Showing three stages of development of apple blossoms and fruit and best time to spray.

No. 1.

Right for 1st application, Bordeaux.

No. 2. No. 3.

Right for 2nd application, Bordeaux and arsenate of lead. Right for 3rd application, Bordeaux and arsenate of lead.

conditions following the applications; another is the method of preparing the mixture and both of those factors seem to be eliminated from this case. There is another, the condition of the tree at the time it was sprayed, the condition of the foliage or the fruit, or the variety, either natural or artificial conditions. I was called on to diagnose a case in Western New York this summer of severe Bordeaux injury on foliage that occurred from early spraying, and I found that the leaves had been killed quite extensively and especially in patches over the leaves. I examined microscopically a large number of those killed areas on the leaves and found in every case that particular surface of the leaf had been previously attacked by the fungus and it had evidently destroyed the protective cuticle of the leaf, making it more susceptible to Bordeaux injury, and I found a difference in the varieties of trees; trees that were more susceptible to scab also had been more severely injured in this way. I do not know positively that the Wealthy is more susceptible to scab on the leaves than the other trees that were in question in this case, but it simply shows that there are a great many factors like that that might explain an apparently contradictory case of this kind.

The use of lime sulphur preparations as a substitute for bordeaux mixture in controlling fungous diseases of plants is a very live topic among fruit growers at the present time. Bordeaux mixture has in the past been recognized by practically all authorities as the leading fungicide, and though very efficient it has in many cases given considerable dissatisfaction on account of the injury to fruit and foliage resulting from its use. Bordeaux injury has been carefully studied by investigators, for several years past. All agree that many cases of injury may be due to carelessness in making or applying the mixture; yet frequently such injury is without doubt due to certain weather conditions following the application, and may occur after all known precautions have been taken. Those wishing to follow this phase of the subject further, are referred to Bulletin 287, N. Y. (Geneva) Agr. Exp. Sta., '07, and Illinois Bulletin 135. The authors of these bulletins agree that rain following within a few days after the application of bordeaux mixture is likely to induce injury. This fact places it largely beyond our control. We cannot afford to delay the application until after the rain for it is before rain and not after that the spray should be applied. I wish to emphasize this point very strongly. Do not wait for wet weather to come

and pass by for fear that the rain will wash off the spray. There could be no more certain way to defeat the object of spraying than this. Remember that each scab spot starts from a spore of the fungus which can germinate only in the presence of moisture. It is as impossible for these spores to germinate on a dry leaf or apple, as it is for a wheat seed to germinate in soil devoid of moisture. We find that these spores can germinate in four or five hours. Any infections thus started during a day or less of wet weather, will continue to develop regardless of any spray that might be applied the day after the rain.

This being true it would be a decided advantage to know of some efficient spray that can be applied when it is most needed without danger of injury. Thus far there are strong indications that some form of lime sulphur preparation will in the near future satisfy this demand. We have in use at present several distinctly different kinds of lime sulphur preparations. First the home boiled solution prepared in dilute form for immediate application as used for scale. Second, the self-boiled mixture as prepared by Professor Scott, Bureau of P. I. as a summer spray for peach rot and other fungus diseases. Third, the commercial concentrated lime sulphur solutions, and fourth, the home boiled concentrated solution as prepared by Cordley of Oregon and Stewart of Pennsylvania. Aside from these some proprietary preparations such as Pratt's sulfocide are now on the market. Experiments up to the present time seem to indicate that each of the above mentioned preparations has fungicidal value. Just what form will prove best for summer spraying yet remains to be determined. The preparation and treatment for each disease must be worked out individually. For example, while self-boiled lime sulphur may be the best remedy for peach rot, the commercial or home boiled concentrated solution may prove to be most desirable for apple scab. There is also great variation in the concentration required for different diseases.

The experiments at Cornell during the past season were limited to the commercial solution. They were carried out on the farm of L. B. Frear near Ithaca, New York, under the general direction of Professor Whetzel of the Department of Plant Pathology. For the work on apple scab, the experimental plat consisted of a block of Rhode Island Greenings and it was so arranged that we had various combinations as to time and number of applications with both bordeaux and lime sulphur. We used the Niagara

Brand, heavy grade, i. e., containing the sediment, diluted 1-30. No comparison of this with the clear solution was made this year. Arsenate of lead was used with both bordeaux and lime sulphur three pounds to fifty gallons, and the application was very thoroughly made with a gasoline power sprayer using quite high pressure, 125-150 pounds. Since we were uncertain as to what the results would be, only a small number of trees were sprayed with the lime sulphur solution. The experiment was not therefore ideally laid out, but the results were so striking as to make them of value. The table summarizes the condition of the crop from plats variously treated.

Table Showing Comparative Results of Spraying During 1909 with Bordeaux and Lime Sulphur.

Table Showing Comparative Value of the Different Times at Which the Applications Were Made in This Particular Experiment, 1909.

The attack of scab was not as severe as sometimes occurs, owing to the dry season. Forty-two per cent, however, of the unsprayed fruit was more or less affected. This was reduced by Bordeaux 3-4-50 with arsenate of lead to 3 per cent and by lime sulphur diluted 1-30 with arsenate of lead to 3.6 per cent. In this case the application just after the petals fell was the all important one and controlled the scab almost as well as where more were given. It would not be safe, however, for growers to depend on a single application of the fungicide since the season being dry