54 NATURAL CONTEOL OF WHITE FLIES IN FLORIDA. 



Examinations by the junior author have shown that even a larger 

 percentage of spores may be lost. It was found that a closely 

 woven cheesecloth removed as liigh as 73.8 per cent to 92.8 per cent 

 of the spores, wliile an ordinary coarse towel removed 41 per cent. 

 In obtaining these results one-tenth cubic centimeter of solution of 

 red Aschersonia spores and water was placed on a glass slide marked 

 off into one-tenth millimeter squares, and the counts made beneath 

 a compound microscope. Wliile the results thus obtained were 

 subject to much variation, they all demonstrate that cloths should 

 be avoided as strainers. Similar examinations of solutions strained 

 tlirough fine-wire strainers showed that practically no spores are 

 lost. 



Amount of fungus to use. — Experiments to determine the most 

 economical amounts of fungus to use per gallon of water have given 

 such varying results that no dependence can be placed upon the 

 data obtained. Even under identical and apparently most favorable 

 weather conditions, in experiments conducted at the same time and 

 on trees equally well infested and favorably located, frequently as 

 good infections have resulted from the use of 200 pustules as from 

 4,000 pustules per gallon of water. This is equally true of results 

 obtained when only a few or a larger number of trees were included 

 in the experiments. Within reasonable limits, the amount of pus- 

 tules to use, therefore, depends entirely upon the amount of fungus 

 obtainable. In all of the experiments herein reported, unless other- 

 wise stated, 200 or more pustules have been used to each gallon of 

 water. 



Advantages of soahing fungous pustules before shalcing or stirring. — 

 A series of experiments in wliich the fungus was allowed to soak for 

 different periods between 5 minutes and 48 hours showed that it is 

 immaterial how long the fungous pustules remain in the water before 

 shaking, provided, of course, that they are not left soaking an unrea- 

 sonable length of time. Experiments have furnished no data to even 

 warrant any soaking of the fungous leaves if they are comparatively 

 fresh, except such as takes place during shaking or stirring. As good 

 infections have been secured repeatedly when pustules were shaken 

 as soon as placed in the water as when soaked several hours. 



Number of times fungous pustules can be used to advantage. — -Several 

 experiments have been conducted to determine this point with definite 

 results. Twelve hundred and 1,800 pustules of red Aschersonia in 

 different experiments were shaken with a quart of water in a 2-quart 

 glass jar for a period of five minutes. After pouring off the water 

 used in the first shaking, fresh water was added and shaken as before, 

 repeating up to four times. The quart of water used in each succes- 

 sive shaldng was diluted to make 4 gallons of spray and applied to 

 a given number of trees. In every test the third and fourth shakings 



