THE ARGENTINE ANT IN RELATION TO CITRUS GROVES. 63 



maintenance would not be justified under present conditions by the 

 increased crop returns. 



In Los Angeles County, CaL, it appears that the citrus mealybug 

 could be completely controlled in many cases merely by excluding the 

 ants from the trees. Should that condition remain indefinitely, band- 

 ing the trees would probably be as cheap a method of checking the 

 mealybug as any other. At all events tree-banding mixtures will 

 always have a use in protecting yard and ornamental trees, beehives, 

 etc., from the ants. They may be used also to advantage in some cases 

 in connection with poisoning and trapping the ants. 



In an endeavor to discover an ant barrier of this nature which 

 would be impervious to changes in the weather, and which would only 

 require infrequent renewal or respreading, more than 20 mixtures 

 were tested upon orange, fig. and other trees. Lack of space prevents 

 including detailed results of the individual experiments, and only 

 the general conclusions already published elsewhere x will be stated. 



Adhesive Mixtures. 



The most effective material of the adhesive type tested was made 

 after the following formula : 



Flowers of sulphur, part by weight 1 



Commercial tree adhesive, parts by weight 6 



All the lumps in the sulphur should be broken and the two in- 

 gredients thoroughly stirred together with a wooden paddle. The 

 sulphur not only greatly prolongs the softness of the material, but 

 appears to have a sufficiently repellent effect upon the ants to prevent 

 them from bridging the bands with bits of trash or their own bodies. 

 This mixture will remain effective in rainy, foggy, or exceptionally dry 

 weather for from 3 to 5 months. If directly exposed for long periods 

 to the sun, however, the surface becomes hard enough for ants to 

 pass, and the bands should, therefore, be applied where the shade of 

 the tree will protect them. This mixture must not be applied di- 

 rectly to the bark of trees, as it will be to some extent absorbed and 

 may in time cause injury. It should be applied to tire tape or other 

 waterproof material which has first been wrapped about the trunk. 



Repellent Mercuric Shellac. 



It is well known that corrosive sublimate has a strongly repellent 

 effect upon the ants, and is the active ingredient in most, if not all, 

 of the "ant tapes " found on the market, as well as of those watery 

 solutions to be applied to household furniture with a paint brush. 



1 Horton, J. R. Some weather-proof bands lor use against ants. In Mo. Bui. Cal. St. 

 Comm. Hort., v. 5, p. 419-421. 1916. 



27139°— 18— Bull. 647 5 



