CONTROL OF ARGENTINE ANT IN ORANGE GROVES 5 



( xcrete by stroking their bodies with its antennae, or feelers. The 

 honeydew of soft scales, aphids, and some other insects forms an 

 important part of the food of the ants. In securing this sweet excre- 

 tion the ants continually surround the scales and aphids and attack 

 any other insects that attempt to reach them. In this way they afford 

 considerable protection to the scale pests and make it possible for 

 certain species which have numerous and effective predacious enemies 

 to thrive and increase to the point of causing severe infestations. 



The Argentine ant does not obtain honeydew from the armored 

 scales, but in patrolling the trees constantly in large numbers in search 

 of insect prey it hinders to a certain extent the work of the natural 

 enemies of these scales, and if the control of the scales is neglected for 

 several seasons the infestation is increased considerably. 



Contrary to the general belief, the ant does not itself distribute 

 the scales and aphids of orange trees to start new r colonies, although 

 an occasional ant is seen carrying living scales or aphids-, or scale 

 shells, to the nest for flesh food and for nest construction. Of course, 

 wherever the abundance of scale insects has become greatly increased 

 through the presence of ants, a more rapid spread of the scales 

 through- the usual agencies, such as winds, birds, etc., naturally 

 follows. 



THE ANT AND SOFT SCALES IN CALIFORNIA. 



Mealybugs.* Infestations of mealybugs of the orange have been 

 increased greatly in Los Angeles County, Cal., by the Argentine 

 ant. In this county the orange trees usually are kept free from other 

 scale insects and in vigorous health, and under these conditions, 

 when protected from their numerous predatory enemies by the ants, 

 the mealybugs are able to thrive. These natural enemies effect a 

 practical control of the mealybugs in mam r Los Angeles County 

 orange groves in the absence of the ant. As a result of the attend- 

 ance of the Argentine ant, infestations of three or four species of 

 mealybugs other than the common one are increasing in number and 

 severity, particularly in the Pasadena district. 



Fluted scale.- The fluted or cottony-cushion scale is almost, if 

 not quite, as eagerly sought and as closely attended by the Argentine 

 ant as are the mealybugs, owing, no doubt, to the large amount of 

 thick excretion which it supplies. At present, however, the ant can 

 not be said to cause the slightest injury to orange trees in California 

 through its relations with the fluted scale. Infestations of this scale 

 become as severe at times in some localities, whether the ant is present 

 or not, as when the insect was at the height of its abundance in earlier 



1 Pseuilocorrus ritri (Risso) and other species of Pseudococcus. 



2 I eery a purcJiafti Mask. 



