THE ARGENTINE ANT IN RELATION TO CITRUS GROVES. 



19 



sound and parasitized scales, the presence or absence of scale enemies, 

 and the activities of the ants. This experiment was started on April 

 28 and concluded October 24, 1914. There was a large colony of the 

 ants about the base of the nonbanded tree throughout the experiment, 

 but the ants did not visit the tree, except to keep it patrolled by 

 scouts, until several soft brown scales became established there, and 

 at no time were they discovered paying the slightest attention to 

 the purple scales. No scale enemies of any consequence were seen 

 on either tree, and there was never any evidence of parasitism. The 

 results of this experiment are summarized in Table I. 



Table I. — Experiment to discover the effect of ants upon the armored scales of 

 citrus. Louisiana, 191Jf. 





Ants present. 



Ants excluded. 



Date. 



Number of sound scales 

 present. 



Number 

 of scales 

 showing 

 parasit- 

 ism. 



Number and activities 

 of ants on trees. 



Number of sound scales 

 present. 



Number 

 of scales 

 showing 

 parasit- 

 ism. 



May 7 



97 





 

 

 





 







Only 3 scouts in tree . . 



283 







125 



591 









198 



do 



591 







July 17 



276 



8 ants capturing white 

 flies. 



530 







Aug. 13 



1,130 



1,372 







Sept. 25 



5,700 (estimated) 



10 ants attending soft 

 brown scale only. 



50 ants, all attending 

 soft brown scale only. 



7,200 (estimated) 



Trunk and main 

 branches literally 

 covered. 







Oct. 24 



Trunk and main branches 

 literally covered. 







Reference to Table I will show that on May 7 there were 97 scales 

 on the ant-invaded tree and 283 on the tree from which ants were ex- 

 cluded. The number gradually increased on each tree from June 

 to October, except that there was a slight and unaccountable decrease 

 on the tree from which ants were excluded during June and July. 

 On September 25 it was estimated that there were 5,700 scales on the 

 ant-invaded and 7,200 on the ant-free tree. By October 24 the trunk 

 and main branches of both were literally covered with the scales, 

 and it was impossible to distinguish between the two as to infesta- 

 tion. The scales had increased at approximately the same rate on 

 both trees. The health of the trees remained good throughout, except 

 for a few yellow spots made on the leaves by the feeding of scale 

 groups. 



In another experiment the ants were excluded from a block of 

 more than 200 bearing orange trees for several months, while an 

 equal number of trees adjoining were left untreated as checks. The 

 color of the trees in the treated block showed improvement over 

 those in the check block, and this improvement was attributed to the 



