GROWTH, DEVELOPMENT, AND SURVIVAL OF THE LARVAE OF THE RED TURNIP BEETLE, ENTOMOSCELIS AMERICANA (COLEOPTERA: CHRYSOMELIDAE), ON BRASSICA CAMPESTRIS AND B. NAPUS (CRUCIFERAE)

Abstract

AbstractGrowth, development, and survival were investigated for the larvae of the red turnip beetle, Entomoscelis americana Brown, fed excised cotyledons or first true leaves of four cultivars of Brassica campestris L. (Torch, Echo, Candle, and R500) or three cultivars of B. napus L. (Midas, Target, and Tower) in the laboratory. The red turnip beetle has four larval instars and its growth curve is S-shaped. The seven cultivars of B. campestris and B. napus tested were suitable host plants for the larvae. On all the cultivars, survival was relatively high, the weights and developmental times were similar, and the percentage of malformed adults was low. In B. campestris and B. napus, the cotyledon stage was marginally better than the first true leaf stage as food for the larvae. Survival usually was higher and in one of the three experiments the adults at emergence were heavier on the cotyledons than on the first true leaves. However, the developmental times were similar, except in one of the three experiments where they were longer on the cotyledons, and the incidence of malformed adults was low on both stages of plant growth.