CONTROL OF ARGENTINE ANT IN CALIFORNIA. 35 



Food Supply. 



Trees severely infested with mealybugs or other honeydew-sxuding 

 insects offer a favorable food supply for the Argentine ant. Control 

 on such trees is difficult at any time of the year and usually not to 

 be accomplished during the summer merely by the distribution of 

 sirup, for the ants prefer their natural food to that furnished arti- 

 ficially. The only way to control the ants under such conditions is 

 to remove the insects furnishing the natural food supply, prevent 

 access of the ants to these insects, or else await the autumn or spring 

 when the natural food becomes much reduced and the cold weather 

 promotes feeding on the poisoned sirup. As an illustration of this 

 condition the case of an orchard at Sierra Madre might be mentioned. 

 On June 1, 100 bags of ant poison were distributed in one corner 

 of the orchard, which at the time contained a few mealybugs. 

 Within two months the ants on these trees had been brought under 

 control. On August 1 poison bags were distributed throughout the 

 rest (about 10 acres) of this ant-infested orchard, which was then 

 severely infested with mealybugs. An inspection on October 19 

 showed no noticeable reduction of ants throughout that part covered 

 by ant sirup in August. The infestation of mealybugs also continued 

 to be severe. With the approach of cold weather and reduction of 

 the numbers of mealybugs the ants fed greedily on the sirup, and 

 by the following spring were practically under control. 



On April 26, 1918, ant sirup was placed on 68 large orange trees 

 at Pasadena severely infested with mealybugs. Forty-two of these 

 trees were banded above the sirup cans to prevent the ants reaching 

 the mealybugs, and the remaining 24 were left unhanded. An 

 inspection on April 30 showed large numbers of ants attending the 

 sirup on the banded trees, but not a single can on the unhanded 

 trees was sought by the ants. The second plot was ultimately 

 banded to compel feeding and accomplish control. 



During the blossoming period ants are attracted to the nectar 

 within the flowers and control is sometimes difficult, especially 

 during a period of warm weather. 



Thus, any attempt at control should give due consideration to 

 the natural food supply of the pest. 



Excellent results in complete ant eradication have been obtained 

 in orchards heavily infested with the soft-brown scale and the black 

 scale by following up the usual full fumigation practice with ant 

 control. 



Season fok Control. 



The spring and autumn, because of the temperature and food 

 supply, are the periods when control or eradication is most quickly 

 effected in southern California. When the ants break up their 



