THE ARGENTINE ANT IN RELATION TO CITRUS GROVES. 3 



pests, as indicated by the number of titles on this subject appearing 

 in entomological literature, has increased greatly throughout the 

 world in the past 10 years. 



The principal convictions which had arisen, on the influence of 

 the Argentine ant on citrus fruit trees in Louisiana, are expressed 

 in the writings of Dr. Titus 1 and Messrs. Newell and Barber. 2 

 Titus states, substantially, that the ants aid in the distribution of 

 aphids and scale insects on citrus and other trees, remove young 

 scales to new territory, establish colonies of certain species, and 

 appear to have become caretakers for all kinds of scales and plant- 

 lice. 



Newell and Barber, in addition to expressing the belief that the 

 ants shelter and protect scale insects, aphids, and white flies, and 

 establish them upon other plants, are of the opinion that it is in the 

 orange groves that this ant has inflicted probably the most serious 

 injury. They note that ant invasion is followed by so rapid an in- 

 crease of scale insects that, unless prompt measures are taken against 

 the ants, the second year of infestation shows a severe reduction in 

 the crop, the third year almost complete loss, and the fourth or fifth 

 year witnesses the death of many of the trees. These authors state 

 further that the ants are particularly severe in their attacks upon 

 the blossoms of the orange. 



The opinion of the Louisiana orange growers themselves on this 

 subject may be summarized from the answers received to inquiries 

 made and submitted in 1914 as to whether the ant injures the trees 

 and in what ways. Of those growers replying to the question, about 

 61 per cent believed it to be injurious, 33 per cent stated that they 

 did not know, and about 6 per cent believed that it was not injurious. 

 The prevailing beliefs as to the nature of the injury were, (1) that 

 it prevents bearing, (2) destroys blossoms and roots, (3) eats feeder 

 roots, (4) destroys the fruit, (5) takes the sap out of the new growth, 

 (6) causes the death of limbs by traveling continuously over the 

 same spot, and (7) injures the bloom, causing the oranges to drop. 

 It was believed also that the ants increase, disseminate, and protect 

 scale insects and drive out lady-beetles. One answer, however, was 

 to the effect that the ants are beneficial because they destroy other 

 msects. It was generally agreed that the ant causes most severe 

 injury to the orange trees, resulting in a complete loss of crop and 

 culminating in the death of the trees. 



A preliminary survey of the orange orchards of Louisiana made 

 it plain that many of them were suffering from some undetermined 

 noxious influences. The trees were, as a rule, undersized, poorly 

 shaped, lacking in the abundance of clear, dark green foliage which 



*Op. cit., p. 79-84. -Op. cit. 



