The heat awakens the Colorado Potato Beetles
The Colorado potato beetles come out of hibernation when the temperature of the soil exceeds 15 degrees. This usually happens at the end of June and the beginning of July, but this year it is estimated that it will occur up to two weeks earlier. The beetles hibernate as adults burrowed into the ground.
The closest permanent colonies of Colorado potato beetles are found in Russia, north and south of Lake Ladoga. In the last few years there have also been findings of Colorado potato beetles in Finland, but they have been successfully destroyed. Most of the beetles have been found close to the eastern border in South and North Karelia. If the beetles manage to reproduce, a large colony of Colorado potato beetles can form in the potato field.
It is difficult to find isolated beetles, but there can be findings of several dozen hibernated adult beetles. If potato leaves in the potato plantings have been eaten, this may be an indication of their presence. In this case the area has to be examined carefully for findings of adult Colorado potato beetles or egg masses. There are no larvae during the early summer.
An adult Colorado potato beetle is about one centimetre long. There are 10 black stripes on the yellow back and the head is orange with black spots. The beetle’s semolina sized yellow eggs are in tight groups on the underneath of the leaves. The adult beetles and larvae first eat holes in the potato leaves, and later they eat the leaves completely.
The Colorado potato beetle is one of the world’s worst potato pests. Its destructive power is based on the large quantity of beetles and at its worst they can destroy the potato crop completely. In Finland the Colorado potato beetle is classified as a harmful organism and so far it has been possible to stop it from spreading. The plant protection authorities, that is to say, Evira and the plant protection inspectors of the TE-centres are responsible for the monitoring and control.
For more information, please contact:
Senior Officer Jaana Hietala, tel. 020 77 25043
Senior Inspector Olli Elfving, tel. 020 77 25048