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Seedling
corn is attacked each spring by a variety of caterpillars. Many cutworms can
damage the emerging corn seedling. The most damaging is the Black
Cutworm. Almost all
cutworm damage to corn is caused by this caterpillar. Black cutworm moths fly
into the Midwest from overwintering sites in the south. Small black cutworms (less than 0.5")
will
feed on leaves, while larger larvae can cut or drill plants. Cutting occurs below
the surface when soil is dry, or above ground when soil is wet and tight around
the plant. Cutting rarely occurs after the fifth true-leaf stage but cutworms
may drill into the side of larger stalks. Other
cutworms damage corn seedlings, but not to extent of the black cutworm. Amongst
these are: Dingy
cutworms rarely cut corn, but the leaf feeding is similar to black cutworm
damage. Dingy cutworms overwinter in the Midwest, after hatching in the fall.
Blacks have grainy skin like sandpaper, whereas dingys have smooth skin. Sandhill
cutworms only occur in areas of very sandy soil. The damage is similar to
that of the black cutworm. Most of the cutting occurs below the soil surface.
Injury first appears as wilted leaves, then as dead plants. This cutworm is
light tan, semitranslucent, and has several pale, longitudinal stripes. It
hatches in the fall then overwinters as a partially grown larva. Glassy
cutworms are oftimes a problem when corn is planted into a grassy pasture.
Injury is similar to that caused by other cutworm species. The head and neck
region is reddish brown. The body is cream colored and semitransparent or
"glassy" in appearance; the internal organs can be seen through the
skin on small larvae. Glassy cutworms overwinter as small larvae. Bronzed
cutworms are also commonly found in grass pastures and sod fields planted to
corn. they feed primarily on grasses, but occasionally can cut corn plants. The
larvae have seven stripes, four brown and three yellow, running the length of
the body. The general body color is dark brown with a bronze sheen. Variegated
cutworms can feed on the ears of maturing corn.
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