The Yellows referred to in the May number as attacking peach budded on plum, was the genuine Yellows - not a starvation or badly drained soil Yellows, but the simon-pure article. My observation teaches that the fungus mycelium is always a concomitant of this. Whether the fungus produces the disease or vice versa is difficult to say. To be more exact, whether the disease may not simply furnish an agreeable state of affairs for the development of the fungi is a question. We never look for the fungus until the disease has manifested itself and then it is too late to tell "which causes which." As to a remedy, I have never seen a tree benefited, much less cured, by any kind of treatment, after an attack of what we call Yellows in Virginia. That is about all I know about it. Do you know anything more? If so, tell us.

[The Editor has little doubt in his own mind that the disease is caused by the mycelium of a species of Agaricus - one of the mushroom tribe. This view he has placed on record before. Most nurserymen of large experience know, that precisely the appearances - we may say precisely the same disease - occurs in many trees, of which the pines and spruces afford notable examples - the white pine particularly. The growth of this fungus is first encouraged by half rotten wood, half rotten roots in the ground - or half rotten moss used for packing plants from Europe. Having once got a fair start in this way it spreads to healthy and sound roots, destroying them also. The exact species of Agaricus that does this has been determined, though at the moment of writing the name of this exact species is not at hand. No one that we know of, has examined the fungus which is always at the roots of a peach with the Yellows in its earlier stages, so far as we know, to see whether it is the identical Agaric or not - the mycelium appears to be the same under a strong pocket lens - but when we. see the exact appearances in so many other trees, and know that this fungus produces them, we may certainly, to say the least, grant the extreme probability of the same fungus producing it.

The experiments of Prof. Penhallow and others showing the deficiency of potash in the diseased wood, does not in the least militate against this view, as the power to apply potash may have been affected by. the diseased roots.

Aside from this the Editor has found the Yellows in the peach follow the placing of a spadeful of fungus-infested soil from around a Norway spruce, suffering from the disease. Of course he understands that an objection may be fairly made, that the peach may have become so diseased, without this application.

Clearly there is no reason why the mycelium of this Agaric is not the cause of disease - but many reasons why it may be. - Ed. G. M].