Field evaluation of a mechanical release prototype of Podisus maculiventrisiox the biological control of Colorado potato beetle

摘要

The Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say) is the major insect pest of potato, Solanum tuberosum (L). The most popular method used so far to control CPB populations is the application of chemical insecticides. However, the CPB succeeded to develop over the years a resistance to most of the registered chemicals, including those that were very effective at one time. Also, heavy reliance on chemical insecticides could result on health and environmental problems. The use of naturalenemies to control the CPB is an interesting alternative to chemical insecticides. However, hand release of predators on a large scale in the field is not realistic. The main objective of this research study was to test a mechanical distributor designedand built at the Department of Soils and Agri-Food Engineering of Universite Laval, Quebec, Canada, to efficiently and safely release the predator Podisus maculiventris, commonly known as spined soldier bug, in potato fields. In this mechanical distributor, masses of predators are placed in small containers and mixed with a carrier material. In the field, the containers are mechanically opened at different locations, based on a source-point mass release option. The mechanical distributor has proved itsreliability and ease of use in the field. Its efficiency in terms of predators leaving the containers to drop on the plant foliage or on the ground surface was as high as 99%. Obtained results also indicated that the use of the second and third instar nymphs of Podisus maculiventris is effective in controlling CPB populations throughout the vegetative season in Quebec. The success of this predator release system in potato crops could be generalized to other predator insects to protect other crops suchas strawberry and lettuce.