Influence of mulches on the colonization by adults and survival of larvae of the Colorado potato beetle (Coleoptera: Chrysomelidae) in eggplant

Abstract

Six treatments (no mulch, black plastic mulch, black plastic painted with reflective aluminum paint, straw mulch, black plastic plus straw, and a living mulch of rye growing between the rows) were used to grow eggplant and to observe the effects on movement of adult Colorado potato beetles, Leptinotarsa decemlineata (Say); oviposition; and density and survival of larvae. Straw mulch and rye treatments reduced movement of overwintered beetles into the plots and also reduced the growth of the plants compared to black plastic mulch. Survival from the egg to small larva (first and second instar was lower in the plots with straw mulch and black plastic plus straw than in plots with rye, bare ground or aluminum-painted mulch. None of the treatments had an effect on movement of the first generation adults, which was primarily determined by the proximity of the plots to the source field of potatoes. It may be possible to combine the positive effects of black plastic on early season growth and straw mulch on reducing the survival of potato beetle larvae by transplanting the eggplants into black plastic mulch, then adding straw as the egg masses of the potato beetle begin to hatch.