Sunburn and aphid injury of soybeans and cowpeas

Gibson, Frederick

Sunburn and aphid injury of soybeans and cowpeas

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rec141-gibson-1922.pdf (671 KB)

Authors

Gibson, Frederick

Description

In a country where the soil is naturally deficient in organic matter, the problem of green manuring is important. For the purpose of supplying this need, and also as cover and forage crops, cowpeas (Vigna sincnsis) and soybeans (Soja max) have been introduced into Arizona. Since the value of these plants for green manure, cover, and forage crops depends chiefly on the production of abundant foliage, any condition which favors injury to the green parts must be taken into account in the selection of varieties, and therefore susceptibility to sunburn and to parasitic diseases, which may result in the destruction of a large part of the leaf surface, are factors which must be considered. During the fall of 1920, the attention of the writer was directed to a spotting of the leaves of cowpeas and soybeans growing on the Salt River Valley Farm near Mesa, Arizona. Indications of sunburn as well as the presence of aphicls and a dense fungal growth, in spots, led to the cultural and histological studies that are described in this paper. It is hoped that the results may prove helpful in the selection of varieties of cowpeas and soybeans suited to the semi-arid conditions that prevail in Arizona and other southwestern states. In pursuing the investigation, field studies were supplemented with laboratory work and with inoculations of plants grown in the greenhouse at the University of Arizona at Tucson.
Originating text in English.
Citation: Gibson, Frederick. (1922). Sunburn and aphid injury of soybeans and cowpeas. Bulletin / University of Arizona, Agricultural Experiment Station, 2, 39-46.