Colorado potato beetle, Leptinotarsa decemlineata (Say), is among the most significant pests of potatoes, largely because it has developed resistance to many insecticides and has few effective biological control agents. The objective of the study was to evaluate the pathogenicity of Heterorhabditis marelatus (Liu and Berry) on Colorado potato beetle at different doses of third-stage infective juveniles under field conditions. In 2000 a field plot (322 m2), naturally infested with eight beetles per plant, was treated with 0, 375, 750 or 1200 infective juvenile nematodes/m2. Nematodes were applied to the soil surface with a hand held sprayer prior to beetle pupation in the soil. In 2001 the same location was used, but the area was 238 m2 and field cages (1 x 1 x 1 m) were assembled in each plot to prevent Colorado potato beetle migration between plots. After nematode application, beetle larvae and newly emerged adults were counted weekly for 7 wks. In 2000 numbers of summer adults were significantly higher in control plots compared to nematode treated plots. There was also significantly more defoliation in control plots compared to nematode treated plots (Fisher LSD, P<0.05). Use of H. marelatus could be integrated with other management tactics for control of Colorado potato beetle.
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA