370 ANNUAL REPORT OF THE Off. Doc. 



Tlu! surface is dotted willi spore ])iistiiles which emit ininnte flesh- 

 colored, waxy masses of spores ralliei early in the developmeut of 

 the rot. The fungus lives over winter in mummied api)les on the 

 trees, but not in those that rot on the ground; and in the limb 

 cankers, when these are formed. Of our commercial varieties Jona- 

 than is likely to sutler most. 



Blotch affects the surface of the fruit, Avithout diiectly causing 

 rot. The skin is discolored, and sometimes thickened so that small 

 raised areas are ajtparent. These are covered with minute black 

 dots in which the spores are formed. When attacked early the fruit 

 is dwarfed and deformed. The fungus attacks leaves and twigs, 

 surviving the winter in the latter. Ben Davis is the most susceptible 

 of our commercial ajtples. 



The Fruit Si)ot that can be controlled by July spraying is char- 

 acterized by numerous small spots, about 1-16 of an inch across, 

 that are at first deeper green or red than the surrounding color; 

 and soon becomes dead, and brown or black. The flesh is not affected 

 deeijly. They are more numerous towards the apex of the fruit, 

 and frequently occur at lenticels. The cause of this fruit spot is the 

 fungus Cj'lindrospoiium pomi, which infects the fruit during July 

 as a rule, and can be readily prevented by one or two ai>i)lications 

 of almost any fungicide during the first half of July. We must not 

 confuse this disease with that known as Fruit Pit which seems noi 

 to be due to fungus attack, and can not be controlled by spraying. 



Let us remember that the requirement for summer spraying, as 

 for any spraying, and the returns to be obtained from it, depend 

 on the presence of certain fungi that develop then, the growing of 

 varieties susceptible to their attack, and the occurrence of weather 

 ■conditions that would favor their development; and that the most 

 satisfactory results will be obtained when judicious spraying is an 

 adjunct to the use of good methods of culture and sanitation. Spray- 

 ing is, after all, an expedient to catch, as it were, the thief after 

 he is in the house. Let us see to it that we do not allow ways to 

 multiply hj which he may enter. 



There are certain transmissible diseases that can not be satis- 

 factorily controlled by spraying, such as Twig Blight, and the cankers 

 produced by the Black Rot and Bitter Eot fungi, and the several 

 wood rots and root rots. Our only means of holding these in check 

 is to discover the trotible at an early period in its development, and 

 thoroughly remove all ati'ected tissue. 



Twig Blight, sometimes known as Fire Blight, attacks young 

 shoots, the bark of older limbs, and sometimes the blossoms or young 

 fruit. As soon as blighted twigs are noticed, they should be cut 

 off' well below the affected part and the cut surface, however small, 

 touched with a swab Avet with a disinfectant, such as 1 to 1,000 

 bichloride of mercury; tools also should be wiped with such a solu- 

 tion at frequent intervals. Cankers can ferquently be cut out ; but 

 often the affected part must be sacrificed. Large cuts should be 

 painted over as well as disinfected. 



Collar Eot as Ave find it causing the death of the bark at the 

 base of the trunk of apple trees, is a perplexing condition. I am 

 not satisfied as to its causation in eA-ery case. Perhaps we ought 

 to bear in mind that this part of the tree is the one Avhere general 

 decay is most likely to occur because moisture from the soil and 



