Friday, December 16, 2011

My Zucchini Has Dimples

Summer squash, like zucchini, are harvested when they are immature.

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Zucchini is a common type of summer squash and is related to other vine crops like pumpkins and watermelons. Although it originated in Central and South America, the zucchini was developed and cultivated in Italy. Several insect pests attack zucchini, but if you are seeing dimpled or puckered spots on your fruit, the squash bug is the likely culprit.

Related Searches: The Squash Bug

Adult squash bugs are members of the order Hemiptera, or true bugs. Adults are around five-eighths of an inch long and are dark brown to black with yellow-orange stripes along their wing margins. Immature squash bugs are greenish gray with red or black legs, heads and antennae. Eggs are laid under leaves and are yellowish brown to red.

Life Cycle

Adults overwinter in crop debris, weeds or other sheltered spots and emerge in the spring to mate and begin laying eggs. Eggs are laid in clusters of 12 to 20 on the undersides of leaves and hatch in 10 to 14 days. Females lay around 250 eggs during their lives. Nymphs begin feeding immediately after hatching and molt five times before becoming adults. It takes between four and six weeks for nymphs to mature into breeding adults. This second generation feeds until winter. When cold weather arrives they will find sheltered spots to wait until spring before mating and starting the cycle over.


Squash bugs use needle-like mouthparts to suck sap from leaves, vines, stems and fruit. As they feed they disrupt the flow of sap through plant tissues, causing necrotic spots. Initial feeding on leaves are yellow spots. These spots eventually turn brown and crispy. Feeding on stems can cause leaves to suddenly wilt and die. On fruit squash bugs cause sunken, puckered or dimpled spots that can reduce storage life. Squash bugs are also known to spread fatal diseases, such as bacterial wilt and cucurbit yellow vine disease.


Manually picking squash bugs, nymphs and eggs off plants is effective for small gardens or small infestations. Row covers are effective at excluding pests from zucchini, but should be removed when the plants begin to flower so pollination can occur. Place boards, cardboard or newspaper next to your vines. Check underneath the boards in the morning and destroy any squash bugs you find. Clean up all crop debris at the end of the season and keep your garden weed free to eliminate overwintering sites.

ReferencesUC IPM Online: Squash BugUtah State University Extension: Squash BugUniversity of Illinois Extension: ZucchiniPhoto Credit Hemera Technologies/ ImagesRead Next:

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