192 MAINE AGRICULTURAL EXPERIMENT STATION. I9OO. 



poison, the}- are no safer to use than any other arsenical insecti- 

 cide. The English Bug Compound was not used in these experi- 

 ments. Black Death was applied once on one-fourth acre by the 

 Station at the rate of 40 pounds per acre and it had no appreci- 

 able effect on the bugs. 



Each of these mixtures are sold, considering their composition, 

 at very high prices and are uncertain and expensive insecticides. 

 If English Bug Compound does not burn foliage, it is only 

 because the manufacturers have used largely of the cheaper 

 plaster, and sparingly of the more expensive white arsenic. 



PRACTICAL CONCLUSIONS. 



In fighting the Colorado' potato beetle no adequate substitute 

 for arsenical poisons has yet been found and there is little hope 

 that any will- be found. The efforts are now limited to finding 

 cheaper or more effective compounds of arsenic than Paris green. 



The arsenical insecticides are best applied with water in the 

 form of a fine spray as soon as the slugs appear. Unless applied 

 in connection with Bordeaux mixture it is safest to use lime with 

 all arsenical compounds. The applications should be repeated 

 as often as necessary. 



Some of the cheaper arsenoids were in these experiments as 

 effective as Paris green. There is no reason for using them or 

 Paragrene in place of Paris green unless they can be had at a 

 lower price. 



Lead arsenate is the most satisfactory of the insecticides used 

 by the Station. It is apparently slower in action than the copper 

 compounds of arsenic, but it can be more evenly applied and it 

 adheres firmly to the foliage without burning. 



DIRECTIONS FOR SPRAYING. 



On application the following special publications of the Station 

 will be mailed free: 



Condensed Directions for Spraying the Potato. 

 Condensed Directions for Spraying Apples. 

 How to Figdit Cucumber Enemies. 



