SPOROTRICHUM. 



35 



In tlio third series of observations tlio junior author selected leaves 

 on whicli all living pupiB had been killed by fumigation. It is proba- 

 ble that fungus had already infected a few d<>a(l ])U])a' but had not 

 broken out around the margin previous to fumigation; yet, consider- 

 ing the comparatively few pujne becoming infected on unfumigated 

 leaves as compared with the unusual numb(^r infected on fumigated 

 trees, there is no doubt that the fungus developed for the most part 

 after the i^uivp were killed by the gas. 



Table Vlll. — Development of luhile-J'ringe fungus on leaves fumigated Sept. 26, 1906. 



Concerning the reported practical results in reducing the wliite 

 flies, it may be said that the occurrence of a very high percentage 

 of the dead larvne and pupjr, especially of the cloudy-winged white 

 fly, as already noted in the grove of Mr. C. W. Ilicks, where OA^er 91 

 per cent of the dead insects were infected, has no bearing on the 

 parasitic nature of this fungus, since an equally liigh rate of mor- 

 tality occurs in gi'oves infested A\dth the same species where very 

 little white-fringe fungus can be found. Its prevalence is evidently 

 only an indication of the extent of the occurrence of unexplained 

 mortahty. The data here presented are regarded by the authors 

 as satisfactory evidence that the Microcera develops almost entirely 

 or exclusively on larvt\3 and pupa? already dead from other causes 

 and should be disregarded as a factor in the control of the white fly. 



SPOROTRICHUM. 



The Sporotrichum is either closely related to or identical with one of 

 the diseases of the cliinch bug wliich attracted so much attention from 

 entomologists a number of years ago. As a white-fly parasite it 

 has been under observation since September 8, 1906, and is largely 

 limited in its spread to the fall of the year, when, under favorable 

 weather conditions, it spreads ^^^th astonishing rapidity among 

 adults of both the citrus and cloudy-winged white flies then crowding 

 the new growth. Tliis fungus does not form pustules like the red 

 Aschersonia. Adults killed by it remain attached to the underside of 

 the leaf, their botUes become shriveled, and in a short time the gi-ayish 

 mycelial threads of the fungus break through the body of the fly and 



