Whitewash found harmless in applications on walnut leaves
California Agriculture 21(3):2-3.
Published March 01, 1967
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Whitewash applied to the leaves of Persian walnut trees of the Payne variety showed no injury to the leaf and did not interfere with photosynthesis. There was no significant effect on total yield in the whitewash tests, but the percentage of larger, sound nuts increased. These studies also indicated that temperatures above 90°F were very detrimental to photosynthesis and temperatures of 95°F or above stopped it completely.