256 



THE MONTHLY BULLETIN. 



and attend them constantly. As the result of these attentions, the 

 mealybugs thrive in numbers and destructiveness to an extent which is 

 impossible wherever the ants are not present." 



Mr. Woglum of the United States Department of Agriculture has 

 shown, by experiments carried on for two years on a rather large scale, 

 that if the ants are kept from the citrus trees the citrus mealybug is 

 kept in complete subjection by its 

 natural enemies. This will probably 

 be found to be more or less the ease, 

 also, with such insects as the black 

 scale and the soft brown scale. It 

 will be seen that the presence of the 

 Argentine ant is of vital conse- 

 quence in the work of introduction 

 of natural enemies of our citrus 

 pests, and it is for this reason that 

 the state inseetary has been paying 

 particular attention during the past 

 season to the Argentine ant problem. 

 The ant constitutes a menace not 

 only in the localities where the 

 mealybugs occur at the present time, 

 but in all of the orchards where it 

 is found, on account of the fact that 

 the mealybugs may at any time be 

 accidentally introduced into the ant- 

 infested regions. It is of the great- 

 est importance from the orehardist's 

 standpoint, therefore, to control, or, 

 if possible, eradicate this insect, not 

 only in the mealybug-infested sec- 

 tions, but wherever it occurs. 



Many different methods of control 

 have been tried out against this ant, 

 the most promising of which may be 

 grouped in two classes, viz, barriers 

 which the ants cannot cross, and 

 poisoning. Since in this article we 

 are considering only its relation to 

 the orchards, we will omit any ref- 

 erence to control as a pest in cities. 



Barriers are of two kinds: those which depend upon their physical 

 properties, i.e., stickiness or viscosity, and which the ants are physically 

 unable to cross ; and the repellent kinds, which depend upon a disagree- 

 able odor or poisonous fumes to keep the insect from crossing. Of the 

 former type two kinds are in use, the most important one being a prepa- 

 ration of commercial tree tanglefoot to which finely powdered sulphur 

 has been added, in the proportion of one part of sulphur to six parts 

 of tanglefoot. This is placed in a band about five inches wide around 

 the trunk of the tree, and is very effective when properly mixed and 

 applied, providing it is kept in good condition. This formula was 



Fig. 70. — Showing poison bag in place 

 on tree trunk. The top of bag is 

 folded over to protect the entrance 

 holes from rain or spray. (Original. ) 



