10 FARMERS 7 BULLETIN 928. 



more than half of the foraging ants will be seen carrying these 

 insects down the trees. 



The continuous patrolling of the trees by large numbers of ants 

 must have the same disturbing effect upon predatory insects which 

 may feed upon the white fly as upon those which prey upon the ar- 

 mored scales. Nevertheless, these enemies do not prevent extremely 

 heavy white-fly infestation in orchards where there are no ants, 

 whereas in groves in which ants are extremely numerous the amount 

 of white-fly infestation often is small. 



PREVENTION OF INJURY TO ORANGE TREES. 



In Louisiana the damage resulting to the orange industry from 

 the presence of the Argentine ant may be prevented largely by one 

 or more of the following measures: (1) General improvement in 

 orchard cultural practices, including the control of such orchard 

 pests as the armored scales, the white fly, and the rust mite. (2) 

 Direct measures for the destruction of the ant colonies and the use 

 of ant barriers. 



In California the means of preventing injury and controlling the 

 ant are somew T hat different. The armored scales are controlled by 

 standardized methods of fumigation ; * and other orchard practices 

 also are standardized to some extent. Banding, as described on 

 pages 19 and 20, to keep ants from ascending and descending the 

 trees, and poisoning (see pp. 17-19), appear to be the most promising 

 methods of control in that State. 



BETTER ORCHARD CULTURE AS A PREVENTIVE OF INJURY IN LOUISIANA. 



In Louisiana the first step toward preventing injury by the 

 Argentine ant should be the control of the armored scales, through 

 which most of this injury occurs, and the improvement of orchard 

 practices in general. The destruction of the ants will not remove 

 the necessity of controlling the armored scales and other principal 

 pests, nor will it prevent injury due to faulty cultural conditions. 



Orange growing in Louisiana never has received the care and 

 attention that it merits, and it is capable of much greater com- 

 mercial development than it has yet attained. In the earlier days 

 citrus trees were grown there mostly for ornamental purposes or in 

 small yard plots supplying only enough fruit for home consumption. 

 Then followed small groves, almost exclusively of hardy seedling 

 varieties largely resistant to insect pests, the fruit from which repre- 

 sented almost clear gain, no money having been expended to grow 

 it, and the profits merely supplementing those from more important 

 sources. 



1 See Farmers' Bulletin 923, " Fumigation of Citrus Trees," which may be had free on 

 application to the Division of Publications, United States Department of Agriculture. 



