40 MASS. EXPERIMENT STATION BULLETIN 355 



mottled, with a scattering of rather long hairs. Body with a narrow dark-brown 

 stripe along the middle of the back; a narrow, broken, and somewhat staggered 

 dark-brown stripe along each side of the back; and a narrow white or pale-reddish 

 stripe along each side below the spiracles, some of the spiracles dipping into it. 

 Spiracles brownish white rimmed with black. Some of the worms had pupated 

 by August 3 and most of them had done so by August 10. 



Pupa: Length, ten to eleven sixteenths of an inch. Color rather dark reddish 

 brown. Cremaster bifurcate at the end and with a denticle on each side of its 

 base. 



Some of the moths emerged from August 13 to 18; some more emerged in 

 October and early November; and, at the date this is written (December 22), 

 live pupae remain,, perhaps to go through the winter. 



This insect ranges from the Atlantic coast west to Calgary in Alberta and south 

 into Virginia. Little about the immature stages has been known heretofore. 



The worms feed on Roman wormwood, dandelion, and other common weeds 

 and grasses. 2 



Cranberry Fruit Worm {Mineola vaccinii). The season's experience with roten- 

 one-bearing sprays in controlling this pest, in both experimental work and com- 

 mercial practice, sustained previous conclusions well.^ It was found, however, 

 that 7 pounds of derris powder (4 percent rotenone) and 2 pounds of soap in 

 100 gallons of water gave as good control as sprays containing more derris. Two 

 applications, both at the rate of 400 gallons an acre, were necessary: one when all 

 but about a third of the bloom was past, and the other ten days later. These 

 two treatments also were an excellent control for the blunt-nosed leafhopper 

 (Ophiola) that carries the false blossom disease. 



Cube dusts, used when rotenone-bearing sprays are most effective, killed the 

 worms fully as well as the sprays did. One dust containing 2 percent of rotenone 

 and an activator controlled the fruit worm almost completely and also killed the 

 blunt-nosed leafhopper well. As the dusting machine was not working well, 

 a good idea of the proper acre-dosage of this dust was not obtained, but 100 

 pounds an acre was clearly enough. The application of a dust containing 1 per- 

 cent of rotenone and an activator was not well timed, but the results suggested 

 that such a dust may prove to be a satisfactory control for the fruit worm. The 

 discovery that this pest can be checked with a dust is gratifying, for cranberry 

 growers have become very generally dust-minded regarding insect treatments. 



The rotenone-bearing sprays killed most of the worms as they were entering 

 their first berry near the stem end. The dusts killed most of them while they were 

 hatching from the egg or soon after they hatched and before they left the cup 

 formed by the calyx lobes of the berr\ . 



Impregnated Pyrethrum Dusts.^ Considerable testing of these materials pro- 

 duced by different manufacturers was done by the station during the season, 

 with good results in most cases; but all of them should have been made some- 

 what stronger for use against gypsy moth caterpillars. Fully 60 percent of the 

 pyrethrum dusts used by Massachusetts cranberry growers in 1938 were im- 

 pregnated and they gave very general satisfaction. The high percentage of these 

 dusts used in this, the season of their commercial introduction to the cranberry 

 industry, is explained partly by the fact that the usual high grade pyrethrum 

 powder was hard to obtain in quantity because of the character of the 1937 

 pyrethrum crop in Japan. The much lower cost of the impregnated material 

 was also an important factor. 



^Reported in a letter by W. D. Wylie of the Department of Entomology of Cornell University. 

 ^Mass. Agr. Expt. Sta. Bui. 347, p. 43, 1938. 



