STATE POMOLOGICAL SOCIETY. 39 



issued daily by the United States Weather Service of the De- 

 partment of Agriculture. The weather map, made up and 

 issued at ii o'clock A. M., also at 8 o'clock in many places, is a 

 satisfactory way of predicting the general conditions. A 

 little study of these maps from day to day will soon place one 

 in position to tell when storm periods are likely to occur. It is 

 commonly known that storm areas travel from west to east. 

 In general, the rate of daily travel is about 500 miles, but 

 there are, of course, many variations from this. One can 

 readily locate storm areas on the map from the fact that such 

 areas are always indicated 'by a low barometer and by the fact 

 that the word "Low'' is printed on the map. 



When to Spray. Having become acquainted with the prog- 

 ress of a storm area by a little daily study, one can then deter- 

 mine with some degree of certainty what day the storm center 

 is likely to be over the state of Maine. With these facts in 

 mind and watching the development of foliage and buds very 

 carefully and knowing the approximate number of days neces- 

 sary to cover a given area of orchard with spray, one can fig- 

 ure ahead when each spraying must be commenced in order to 

 finish ahead of the storm. If there is some one in the com- 

 munity who can use a compound microscope, he can follow 

 the development of spores on the fallen leaves and in this way 

 the number of days can be narrowed down even more. 



That one not especially trained can predict storm periods 

 with some degree of certainty is attested by the fact that the 

 speaker some years ago, in doing vineyard spraying in the 

 state of New York, was successful in predicting storm periods 

 at the five critical times for grape spraying and in every case 

 the applications were made before infection occurred. In 

 one case rain began falling in less than an hour after the 

 spraying was finished, while in another case rain did not occur 

 for about 24 hours. These grapes were carried through the 

 entire summer absolutely free from rot, whereas grapes on 

 adjacent unsprayed rows were so badly rotted as to be unmar- 

 ketable. 



That one cannot always be so successful in predicting rains 

 may be showni by the fact that the speaker, only last spring, in 

 connection with some orchard spraying, made an application 



