecticides. The normal scouting methods employed in seedling corn will detect economic infestations if properly done. Sometimes webworms are one of several seedling insect pests acting in concert to threaten a seedling stand (see Scouting for seedling insects).

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Other Resources

  • North Carolina Agricultural Chemicals Manual
  • North Carolina Cooperative Extension Service
  • Return to Vernon James Center Publications Page

    John W. Van Duyn Ph D. Extension Entomologist, Wayne Modlin, Res. Tech. III.

    Date Created 1/30/01.
    Last revised on 1/30/04.

    Published by North Carolina Cooperative Extension Service

    Distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914. Employment and program opportunities are offered to all people regardless of race, color, national origin, sex, age, or disability. North Carolina State University at Raleigh, North Carolina A&T State University, U.S. Department of Agriculture, and local governments cooperating.

    CAUTION: The information and recommendations in these Notes were developed for North Carolina conditions and may not apply elsewhere.