12 



NATURAT. CONTEOL OF WHITE FLIES IN FLORIDA. 



Occurring coincidently with one of the most unusual periods of 

 drought ever recorded in Florida, the reduction of white flies through- 

 out the city limits of Orlando and in the majority of the infested 

 citrus groves in the vicinity was at first thought to be due to the 

 weather conditions. An analysis of the available data concerning the 

 weather conditions in different locations where the white flies have 

 become successfully established indicates that with little doubt this 

 idea was erroneous. 



Fungous parasites were thought by some to have been responsible 

 for the situation here considered. Wliile such a conclusion might 

 have been drawn in 1906 from observations in a few selected groves, 

 the white-fly conditions in 1907 in these same groves offered positive 

 proof that the fungous parasites exerted an insignificant, if appreciable, 

 influence toward the general reduction in the numbers of white flies. 

 The brown fungus appeared to be efl'ective in one small grove of about 

 100 trees located near the center of the city of Orlando. Aside from 

 this, no instance of effectiveness of fungous parasites in the locality 

 referred to was known to the senior author, who is responsible for the 

 observations. A comparison of the conditions during 1906 and 1907 

 in representative groves and in yards in and near Orlando will show 

 the status of fungous parasites with relation to the situation. (See 

 Table I.) 



Table I. — White-fij conditions in and near Orlando, Fla., daring 1906 and 1907. 



Grove No. 1 is that belonging to Capt. J. S. Jouett and is located 

 near the north end of Orange Avenue in Orlando. 



Grove No. 2 is that of Mr. C. B. Thornton and is located near 

 Orange Avenue, a few hundred yards southeast of 'grove No. 1. 

 The condition in this grove (No. 2) is especially significant, since, 

 notwithstanding the comparative abundance of the parasitic fungi 



