127 



JDJiiry althoug:h slij^lit (»n individual apples was sufficient to 

 1 otieeal)]y impair their General appearance and finish. The 

 apples sprayed with the finely divided siilfnr-arsenate of 

 lead combination in suspension were small and poorly 

 colored. The apples sprayed with the concentrated lime- 

 sulfur ai-senate of lead combination and with the fine sulfur 

 arsenate of lead dust were noticeable for their superior fin- 

 ish and licneral excellent a]ipearance. Both the sulfur- 

 arsenate of lead dust and sulfur-arsenate of lead suspension 

 gave almost perfect contrt)l of peach scab, but caused serious 

 defoliation of the trees. Self-boiled lime-sulfur gave satis- 

 factory commercial control of peach scab without injury to 

 the foliage. These indicate that the sulfur dust treatment 

 may be e(|ual to our common wet sprays as far as apple and 

 peach scab, codling moth and curculio are concerned, but is 

 liable to cause serious injury to peach foliage. Tt is quite 

 ])roliable that dusting Avould be very satisfactory jirovided 

 the application could be made in accordance wdth local 

 weather conditions. However, such an arrangement is en- 

 lirely impi-actical for the average fruit-grower. The chief 

 advantage claimed for the sulfur equipment is its rapidity 

 of application, permitting the grower, Avhen weather condi- 

 tions favorable to scab infection occur, to ])rotect a much 

 larger area of his orchard in a given tinu' and Avith the same 

 labor than is possible Avith a wet spray. This advantage 

 is of doubtful value under average conditions, while against 

 it must be charged the greater cost of the material, the ne- 

 cessity of maintaining a wet spraying apparatus for San 

 Jose Scale and peach leaf curl in addition to the dusting 

 machinery and the impossibility of using black leaf 40 or 

 similar decoctions for the control of aphis. 



TIME OF APPLICATION. 



We should never lose sight of the fact that none of the 

 spray materials mentioned will give satisfactory results un- 

 less the application is made at the proper time. There is a 

 certain time during the life cycle of every insect and fungus 



