300 



THE MONTHLY BULLETIN. 



BROODS. 



There are three regular, well-defined broods of the common whitefly, with some- 

 times a partial fourth brood in winter. The first brood of adults generally emerges 

 during March, the second during June, and the third during August and September. 

 The second and third merge more or less into one, there being some adult whiteflies 

 out during what is regarded the interval in July between the second and third 

 broods. An understanding of the time and occurrence of the broods of adults is 

 important for a proper understanding of the control measures, especially for spraying 

 with insecticides. 



The relative occurrence of the broods of the common whitefly. the cloudy-winged 

 whitefly, and the woolly whitefly are shown in the following diagram (Fig. 100) : 



CONTROL MEASURES. 



Control measures for the common whitefly consist either in the use of the several 

 fungus parasites that generally infect it in Florida, or in spraying with emulsions 

 of oils and soaps. 



Jan. 



Feb. Mar. 



April May June July Aug. 



Woolly whitefly. 



Common citrus whitefly. 



.... Cloudy-winged whitefly. 



Sept. Oct. Nov. Dec. 



Fig. 100. — Diagram showing relative date of emergence of adults. 

 (Courtesy Fla. Exp. Station, Bui. 126.) 



FUNGUS PARASITES. 



There are three principal fungus parasites of the common whitefly. These are the 

 red aschersonia (Figs. 101 and 102), the brown fungus and the white fringe fungus. 

 These are so effective that a grower may count on a clean crop of fruit, free from 

 sooty mold, about every third year, with only partial control during the other years. 

 While this extent of control does not satisfy all the most fastidious growers, many 

 depend wholly upon the fungi and apply no other remedies. 



The fungi were originally spread artificially by planting a few trees, having a 

 fungus upon them, in a grove into which it was intended to introduce it. Later, 

 leaves with fungus were pinned onto the leaves of trees infested with whitefly, and 

 finally, mixtures of fungus spores and water, made by mixing leaves having fungus 

 upon them, were sprayed into whitefly-infested trees. The last method is the one 

 now generally employed. While fungus obtained from leaves is still used, this prac- 

 tice is being discouraged since the advent of citrus canker, and the use of pure 

 cultures recommended. When fungus obtained from leaves was used, 30 to 40 

 fungus spots per pint of water gave good results. 



As indicated in the preceding paragraph, the use of pure cultures of fungus is 

 recommended, as that obviates the risk of getting canker or other diseases with the 

 fungus material. While it is true that the danger of getting canker with fungus 

 material on leaves is remote, since all canker-infected properties are under quaran- 

 tine, including a radius of a mile, there is still a possibility of getting leaves from a 



