Extension Work in Plant Pathology, 1923 



13 



farm orchards. The combination sprayers equipped with 4<-horsepower engines 

 or better, with pump of 10 gallons per minute capacity, are proving very satis- 

 factory. They are readily converted from potato and truck sprayers to orchard 



sprayers merely by removing the spray boom and attaching a lead of hose and 

 a spray gun. These machines ate readily adaptable to other operations 

 around the home, such as disinfecting and whitewashing farm buildings and 

 fences. They are purchased and operated either by individuals or cooperatively 

 by two, three, or four farmers. During 1923, combination sprayers served 390 

 farm orchards and as many potato patches in Pennsylvania. 



(4) Spray service. — Under this heading comes such work as the 

 giving of method demonstrations in spray mixing and mechanics of 

 application; and the development of means for obtaining accurate 

 information as to when spraying should be done and arranging for 

 dissemination by mail, telephone, or radio, of this information when 

 it is finally obtained. 



IMPORTANT SPRAY PROJECTS 



Some idea of the extent of spray operations influenced hj exten- 

 sion forces can be gained by study of the diseases listed in the table 

 on page 20. In general, extension activities led to spray work with 

 more than 14 crops. The most noteworthy features of this work dur- 

 ing 1923 were the continued development of the spray ring, increased 

 use of the combination sprayer, and improvement of spray service to 

 commercial and home orchardists. The major portion of the work 

 done was in connection with projects on potato spraying, orchard 

 spraying, and truck-crop spraying in the South. 



POTATO SPRAYING 



It has been found in many States that potato spraying results in 

 increased yields even in years when late-blight does not occur and in 

 sections where the disease is not prevalent. This is probably due in 

 large measure to the fact that Bordeaux mixture is effective in re- 

 ducing injury from leaf hoppers, flea beetles, and true tip-burn. 



During 1923, in 10 of the 46 States reporting potato spray activi- 

 ties, extension plant pathologists conducted organized projects in this 

 work. As an example of what may be accomplished in this field we 

 have the work in Penns}dvania, which during 1923 was in its sixth 

 year. The following summary indicates the part which the result 

 demonstration has played in the development of potato spraying in 

 Pennsylvania : 



Results of potato spraying in Pennsylvania, 191&-1923 



Item 



1918 



1919 



Number of counties conducting work. 12 



Number of demonstrations conducted 32 224 



Number of acres sprayed 314 1,787 



Average yield per acre sprayed busnels.. 142 



Average increase in yield per acre do 34.8 42.9 



Average per cent of increase 32.2 34.2 



Average cost per acre. $8.26 j $10.85 



Average number of times sprayed 5 5.5 



1920 



1921 



1922 



46 



57 



63 



318 



402 



447 



6,192 



10, 140 



16,680 



258.3 



233.5 



220 



74.7 



74.3 



66 



41.0 



47.7 



44 | 



$10.56 



$11.03 



$10. 34 



6 



6.5 



6.8 



1923 



63 

 220 



23,000 



257 



58 



30 



$11.00 



Careful work by the extension pathologist of Pennsylvania led to 

 installation of effective machinery on the larger farms and made 

 possible the development of spray rings where good equipment could 

 not otherwise be financed. In 1923, 220 spray rings reached 1.934 



