EXPERIMENTS ON THE APPLE WITH SOME NEW FUNGICIDES. 15 



nate of lead might possibly still be used, although it is a little too 

 severe on the leaves. 



On the other hand, under the conditions obtaining at Winchester, 

 Va., and the same was true at other points in Virginia during 

 1909, the self-boiled lime-sulphur with the arsenate of lead added 

 gave practically perfect commercial results on the fruit and entirely 

 satisfactory results on the foliage except where cedar rust was abnor- 

 mally bad, without any russeting or leaf injury whatever. The fruit 

 seemed to be even brighter and yellower than normal fruit. This 

 mixture has not proved to be a very powerful fungicide for apple 

 diseases under extreme conditions. 



It should be noted that Mr. W. M. Scott, of the Bureau of Plant 

 Industry, has developed the self-boiled lime-sulphur mainly as a 

 fungicide for use on the peach, for which purpose it is eminently 

 successful. The down on the peach skin serves admirably in retain- 

 ing the mixture on the fruit. Mr. Scott has also obtained some very 

 good results on the apple under favorable conditions, but has pointed 

 out that this mixture has not given entirely satisfactory results in the 

 treatment of apple scab under extreme conditions. In the experi- 

 ments on pecan scab carried on by the writer during the last year in 

 South Carolina, where heavy and frequent rains occurred, self-boiled 

 lime-sulphur failed in preventing the attacks of this fungus. 



The self-boiled lime-sulphur does not appear to withstand heavy 

 washing rains. This throws some doubt on the ability of the straight 

 self-boiled lime-sulphur to protect against the attack of fungous 

 diseases under varied and unfavorable conditions. 



It should be noted that the self-boiled lime-sulphur permitted 

 2 per cent of infection on the leaves of the Ben Davis, 3 per cent 

 on the Yellow Newtown, and 4 per cent on the York Imperial in 

 Series I. While this amount of fungous disease on the leaves is 

 insignificant, nevertheless, it was the highest obtained in any of the 

 plats of this series. It therefore brings out the doubt as to the 

 fungicidal strength of this otherwise remarkably good mixture. 



The new form of iron sulphid gave practically perfect results on 

 both leaves and fruit of all varieties. It was absolutely noninjurious. 

 Furthermore, it gave the most perfect protection from fungi, the fruit 

 having no infection whatever and the leaves being given a mark of 

 one-half of 1 per cent of fungous injury on all varieties. The foliage on 

 this plat had a particularly fine dark-green color and held on later than 

 any other leaves in the orchard. The twigs were stockier and the 

 buds were finer and plumper than on any other plat, although the 

 self-boiled lime-sulphur plat was a close second in this regard. It 

 should be noted, however, that the fruit was slightly greener in color 

 and apparently a little later in ripening than on the other plats, 



[Cir. 58] 



