WEATI£ER BUREAU. 77 



made -with the expedition to take twice-daily weather observations 

 and transmit them to tlie Weather Bureau. A number of observa- 

 tions ahvady have been received. This arrangement will provide 

 valuable observations from the most northern points at which obser- 

 vations have ever been taken and transmitted as a daily program. 

 The ship is also equipped with pihit balloons and it is expected that 

 these observations also will be radiographed daily. 



Orchard spraying service. — The special forecast service in con- 

 nection with the orchard spraying activities in the apple-growing 

 sections in the northern part of New York w^as continued during 

 the past season, and similar work to a limited extent was conducted 

 in localities in Pennsylvania, West Virginia, and Virginia. The 

 forecasts for the New York areas were distributed in previous 

 seasons from the Weather Bureau office at Eochester, but during the 

 past season this work was conducted from Ithaca, where closer co- 

 operation with the State Extension Service and the county agents 

 was obtainable. This arrangement proved more satisfactory and 

 effective work was accomplished. 



Damage from frost is not a serious menace to apple growing in 

 northern New York. Serious loss from this cause occurs on an 

 average less than once in 10 years. Scab, a fungous disease, is the 

 worst enemy. It remains dormant so long as the weather is dry. 

 The spores come into acti\T.ty when moistened and, unless killed by 

 spraying, trees may become infected within 24 hours. The problem 

 is to apply the spray just before a rain because when the rains occur 

 the fungi^ begin to grow and are killed by the poison in the spray. 

 If tlie spray is applied *and rains do not occur within about three 

 days thereafter the effect of the poison is minimized or lost entirely. 

 There are about 12,000 commercial apple growers in seven counties 

 in New York who are equipped for spraying. At least three appli- 

 cations are necessary each season. It is estimated that the total cost 

 of apple-tree spraying for one season in the seven counties is about 

 $3,500,000. Therefore, accurate and timely forecasts of the occur- 

 rence of rains in the spraying season are of great importance to the 

 growers in determining when the spray shall be applied, and the 

 responsibility placed on the Weather Bureau in giving correct infor- 

 mation is apparent. If the forecaster fails to predict a rain and 

 spray is not applied the trees become irremediably affected; if rain 

 is predicted and spray is applied but the rains fail to come the effect 

 of the spray is lost entirely, or considerably reduced, and heavy loss 

 results. 



The following is quoted from a report made on this special forecast 

 work during the past season by Professor Crosby, of the Department 

 of Entomology, and Professor Horner, plant pathologist of the 

 New York State Extension, which was based on information sub- 

 mitted by field assistants and county agents : 



The special forecasts for the spray service were sent to tlie following eight 

 counties: Orleans, Monroe, Wayne, Genesee. Onondaga, Chautauqua, and Ulster. 

 They were used constantly by the field assistants in timing their recommenda- 

 tions for spray. In the case of sprays involving fungous diseases these special 

 forecasts are especially important, because it is well known that fungous dis- 

 eases are vitally affected by the periods of wet weather. Four of the most 

 important counties had a telephone relay system by means of which it v^as 

 possible to warn the growers quickly when it was time to apply the spray. 

 This system was used throughout the season whenever occasion demanded. 



