Control

The management of the Colorado potato beetle consists of a combination of several methods, which may include cultural, biological, physical and chemical practices:

• control of groundkeepers and weeds as well as crop rotations can reduce or delay the pest pressure. Because overwintering adults need to feed before walking or flying into new fields, controlling groundkeepers and weeds, such as nightshades, reduces the early food source for the emerging adults and this may reduce or delay population growth. As these beetles are weak flyers, crop rotation and planting crops such as cereals after potatoes help to reduce their migrations from overwintering sites to new fields;

• avoid cultural operations when the larvae are trying to penetrate the soil (summer), as this helps them to bury themselves deep down;

• other control methods have been developed in some countries to trap or kill the insects (with the use of plastic-lined trenches, propane flamers, or vacuum traps) to limit the use of insecticides (although the cost of such techniques is usually higher than that of chemical control methods);

• several insecticides are effective for controlling the Colorado potato beetle, but it is recommended to change the type of the applied product at each application in order to avoid the development of resistance. Many of the insecticides authorised against aphids are also effective against the Colorado beetle, especially on the young larvae which are the most susceptible to insecticides, whereas the adults, eggs and pupae are very resistant. Early chemical treatment of young larvae can more efficiently prevent the feeding damage made by the older larvae which are difficult to kill and can be devastating;

• biological insecticides such as Bacillus thurigiensis are authorized in some areas for the management of Colorado potato beetles in potato crops.