New York Agricultural Experiment Station. 55?» 



Distrihution. — The pistol-case-bearer is becoming well known 

 throughout the apple-growing sections of the state. It has also 

 been reported from the south, from the central states and from 

 Canada. It is an American species. 



Distribution hij means of nursery stock. — We have occasionally 

 found this insect on nursery stock. It is undoubtedly in this 

 way that it is carried from one part of the country to another. 



Natural enemies. — At least three species of parasitic insects 

 prey upon the pistol-case-bearer. We bred this number from 

 specimens kept in the laboratory. The number of parisitized 

 case-bearers was suflScient to indicate that these little parasites 

 may be an important check to the increase in numbers of this 

 pest. 



Remedial Measures. 



As shown by the above account, the pistol-case bearer belongs 

 to that class of insects which in their larval state devour the 

 tissue of the food plant instead of sucking the juices, as is the 

 case with certain other insects, such as plant lice, scale lice, 

 etc. It is therefore reasonable to expect that this insect can be 

 controlled by spraying with an arsenical poison, provided the 

 poison is applied at the right time. As we have already seen, 

 the caterpillars do not feed openly on the leaves until quite late 

 in the season, but feed for the most part on the interior of the 

 buds and young leaves. The poison, then, should be applied be- 

 fore the winter buds begin to swell, so that the first meal of the 

 young case-bearers as they begin to burrow into the buds may be 

 a poisoned one. Another application made when the leaves are 

 half grown, at which time the case-bearers begin eating holes 

 clear through the leaves, should prove effectual. 



With this in mind the following experiments were made. Full 

 grown Baldwin apple trees were used in the experiments. All 

 of them were badly infested with the pistol-case-bearer. 



Experiment No. 1. — On April 20, May 1 and May 6. twelve 

 trees were sprayed with Paris green used at the strength 

 of one pound to 150 gallons of water. At the time of the first 



