38 Transactions British Mycological Society. 
Aschersonia Goldiana has been recommended for the control of 
Aleyrodes, and Sphaerostilbe, Pseudomicrocera, and Podonectria 
for the control of Aspidiotus, Lepidosaphes, etc. For several 
years, these were regarded as the sole instances of successful 
control of insects by the use of entomogenous fungi, though 
adverse criticism was not lacking. Finally, the United States 
Bureau of Entomology undertook a special investigation into 
the subject, and the results of four years enquiry and experi- 
ment have been published by Messrs Morrill and Back* in a 
Bulletin entitled, ‘‘ Natural Control of White Flies in Florida,” 
from which the following extracts are quoted. 
“Much damage has resulted in the past from ill-advised 
attempts to check the spread of white flies in newly infested 
localities by means of fungus parasites. The control of de- 
structive diseases affecting citrus trees has been interfered with 
by (these) fungus parasites and much preventable loss thereby 
incurred. This interference is due to the fear that the fungicides 
recommended for the diseases referred to, would, if applied to 
the trees, check the white fly fungus parasites with injurious 
results. 
“Under natural conditions, without artificial assistance in 
spreading, the fungi have ordinarily in favoured localities, con- 
trolled the white fly to the extent of about one-third of a 
complete remedy through a series of years. 
“The most successful method so far devised for introducing 
the red and yellow Aschersonias into groves where they do not 
occur is the spore spraying method, first successfully employed 
and recommended by Dr E. W. Berger. For the introduction 
of the brown fungus the brushing or dipping and the rubbing 
methods first used by the authors are as successful as any yet 
discovered, but are not so reliable as the spore spraying methods 
for the Aschersonias. The infections secured by artificial means 
of introducing fungi, while successful in introducing the fungi, 
have thus far proved of little or no avail in increasing their 
efficacy after they have once become generally established in 
a grove. Experiments by the authors, and by citrus growers in 
co-operation with the authors, involving the treatment of 
thousands of trees with suitable ‘checks’ or ‘controls’ have 
shown that when fungus (red or yellow Aschersonia) even in 
small quantities is present in a grove there is no certainty that 
from three to six applications of fungus spores in water solution 
will result in an increased abundance of the infection on the 
treated blocks of trees by the end of the season. In some of 
the most important and carefully planned and executed ex- 
periments the fungus has increased more rapidly in sections of 
* U.S. Dept. of Agric., Bureau of Entomology, No. 102. 
