67 



sooner than from seven to ten days after infection. An expert — 

 a blight chaser — can tell it in from five to six days. He could tell 

 it in its very early stages. It causes a slight wilting of the tip. I 

 know that Mr. Repp is skeptical. We would like to show him. I 

 know I am safe. He is in New Jersey and I in New York, you see. 



Member. How would you treat canker? 



Prof. Whetzel. It depends on the kind of canker. 



Member. The kind that makes a spot rough and black on the 

 limb. 



Prof. Whetzel. Is it particularly black and rough before the 

 bark peels ? 



Member. Yes, the bark itself runs a circle. 



Prof. Whetzel. That's almost certainly the New York Apple 

 Tree Canker, caused by a fungus. Black Rot Canker, or New York 

 Canker, is common in Western New York, the Northeastern United 

 States, and West as far as Iowa. It is very common. It is started 

 by the fungus getting into some wound. It very frequently follows 

 fire blight. The general opinion of the fruit growers in Western 

 New York is that where they soak the limbs and body of the tree 

 with Bordeaux Mixture, they are not particularly troubled. 



Member. Would Lime and Sulphur control it? 



Prof. Whetzel. I do not know. 



Member. What treatment do you advise for the Collar Rot? 



Prof. Whetzel. I would advise that you go over your trees 

 carefully and frequently, and inspect the base of the trees. If you 

 find there are spots in the bark, cut them out, disinfect and paint 

 until they heal. 



Member. What disinfectant do you use ? 



Prof. Whetzel. Mercuric chloride — corrosive sublimate. 



Prof. Whetzel. Perhaps you people would be interested in the 

 methods we are now using in the Department of Plant Pathology to 

 solve the plant disease problems in the State of New York. All of 

 the investigation work during the growing season is now being done 

 in Field Laboratories in different parts of the State. We had seven 

 of these Field Laboratories last season. Each man in the depart- 

 ment who has a piece of investigation on hand (and every man in 

 our department has his problem) goes into the particular locality 

 where the disease he is studying is most apt to be abundant. He 

 takes with him, a full equipment of laboratory apparatus, micro- 

 scopes and materials, so that he can do everything that could be done 

 in the laboratories at the college. And there he is right in the midst 

 of the enemy, where he can see the disease in its various stages of 

 development every day during the growing season. He learns to 

 know the disease in its natural relations to the crop and the weather 

 conditions which affect it so markedly. He also learns the crop, the 

 diseases of which he is studying. He gets the grower's point of 

 •view. He at once sees that measures which he proposes for con- 

 trolling this malady must be not only theoretically correct, but prac- 

 tically possible and profitable. He puts on his overalls, and blue 

 shirt ; he rolls up his sleeves ; he tramps the orchard or fields in 

 rain and blistering sun ; he learns to liye and deal with men, the men 

 whose problems he is to solve ; he learns to respect the grower's ex- 

 perience. And the grower, what of him? Four of our seven field 



