Repulsion of Cucumber Beetles in Cucumber and Squash Using Aluminum-coated Plastic Mulch

Abstract

Cucumber (Cucumis sativus L.) and squash (Cucurbita pepo L.) were grown in a replicated trial on three types of plastic mulch: solid black plastic mulch, solid aluminum-coated plastic mulch with a silver reflective appearance, and black plastic mulch with two aluminum-coated strips attached. Striped cucumber beetle (Acalymma vittata Fabricius) and spotted cucumber beetle (Diabrotica undecimpunctata howardi Barber) (Coleoptera: Chrysomelidae) counts on yellow sticky cards were obtained over eight weekly samplings. For cucumber, on the peak beetle population date, there were six times as many striped cucumber beetles in solid black plastic mulch as in aluminum-coated plastic mulch, and nearly three times as many as in black plastic mulch with aluminum strips. For squash, both striped and spotted cucumber beetle counts were significantly higher on solid black plastic mulch on three peak sampling dates than on aluminum-coated plastic mulch and black plastic mulch with aluminum strips, with counts 4.9 to 5.5 times higher in solid black plastic mulch than in aluminum-coated plastic mulch, and 2.2 to 2.6 times higher than in black plastic mulch with aluminum strips. Using a threshold of 15 beetles/sticky card, no insecticidal applications were needed on solid aluminum-coated mulch, while an average of 1.8 insecticidal applications were needed on solid black plastic mulch, and 0.8 insecticidal applications on black plastic mulch with aluminum strips. The cost of solid black plastic mulch and its insecticidal applications, $186/acre ($459/ha), was $102/acre ($252/ha) less than the cost of aluminum-coated plastic mulch without insecticidal application, $288/acre ($711/ha). However, squash fruit from plants grown on aluminum-coated plastic mulch could be direct marketed as pesticide-free, at a price 25% higher than fruit on which pesticide had been applied. For an average yield in Virginia of 600 boxes/acre (1,482 boxes/ha) [20 lb/box (9 kg/box)] of squash, this translates to a $1,200/acre ($2,964/ha) increase in revenue. Yield on aluminum-coated plastic mulch was delayed by one week, but there were no significant differences in cumulative yield over 14 harvests.