NATTJBAL CONTROL OF CITRUS MEALYBUG IN FLORIDA. 17 
ment of artificial methods or he can foster in several ways the de- 
velopment of the natural enemies. Unfortunately, however, no 
wholly successful artificial control measure is known. Suitable 
sprays have not been found in Florida. In certain instances a solid 
stream of water directed at high pressure against the mealybugs in 
order to knock them forcibly from the trees is advantageous. As the 
mealybugs' habit of clustering between adjacent grapefruit renders 
them somewhat inaccessible, however, such a spray must be applied 
several times for best results, and from the viewpoint of economy 
is not wholly satisfactory. 
It should be remembered that the insect pest herein considered 
is one that becomes a nuisance periodically only, and that during 
many seasons it is unnecessary to employ any treatment to control 
it. The grower has learned that a few scattering colonies of mealy- 
bugs do not necessarily indicate that there is going to be a serious 
infestation, and that often the insects will not become abundant 
enough to justify spraying. For economic reasons, therefore, he 
will defer as long as possible the application of any control measure, 
hoping in the meanwhile that the mealybugs will disappear. Arti- 
ficial measures are employed only when considerable injury has been 
wrought and when there are no apparent signs that it is going to 
cease. The observations of the past two years indicate that the 
fungous parasite will be invariably present at such times. Inasmuch 
as the known sprays, while of little value in themselves, actually 
tend to inhibit the disease in that diseased or dead individuals present 
at the time of spraying are dislodged, and thereby rendered im- 
potent, while the healthy ones which the sprays do not dislodge or 
kill remain and reproduce unimpeded by the fungus, it is obvious 
that in rare instances only will it pay to employ artificial measures. 
On the other hand, the grower can aid appreciably in restoring the 
natural balance in his citrus grove by introducing the fungus from 
available sources as soon as possible in the spring. Unfortunately 
the organism has not yet been cultivated on artificial media. There 
is. however, a method by which large quantities of the fungus can 
be produced. Smith and Armitage 10 have shown that the citrus 
mealybug can be cheaply and successfully grown upon potato 
sprouts. With an abundance of insects it is a relatively simple 
matter to propagate the disease among them. The method employed 
is substantially the same as that used so successfully in growing 
large quantities of the brown-tail moth fungus, and consists briefly 
in obtaining a quantity of diseased insects and distributing them, 
while yet alive, in the field among the healthy ones. The success 
of this method depends upon getting the fungus established in the 
field early in the season. The State or Federal Government should 
Smith, Harry S., and Armitage, H. M. Op. cit., p. 121. 
