164 INSECTS AFFECTING VEGETATION 



brush the insects off, and they are followed at once by the cultivator, 

 which buries the lice and prevents their getting back on the vines. 

 The operation has to be repeated a few times, but the results have 

 proved entirely satisfactory and warrant the labor and expense. 



POTATO. 



Colorado Potato Beetle. Is so familiar to everyone that it is 

 hardly necessary to give any description of the destructive creature. 

 The adult beetles come out of their winter hiding places about the 

 end of May and feed at once upon the earliest appearing potato 

 plants; soon after this the females lay their bright orange colored 

 eggs on the under side of the leaves in batches of various numbers 

 tip to fifty or more. The grubs hatch out in about a week and set 

 to work to devour the foliage ; their dark orange color renders them 

 somewhat conspicuous, so that an attack can hardly fail to be no- 

 ticed. When fully grown the insect changes to the pupal stage in 

 a cell a few inches below the surface of the ground. A period of 

 about eight weeks is required to complete a life cycle, and then a 

 second brood of beetles appears, lays its eggs and starts new colonies 

 of grubs; the third brood comes out in September and may be ob- 

 served crawling or flying about in search of winter quarters. The 

 broods are by no means distinct, as all the grubs do not mature at 

 the same time, consequently the insect may usually be found in all 

 its stages at any time during the summer. 



The well-known and long-tried remedies are Paris green or 

 arsenate of lead combined with Bordeaux mixture, the latter in- 

 gredient assisting in warding off the attacks of fungous diseases and 

 also in destroying Flea-beetles, when they are present, as they com- 

 monly are. Spraying should be done early in June as soon as any 

 grubs are to be seen, again a month later, and three times, at in- 

 tervals of a fortnight, between the end of July and the first of 

 September. 



Three-Lined Potato Beetle. Looks very like the Striped Cu- 

 cumber beetle, but is larger and of a darker yellow color. Before 

 the coming of the Colorado beetle this was the chief insect enemy of 

 the potato, but now, though common, it is not usually particularly 

 destructive; its life-history is much the same, the adult beetle com- 

 ing out in the spring and laying her eggs on the under side of the 

 leaves of the young plants; these are yellow in color and are laid 

 along the midrib of the leaf. The larvae have the extraordinary 

 habit of piling their excrement on top of their backs, possibly as a 

 protection against their enemies, and thus present a disgusting ap- 

 pearance. The grubs appear in June and go through their trans- 

 formation in time for another brood to come forth in August; the 

 beetles from this later brood do not emerge till the following 

 spring. When this insect is at all abundant, it can be easily con- 

 trolled by the application of Paris green; the measures everywhere 

 taken to check the Colorado beetle have no doubt prevented this 

 species also from becoming numerous. 



Potato Flea-Beetle. Is one of the most serious pests of the 

 potato plant. The tiny creature it is less than one-twentieth of 



