30 



MASS. EXPERIMENT STATION BULLETIN 447 



The fruitworm (Fig. 24) has taken an estimated third of the whole Cape crop 

 in some \ ears. It may be checked by holding the winter flowage till late May or 

 by spraying or dusting in the middle of the blossoming period and again ten 

 days later with derris or cryolite. 



The black-headed fireworm (P^ig. 25A) seldom harms stricth' dry bogs much. 

 It may be treated by flooding tor ten hours at the end of May and again a week 

 later. Dusting with DDT or p\Tethrum or dusts containing rotenone is very 

 effective. 



Small patches infested with root grubs (F"ig. 26) are treated with a solution of 

 7 ounces of sodium cyanide in 100 gallons of water, a gallon to a square toot 

 (Fig. 27). This is fairly effective, but must be repeated in five years. A better 

 treatment for large infested areas is to let the winter flowage off early in April, 

 reflood about May 12, and hold the water till July 12. This usually cleans out 

 grubs of <dl kinds well, but at the cost of the crop. This pest has taken 150,000 

 barrels a year from the Massachusetts cranberry crop for some time. 



The gypsy moth (Fig. 25 B) may be controlled by holding the winter flowage 

 till May 25, by reflooding about May 25 for twenty-four hours, or by spraying 

 with 3 pounds ot dr\ lead arsenate in 50 gallons of water about May 20. Flooding 



Fig. 25. 



A. Webbed Cranberry Branches, work of the Black-headed Fireworm. 



B. GypsyiMoth Caterpillar Defoliating a Cranberry Branch. 



