TOBACCO FLEA BEETLE (COLEOPTERA: CHRYSOMELIDAE) DISTRIBUTION ON SEEDLING TOMATOES
Twelve commercial tomato fields were sampled for Epitrix hirtipennis (Melsheimer) feeding damage at the seedling stage in the first year of the study. Samples were taken at distances of 1.7, 33, 67 and 100m from all field margins and at the center, with 25 plants sampled at each location. Analysis showed that percent damaged plants differed significantly (F=4.80, P<0.001) by distance across fields, with fewer plants damaged at distances of 100 m or more from field margins. Number of damaged plants ranged from 48-88%, and most of the cotyledons of infested plants were also damaged. Differences between field margins and centers were less pronounced at lower damage levels, suggesting that some of the infestation might have been originating from within fields rather than by migration exclusively. Ten commercial tomato fields were sampled for E. hirtipennis feeding damage in the study's second year at the same locations in relation to field margins as in the first year. In addition, emergence cages were placed over seed rows at each location to exclude movement of insects into or from the cages. Four fields had tomatoes planted the previous year, four followed wheat, and two followed sunflowers. As in the previous year, damage decreased by distance from field margins, but it was not uncommon to find E. hirtipennis damage within the cages indicating presence of resident field populations. A significant difference (F=54.368; P<0.0001; df=2,47) was observed by previous crop with more damage observed in fields previously planted to tomatoes as compared to wheat or sunflowers.
Zalom, F.G. (2003). TOBACCO FLEA BEETLE (COLEOPTERA: CHRYSOMELIDAE) DISTRIBUTION ON SEEDLING TOMATOES. Acta Hortic. 613, 247-250
Epitrix hirtipennis, Lycopersicon esculentum, damage, biology, California