CONTKOL OF ARGENTINE ANT IN CALIFORNIA. 35 
Food Supply. 
Trees severely infested with mealybugs or other honeydew-exuding 
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 fall fumigation practice with ant 
control. 
Season for 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 
