132 MASS. EXPERIMENT STATION BULLETIN 192. 



off. It is now doubtful if late holding can be relied on to eradicate the 

 pest entirely unless it is contmued to the 1st of August. The most success- 

 ful treatment applied on large bogs in 1918 was that of letting the winter 

 flowage off about June 1 and flooding again from three weeks to a month 

 later. This has been reported as very effective heretofore.^ 



In 1917 the first brood was first found hatching on June 4, the spring- 

 having been very late and cold. At this time none of the worms observed 

 seemed more than two days old. This is the latest date for the beginning 

 of the hatch the writer has ever noted. 



The Cranberry Fruit Worm {Mineola vaccinii Riley). 



In 1917 the eggs of this insect showed a range in Ohalcidid {Tricho- 

 gramma minuta) parasitism of from 83 to 89 per cent on dry bogs, and 

 from 29 to 88 per cent on those with winter flowage. In 1918 the range 

 was from 36 to 89 per cent on dry bogs and from none to 15 per cent on 

 flowed ones. 



The fruit worm did much more injury in 1917 than in 1916. 



On June 27, 1917, the writer covered large numbers of fruit-worm 

 cocoons, in quart cans partly filled with moist sand, with measured and 

 uniform one-third inch, one-half inch and 1 inch depths of sand. Checks 

 of cocoons without any covering were kept for comparison. The cocoons 

 had been kept in good condition on sand in cans during the preceding 

 fall, winter and spring, and it is certain that when these tests were started 

 the worms had all either pupated or been destroyed by the formation of 

 the parasite pupa). As in like tests previously reported,^ both the moths 

 and parasites emerged through the one-third and one-half inch coverings 

 fairly freelj^ but the inch covering smothered them almost completely. 



Large numbers of cocoons of fruit worms were buried under a measured 

 inch of sand in the late fall of 1917. Most of the worms left their cocoons, 

 worked their way up through the sand, and in some cases built very 

 meager secondary cocoons after reaching the surface. The pupa? of the 

 worms and parasites were formed on or near the surface. 



These results show that the fruit worm may be smothered by heavy 

 sanding, but that the sand must be applied after pupation to be effective. 

 As shown heretofore,^ pupation is not completed until the middle of June, 

 and bogs cannot be sanded then without doing much injury. 



The difference in the results obtained with this insect by covering 

 cocoons heavily with sand before the worms pupate as compared with 

 like covering aftei' pupation may explain why the ^Titer * had so much 

 greater success than Scammell ^ in smothering the girdler (Cratnbus hortu- 

 ellus Htibner). The writer applied the sand late in May, while Scammell 

 applied it in November. The girdler usually pupates in the last half of 



1 Twenty-fifth Ann. Rept., Mass. Agr. Expt. Sta., Pt. I, 1913, p. 232. 



2 Bui. No. 180, Mass. Agr. Expt. Sta., 1917, p. 228. 



3 Bui. No. 168, Mass. Agr. Expt. Sta., 1916, p. 40. 



4 Twenty-fourth Ann. Rept., Mass. Agr. Expt. Sta., Pt. I, p. 19, 1912. 

 6 Bui. No. 554, U. S. Dept. of Agr., 1917, p. 18. 



