Horticultural Division. 451 



ashes — was the best of the remaining plots although its advan- 

 tage was slight. Between the other seven there was no obvious 

 differences. 



Plot 4 — nitrate of soda — was conspiciously darker in foliage 

 than any other throughout the season. The vines matured well, 

 although the yellow leaves stiU hung to the plants in the middle 

 of October. Plot No. 5 — sulphate of ammonia — was perhaps 

 ten per cent below No. 4 in amount of growth, and the wood was 

 not so well ripened as in the other. 



THE BLACK -KNOT OF THE PLUM AND CHERRY. 



The New York Law. 



The black-knot is a serious disease, attacking the branches and 

 twigs of the plum, sour cherries, and sometimes sweet cherries. 

 It is also common upon wild choke- cherries, from whence it spreads 

 to the orchards. The most prolific source of the disease, however, 

 are the neglected hedge-rows of plums and Morello cherries along 

 road-sides and about old buildings. Sometimes black-knot will 

 be noticed sparingly in a community for several years before it 

 seriously attacks cultivated trees, and this fact has caused people 

 to become indifferent to it; but sooner or later it will spread and 

 become a most pernicious evil. Plum growing is abandoned in 

 some parts of the Hudson river valley because of the incursions of 

 black-knot, and a similar fate is likely to overtake any community 

 which neglects it. It is the duty of every citizen to exert himself 

 towards the extirpation of this pest, and New York and Michigan 

 now have laws to compel its removal. 



Black-knot is a fungous disease, and the only reliable treatment 

 yet known is to cut off the knot and bum them. This operation 

 should be done just as soon as the leaves fall, at the latest. Good 

 plum growers inspect the trees once or twice during the summer 

 if black-knot is feared. Always bum the knots; if they are not 

 destroyed tlie spores of the fungus will stiU develop, even after the 

 knot is cut from the tree. The old knot often contains worms, 



