THE ARGENTINE ANT IN RELATION TO CITRUS GROVES. 71 



to which must be added an additional $0.08 for transportation and 

 setting up, making a net cost of $0.31 each. The covers were made 

 and delivered for $0.75 each. On this basis the first cost of traps 

 and covers per acre would be about as follows : 



25 traps, at $0.31 each $7. 75 



3 covers, at $0.75 each 2. 25 



Net cost of traps and covers per acre 10. 00 



A crew of three have in practice fumigated 400 traps in 1^ eight- 

 hour days, their services, at the rate of $1.25 per day each, costing 

 $5.62. The carbon disulphid at that time cost $10.75 per hundred 

 pounds. On this basis the cost of fumigating per acre of 100 trees 

 per time would be about as follows : 



Cost of labor fumigating 25 traps, at $0.014 $0. 35 



Cost of fumigant, 25 traps, at $0.013 . 325 



Net cost of fumigation per acre . 675 



SUMMARY AND CONCLUSIONS. 



Most of the orange groves of southern Louisiana, with the excep- 

 tion of well-tended groves and seedling orchards, have been de- 

 clining in the last seven or eight years. As a rule, maximum pro- 

 ductiveness is reached at from 7 to 10 years of age, after which it 

 diminishes, the actual crop loss up to 1914 being approximately 37 

 per cent of the known possible production. The principal cause of 

 this decline of trees and loss of crop, which has been largely blamed 

 upon the Argentine ant, is cultural neglect. 



The part played by the ant in causing this condition has been 

 exaggerated. The only direct injury done by the ant is to destroy a 

 negligible number of orange blossoms. The ants do not attend the 

 armored scales of citrus or secure honey dew from them, nor do 

 they disseminate the living scales. They do, however, disturb the 

 predatory enemies of these scales, preventing the destruction of as 

 large a proportion of them as would otherwise occur. Nevertheless, 

 the natural enemies of the armored scales do not prevent heavy in- 

 festation even in orchards free from ants. The ant can not prevent 

 the control of the armored scales in Louisiana by spraying nor will 

 it increase the cost of spraying. Destruction of the ants will not 

 control these scales, and they must be controlled if orange growing in 

 that State is to be made profitable. 



L T nder present conditions the Argentine ant does not cause excep- 

 tionally severe infestations in the orange groves of Louisiana, even 

 of those soft scales to which it is most favorable. The mealybugs 

 have not been of importance as an orange pest in ant-invaded or- 

 chards during the years 1913 to 1915, partly due to the effective- 



