216 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 13 
tical value of these forecasts occurred on May 12, when the forecast 
indicated that a rain was probable in three or four days. Scab infec¬ 
tions had already occurred in considerable numbers in orchards that 
had not received the delayed dormant spray. A spray warning was 
issued calling for the application of the blossom pink spray immediately 
although the blossoms did not yet show pink. The rain began in the 
afternoon of May 16. Subsequent events showed that this was the 
critical application for the commercial control of apple scab in west¬ 
ern New York this season. In orchards where the application was 
delayed until after the rain of May 16-17, the leaves became badly 
infected with scab and a serious defoliation and fall of fruit resulted. 
Furthermore, in these orchards, it was very difficult to keep the fruit 
free from later infections. Had the special forecast of the Weather 
Bureau not been available, most of the growers would have waited 
until the 19th or 20th before making the application, when it was too 
late to protect the foliage. 
In order to have a check on the accuracy of the recommendations 
made through the spray service, each assistant had certain demonstra¬ 
tion or criterion orchards in which the spray was applied at the time 
advised. These orchards not only served to show the value of thorough 
and timely spraying, but also demonstrated the soundness of the ad¬ 
vice given. They were of great educational value in teaching the 
necessity of having the fungicide on the trees before rainy periods. 
In addition to the criterion demonstration orchards the assistant 
conducted fifteen or twenty demonstrations in the control of particular 
insects or diseases or in the use of spray materials or methods of appli¬ 
cation. Even in these demonstrations care was taken to have the 
work fit into a seasonal spraying program so that the results would 
not be obscured in the mind of the grower by the ravages of other 
pests or diseases. 
In the fruit growing counties the assistant devoted all of the early 
part of the season to orchard work but later conducted demonstra¬ 
tions with potato growers. In one county the assistant devoted most 
of his time to the problems of onion growers. 
For most effective work the number of demonstrations personally 
supervised by the assistant should not exceed twenty-five or thirty. 
The number of persons receiving the spray information service need 
not be limited but the assistant cannot be expected to visit all the men 
on such a list except in urgent cases and then only on special request. 
If he attempts to visit any very large number of growers the demon¬ 
strations and criterion orchards are sure to be neglected to the great 
detriment of the work. 
The criterion demonstration orchards should be selected with care. 
