Effects of Straw and Leaf Mulches and Trickle Irrigation on the Abundance of Colorado Potato Beetles (Coleoptera: Chrysomelidae) on Potato in Connecticut

Straw mulch reduced the number of Colorado potato beetle, Leptinotarsa decemlineata (Say), larvae on potato during the first generation, and reduced the proportion of stems that were more than 50% defoliated compared to unmulched and unirrigated control plots. Leaf mulch and trickle irrigation did not affect number of larvae or the proportion of heavily defoliated plants compared to the control. None of the treatments significantly affected the number of adults per stem until the end of the first generation and none affected the number of egg masses, so the straw mulch must affect mortality or development of eggs and larvae. Both types of mulch and trickle irrigation increased yield relative to the control, perhaps due to lower soil temperature in a hot, dry year.