1913.] PUBLIC DOCUMENT — No. 31. 233 



reasons given above for the success of this treatment are cor- 

 rect, it seems probable that spraying for a heavy infestation of 

 this insect would be most successful if it were done after first 

 bunching the hatching of the eggs by holding the winter flowage 

 late. If the water is held late, the first spraying should be all 

 done within a week after the flowage is taken oft". 



There is little doubt that any bog can , be freed from this 

 pest by treating it as a strictly dry bog for a few years (i.e., 

 not flooding it at any time under any conditions), thus allowing 

 the natural enemies of the insect to accumulate against it, and 

 at the same time spraying at proper times with arsenical poi- 

 sons. The danger of loss from winter-kill and from fruit-worm 

 infestation is, however, considerable under such conditions and 

 must not be overlooked. 



Small bogs can probably be rid of infestation by thorough 

 spraying without omitting winter flooding. 



The season's observations indicate that spiders (of several 

 different species) and Tachina flies are the most numerous 

 and useful of the natural enemies of the fireworm. Spiders 

 attack and destroy the worms, and some of the jumping species 

 have been seen to leap into the air after the millers. The Tach- 

 ina flies lay the white eggs often seen on the worms, espe- 

 cially on and near their heads. 



The Cranberry Girdler (Crainbus hortuellus (Hlibner)). 



The season's observations on this insect sustain in every par- 

 ticular the conclusions concerning it reached in the past two 

 years. A serious infestation by this insect, at least on a bog 

 of small or medium size, is almost a certain sign of neglect. It 

 apparently never succeeds in getting a foothold on bogs which 

 are kept well sanded. Eesanding every other year is usually 

 sufficient to prevent infestation by it. Badly infested bogs al- 

 most invariably have an accumulation of old leaves over the 

 sand under the vines, and usually the worst infestations arc on 

 heavily vined bogs. 



There are indications that the girdler is often favored by 

 man's flooding operations in the same way that the flowed bog 

 fireworm is favored, — i.e., by the destruction or driving ashore 

 of its natural enemies. Winter-flowed bogs which cannot be 



