362 MANUAL OF FRUIT DISEASES 



satisfactory program of eradication. There is no objection to 

 more frequent inspections, but a single annual inspection, if 

 carefully done, should prove sufficient. It is necessary to 

 destroy these knots, otherwise the spores contained therein are 

 likely to be liberated and start the trouble again. This method 

 of control has not given the satisfaction that it should, the 

 difficulty apparently lying in the carelessness of the inspector 

 and the failure of the neighbor to cooperate. It is obvious that 

 if but a few knots are overlooked, the fungus may still operate 

 successfully. And the growers of a given region must make the 

 plan one of joint-action; one individual cannot exterminate 

 the fungus in a locality. If the existing laws were enforced, the 

 extent of injury from this disease would be greatly diminished. 

 The reward for any such eradication measures will be reaped in 

 accordance with the vigilance of the local orchardists. 



As a measure purely supplemental to the one just outlined the 

 trees should be sprayed with bordeaux mixture, the number of 

 applications depending upon the severity of the case in hand. 

 In cases of a threatening nature the sprayings should begin late 

 in March; five or six subsequent applications at intervals of 

 two or three weeks should be made. 



REFERENCES 



Farlow, W. G. The black knot. Bussey Inst. Bui. 1876 : 440-453. 



1876. 

 Beach, S. A. Black knot of plum and cherry. New York (Geneva) 



Agr. Exp. Sta. Bui. 40 : 25-34. 1892. 

 Hesler, Lex R. Diseases of the plum. Black knot. In The Fruit 



Industry in New York State. New York Agr. Dept. Bui. 79: 



1190-1192. 1916. 

 Humphrey, J. E. The black knot of the plum. Massachusetts 



(Hatch) Agr. Exp. Sta. Rept. 1892 : 27-30. 1893. 

 Humphrey, J. E. The black knot of the plum. Massachusetts 



(Hatch) Agr. Exp. Sta. Rept. 8: 200-210. 1891. 

 Halsted, B. D. Destroy the black knot of plum and cherry trees. 



An appeal. New Jersey Agr. Exp. Sta. Bui. 78 : 3-14. 1891. 



