California Agriculture
California Agriculture
California Agriculture
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…Walnut aphid and the sunburn problem

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Authors

G. Steven Sibbett, Tulare County
C. S. Davis, Extension Entomologist, Berkeley
M. M. Barnes, Professor of Entomology, Riverside

Publication Information

California Agriculture 25(5):13-14.

Published May 01, 1971

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Abstract

Abstract Not Available – First paragraph follows: Trials conducted in Tulare County (reported in accompanying article) have demonstrated that the walnut aphid has a profound influence on walnut production and quality. Observations on infested trees during 1969 showed that honeydew accumulations on developing nuts had a phytotoxic effect on husk tissue which resulted in killing surface cells (photo 1). These turn black and together with subsequent sooty mold aggravate sunburn, since dark surfaces have the capacity to absorb more heat. It was also noted that sooty mold developed through the whitewash deposits. This situation of dark husk surfaces due to honeydew (photo 2) compounded by sooty mold accumulation (photo 3), was studied in relation to the sunburn problem of walnuts grown in interior valleys.

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…Walnut aphid and the sunburn problem

G. Steven Sibbett, C. S. Davis, M. M. Barnes
Webmaster Email: wsuckow@ucanr.edu

…Walnut aphid and the sunburn problem

Share using any of the popular social networks Share by sending an email Print article
Share using any of the popular social networks Share by sending an email Print article

Authors

G. Steven Sibbett, Tulare County
C. S. Davis, Extension Entomologist, Berkeley
M. M. Barnes, Professor of Entomology, Riverside

Publication Information

California Agriculture 25(5):13-14.

Published May 01, 1971

PDF  |  Citation  |  Permissions

Author Affiliations show

Abstract

Abstract Not Available – First paragraph follows: Trials conducted in Tulare County (reported in accompanying article) have demonstrated that the walnut aphid has a profound influence on walnut production and quality. Observations on infested trees during 1969 showed that honeydew accumulations on developing nuts had a phytotoxic effect on husk tissue which resulted in killing surface cells (photo 1). These turn black and together with subsequent sooty mold aggravate sunburn, since dark surfaces have the capacity to absorb more heat. It was also noted that sooty mold developed through the whitewash deposits. This situation of dark husk surfaces due to honeydew (photo 2) compounded by sooty mold accumulation (photo 3), was studied in relation to the sunburn problem of walnuts grown in interior valleys.

Full text

Full text is available in PDF.

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