File:Walnut aphids in California (1914) (14782630972).jpg

Identifier: walnutaphidsinca100davi (find matches)
Title: Walnut aphids in California
Year: 1914 (1910s)
Authors: Davidson, W. M. (William Mark), 1887-
Subjects: Aphids Walnut Diseases and pests
Publisher: Washington, D.C. : U.S. Dept. of Agriculture
Contributing Library: U.S. Department of Agriculture, National Agricultural Library
Digitizing Sponsor: U.S. Department of Agriculture, National Agricultural Library

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Text Appearing Before Image:
The Ashy-Gray Ladybird (Olla abdominalis).(A, adult; B, eggs; C, larva; D, pupa. (After Essig.) ) Bui 100, U. S. Dept. of Agriculture. Plate IV.
Text Appearing After Image:
Fig. 1 .—Tree of the Royal Hybrid Walnut in Grove of Mr. F. Leib, San Jose, Cal. T^L^ Jt. W *5F 1 v^^tfa—„^_ - 1 ; Fig. 2.—General View of Walnut Grove of Mr. F. Leib, San Jose, Cal WALNUT APHIDES IN CALIFORNIA. 41 Commercial lime-sulphur, 1-50, combined with commercial tobacco extract No. 1,1-200, effective. Commercial lime sulphur, 1-70, combined with commercial tobacco extract No. 2,1-1,000, effective. Commercial lime-sulphur 1-45, combined with commercial tobacco extract No. 2,1-2,000, effective. It is noticeable that the weaker solutions of tobacco extracts werenot effective alone, but when combined with distillate-oil emulsion orlime-sulphur proved quite satisfactory. Possibly the most success-ful result was obtained with distillate-oil emulsion of only 2 per cent.Field experiments failed, however, to justify the use of this wash alone,for it proved to lack the killing power found in the tobacco-extractsprays. The emulsion serves, however, as a very good spreaderfor the

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