92 



THE AEGENTINE ANT. 



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oranges of exceptionally high qualitj^, and the industry has prov^en a 

 paying one for many years past. A considerable number of localities 

 have during the past 15 or 20 years become infested by the Ai-gentine 

 ant, due, no doubt, to drifting logs containmg ant colonies that 

 lodged along the banks of the river. The warm wmters, coupled with 

 the presence of considerable moisture at all times, have made possible 

 very rapid increase of the ants, and the first result of their activities 

 has been a greatly accelerated rate of increase by all scale insects, and 

 particularly by the chaff scale (Parlatoria pergandii Comst.). Not 

 only do the ants protect this scale from its natural enemies, but they 



colonize the larvae up- 

 on the young growth 

 of the orange trees and 

 upon trees not pre- 

 viously infested. 



At times the ants 

 eat into the orange 

 buds, evidently in 

 quest of nectar, and 

 buds thus injured do 

 not set fruit. This 

 habit is not always 

 exhibited by the ants, 

 and it may be that it is 

 more or less dependent 

 upon the prevalence 

 of scale hisects on the 

 trees. The secretions 

 of aphides and scale 

 insects are preferred 

 to other food, and it 

 seems not unlikely 

 that when honeydew 

 is abundant the buds are not molested b}^ the ants. Whether 

 or not the ants do any other direct damage to the trees is still 

 an unsettled question, but certain it is that the bearing qualities 

 of an orchard are seriously impaired by the second season of 

 infestation, the crop is almost entirely lost by the third season, 

 and the trees are dying rapidly by the fourth year of infesta- 

 tion. (See PI. VIII.) One orchard which well illustrates the rate 

 of destruction consisted of a 20-acre tract of young grapefruit 

 trees, visited by the authors in March, 1910. The trees at this 

 time were about 4 to 5 feet m height and appeared very vigorous and 

 healthy. The ants were, however, rapidly infesting the field from 

 adjoining orclianls. During the summer of 1910 the ants increased 



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Fig. 13. — Sectional view of ant-proof hive stand from above, shoW' 

 ing construction. (Senior author's illustration.) 



