INSECTS INJURIOUS TO POTATOES AND TOMATOES 295 



of their powerful biting jaws. These beetles are also exceedingly 

 beneficial in feeding upon many other injurious insects, and are 

 among the farmers' best insect friends (Fig. 215). 



Remedies. As an artificial remedy for this pest, Paris green 

 has long been proven to be both effectual and practical. For 

 small areas it may be used dry by mixing it with fifty times 

 its weight of dry flour, land-plaster, or air-slaked lime, and should 

 be applied while the plants are still wet with dew, either by a 

 perforated can, or, better, by one of the improved powder-guns 

 such as Leggett's, by which two rows of plants may be powdered 

 at once. On larger areas spraying will be found more satisfac- 



FIG. 215. Murky ground-beetle (Harpalus caliginosus) ; a, its larva; b, head 

 of larva showing mouthparts. (After Riley.) 



tory. One pound of Paris green and 1 pound of freshly slaked 

 quicklime to 50 gallons of water will kill all the larvae, but 

 often 2 to 3 pounds are necessary to destroy the beetles. 



Many growers now prefer to use arsenate of lead at from 3 to 5 

 pounds to the barrel, as there is no danger of burning the foliage 

 with it, and it is much more adhesive. Where Bordeaux mixture 

 is not used the arsenate of lead is much preferable on account of its 

 superior adhesiveness. Where Bordeaux mixture is used, arsenite 

 of lime, or arsenite of lime made with soda, may be used, but these 

 homemade arsenicals should not be used alone, on account of 

 their burning the foliage. 



The vines should be sprayed first when they are a few inches 

 high, and the spraying repeated once or twice at intervals of ten 



