586 ANNUAL REPORT OF TUB Ofif. Doc. 



more important to get it removed from the trees than from the 

 ground. The bacteria die quickly in pruned twigs, some tests made 

 last summer indicating that four or five days is about as long as they 

 can be expected to live in these under ordinary conditions, while on 

 the trees they might continue active development for weeks or 

 months. 



In this general connection comes the matter of collar-rot, crown- 

 rot or root-rot of apple trees. The exact nature and all the factors 

 concerned in the development of such troubles, are not understood. 

 It is likely that two or three distinct troubles affect the region of 

 the tree in question. It may be that the blight organism iself plays 

 a part at times, at least in extending the rot. The matter is under 

 investigation, but the problem is a complex one, and work must be 

 carried on for several seasons before definite conclusions can be 

 reached. Meanwhile, I should like to know from you and others 

 as much as possible about the occurrence of such trouble in the or- 

 chards of the State. For control, I would suggest the importance 

 of guarding against the spread of possibly contagious material from 

 tree to tree especially in worming. The use of 1 to 1000 corrosive 

 sublimate solution on all wounds and tools is a reasonable pre- 

 caution in such work. If the affected bark can be reached and cut 

 away thoroughly at an early stage, so that there is a border of good 

 live bark around the wound; and if the wound is disinfected with 

 corrosive sublimate or lime-sulphur and jjainted with thick lead 

 and oil paint or tar, so as to promote healing, the lives of some of 

 the affected trees may possibly be saved. I realize the difficulty in 

 most cases of reaching the undergrovmd parts satisfactorily and of 

 applying these measures in advanced stages of the disease; but I do 

 not believe it is worth while making an effort to check the spread 

 and to prevent early girdling of the tree. In some cases bridge graft- 

 ing may be resorted to advantageously. 



Another thing to do is to give each affected tree every chance 

 to make vigorous, thrifty growth, and as we say, to outgrow fhe 

 trouble. The sooner the diseased condition is recognized, and these 

 methods adopted, the better the chances for success. If the soil 

 seems thin or packed, resort to judicious fertilization or cultiva- 

 tion. Guard against drouth conditions by adding humus or by 

 mulching or by practicing shallow cultivation. Try to give the sick 

 tree proper food and moisture and soil conditions. Check the na- 

 tural tendency to over-bearing that comes from partial interference 

 with the normal transportation of food from tops to roots; the 

 tree will need as much building material as possible for the re- 

 placement of the diminished root system. Therefore, prune judic- 

 iously to retard top growth and to reduce a large leaf area that 

 would make excessive demand for water upon the roots. Thin tbe 

 fruit freely or remove it entirely. It is well w^orth losing a crop 

 or two from an infected tree if the life of the tree can be saved 

 thereby. 



I would like to discuss the other bark and wood diseases found 

 in our apple orchards, but time does not permit. In general, for all 

 of them, the means of control are the prompt recognition of the 

 disease and thorough destruction of affected parts, which serve as 



