Improved chemical control of cucumber beetles in California melons

In recent years cucumber beetles (Chrysomelidae) have become increasingly problematic as pests of melons grown in the Sacramento and San Joaquin Valleys of California. Current control measures require frequent applications of insecticides throughout the growing season. An insecticide trial was conducted on the UC Davis campus in the summer of 2007 in the hopes of improving the chemical control of cucumber beetles in melons. Efficacy was determined by counting beetles observed on the plants, using sticky traps to catch beetles and rating the damage on the fruit. The study focused on a gustatory stimulant called Cidetrak® which contains cucurbitacins which have been shown to be powerful feeding stimulants for cucumber beetles. In 2007, Cidetrak combined with spinosad did not significantly reduce damage or beetle numbers when compared to the untreated plots. When combined with a low dose of carbaryl, Cidetrak did significantly lower the number of beetles but not damage to the fruit when compared to untreated plots. The study will be repeated in the summer of 2008 with the inclusion of a field cage trial to eliminate inter-plot effects that may have reduced the accuracy of the 2007 trial.