380 INJURIOUS AND BENEFICIAL INSECTS OF CALIFORNIA. 



ceous and parasitic insects. Consequently, these insects increase in 

 sufficient numbers to do much damage in the orchards, particularly 

 the orange groves. In California this condition is not. very evident, 

 except perhaps with the soft brown scale, but with the increase of the 

 ant a very serious and new problem may face the citrus fruit growers. 

 The author has observed the ants in Berkeley attending colonies of 

 the black cherry aphis (Myzus vera si Fab.) on cherry trees, there 

 being myriads of the ants present. They are also troublesome in the 

 chicken yards to setting hens and to hatching chicks, often swarming 

 over them in numbers sufficient to cause death. If one can imagine 

 an ant many time more troublesome and prolific than the native house 

 and field ants, much more aggressive and persistent and capable of 

 bothering nearly everything, he gets a fair idea of the Argentine ant. 

 It appears to be little less than a scourge to a community. 



Distribution. — Professor C. W. Woodworth lists the following locali- 

 ties in the State as infested with the Argentine ant: Alameda, Azusa, 

 Berkeley, Byron Hot Springs, Campbell, Claremont, College Park, 

 Corona, Cupertino, Emeryville. Fruitvale, Los Angeles, Martinez, Mel- 

 rose, Monrovia, Montecito Canyon, Oakland, Piedmont, Riverside, San 

 Francisco, San Jose, Santa Clara, San Mateo, Stege, Stockton and 

 Upland. 



Food. — The ants are exceedingly fond of any sweetened material, 

 which largely accounts for their invasion of houses, grocery stores, 

 candy shops, restaurants, hotels, bee hives and their attendance upon 

 insects which secrete honey-dew, as the scale insects, plant lice and 

 white flies. Certain greases and fats, fresh meats, etc., are also eager' y 

 sought by them. Many seeds, as lettuce, are even carried away. The 

 young and adults of many insects, as bees, midges, wasps, cockroaches, 

 etc., are greedily devoured and in destroying some of the injurious 

 insects the ants do a good turn, but this is so insignificant, compared 

 with the harm, that it should hardly be mentioned. 



Control. — The control of this pest is exceedingly difficult. In many 

 districts, especially in Berkeley and Oakland, Professor Woodworth 

 nas had excellent success in keeping the numbers so small that the 

 ants ceased to be a household pest. His recommendations are given 

 as follows 272 : "We obtained by far the best results by the use of a 

 very weak solution of arsenic and syrup. Most of the commercial ant 

 poisons commonly known as ant pastes consist of arsenic and syrup, 

 but are made very strong in arsenic. This kills the foraging ants 

 almost immediately. We found by reducing the arsenic to between 

 one fourth and one eighth of one per cent they would take large 

 quantities of the material to their nests and feed it to the young, and 

 the whole nest would be killed by a slow poisoning. 



"The most convenient way of exposing the poison to the an's is to 

 use a large jar with a perforated cover and within it place a sponge 

 saturated with the arsenic solution. The ants will enter through the 

 perforations in the cover, fill themselves with the arsenic solution and 

 carry it to their nests. The sponge will hold enough poison to require 

 two or three weeks to empty it. and before that time the ants will 

 almost entirely disappear. 



- T -Rul. No- 207, Cal. Agrcl. Exp. Sta., p. 81, 1913. 



