CRANBERRY STATION. 159 



when not treated. With such a light attack, it may not pay to spray if 

 the bloom is heavy and the crop prospect good, because of the mechanical 

 injury done in spraying. If the crop promise is poor, however, it is best 

 to treat even a light infestation to save trouble the next year. The writer 

 observed a case in which an infestation giving 27.5 worms to 50 sweeps 

 of the net destroyed fully three-fourths of a fine prospective crop. One 

 experienced with this pest can gauge a coming attack fairly well by the 

 numbers in which the moths appear in mid-June. 



The spraying should be done when the eggs begin to hatch, for the 

 worms are poisoned most easily in their first stages, and they are some- 

 times numerous enough to destroy a fine crop promise within four days 

 after hatching begins. Therefore an infested bog should be examined with 

 an insect net daily from June 20 until the worms are found. If the in- 

 festation is severe and the area involved is so large that it will take several 

 days to t.'eat it, the spraying should begin a few clays before the worms 

 are expected, and the less heavily infested vines should be treated first. 

 Under such conditions the work usually should start about June 26 on bogs 

 from which the winter water has been let off before May 5. 



The small worms seem usually to attack the flower buds as soon as 

 anything, a hole commonly being eaten through the ovary. Often in 

 moderate infestations they work like the blossom worm mentioned above, 

 the flowers being nipped off and dropped to the ground. 



When this species attacks severely enough to turn the vines brown it 

 alwa^^s destroys all chances of a crop in the followmg year, even if it is 

 completely controlled that season, and sometimes patches of vines fail to 

 recover for two or three years. 



The period of activity of the green spanworm moths coincides with that 

 of the worms of this insect, and as both species often abound on the same 

 area, they are much confused in the minds of growers. 



The Cranberry Girdler {Crambus hortuellus Hiibner). 



This pest was much more prevalent, especially in 1920, than it had 

 been for many years. Its increase was pretty certainly due to the general 

 neglect of resanding during and since the war. 



Hitherto unreported parasites of the girdler were reared, as follows : — 



1. C remashis facilis (Cress.). ^ This species makes a delicate brownish- 

 gray cocoon inside that of its host. Apparently no girdler cocoon ever 

 contains more than one of these parasites. The adult parasites emerged 

 June 6 and 7, 1919, from cocoons collected on a bog the former day. About 

 10 per cent of the cocoons harbored this parasite. 



2. Macrocenlrus sp. ^ Several cocoons of this species were found to- 

 gether in each of two host cocoons collected on a bog May 31, 1919. The 

 adults emerged from one to four days later. 



3. Phygadeuon sp. ^ The cocoons of this parasite are yellow and 

 astonishingly tough. As with Cremastus, there is but one in a host cocoon. 



1 Identified by R. A. Cushman of the Bureau of Entomology. 



