Bug of the Month: Cucumber Beetles

And the winner of the bug of the month contest is the cucumber beetle.  They have hit vine crops hard this year.  The striped cucumber beetle is one of the most damaging pests on cucurbits, such as squash, cucumber, melon and pumpkin. The larvae can cause severe damage to roots. A single adult beetle can cause severe damage to an emerging plant by feeding on the lower surface of leaves. Next generation adults (overwintering) are known to feed inside flowers, preventing pollination and fruit set. These beetles also spread bacterial wilt, cucumber mosaic, and squash mosaic virus.

Because overwintering cucumber beetles are around by the time cucurbits are up or transplanted, it is important to check at least daily to control the pest. Handpicking is most effective if done early in the morning when most feeding occurs. These beetles are easy to kill, but because more keep arriving on the plants, it sometimes seems as though controls are not effective. Barriers of row covers, spunbonded remay, cheesecloth, etc., can protect your plants; remove by midsummer to permit pollination.

Removal of goldenrod, aster, etc., from the vicinity of cucurbits helps reduce the number of beetles. Removing plant debris or keeping it to a minimum is also advisable.

Insecticides labeled for vegetables containing pyrethrum, rotenone, methoxychlor, or carbaryl (Sevin) should control the beetles.

Source: Dill, J. & C. Kirby, Striped Cucumber Beetle, Pest Management Factsheet, UMaine Extension, 2004.

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