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whether the two varieties which I have indicated will succeed in your locality, but 
the probabilities are that they will do very well as stocks, even if they should not be 
desirable to grow for their fruit. I shall be glad to learn the course pursued by you 
and its success. 
The Grape Phylloxera in the United States. 
May I venture to ask you to write me briefly your views of Phylloxera in the United 
States. If, in your opinion, it is on the increase or decrease, and if there is occasion 
for any serious alarm in any section of this country as to the future of the grape 
crop. I desire the information for a French correspondent prominent in the agri- 
cultural societies of France.—[Burnet Landreth, Pennsylvania, September 19, 1891. 
Repity.—There is in this country, for the most part east of the Rocky Mountains, 
very little to be feared from the Phylloxera, at least so far as our native vines are 
concerned. Most of the American varieties of grapes are resistant to the root-form of 
this insect and hence suffer little injury. The leaf-gall form is not particularly seri- 
ous in its effect on the vine, except in a few thin-leaved varieties. The damage done 
by the Phylloxera in France and other parts of Europe where it has obtained a foot- 
hold is due to the root-form exclusively. All European vines or varieties derived 
from the European grape, Vitis vinifera, are especially liable to this form of attack 
and rapidly succumb to the Phyloxera. 
The danger in this country then is confined to those localities, chiefly in California, 
where European varieties are grown, and in the Sonoma Valley region considerable 
difficulty has already been experienced. The remedy here will be the adoption of 
the means which long experience has shown to be valuable in France, viz, grafting 
susceptible European sorts on resistant American varieties, and also the use of such 
remedial measures as experience has shown to be practically valuable. These reme- 
dies are referred to in the publications which I have already mailed to you. In other 
parts of the United States it will occasionally be necessary to abandon the cultiva- 
tion of particular varieties, such as the Catawba and Delaware. The Clinton is par- 
ticularly liable to the attacks of the leaf-gall form, and occasionally the multiplica- 
tion of the lice upon the leaves is so great as to seriously injure the plant. The 
Catawba and Delaware and various hybrids with vinifera succumb occasionally to 
the root form. The Clinton stocks, however, are especially valuable on account of 
their resistant qualities, since the lice are seldom found to any great extent on the 
roots of this variety and the vine is so vigorous a grower that a slight attack does 
little injury. As long, therefore, as we continue to grow our native grapes, we need 
have little fear of Phylloxera. This insect, as you doubtless know, is a native of 
this country, and our native vines have acquired, by long association with the Phyl- 
loxera, certain resistant qualities which are entirely wanting in the European 
grapes. 
With regard to Phylloxera damage to grapes grown under glass I would refer you 
to a report by myself, published in the Annual Report of the Department of Agri- 
culture for 1884, pp. 408-9, which you will probably find of interest in this connec- | 
tion.—[September 24, 1891. ] 
Mites on a Maple Aphid. 
I mail you to-day slides with mite which attacks Drepanosiphum acerfolti, Thomas. 
Saw a great number of these scarlet mites each fastened at base of wing of this com- 
mon Maple Aphid, but the Aphid is so active that I secured but three specimens. 
Have also seen this mite on the Hickory Callixtenus. Can you give me name of 
mite in case you recognize it, without trouble or especial study?—[J. G. Monell, 
Missouri, August 5, 1891. 
REPLY.—* * * The mites which you send are immature and in bad condition. 
They evidently belong tothe genus Erythreus, but it will require better material to 
enable a correct determination.—[August 4, 1891.] 
