REPORT OF CRANBERRY SUBSTATION FOR 1914. 109 



each it would take to kill the worms in this way. They were not killed 

 when the cocoons were kept wet with a mixture of 1 part of "Scalecide" 

 in 5 parts of water for a whole hour. As it would take not less than 600 

 or 700 gallons to wet down the surface of the sand on a bog, especially if 

 the vines were at all thick, it became evident without further tests that 

 "Scalecide" could not be used successfully in this Avaj^ because of expense. 

 It took a strength of 1 gallon of "Black Leaf 40" in 100 gallons of water 

 to kill the worms when sprayed on the cocoons, and therefore treatment 

 with this insecticide also seems too expensive to be practicable. However, 

 further tests with other contact sprays are planned. 



For dry bogs (without winter flowage) the possibilty of starving out 

 this insect by destroying the bloom in seasons of light crop promise is 

 still under consideration. Success in kiUing the blossom by spraying 

 with a 20 per cent, solution of iron sulfate was reported last year. As it 

 took three sprayings to destroy all the blossoms, however, it appeared 

 that there might be danger in this method of treatment, as the applica- 

 tion of so much iron sulfate might injure the vines. To deteraiine this 

 point, the sulfate salt was appUed broadcast on two bog plots on June 17, 

 this year, at the rate of 1 ton to the acre. A few of the vines showed a 

 little injury afterward, but as far as the evidence obtained went, the 

 sulfate may be used to kill the bloom without fear of its doing much 

 damage. It is planned to test this matter further, however. 



The study of the natural enemies of the fruit worm were continued, and 

 many things of scientific importance were learned about its parasites. 

 Some of this new information may in time lead to valuable practical re- 

 sults. In all, nearly a dozen species parasitic on this pest have been bred, 

 but only three of them are abundant enough to be of much importance. 

 These three species are : — ■ 



1. A Braconid {Phanerotoma tibialis Hald.), discussed in last year's 

 report (pages 55 and 56). Cocoons containing worms parasitized by this 

 species can usually be readily distinguished from those of normal, un- 

 parasitized worms by their much smaller size. When this parasite was 

 reported on last year, it was assmned that it laid eggs in the eggs of the 

 fruit worm when it parasitized them. This year's observations, however, 

 seem to indicate that instead of laying eggs it injects living young into the 

 fruit worm eggs, and is therefore viviparous. The writer failed to find the 

 eggs of the parasite, but its larvae can readily be found in fruit worm eggs 

 even before the worms themselves have taken distinct form. 



2. An Ichneumonid {Pristomeridia agilis (Cress.) Ashm., determined by 

 R. A. Cushman of the United States national museum). This species was 

 also mentioned in last year's report (page 56), but more knowledge concern- 

 ing it has been obtained this j^ear. It inserts its elongate, curved, black 

 eggs into the body of the fruit worm, usually accomplishing this by stick- 

 ing its egg-laying apparatus into the hole made in the berry by the worm. 

 The eggs hatch within a few days after they are deposited in the tissues 

 of the worm. This is a far less important parasite than the Braconid 



