- 3 - 



gested by Cordley in Oregon in 1908. It has been very comr.ionly used m the 

 control of apple scab for more than 20 years altnough theru is evidence that 

 it has been responsible for a reduced yield in several sections. In tho 

 Annapolis Valley, for example, the total yield of apples amounted to 1.7 

 ifiillion barrels in 1911. That was before lime sulfur was used. During the 

 next eight years the yield never uttuined 1 million barrels. This reduction 

 is believed to be due in part to the effect of lime sulfur on leaf activity. 

 By 1921, there was a decided shift to fungicides oth^r than liquid lime sul- 

 fur and the apple crop in that year rixiounted to 1.5 million barrels. 



The early reports of lim.e sulfur injury were made largely on the 

 basis of foliago burn apparent to the naked eye. In reCunt years refined 

 iLc^thods of measuring leaf efficiency have been devised. The method involves 

 a determination of the carbon dioxide content of air before and after it 

 passes over a leaf enclosed in a transparent container. The absorption of 

 carbon dioxide is proportionate to the food manufactured by the leaf. It 

 is possible by this method to determine the efficiency of leaves under con- 

 trolled conditions, including leaves v/hich have been sprayed by different 

 materials. The behavior of such leaves may readily bo compared vd.th other 

 leaves which have not been influenced by caustic i.;aterial. Studies by 

 Hoffman sho^v that the efficiency of apple leaves nay be reduced 10 to 100 

 per Cent by 1-40 lime sulfur. In Ohio it has been found that solutions 

 at strengths of 1-80, 1-100, or eVen 1-125 may cause equally as severe re- 

 ductions, especially when the temperature reaches 90° F. Christopher of 

 Rhode Island reports a reduction of 10 to 20 per cent in leaves sprayed 

 with a wettable sulfur only. A 5-10 per cent reduction has been reported 

 for a period of a v/eek after the application of a straight sulfur dust. 

 Dry lino sulfur soems to have less effect on photosyntnesis than liquid 

 lime sulfur although somewhat more than the wettable forms. 



Ghilders, in the ubove article, concludes by making the follovifing 

 statement; "If liquid lime-sulphur should be cut from the calendars and 

 replaced entirely by elemental sulphurs, it would be well to keep in mind 

 a statement recently made by an Ohio grov/er, 'As far as I am concerned, I 

 intend always to keep a drum of liquid lime-sulphur in the back of my shed 

 in case I should get caught with a bad case of scab- That's one spray we 

 can depend on to burn it out.' This is not a bad suggestion." 



Spraying Techniqu e as See n from the Side Lines 



In the rush of the spraying season it is easy to overlook some fund- 

 amentals in orchard pest control. Holding ^^ spray nozzle from daylight un- 

 til dark leaves little tirr.e for reviewing one's efforts and studying ways 

 of doing the job more efficiently. The operator is in a poor position to 

 judge the thoroughness of coverage. It is so much easier for someone "on 

 the side lines" to criticise the job and make suggestions for improvement. 

 The writerrecommends taking time off occasionally to observe the coverage 

 of a tree while someone else holds the nozzle. 



In about 9 cases out of 10 a tree is unevenly covered because too 

 much of the spray material is directed from a point 6 or 8 feet from the 

 ground and just outside the tips of the branches. This generally results 

 in an excessive coverage of the outer branches and a very scanty cover^.ge 

 in the top center of the tree. Those outer branches, if sprayed entirely 

 from the one position, may actually drip vi^hile the top center has only 

 the most spotty kind of coverage. This suggests an urgent need for a 



