“The western striped and western spotted cucumber beetles both occur in Utah, and feed on leaves, flowers, and fruit rinds. Both species begin activity in the spring, and are around for most of the summer. They are in their second generation now, actively feeding on the skins of watermelon, cantaloupe, zucchini, winter squash, pumpkin, and cucumber. The ripest vegetables are most attractive to feeding.
The first step in managing these beetles is to monitor for their presence. Examine all plant parts including undersides of leaves, at least once/week, starting when vegetables begin to ripen. No thresholds have been set for mature plants, but in general, 4-5 beetles per plant may warrant attention. Keep in mind that most mature plants can support substantial numbers without serious damage.
Three alternatives to an insecticide application are to hand pick beetles (and drop in soapy water), use strips of yellow sticky traps baited with a cotton ball soaked in clove or cinnamon oil, or spray the plants/melons with Surround (kaolin clay), which acts as a deterrent.”- Utah State Extension Small Fruits and Vegetable IPM Advisory
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