Neonicotinoid seed treatments for early-season management of cucumber beetles in cucurbits

摘要

In North America, the striped cucumber beetle, Acalymma vittatum (Fabr.), and the spotted cucumber beetle, Diabrotica undecimpunctata howardi Barber, are serious pests of cucurbit crops, especially cucumbers, muskmelons and squash. Adult beetles emerge in the spring and aggregate on cucurbit plants. Female beetles oviposit in the soil at the base of plants where larvae subsequently feed on roots, occasionally reducing plant vigour and yield. However, it is the adults that cause the most severe damageby feeding on foliage and by transmitting the bacterial wilt pathogen, Envinia tracheiphila, which they harbour within their bodies. Young plants are most susceptible to beetle feeding injury and bacterial transmission. Most plant mortality occurs at the cotyledon and first true leaf stage. Cucurbit plants typically can overcome the feeding injury inflicted by cucumber beetles past the second and third true leaf stage.