Location: Sugarcane ResearchTitle: Leptotrachelus dorsalis: the prodigal son returns Author
Submitted to: Sugar Journal
Publication Type: Trade Journal
Publication Acceptance Date: 11/4/2010
Publication Date: 11/19/2010
Citation: White, W.H., Erwin, T.L., Viator, B.J. 2010. Leptotrachelus dorsalis: the prodigal son returns. Sugar Journal. 73:22. Interpretive Summary:
Technical Abstract: Insecticides are well established as a production practice that can de-stabilize agricultural ecosystems. This occurs because insecticides frequently control not only the pest, but they also kill beneficial insects. These beneficial insects help to maintain the pests bellow economic levels and if they are eliminated the pest population begins to fluctuate wildly, often at a level resulting in serious damage to the crop. Recent advances in insecticide chemistry have seen the development of highly selective insecticides, those that only kill the specific pest leaving beneficial insect populations intact. Since registration of tebufenozide in sugarcane, an insecticide that only kills the sugarcane borer; beneficial insect heretofore killed off are now being detected. One insect that has benefited from the use of tebufenozide is the ground beetle, Leptotrachelus dorsalis. Larvae of this beetle forage behind leaf sheaths of the sugarcane stalk where they are voracious predators of the sugarcane borer. We discuss aspects of the biology of the predator and report preliminary findings on larval developmental times and results from voracity studies. L. dorsalis requires approximately 30 days from egg to adult beetle and as a larva, it can devour up to 600 sugarcane borer larvae. Although a ground beetle, it appears to be arboreal and all three larval instars are found in sugarcane fields throughout the year. This occurs because female beetles lay eggs over an extended period of time. As information on the biology of the beetle becomes known, opportunities for exploiting the insect as a predator become apparent. One thought would be to hold adult beetles over the winter in a diapause state and release them in sugarcane fields the following spring.