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- New York AGricutturaL Exrreriment STarion. 339 
ate of soda. After the two solutions have been mixed, and chemi- 
cal action has ceased, add one and one-half pints of commercial 
‘ammonia and dilute to thirty gallons with water. Extended 
experiment is still needéd to determine the time at which the first. 
spraying should be made, also the number necessary, and the 
strength of the solution required to obtain the best results, as by 
dilution the cost is lessened, and also the danger of injury to 
the foliage reduced to the minimum. 
Black-knot of the plum and cherry.— The black-knot of the 
plum and cherry is distinctly an American disease and is recog- 
nized at a glance by the rough wart-like swelling which cover the 
_ branches and sometimes even appear on the trunks of the trees. 
Where the fungus is not checked, whole orchards soon become 
affected, and are a serious menace to every healthy tree in the 
vicinity. The fungus was described about seventy years ago by 
the mycologist Schweinitz, who thought, however, as many do 
still, that the trouble was due to insects, from the fact that there 
is often found the larva of insects imbedded im the galls. But 
since the very careful and systematic study of the black-knot by 
Dr. W. G. Farlow, in 1886, there is no reason to doubt that it is 
caused by a parasitic fungus, the spores of which, after ripening, 
become detached from the knots and are carried by the wind or 
by insects to healthy trees, where in some'manner they penetrate 
to the cambium layer, where they take root and grow, reproducing 
galls similar to the one from which they become detached: 
Preventives and remedies.— As the galls are found on the native 
plum and cherry, growing wild in fence corners and abandoned 
places, they should be sought out and burned. When found 
on cultivated trees, the knots should be at once cut and burned, 
and the wound treated with a strong thirty per cent solution of 
iron sulphate. If the work is done while the trees are dormant, 
they can be sprayed with the same solution, which will be likely 
to destroy any spores resting on the trees awaiting a favorable 
time for development. Where the knots are cut off, after treating 
‘the wounds with iron sulphate, cover with a linseed oil paint. 
‘ INSECTS AND REMEDIES. 
The apple.— Attacking the trunk; is the flat-headed apple-tree 
borer (Chrysobothris femorata, Fabr.) and the round-headed 
apple-tree borer (Saperda candida, Fabr.). The eggs of the flat- 
