Leptinotarsa decemlineata

(Colorado potato beetle)

• Causal agent

The Colorado potato beetle (CPB) is a small insect from the order Coleoptera, originating from central America but which is now present worldwide. It may cause severe problems in areas with a hot growing period, where several generations of the insect may exist during the season.

The adult has a length of about 10 to 12 mm and a rather rounded aspect. Its anterior part (head and thorax) has an orange-yellow-colour with several black spots and the two hardened forewings (elytra) are pale yellow with five black stripes on each elytra (photos 1 and 2).

The adult lays orange-yellow eggs (photos 3 and 4) grouped in clusters on the underside of the leaves.

The larva, which is slightly curved and orange-red in colour, has a double row of black spots on the abdomen (photo 5). Larvae pass through four larval stages and those of the third stage (L3) are especially voracious. Numerous larvae and/or adults can quickly defoliate a crop.

At the end of the last field generation, the larvae enter the soil of potato fields or adjacent borders and transform into pupae and later on into adults which can overwinter in the soil. 

Colorado potato beetle develops mainly on potatoes but it can also attack other cultivated or wild Solanaceae (eggplants, tomatoes...).

• Significance

In the event of high infestation, larvae of the Colorado potato beetle can severely defoliate the potato crop and seriously impair the enlargement of the tubers. Early attacks of the Colorado potato beetle can thus result in heavy yield losses.

The introduction of this pest is forbidden in some protected areas which impose strict controls on imported plant materials.

However, a warm climate is an  essential factor for its development.