Eggs appear white when first deposited, and then turn a yellow-gray color.
Pale Western Cutworm DescriptionĪdult: Mottled gray with yellowish and brownish spots on the forewing and a wingspan of 1.25 inches (32 mm).Įgg: Spherical and about 1/16 inch (1.6 mm) in diameter. Several larvae may also feed on a single ear of corn, especially during high infestations. Larvae from a single egg mass can invade nearby plants within a 6 to 10 ft circle, causing patchy infestations throughout the field. Injury from larval feeding can result in lower quality and reduced yield.
Damaged kernels are more prone to molds and mycotoxin infection. Larvae enter the ear through the tip or by chewing through the husk and feeding directly on developing kernels. Larvae feed on leaf tissue, fallen anthers/pollen, and silks on their way to the ear where most of the feeding is concentrated. Western bean cutworms have a single generation each year. As temperatures rise the following spring and early summer, larvae pupate and complete development into adults. These larvae remain in a dormant state throughout the winter. Once in the soil, larvae construct earthen overwintering chambers with their salivary gland secretions. When feeding and development is complete, fully mature larvae drop to the ground and burrow 3 to 9 inches beneath the soil. Larvae feed on corn plants for about 30 days. Newly hatched larvae feed on their egg shells before moving to other protected feeding sites. Egg masses contain an average of 50 eggs, but can range from 5 to 200 eggs per mass. They lay eggs in masses primarily on the upper surface of leaves. Females are attracted to fields with corn that is in late whorl or tasseling stage. Females lay eggs in July and August on a variety of non-cultivated and cultivated host plants including sweet corn. Adult moths emerge mid-summer and mate shortly afterwards. The western bean cutworm is a late-season pest of corn. Pupa: Dark brown, oval shape Life History As larvae mature they lighten to a gray-pinkish color and are about 1.5 inches (38 mm) long with three short dark stripes on the first segment behind the head. Larva: Brown with faint crosshatching on their backs when newly hatched. Eggs change color with age from white to brown, and then finally turn a dark purple just before hatching. The hind wings are light colored with no distinct markings.Įgg: Dome-shaped and pinhead-sized, white with a thin, red ring around the top when newly hatched. A crescent shaped mark is also located between the spot and the tip of the wing. Adjacent to the stripes, towards the center of the body, and in the middle of the wing lengthwise, is a circular white and tan spot. Western Bean Cutworm and Pale Western CutwormĪdult: Brown bodied moths, about ¾ inches (19 mm) long with a wingspan of 1.5 inches (38 mm) and marked with creamy white stripes on the leading edge of the forewings.
0 kommentar(er)
