CORNELL UNIVERSITY EXPERIMENT STATION BULLETINS. 305 



although this fact may not be noticed at first glance in the much 

 reduced illustrations. But the gain in size and uniformity in Figs. 3 and 

 4 is considerable. 



The combination of Bordeaux mixture and Paris green reduced the 

 per cent, of scab in both Kings and Baldwins to a trifle more than 50 per 

 cent. 



The combination containing the London purple was not so effective, for 

 59 per cent, of the Kings and 67 per cent, of the Baldwins were badly 

 injured. Fig. 3 is a fair representation of apples treated with this 

 combination. 



The action of the Paris green is particularly interesting. When used 

 alone it reduce the injury from scab upon the King apples 17.7 per cent., 

 upon the Baldwins 7 per cent. This unequal gain may probably be 

 explained to a certain extent by the fact that the Baldwins were not so 

 severely attacked. When used with the Bordeaux mixture upon the Kings 

 a gain of 4 per cent, stands in favor of the Paris green when compared with 

 the London purple, while in the case of the Baldwins the gain is 15 per 

 cent. This would go to show that Paris green possesses marked fungi- 

 cidal properties, but it is not so valuable in this respect as the Bordeaux 

 mixture (Fig. 4). 



By comparing Figs. 2, 3, and 4, it will be seen that the sprayed apples 

 are decidedly larger than those not treated. This may possibly be but the 

 natural variation in the size of the fruit borne by different trees, but since 

 the unsprayed trees bear uniformly smaller fruit it is scarcely probable 

 that the applicptions were not in some way connected with the increase in 

 size. And this agrees with results obtained in Ohio during 1891 by W. J. 

 Green. He found that "Aside from the inferior appearance of scabby 

 fruit, the effect of the scab is to retard the growth of both foliage and 

 fruit; hence, scabby apples are smaller than those free from scab. The 

 difference in size between apples that are affected with scab, and those 

 that are free from it is not the same with all varieties, nor with any given 

 variety in different localities. That the difference may often be con- 

 siderable is shown by some comparisons between scabby Newtown 

 Pippins and those that were free from the disease. One bushel of that 

 variety that was free from scab was found to contain 202 apples, while 

 the same quantity of scabby apples contained 317 apples. The average 

 weight per apple was 4 and 2^ ounces respectively. This comparison was 

 between extremes, but those of the second class were, in size, far below 

 those that were free from scab. It is no doubt true that scab may cause a 

 diminution in size of fifty per cent., but in most cases the loss is below 

 that figure. In all cases scab hinders development, but not always in pro- 

 portion to the amount found upon the fruit. Wherever scab is present at 

 all, either upon fruit or leaves, the effect must be considerable in arresting 

 the development of the fruit." 



The effect of the applications upon the larvte of the codlin-moth was 

 very marked. When the Paris green was applied alone it reduced the 

 injury from 25 per cent, to 2 per cent, in the case of the King apples. The 

 Baldwins show a marked difference also, the reduction being from 38 per 

 cent, of wormy apples to only 4 per cent. When applied with the Bor- 

 deaux mixture upon the King apples, the per cent, of wormy fruit was even 

 less than when the Paris green was applied alone; but the reverse is true 

 in the Baldwins. The experiment indicates that the beneficial action of 



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