,448 
ANNUAL REPORT OP NEW YORK 
nOP-APUIS. HONEY DEW AND BLACK BLIGHT. HOW PRODUCED. 
judge from the published accounts, one writer seeming to regard, the aphis 
as the principal evil, whilst another wholly ignores this insect and dwells 
upon thd black blight as being the cause of the failure of the crop. And 
it is not a little amusing to observe how very wise the reporters to some of 
the newspapers appear in giving an account of these diseases, and what a dis¬ 
play of scientific lore they make, when th^ir statements betray to us the fact 
that they have not the first correct idea upon the subject on which they are 
writing. 
The truth is, these three maladies, about one and another of which so much 
has been said, are all one thing—differing merely as cause and effect. If there 
were no lice on the hops there, would be no honey dew an<j no black blight. 
I am aware the hop growers will be much surprised at this statement, and 
will scarcely credit it, they have been so accustomed to regard these things 
as distinct from and in no wise connected with each other—deeming the 
honey dew to be a fluid which has exuded from the leaves in consequence of 
some disease therein, and the black blight to be, as already stated, a kind of 
fungus growing from the leaves, whilst the plant-lice, occuring only oh the 
opposite or under side of the leaves, appear to be wholly separated from these 
substances upon their upper surface. But I am perfectly assured of the cor¬ 
rectness of what I say, and can produce specimens which will demonstrate 
that I am correct. I regret that this subject did not occur to my mind last 
summer, or I would have such specimens on exhibition at this time. Upon 
the first opportunity, I will procure and place in the Museum of our Society, 
specimens of leaves showing this honey dew upon them, and others showing the 
black blight; and by the side of these leaves I will place white paste-board 
cards having the same honey dew and the same black blight upon them—thus 
demonstrating that these substances do not exude and grow from the leaves 
unless they also exude and grow from the paste-board cards. 
I will now briefly explain how these two substances come upon the leaves. 
Each aphis has two little horns projecting from the hind part of its back, 
which horns are termed the honey tubes From these tubes the fluid called 
honey dew is ejected, in the form of minute drops, like particles of dew, 
which falling upon the leaves beneath thorn, the upper surface of the leaves 
becomes coated over with this fluid, more or less copiously as the Aphides 
producing it are more or less numerous. And now, this deposit of honey 
dew being exposed to the action of the atmosphere, and alternately moistened 
by the dews at night and dried by.the sun by day, is gradually decomposed, 
changing from a clear, shining, transparent fluid, to an opake, black substance 
resembling soot, and it is then the black blight. In this simple manner do 
we account for and explain these phenomena—these three important diseases 
of the hop, about which so much has been said and such erudition has been 
displayed by some pf the writers in our newspapers. 
1 These same phenomena, called honey dew and black blight, are not pecu¬ 
liar to the hop, but occur on other kinds of vegetation when infested by plant- 
lice; and an abundance of authority will substantiate my statement that this 
honey dew is caused by these insects. But I find no allusion to the black 
blight in any author, aud what I state of that is the result of my own observa- 
