98 INSECTS AFFECTING VEGETATION 



of tank from which, the spraying is done and the way in which it 

 is mounted must vary according to circumstances. 



It may under some conditions be more satisfactory to apply 

 a dry insecticide, and for this purpose there are now several dust 

 sprayers and powder guns on the market. By means of a fan 

 blower a fine powder can be rapidly and evenly distributed over a 

 large area, and this would naturally lodge just where it was needed. 

 A good mixture for such application is 1 pound of fine Paris green 

 to 10 pounds of dry hydrate or fresh air-slaked lime. The lime 

 should be sifted, thoroughly mixed with the Paris green, and the 

 combination applied while the vines are slightly moist. 



The Cranberry Tip Worm. This is a minute orange-red or 

 yellowish grub about one-sixteenth of an inch in length, found 

 in the growing shoots, whether uprights or runners. It is com- 

 paratively rare on Cape Cod and is not common on all the New 

 Jersey bogs, though more plentiful there than anywhere in Massa- 

 chusetts. It appears on the vines soon after they make a start, and 

 the first indication of its presence is when the small leaves of the 

 tip cease to unfold and become bunched into a compact, bulb-like 

 mass. When this mass is opened, from one to five, and usually 

 two or three, of the little grubs will be found at the very heart of 

 the growing tip, feeding upon the juices and completely checking 

 growths. If it is a runner that is attacked, it is destroyed; if a 

 fruit-bearing upright, the flower buds come out below the infested 

 tip and no harm is done to the crop. But the insects continue to 

 appear on the bogs at intervals throughout the season, and the 

 danger is that the late-tipped uprights will form no fruit buds for 

 the next year. 



The little grab is rather a helpless sort of a creature, without 

 legs and even without distinct jaws; but it has on the underside 

 of the body a little horny process or breast bone by means of which 

 it scrapes the plant tissue until the cells break down and their con- 

 tents may be absorbed. In about ten days it reaches full growth, 

 envelops itself in a thin, white, silken cocoon, and two or three 

 days thereafter changes to an adult a minute, two-winged fly or 

 midge whose wings when expanded measure less than an eighth of 

 an inch from tip to tip. The male is quite uniformly yellowish- 

 gray and inconspicuous, but the female has the abdomen deep red, 

 the upper surface of the body gray, the sides yellowish, the head 

 and eyes black. She also has a slender, extensile tip to the abdo- 

 men, by means of which the minute white eggs are laid in the 

 very heart of the bud. 



After the fly has emerged from one of the infested cranberry 

 tips the leaves that were massed together turn red or brownish, die, 

 and break off, leaving a stub above the fully developed leaves. If 

 the tips are killed early in the season fruit buds may form at the 

 axils of the leaves, or one or more little spurs may start lower 

 down on the shoot, at the tips of which normal fruit buds may de- 

 velop. On new bogs, with young, vigorous vines, the early broods 



