18 EXPERIMENTS OX THE APPLE WITH SOME NEW FUNGICIDES. 



Where a dangerous outbreak of bitter-rot occurs late in the season, 

 probably, with our present knowledge of the subject, a moderately 

 strong Bordeaux mixture — say 4-4-50 — would still be the safest 

 thing to recommend for use. 



CONCLUSIONS. 



All the fungicides containing copper used in the tests here reported 

 upon russeted the fruit of the Ben Davis apple seriously, injuring it 

 from 10 to 60 per cent. 



The copper-sulphid preparation made from self-boiled lime-sulphur 

 was the least injurious copper spray, causing only 10 per cent of 

 injury to the fruit of the Ben Davis trees. 



Xeutral Bordeaux mixture proved the worst spray mixture used, 

 even injuring the fruit of the York Imperial. An excess of lime, 

 therefore, is an advantage in tending to render Bordeaux mixture 

 harmless. 



Standard Bordeaux mixture, 3-3-50, was the next to the worst 

 mixture for spray injury, giving 60 per cent of injury on the Ben 

 Davis fruits. Cutting down the quantity of copper sulphate in 

 Bordeaux mixture from 3 to 2 pounds reduced the injury, but did 

 not prevent it. 



Copper poisoning occurs seriously on the leaves, even damaging 

 them to a greater extent than the fruit, reaching 80 per cent on the 

 Yellow Newtown when Bordeaux mixture is used. 



The susceptibility of the leaves to copper poisoning bears no direct 

 relation to the behavior of the fruit in this regard. The leaves of 

 any variety may be badly injured while the fruit is not hurt, or vice 

 versa. 



Adding certain materials, such as gypsum, iron sulphate, lime- 

 sulphur solution, etc., to Bordeaux mixture in all cases reduced the 

 injury, but did not entirely prevent it except in the case of the 

 self-boiled lime-sulphur in part, where a new compound was 

 formed. 



A new form of copper sulphid was made, the self-boiled lime- 

 sulphur being used as a basis, and tested for the first time, proving 

 effective and almost completely noninjurious except to the fruit of 

 the Ben Davis variety. 



A similar fungicide made with the commercial lime-sulphur solu- 

 tion was only slightly more injurious to the fruit, but was distinctly 

 injurious to the foliage. 



A new iron-sulphid fungicide was made and tested for the first 

 time. It was entirely harmless and gave remarkably good results 

 under the conditions at Winchester, Ya., in 1909, except that it 

 produced distinctly greener fruits. It may therefore be regarded as 

 promising. 



[Cir. 58] 



