56 BULLETIN 647, U. S. DEPARTMENT OP AGRICULTURE. 



CULTURAL CONDITIONS IN ANT-INVADED VS. ANT-FREE 

 ORANGE GROVES IN LOUISIANA.* 



As already stated, the Argentine ant infests only slightly mor 

 than 26 per cent of the orange groves of Louisiana as yet. It wa 

 found that 40.7 per cent of the groves that had never had the ant. 

 in them were in " poor " condition, while about the same proportioi 

 (43.9 per cent) of those that were infested with ants were in gooc! 

 condition. In other words, about 15.4 per cent more of the ant 

 invaded groves were in "poor' 1 condition than of the noninvadec 

 groves, but this is probably in large part due to the greater negleci 

 of the ant-infested trees because of that infestation, many of th( 

 owners becoming discouraged as soon as they found the ants present 

 A considerable number of groves had been abandoned completely 

 because the ants had gotten into them. A slightly greater reduction 

 in crop had occurred in the groves infested by ants, this reductior 

 being, however, only about 0.22 box per tree greater than in those 

 free from ants. Both the maximum and the last (1914) crops were 

 far below what they should be in both ant-invaded and ant-fre€ 

 orange groves for trees of their age, being in each case less than 

 1 packed box per tree. In Cameron Parish the large sweet seedling 

 orange trees, in which the Argentine ant does not occur, helped tc 

 raise the production average for the groves free from ants, as these 

 trees produce from 5 to 15 boxes each. 



Thus it is seen that there is practically no difference between those 

 groves in Louisiana where the ants are present and those where they 

 are not, either in the condition of the trees or in the amount of fruit 

 produced. It is undoubtedly true, however, that where the scale, 

 white-fly, and rust-mite infestations are heavy and no attempt is 

 made to control them the crop will be reduced considerably. The 

 effect of these insects also will be unusually pronounced on trees that 

 are weakened by too close planting, poor drainage, and cultural 

 neglect. The ants appear to have no effect on the rust mite. 



That groves completely overrun Avith the ants and in a badly run- 

 down condition from neglect can be revived and brought back to 

 their normal bearing condition without treating the ants or keeping 

 them from the trees has been demonstrated. The principal features 

 of this work will be related here briefly. 



1 The data on conditions affecting the culture of orange trees in Louisiana were obtained 

 partly by means of questions submitted to the orange growers, partly by personal inspec- 

 tion of the groves, and are complete on about 96 per cent of the groves of the State. 

 Those groves with a large percentage of trees fairly large for their age, symmetrical, 

 with moderately dense foliage, of good color, and bearing an average-sized crop according 

 to local standards, were classed as " good." Those showing a large percentage of under- 

 sized trees, with thin foliage, many dead and dying branches, poor color, lack of growth, 

 and poor crop were classed as " poor." 



