INJURIOUS AND BENEFICIAL INSECTS OP CALIFORNIA. 261 



second brood begin to emerge in July and August, when they become 

 very troublesome to the foliage of plants. They are more numerous 

 and injurious in dry hot seasons. There are two broods a year. 



Nature of Work.— The beetles begin by eating small holes in the 

 leaves. When very numerous all of the foliage excepting the larger 

 veins and the midribs may be devoured. Fig. 252 shows well the work 

 of an average infestation. The larva? cut off the fine roots and some- 

 times eat small holes in the tubers, causing pimply potatoes, and 

 burrow into the stalks. 



Distribution. — This beetle is quite common throughout the State. 



Food Plants, 167 — Though commonly found upon solanaceous plants, 

 the adult of this species is a very general feeder and has been reported 

 as attacking the following plants: apple, trailing arbutus, ash, bean, 

 beet, bilberry, cabbage, carrot, celery, wild bird cherry, clover, corn, 

 cucumber, dogbane, eggplant, elder, ground cherry, holly, honeysuckle, 

 hop. horse-chestnut, horse-nettle, jimpson weed, lettuce, maple, musk- 

 melon, nightshade, pepper, petunia, phlox, plantain, potato, sweet 

 potato, evening primrose, pumpkin, radish, raspberry, rhubarb, St. 

 John's wort, sarsaparilla, sorrel, spinach, squash, sumach, sunflower, 

 tobacco, tomato, turnip, Viburnum, violet and watermelon. 



Control. — Bordeaux mixture, which is so often used in controlling 

 fungous diseases of plants, acts in a large degree as a repellent to flea- 

 beetles. When thus used the 5-5-50 formula is recommended at the 

 rate of 100 gallons per acre. If the flea-beetles are present in great 

 numbers, ^ pound of Paris green or 2 pounds of arsenate of lead should 

 be added to the above formula of the Bordeaux mixture. Clean cul- 

 ture and the burning of all dead plants and rubbish during the fall of 

 the year are valuable aids in reducing the over-wintering forms. 

 Besides devouring the foliage, flea-beetles spread fungous diseases, espe- 

 cially of potatoes and tomatoes, and this alone makes it very desirable 

 to use a combination Bordeaux mixture and arsenate of lead, as recom- 

 mended above, whenever this pest becomes present in potato or tomato 

 fields in any considerable numbers. 



'Johannsen, O. A.; Bui. No. 211, Me. Agrcl. Exp. Sta., pp. 43-44, 1913. 



