April, '15] 



HEADLEE: ESSENTIALS OF INSECT CONTROL 



271 



mountain sides. Some of the blocks of one- and two-year trees had 

 suffered injury to the extent of 95 per cent of the entire stock. In 

 other places the rabbits had not begun to work. 



Electric welded wire screen of one-fourth inch mesh, had 

 been used in many of the orchards with success at a cost of one-half 

 cent per tree, where the wire was bought by the carload, plus labor cost. 

 Various w^ashes of fish oil soap, blood, glue, hair, lime, and other in- 

 gredients had been used with little or no success. White lead and 

 raw linseed oil in the proportion of | part lead to J part oil had been 

 used on a large number of trees. This cost approximately three-fourth 

 cent per tree, labor being one-fifth cent per tree. The rabbits gnawed 

 through this covering in most instances. 



The writer visited the place and demonstrated the preparation of 

 concentrated lime sulphur and the method of thickening the material 

 for brushing on the trees. Some commercial lime sulphur was used. 

 About 600,000 one- and two-year apple trees were treated. 



The lime sulphur was diluted at the rate of 1 to 9 and approximately 

 30 pounds of stone lime used to each 50 gallons of the diluted wash to 

 thicken it. Five gallons of lime sulphur was placed in a barrel and 

 stone lime gradually added and slaked in it. This tended to combine 

 any free sulphur that remained. Water was gradually added, as 

 needed to prevent burning and at the conclusion of the slaking to make 

 up the wash to 50 gallons, thus giving a thickened wash of lime sulphur 

 at a dilution of 1 to 9. Other lots were made up by first slaking the 

 lime in large quantities, and adding the milk of lime to the diluted lime 

 sulphur. 



This material was apphed by gangs of men, each of whom was sup- 

 plied with a gallon bucket and a three-inch varnish brush. Each man 

 was able to cover about 700 trees per day at a cost of one-fifth cent per 

 tree for labor and slightly over one-sixth cent per tree for material. 



The material proved very successful and the most economical wash 

 that can be used on a large orchard. 



THE ESSENTIALS OF INSECT CONTROL 



By Thomas J. Headlee, Ph.D., State Entomologist of New Jersey 

 Introduction 



It is purposed to treat this subject briefly from the standpoint of 

 the insect control official. It is understood that all consideration of 

 experimental studies so necessary to carrying on the control official's 

 work will be disregarded and attention centered on the routine work 

 of preventing insect pests in other states and in foreign lands from be- 



