Tomato Yield Loss as a Result of Simulated Colorado Potato Beetle (Coleoptera: Chrysomelidae) Feeding

Abstract

Tomato crop losses resulting from feeding by the Colorado potato beetle, Leptinotarsa decemlineata (Say), were estimated. Because of the difficulty in restricting adult beetle movement, feeding was simulated by removing foliage three times a week. The quantity of foliage removed was calculated from a model developed earlier. The effects were measured of foliage removal by the offspring of simulated beetle densities of 0.0006, 0.002, 0.006, 0.017, 0.05, 0.15, 0.45, and 1.35 fertile female beetles per plant at the beginning of the season on fruit weight and number of a determinate and an indeterminate tomato cultivar. Regression equations provided an excellent projection of crop losses. The indeterminate cultivar had significant yield loss above a level of 0.002 initial females per plant, and the determinate cultivar above a level of 0.017 initial females per plant. Yields accumulated over 14 weeks showed when significant yield reduction occurred. For the determinate cultivar at harvest time, the yield was reduced significantly at initial beetle levels of ca. 0.05 females per plant and higher. For the indeterminate cultivar, 0.05 females per plant had no significant effect on yield until week 8 of harvesting.