October, '15] CHILDS: CONTROL OF THE APPLE LEAF-ROLLER 461 



In times past, oils have been used by local growers in an attempt to 

 control the leaf-roller, with rather indifferent success. Owing to exist- 

 ing conditions it was thought best to test out a series of materials. 

 Four oils were used in eight experiments as follows: kerosene emulsion, 

 18 per cent, distillate emulsion, 18 per cent, crude oil (Balfour Guthrie 

 Co.) in the ratio of 1 to 12 and 1 to 15 and miscible oil No. 1, manu- 

 factured by the above company, in four strengths, 5, 6, 7, and 8 gallons 

 to the 100 gallons of water. 



Some of the pioneer workers in leaf-roller control have at various 

 times recommended kerosene as an effective means of destroying 

 the eggs of the leaf-roller and the 18 per cent emulsion of this material 

 was placed on the trees with confidence that many eggs would be 

 destroyed. The trees were thoroughly covered, in fact drenched, 

 5 to 6 gallons of the material being applied to each tree. When a 

 count of the eggs on the experiment and check was made, it was found 

 that a larger portion of the eggs on the sprayed trees, or 96.4 per cent, 

 hatched as compared with 95 per cent hatched on the control trees. 

 A duplication of this experience was encountered with the distillate; 

 here again no ovicidal properties were found to exist when applying 

 an 18 per cent emulsion. The trees were examined the day after 

 the material had been applied and it was found that nearly all of the 

 evidences of the oil had disappeared. When used within the bounds 

 of economy, both of these materials are lacking in sufficient penetra- 

 tion qualities to be considered a means of destroying leaf-roller eggs. 



The results that were obtained with the crude oil proved disap- 

 pointing, also, from a point of control. The material was used in two 

 strengths, at the rate of 1 gallon of oil to 12 gallons of water and 1 

 gallon of the oil to 15 gallons of water. These emulsions were applied 

 May 27. The variety of trees in the experimental plats were twelve- 

 year-old Spitzenburgs on which many egg masses could be found. 

 On the day that the spray was applied the more advanced buds were 

 noted already burst and some of the first leaves were out. Upon 

 examining the plats a few days later many of the early leaves were 

 found to be injured. They, for the most part, were not burned but 

 t seemed to be stunted and had an oily appearance for several weeks, 

 ' a condition which was not observed in the other experiments. This 

 greasy condition existed on much of the foliage for several weeks, 

 retarding and causing a malformation of the leaf growth on many of 

 the trees. While the crude oil was being applied, a very strong wind 

 was blowing making thorough work very difficult. This may have 

 affected the results to a slight degree for a few egg masses here and 

 there were found to have been slighted. In experiment 9, or where 

 the 1 to 12 formula was used, 43 per cent of the eggs failed to hatch. 



