80 Report of State Board of Horticulture. 



more abundant, and there was thus more opportunity for ihe 

 spread of the contagion, I abandoned the idea. It was only 

 too evident that the organisms were too dependent upon fav- 

 orable conditions for their development, to be reliable agents 

 in insect warfare. Spraying the trees with cultures of these 

 diseases might give good results under certain circumstances; 

 but the results, being so dependent upon conditions, would be 

 uncertain, and the practice therefore unsafe. In all economic 

 work with diseases of insects, two conditions have been found 

 essential to success ; the climatic conditions must be favorabb 

 for the development of the disease and the insect must be 

 gregarious. The first condition can not be controlled; the 

 second does not exist in this particular instance, the larvae 

 being not only solitary in their habits but deeply buried in 

 the fruit. I, therefore, do not believe the use of disease 

 germs in controlling the codling moth can be made practical. 



I fully agree with Slingerland that "the most efficient aids 

 to man in controlling the codling moth are birds. * * 

 Any one who tries to collect the apple worm " on the trunks 

 of trees in early spring, will be surprised to find how many 

 empty cocoons there will be. Usually, however, a telltale 

 hole through the bark into the cocoon explains the absence of 

 the occupant. Our observations lead us to agree with Riley 

 and Walsh that 'almost all the cocoons of the moth that have 

 been constructed in the autumn on the trunks and limbs of 

 apple trees, are gutted before the spring opens.' * * ;= 

 One finds such an astonishingly large number of empty co- 

 coons that it would seem as though the birds must get the 

 larger proportion of the worms which go into hibernation in 

 the fall." Probably the flickers and nuthatches should be 

 given first rank as codling moth destroyers, but they are ably 

 seconded by the jays, chickadees, wrens, sparrows, swallows, 

 titmice, kinglets, and bluebirds. 



I believe there is little prospect that any practical benefit 

 will come from the introduction of foreign enemies of the 

 codling moth, or from attempts to increase the usefulness 

 of those already present. The "strenuous life" of the fruit 

 grower alone will protect his fruit. He must be persistent 

 in the use of the best known remedies. The most successful 



