NATUEAL CONTEOL OF CITEUS MEALYBUG IN FLOEIDA. 17 



inent 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 emploj^ed 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^° 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 



10 Smith, Harry S., and Armitage, H. M. Op. cit, p. 121. 



