Insect Management
Cotton Insect Management
Cutworm -
Various Species
Description
The primary cutworms that attack cotton are the black cutworm, variegated
cutworm, and granulate cutworm. The eggs are laid singly or in groups. The
larvae vary in color and are usually 1-1 /4 to 1-1 /2 inches long at maturity.
The larvae usually feed during the night and hide under clots and leaf trash
during the day. The larvae are often greasy-looking and will curl up into a ball
when touched.
Biology
Cutworms have one to four generations per year depending upon the species.
The eggs are laid singly or in groups on and near the plant. The eggs hatch in 3
to 5 days. The average life cycle is complete in about 30 days, but may range
from 2 weeks to 4 months. Many plants are hosts of cutworms including corn,
beans, cabbage, peanuts, cotton, tomatoes, and clover. Cool, wet weather is
ideal for cutworm damage to occur.
Damage
Cutworms damage cotton in the seedling stage by cutting the plants off at the
ground. They also feed on foliage, roots, and stems. Loss of stand to cutworms
is the most serious consequence of their damage.
Scouting
Symptoms of cutworm damage are wilted plants or plants cut off at the
ground. Cutworm larvae may be found around the base of the plant. Check for
larvae in the soil by gently digging soil around plants. Infestations should be
reported according to following criteria:
None - No damage
Light - 1 to 5% of the plants damaged with some live cutworms found.
Medium - 5 to 15% of the plants damaged and live cutworms present and
cotton stand
threatened.
Heavy - Greater than 15% of the plants damaged, live cutworms present,
and cotton
stand significantly reduced.
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