HOW TO INCREASE THE POTATO CROP BY SPRAYING. 9 



the striped ^ blister beetles, shown in figures 8 and 9. These insects 

 are gregarious and migratory in habit, feeding most voraciously, 

 running rapidly, and flying from time to time. Frequently they 

 descend on a crop and ruin it in a few days, eating both foliage and 

 stems. They appear at different times, according to temperature, 

 usually being most abundant from July to September. 



REMEDIES FOR BLISTER BEETLES. 



Arsenate of lead is the best remedy for blister beetles. It is pre- 

 pared and apphed as directed for the Colorado potato beetle. In 

 addition, in some portions of the West a line of boys and men is sent 

 through infested fields to drive the beetles ahead of them by short 

 flights or running until they alight or come to rest in windrows of 

 hay, straw, or other dry material, which previously has been prepared 

 along the leeward side of the field. When the beetles take refuge in 

 such a windrow it is burned promptly. Tliis procedure has been 

 followed with success. 



Prompt application of remedies at the very outset of attack is necessary 



to save the crop. 



FLEA-BEETLES. 



Potatoes are attacked every year by flea-beetles, some of which are 

 specific enemies of the crops of the potato family. Flea-beetles begin 

 their work early in the season. The beetles riddle the leaves of young 

 and tender plants with punctures, causing the leaves to die, thus 

 depleting the vitality of the plant ; and the larvae, or young, feed at 

 and injure the roots. These insects, a little larger than a flea, derive 

 their common name from their smaU size, and from the fact that their 

 powerful hind legs enable them to take long leaps. 



The most important of these insects is the potato flea-beetle.^ 

 (Fig. 10.) This species occurs practically throughout the potato- 

 growing regions of the country from Canada and New England to the 

 Gulf region and in some districts in California. The most severe 

 injury, however, is done in the North. The larva is the cause of 

 "pimply" potatoes, which bring a lower price in the market, some- 

 times 5 cents a bushel less than the regular price. Eggplant, tomato, 

 and tobacco also are attacked, and when this insect is numerous it 

 sometimes attacks other plants. Occasional injury is done to pota- 

 toes and tomatoes through gnawing of the sprouts. Eggs are laid 

 early in May or June, and the life cycle may be completed in mid- 

 summer m about 35 daj^s. 



During recent years this species has shown a great fondness for 

 tomato, and during the spring and summer of 1917, from April 19 to 

 about the middle of July, injury was widespread. In the case of 

 tomato, the plants were sometimes destroyed by defoliation when 



1 Epicauta vittata Fab. « Epitrix cucumem Harr. 



528°— Bull. 868—17 2 



