612 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



threads or hyphae extend out in every direction and carry the disease 

 to other young on the same leaf without the production of more 

 spores. The hyphcs grow around the edge of the leaf to the upper 

 surface and there produce the spores. When the spores are pro- 

 duced they are carried by the wind and other natural agencies and 

 are quite likely to infect all the flies on a tree or even in a grove. 



This fungus appears mainly in the late summer and in the 

 autumn and grows best in wet weather. It attacks both the 

 Common Whitefly and the Cloudy-Winged Whitefly. 



The Red Fungus or Red Aschersonia (Aschersonia aleyrodis), 

 is next in importance. It develops in and on the young fly and 

 does not send out the hyphae as does the brown fungus. It can 

 therefore be carried only in the spore form. The spores are formed 

 in small pits on the fungus growth, such growths being called fungus 

 pustules. This species thrives earlier in the season than does the 

 brown fungus and it also is effective against both the common 

 species. 



The Yellow Fungus, or Yellow Aschersonia (Aschersonia flavo- 

 citrind) is interesting as well as important. In appearance and 

 growth it is almost exactly like the red fungus, but bright lemon 

 yellow. It affects only the Cloudy-winged Whitefly, of which it 

 is an important parasite. 



The fourth species of importance is called Microcera (Fusarium) 

 and is particularity destructive to the Cloudy-winged Whitefly. 

 It attacks several of the scale insects as well as the whitefly and is 

 of importance in their control. It grows more quickly than the 

 other fungi, requiring less than a week for the formation of spores 

 where the other species require nearly a month. It infests young 

 larvae to the greatest extent, but attacks both eggs and adults as 

 well. It thrives better during cooler weather than do the others, 

 but it needs plenty of moisture. 



All fungi do best under rainy weather conditions, and it is 

 said that if the rainy season persisted throughout the year there 

 would be no need for artificial measures of control for the whitefly 

 and possibly also for some of the scales. 



Preservation and distribution of fungi. These fungi may be 

 preserved until needed by placing leaves with the fungus and 

 spores present on them in cold storage or by drying the leaves and 

 storing them. From such material, cultures may be introduced 



