FORTY-FIFTH ANNUAL REPORT. 81 



on the fruit; first, as a small, circular, brown spot, which, under normal 

 conditions, rapidly enlarges, until within two or three days the entire 

 fruit goes down in decay. The object of this discussion is to point 

 out other phases of the disease with which the grower is less familiar. 



Brown rot also attacks the blossoms, turns them brown, and pre- 

 vents the fruit from setting. This is commonly known as blossom 

 blight. Whether it is the blossom or the fruit that is attacked, the 

 fungus often passes into the fruit spur, and from the spur, into the 

 twig. Affected twigs usuallA' are girdled, and the leaves beyond the 

 point of entrance wilt and turn brown. The disease may follow down 

 the affected twigs into the larger limbs where it spreads in all direc- 

 tions. Soon a sinking of the tissue is noticed, and this is followed by 

 the foundation of a gum pocket. A little later the bark splits, forming 

 a typical brown rot canker froni which the gum oozes in a sticky, gela- 

 tinous mass. If we examine the gum with the microscope, spores of 

 the brown rot fungus will be found. The fungus lives in these peach 

 cankers for man}' years and not only kills (he tree, bnl also serves as 

 a source of infection to every succeeding crop of fruit. 



These, then, are unnoticed phases of one of the most important factors 

 tending to undermine the peach industry of Michigan, and they can be 

 found in every Michigan orchard. How will we meet this problem? 



It is obviously much better to prevent the formation of peach cankers 

 than to treat them after they appear. 



IJemove all cankered branches in pruning. In case of serious cankers 

 on the trunk or main limbs it may be advisable in some cases, to remove 

 all diseased tissue and apply some disinfectant dressing. 



The control of blossom blight is an important factor in the prevention 

 of canker formation. This mav be accomplished bv destroving the 

 mummies which are the source of Sj>ring infection; either by plowing 

 the orchard before the blossoming time in the Spring, or, by destroying 

 all rotted fruits in the orchard at the harvest time. 



Likewise, the control of fruit rot is involved in canker prevention. 

 Tliis may be accomplished by the use of self-boiled lime-sulphur one 

 month after the petals fall and again, one month before the fruit ripens. 

 Since brown rot may enter through the injury of the curculio, these 

 sprays should follow the poison spray. Self-boiled lime-sulphur, proper- 

 ly prepared and applied, will injure neither the foliage nor the fruit, 

 will entirely control peach scab, and will reduce brown rot infection to 

 a minimum. 



These measures are sufficient to control rot and I make an earnest 

 appeal to Michigan fruit groAvers that they employ everj^ possible re- 

 source to stamp out brown rot in Michigan. 



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