the scale insects and other pests upon which they live there is no more food for them to exist upon, and consequently they must perish. One of our best orchardists, having extensive orchards in the State, has frequently said that he would prefer to have always two or three scaleinfested trees in the orchard. As long as he had these scale-infested trees he was sure of knowing just where he could put his hand on fungus material to keep down the scale insects in the other trees. Of course in a short time the trees that were originally scaly would become entirely free from scales, and he would have to look for fungus in other places. The same speaker stated, that one among the many regrets he had after the great freeze was that he had lost not only a considerable amount of well-grown wood from his trees, but had also lost all of his friendly fungi; and that he would be somewhat perplexed to know just where to get these fungi again to protect his trees against the scale insects.

It is nearly certain-one might say almost beyond question-that for the most part the diseases of scale insects and whitefly are native to Florida. While this cannot be stated with absolute certainty, still the fact that the different fungus diseases appear spontaneously in widely-separated orchards of the State rather confirms one in this opinion. In addition to this, quite a number of the fungi which attack scale insects have been found on trees growing near hammocks in localities where it would not be probable that they could have been carried from cultivated orchards.

CARE NECESSARY FOR SUCCESS.

To control scale insects and whitefly by means of the fungus diseases one must pay close attention to minor details, and must make intelligent observations. It is as impossible to carry out this work successfully without due regard to the needs of the fungus and the peculiarity of the insect pest that is to be controlled, as it would be to use insecticides with the same disregard to details. The writers have frequently met orchardists who have pinned in a few leaves bearing whitefly diseased with fungus, and who in six weeks had actually forgotten where these leaves had been pinned. In some cases, the orchardists expect the fungus to be disseminated to all parts of the grove after simply tying a few sprigs of such fungus material in one tree. For such work to be effective it would be necessary to make close observations of the entire orchard; to find where the greatest amount of scale or whitefly was located; and to introduce the fungi in such positions as would give the best opportunity for the spores to spread from one limb to another, and from one tree to another.

It sometimes happens that orchards become very badly infested with scale insects before one is aware of the fact; or, stating it in other words, the orchardist becomes careless and neglects to make observations in his field as frequently as he should. When such a condition has arisen, especially in connection with recently-planted or scattered trees, it will be best to relieve the condition temporarily by spraying with some contact insecticide; such as whale-oil soap or kerosene emulsion (see Florida Agricultural Experiment Station Bulletin 76). This will give the trees relief by reducing the amount of scale present; and

then as soon as the insecticide has disappeared, the fungi may be introduced. Spraying for scale insects in Florida must be looked upon as merely an expedient for helping any one out of a position into which carelessness has allowed him to fall.

TIME NECESSARY TO SECURE INFECTION.

In treating any kind of an orchard with fungus to destroy scale insects or whitefly, one should not lose sight of the fact that it requires a certain time before the fungus can be sufficiently disseminated throughout the tree, or throughout the orchard, to do effective work. During the most favorable weather it will require about four weeks. for the infection to make itself visible to the unaided eye. In the case of the red-headed fungus of scale insects the minimum time is a little less than this. During dry weather in summer, or during cold weather in winter, it will take much longer for the fungus to make a visible infection. It should be said, however, that many infections occur which are not visible to the unaided eye. It not infrequently happens, especially in the case of the San Jose scale, that the red-headed fungus kills off a very large percentage of the scales without producing any of the red pustules.

A PRIVATE ENTERPRISE.

Mr. F. P. Henderson, formerly of Arno but now of Gainesville, Fla., has supplied the fungus material with which hundreds of acres have been treated during the last two years. He has done this work as a private enterprise, independently of the Experiment Station, and is in no wise connected with this institution. The material that he supplies has been, for the most part, so far as our observations go, a mixture of the red-headed fungus and the black fungus. From a practical point of view, it should be regarded as rather better to have both fungi than to have either one of them separately, since they thrive best under slightly different climatic conditions; and therefore if conditions are such as to cause one fungus to make a weak growth, the other might probably find conditions suitable for making a stronger growth.

THE EXPERIMENT STATION CANNOT SUPPLY FUNGI.

The Experiment Station is maintained by funds received from the Federal treasury. The laws and regulations under which the money is expended are made by Congress for the United States Department of Agriculture. As the collecting and distributing of fungus is not an experiment, it could not justly be charged to this fund.

legislature could easily make provision for such work if it was considered desirable. Fungus material, however, can readily be obtained from private sources.

WHERE FUNGI MAY BE BOUGHT.

Black and Red-headed Fungi for Scale Insects: F. P. Henderson, Gainesville, Fla.

Red and Brown Fungi for Whitefly: A. J. Pettigrew, Manatee, Fla.; A. F. Wyman, Bradentown, Fla.; F. D. Waite, Palmetto, Fla. Red, Brown, and Yellow Fungi for Whitefly: C. A. Boone, Orlando, Fla.

