Squash Bugs

Description: Eggs are 1/16-inch in diameter and change from light brown to dark red. Young nymphs are pale green with red antennae which later turn black. As the nymphs develop, they turn a light to dark grey color. Mature nymphs are up to ½-inch long and wingless. Adults are ½ to ¾-inch long and dark-brown in color. The wings are brownish-black with orange markings on the outer edge of the body. If crushed, adult squash bugs emit a foul odor.
Life Cycle: Squash bugs overwinter as adults. From late-May through June they seek a plant host. From June through mid-August, after mating, females lay eggs in clusters on the stems and undersides of leaves. Within 7 to 14 days nymphs hatch and go through multiple stages of development. By 4-6 weeks, the adult squash bug is fully developed.
Damage:  The primary hosts for squash bugs include summer/winter squash and pumpkins but they will feed on other cucurbits as well. Adults and nymphs have piercing-sucking mouthparts which they use to suck fluids from leaves, stems and fruits. Young plants are at a great risk for destruction from squash bugs, though mature plants can be severely damaged as well if the pest population is high. Damage appears as small yellow specks on leaves. Stem damage causes wilting and leaves will dry up and shrivel. Feeding on fruit affects the quality by causing distortion and scarring along with sunken areas.
Control: Preventative management is the best recommendation. Scout for pests in the garden regularly. Look on the undersides of leaves and the stems for eggs early in the season. Remove plant debris to reduce overwintering habitats. Physically remove and destroy eggs, nymphs and adult bugs from plants as you find them. Use floating row covers, if garden size allows, to exclude pests from accessing plants.
Horticulture oils can be effective if applied on eggs. Young nymphs can be controlled with insecticides. Weekly application may be necessary for complete control. Adult squash bugs have a thick, waxy cuticle that makes insecticides ineffective. Ensure thorough coverage of the plant for best results. See your local extension agent or KSRE Publication: Squash Bugs for insecticide recommendations.
For more information about squash bugs see KSRE Publication: Squash Bug


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