COLORADO POTATO BEETLE 
( Leptinotarsa decemlineata Say) 
Life History 
The eggs of the Colorado potato beetle are laid on the under side of 
the leaves. These eggs hatch in from 4 to 9 days. The resulting larvae 
(or slugs) feed on the plant. The larva grows rapidly, passing through 
four stages, or instars, similar in appearance except that each stage is 
larger than the preceding one. It becomes full grown in 10 days to 
3 weeks after hatching from the egg. The full-grown larva then 
burrows into the ground and changes to a pupa, or resting stage. After 
5 to 10 days the adult beetle emerges from the pupa, crawls up out of 
the ground, and, after feeding on the plants for a few days, may lay 
eggs for another brood of larvae. 
Control 
Dust the foliage thoroughly with a 3-percent DDT dust. 
Sprays are also effective if applied with a good sprayer throwing a 
fine mist. Use 2 level tablespoonfuls of 50-percent DDT wettable 
powder or 2 level teaspoonfuls of 25-percent DDT emulsion concentrate 
per gallon of water. To make 100 gallons of spray use either 3 pounds 
of the 50-percent wettable powder or 2 pounds of the 25-percent DDT 
emulsion concentrate. If sprays are to be used for disease control, 
either of these DDT preparations may be added to the fungicidal spray 
rather than to water, and both materials applied with one operation. 
Begin spraying or dusting when the beetles first appear. Spray or 
dust for the slugs when eggs are hatching, and repeat the treatment 
as often as necessary. 
Caution. — Insecticides are poisonous and should be handled with 
care. Store in a dry place where children and animals will not have 
access to them. 
Revised April 1949 
U. S. Government Printing Office 
For sale by the Superintendent of Documents, Washington, D. C. Price 5 cents 
832648°— 49 
