18 
BULLETIN 1178, U. S. DEPARTMENT OP AGRICULTURE. 
Table 10. — Effect of spraying materials on the development of entomogenous fungi, the 
white fly, and the purple scale in 1920. 
Spraying material. 
Number 
of appli- 
cations. 
Pustules per leaf. 
Brown 
fungus. 
Red 
fungus. 
Scale 
fungus. 
Number per leaf. 
White- 
fly 
pupae. 
Adult 
female 
purple 
\ per cent oil 
1 per cent oil 
3-4-50 plus 1 per cent oil 
3-4-50 plus \ per cent oil 
3-4-50 plus 1 per cent oil (March 25) . 
Check 
3.0 
6.6 


6.2 
7.2 
2.6 
.24 
.2 
1.2 
9.5 
2.2 
1.0 
.08 
.3 
12.0 
6.5 
0.5 
.08 
4.3 
4.0 
«6.6 
1.3 
2.0 
3.4 
.5 
4.5 
Ml. 6 
2.3 
a White fly, estimated. 
b Not followed by straight oil emulsion. 
The entomogenous fungi did not develop normally where the 
Bordeaux-oil emulsion was applied. The oil-emulsion plats had 
nearly as many entomogenous fungi as the unsprayed checks. The 
trees sprayed once with Bordeaux-oil emulsion on March 25 and left 
without the special spraying with oil emulsion later were very se- 
verely damaged by scales, but the entomogenous fungi were present 
in great abundance on December 8. Although it is not shown in the 
table, there were more " beneficial" fungi present on December 8 than 
on September 10. 
CITRUS NURSERY. ORLANDO. FLA. 
The Government nursery of rough-lemon, sour-orange, and grape- 
fruit seedlings at Orlando was sprayed at weekly intervals from 
March 25 to August 2, 1919, with various materials, among them 
plain Bordeaux mixture, Bordeaux mixture plus one-half oi 1 per 
cent of oil, and Burgundy mixture. In 1920 this nursery was sprayed 
with seven kinds of copper materials at intervals of two weeks from 
March 10 to September 23. In both years citrus scab was controlled 
perfectly, and no spray injury was noted. No scale insects showed 
up on any of these plats except the checks, where there was a mod- 
erate infestation. 
The plat receiving plain Bordeaux mixture had about the same 
number of white flies as the check, but all the other plats which 
received the Bordeaux-oil emulsion had many less. The plats 
sprayed with copper compounds, such as homemade Bordeaux 
paste plus one-hali of 1 per cent of oil and commercial paste plus 
one-half of 1 per cent of oil, became very heavily infested with red 
spiders. The plats sprayed with homemade Bordeaux mixture plus 
one-half of 1 per cent of oil were also infested, but not to the extent 
of the plats previously mentioned. There were practically no red 
spiders on the unsprayed check when the observation was first 
made, but they gradually spread from the severely infested plats 
to the unsprayed plats. Several examinations were made from 
time to time to ascertain whether an entomogenous fungus was 
present, but none was seen. 
In 1922 this nursery was sprayed at intervals of four weeks from 
June 24 until November 25 with various strengths of Bordeaux mix- 
ture plus 1 per cent of oil. These infrequent applications, even 
during a very rainy season which was especially conducive to disease 
outbreaks, gave good commercial control of citrus scab. Since the 
