NATURAL CONTROL OF CITRUS MEALYBUG IX FLORIDA. 15 
fungi are antagonistic, and in view of the effect of fungicides upon the 
latter, these facts should be kept in mind. It has been repeatedly 
shown, for example, that Bordeaux mixture, when employed to de- 
stroy the organisms causing citrus disease, at the same time de- 
stroys the entomogenous fungi ; thus the natural balance that other- 
wise exists, imperfect though it may be at times, but upon which 
the grower, perhaps unconsciously, has relied, is upset to such a 
degree that great injury results from attacks by insect pests. There- 
fore a spray which may be of great importance as a control measure 
for citrus diseases becomes to a large degree of no commercial im- 
portance because the grower must choose either to control the diseases 
or to permit the natural agencies to control the insects. If he feels 
that the insects are more injurious than the diseases he will let the 
entomogenous fungi control the insects, especially since their work is 
performed at no expense whatever to him. The only alternative is 
to follow the fungicide with an insecticide, or it may be possible to 
apply the fungicide and insecticide in one mixture, but these are 
expensive processes that may prove to be unjustifiable economically. 
With regard to the effect of fungicides upon the mealybug fungus, 
specific data are available in one instance. On August 11 and 12. 
1921, a count was made of mealybugs in a grove in Orlando, a part 
of which had been sprayed with fungicides by the Bureau of Plant 
Industry, for the control of melanose. and a part of which had not 
been thus treated. Although some plats were sprayed with Bordeaux 
plus oil emulsion, some with copper soap, some with barium tetra- 
sulphid. and some with lime-sulphur, for the present purposes all 
the sprayed trees will be lumped together in one category as 
i; sprayed." While certain of the sprays employed contained an 
insecticide, the presence of the latter has been entirely disregarded 
because it has been repeatedly shown that such insecticides are 
relatively impotent in so far as mealybug control is concerned. In 
counting the mealybugs such arbitrary categories as " absent." " very 
scarce." " scarce." " abundant." ; " very abundant." and " has been very 
abundant" were employed; and, although crude, these will serve to 
show the relative degree of infestation. Within the last-named 
class were included those trees which showed evidences of a previous 
heavy infestation, but which at the time of the count were free from 
insects. The other terms are self-explanatory. There were 255 
trees in the unsprayed area and 74 in the sprayed. Of the former. 
4. or 1.6 per cent, were placed in the class "very abundant " and 6, 
or 2.4 per cent, in the class " has been very abundant." Of the 
sprayed trees 6, or 8.1 per cent, showed an infestation classed as very 
abundant, whereas 1. or 1.4 per cent, in a plat sprayed with lime- 
sulphur, showed evidences of having recovered from a past heavy 
infestation. 
