The Plum Leaf-miner 227 



in fall and spring since that time. Beneficial restdts of this cultivation 

 were not apparent in 19 10. The trees were as badly infested as in former 

 years. This was due, in part at least, 'to the fact that the soil close around 

 the trees, where the greatest number of cocoons occur, was not disturbed. 

 In the fall of 19 10 they had their men hoe around the trees, but in many 

 cases they failed to disturb the cocoons lying between the base of the trunk 

 and the surrounding soil. In spite of this fact the number of moths 

 issuing in the spring of 191 1 was much smaller than in former years. This 

 decrease may be due in part to the presence of the parasites mentioned 

 above. 



The present season the orchard has again received thorough cultivation, 

 and the hoeing around the base of the trees has been more thorough; 

 this precaution, together with the great increase in the number of parasites 

 found in the cocoons, will probably lead to the elimination of the plum 

 leaf -miner as a pest in this orchard. 



In the present state of our knowledge it does not seem probable that the 

 plum leaf -miner will ever become a general or serious enemy of the plum. 

 If it should appear in other orchards, clean and persistent cultivation 

 will probably prevent its becoming established in injurious numbers. 



In conclusion, the writer wishes to thank Messrs CM. Hooker & Sons 

 for their hearty cooperation in conducting the work and for many sug- 

 gestions of great practical value. Mr. C. M. Hooker was one of the first 

 to use paris green against cankerworms on apple trees, and was probably 

 the first to introduce its use into Western New York. The following 

 entry copied from his diary is of historic interest: "June 7, 1873. 

 Applied 1 5 parts flour, i part paris green, to apple trees in stump lot to 

 destroy the cankerworms. Had a fine shower yesterday. Worms all 

 killed next day." 



