17 



spirit, or too little faith in "new-fangled notions" to coiiperate in 

 an}' systematic attempt to conquer the trouble. General cooperation 

 over a considerable area is an important prerequisite to success, 

 especially in dealing with diseases of long-lived plants, like trees. 

 But unfortunately, there is found in almost every community, the 

 slip-shod man who reasons that, because his trees have suffered so 

 long from black-knot, they always must, and whose simple laziness 

 and conservatism lessen the results of the intelligent efforts of his 

 progressive neighbors. 



But attention must be paid, in fighting the black-knot, to otiier than 

 cultivated trees, merely. Since, as stated above, the disease attacks 

 some of our common species of wild cherry, care should be taken to 

 destroy ail such trees within a considerable distance of the cultivated 

 trees, for the}' may serve, as well as any others, to spread the infec- 

 tion. Since one species of wild cherry, the black rum-cherry, is said 

 not to he attacked by the black-knot, it would be safe to destroy those 

 wild trees seen to be affected and keep all others in the neighborhood 

 under careful observation. 



THE POTATO BLIGHT AND ROT. 



Phytoplithora infestans deBy. 



The combined warmth and moisture of the season justplosing have 

 been very favorable to the development of fungi, whose attacks have 

 consequently been, in many instances, unusually severe. Probabl}- 

 no one disease has been more generally prevalent or more disastrous 

 in its eff'ects throughout the state than the blight or rot of potatoes. 

 It may be worth while, though it may seem like guarding the barn 

 door after ihe horse is stolen, to discuss briefly our knowledge of its 

 cause and to give some hints as to treatment which gives promise of 

 usefulness in aiding to ward off threatened attacks in future years. 



The potato rot is caused by the development within the potato plant 

 of a fungus closely related to. these which cause the mildewing of 

 grape leaves, of lettuce, etc. The threads of the fungus grow in the 

 tissues of the stems and leaves of the host and send out fruiting 

 threads, through tiny openings or pores which exist in the surface, 

 into the outer air, where they produce the spores. These spores 

 germinate readily in a warm, moist place, and give rise to new threads 

 which, when produced on the surface of a fresh potato leaf, make 

 their way into its interior and quickly spread throughout the plant. 



