44 MASS. EXPERIMENT STATION BULLETIN 378 



for this pest. A spray of cryolite, 6 pounds in 100 gallons of water, 300 gal- 

 lons to an acre, was very elTective against the first brood but failed to 

 curtail the second well. Dusting with cryolite proved to be unreliable 

 for either brood. 



Blunt-nosed Leaf hopper (Ophiola). Cryolite, 6 pounds in 100 gallons of 

 water, 400 gallons to an acre, failed entirely as a control for this pest. 



Cranberry White Grub (Phyllophaga). Considerable cranberry infestations 

 by this species are found only in bogs that are flooded during the winter 

 and have not been reflowed in late May or June for several years. Appar- 

 ently such late reflooding interferes with the egg-laying of the beetles enough 

 to serve as a control. Individual grubs of this insect are three times as 

 destructive as those of the cranberry root grub (Amphicoma). and they travel 

 around in the soil much more. The cyanide and the flooding treatments 

 used against the root grub are also eflfective against the white grub. This 

 white grub is always present more or less in the soil of the uplands around 

 the bogs and it attacks the roots of cultivated blueberry plants extensively. 



Cranberry Fruit Worm (Mineola vaccinii). Cryolite, 5 pounds in 100 gal- 

 lons of water, 400 gallons to an acre, was fully eflfective against the fruit 

 worm. Dusting with a mixture of 60 pounds of talc and 40 pounds of 

 cryolite, at the rate of 60 pounds to an acre, was also eflfective. Spraying 

 for this insect, in spite of its greater cost, is fully as advisable as dusting, 

 for dusting seems to do more mechanical injury to the crop after the 

 berries have begun to grow than does spraying. 



Colaspis Rootmortn (Colaspis brunnea var. costipennis). The infestation 

 of this species described in last year's report* was kept under observation. 

 The description of the full-grown grubs on June 12 was as follows: Length, 

 about a quarter of an inch. Head pale yellow, the antennae not nearly 

 reaching the tips of the mandibles. Body nearly white, without markings; 

 the back and sides scattered over with simple pale hairs noticeable under 

 a lens. Abdomen not noticeably darkened by its contents; the venter 

 covered with a brush of brown hairs, those at the sides in clusters and 

 larger than those across the middle, the latter arranged in transverse lines; 

 the tip with a considerable prominence, ridged vertically at the end, ex- 

 tending caudad on each side of the anal opening. All the tarsal claws 

 single, simple, slender, and sharply pointed. 



This grub is much like that of the cranberry rootworm (Rhabdoptcrus), 

 but its head is somewhat narrower relative to the width of the body than 

 the head of that species. 



The grubs all pupated about June 14, the winter water liaving been re- 

 moved from the infested area early. The description of tlie pupa follows: 

 Length about three-sixteenths of an inch. Color waxy white. Rather 

 long, light brown hairs scattered freely over the upper surface of the head, 

 thorax, and abdomen, many of them borne on conical pustules. Under 

 surface of the body without hairs. Tips of the sheaths of the middle 

 and hind legs each with a noticeable spine. Tip of abdomen truncate, 

 with a strong, brown, somewhat curved spine on each side extending 

 caudad; somewhat in front of these spines, a smaller straight spine ex- 

 tending squarely laterad on each side, and in front of this another spine 

 extending caudolaterad. 



Maes. Agr. Expt. Sta. Bui. 369:33. 