Yellow and Red Fungi for Whitefly: C. B. Thornton, Orlando, Fla. The cost will vary according to the amount needed and the season at which it is wanted, but two or three dollars will usually buy enough to treat an acre.

THE RED-HEADED FUNGUS.

(Sphaerostilbe coccophila, Tul.)

Figure 2 is from a photograph of the red-headed fungus growing on the purple scale on a stem of an orange tree. The red color of the fungus shows whitish in the illustration.

The senior author of this bulletin was the first to call attention to the fact that the red-headed fungus is parasitic on the San Jose scale. The discovery was made at De Funiak Springs, Fla., in May, 1896, and was subsequently published in "Garden and Forest," 18. Studies on this fungus were reported in Florida Agricultural Experiment Station Bulletin No. 41 (1897) 19.

Immediately after making this discovery steps were taken to find means of using it in a practical way to control this pernicious scale. The results of these experiments showed that it was not only easy to infect scales that were previously free from the disease, but that the work could be done profitably under field conditions.

An important fact that was brought out in the laboratory investigations, and one that is usually overlooked by those who use the handlens only, is that myriads of scales are infected and killed by this fungus without its being externally visible. It therefore frequently happens that a scaly tree may be thoroughly overrun with this fungus, although no pustules are visible. This point should be especially remembered when one is introducing the red-headed fungus.

Dr. S. A. Forbes, State Entomologist, gave this fungus a thorough trial in Illinois in 1898, 9 and found that the climatic conditions there were not such as to make it a practical remedy. Dr. J. B. Smith, 21 of the New Jersey Experiment Station, also gave this fungus a thorough trial. In both Illinois and New Jersey it is able to live over winter and to do some good in the way of reducing the San Jose scale; but in neither case did it flourish as it does in Florida, where our climatic conditions are peculiarly favorable to its growth. Even as near to Florida as in Middle Alabama, Professor Earle 6 found that the fungus was not active enough to be considered sufficient to hold the San Jose scale in check. There can be no longer any ques

tion as to its efficiency in Florida, since hundreds of acres have been treated by practical orchardists, and since such able men as Prof. H. A. Gossard 10, Prof. H. Harold Hume 12, Dr. E. H. Sellards, and Dr. E. W. Berger 1, have observed it from a technical point of view.

No. 3 of Figure 3 represents a cross section of a scale insect and a pustule of the red-headed fungus as seen under a microscope. Nos. 4 to 27 show different forms of spores and hyphae as they occur in nature and on culture media. (See Bulletin 41.)

Mr. C. W. Griffing had the Komoko peach orchard of 650 acres. treated with this fungus during 1906; and at the meeting of the Florida State Horticultural Society at St. Petersburg in May, 1907, he reported that this treatment was more effective than spraying had been, with a saving of about 90 per cent. of the cost of the latter operation.

SPECIES OF INSECTS INFECTED.

This species of fungus is effective on a large number of scale insects. Its virulence varies with regard to different species in Florida. In Japan 14 it is more effective on Diaspis pentagona than on the San Jose scale. Next to the San Jose scale, the purple scale (Mytilaspis citricola) is most frequently affected. Professor Earle 7 found this scale attacked by it in Porto Rico. The long scale (Mytilaspis gloverii) is also frequently destroyed by it. The round scale (Aspidiotus ficus) is frequently killed by it. The scale (Aspidiotus nerii) of the China-berry tree is usually destroyed by it. Among wild trees it may be found in great abundance on the obscure scale (Aspidiotus obscurus) on water-oaks, and on Aspidiotus tenebricosus, a similar scale on red maple. It has also been found on the chaff scale (Parlatoria pergandii), which inhabits the limbs and trunks of citrus trees. It also occurs, but very rarely, on the citrus whitefly.

Fig. 4. Perithecium.
Enlarged 75 times.

Cook and Horne 3 found it present on the purple scale and on Chionaspis citri, though it was less effective on the latter. Parkin 15 found it present in Ceylon on the purple scale, and also on Aspidiotus aurantii, Aspidiotus camelliae, Aonidia bullata, and A. crenulata. He reports it also as occurring on Fiorinia fioriniae in Mauritius, on Aspidiotus articulatus in West Africa, and Ischnaspis filiformis and Aspidiotus articulatus in the West Indies. These references are sufficient to show the world-wide distribution of the fungus, and also its habit of attacking many species of exceedingly troublesome scale insects.

Fig. 5.
Ascus.
Enlarged
200 times...

Figure 4 represents a cross section of a perithecium of this fungus as seen under a microscope. These forms occur rather rarely in the groves, but are easily recognized when they do occur by their shape and deeper red color. The perithecia are much smaller than thepycnidia.

Figure 5 shows a single ascus of the red-headed fungus greatly enlarged. The perfect spores are borne inside the ascus.

HOW TO APPLY THE FUNGUS.

Figure 1 shows how the fungus material should be applied to the tree. The portion of the tree to which it should be tied is that which is most thoroughly infested with the scale insect which one wishes to destroy. During the dry weather the fungus spores will remain