MAINE AGRICULTURAL EXPERIVetvIT STATION. I913. 5I 



sulphur just before the leaf buds opened were practically free 

 from scab on the fodiage during the summer of 1913. It would 

 seem then that to control this form of the disease requires 

 a dormant spray, just before the leaf buds open. 



It is not claimed that the spores of the perfect stage of the 

 apple scab fungus, formed on the leaves of the season before, 

 which have lain on the ground under the trees during the win- 

 ter, are not the source of a large amount, and usually all of 

 the spring infection. It is maintained, however, that with cer- 

 tain varieties limb infection is an important and serious factor 

 in carrying the disease over winter and that this form requires 

 a special treatment with a dormant spray if it is to be effect- 

 ually controlled. 



The data regarding varieties of apple trees which are af- 

 fected in this way is incomplete, but while this form of the dis- 

 ease has been recorded before in this country it must be re- 

 membered that this is the first case where it has been definitely 

 proven in America that apple scab remains alive over winter 

 on infected limbs. It is to be expected that those varieties 

 which are most susceptible to leaf and fruit infection will be 

 more likely to have the limbs attacked. Observations so far 

 made indicate that this supposition is correct. In an orchard 

 containing 7 varieties, Mcintosh and Pameuse were the worst 

 attacked. Milden and Westfield ranked next in order of sus- 

 ceptibility. Only an occasional twig was found affected on 

 the Northern Spy trees and these but slightly, while Oldenburg 

 and Tolman trees were entirely free from injury. 



THE EUROPEAN APPLE CANKER IN MAINE- 



Observations made during the past season show that the 

 European apple canker is not only present in Maine but that 

 in some localities it is quite common. In one young orchard 

 the cankers were found on the trunks of several trees whiie 

 in older orchards they appeared more abundant on branches 

 an inch or two in diameter. Several w^ere found in crotches, 

 suggesting that they might have followed winter injury. The 

 larger part of them, however, showed the remains of a dead 

 twig in the center indicating that the fungus may have gained 

 entrance thereby. 



