Nutritive Value of Rust-infected Leaves

Abstract

In nature it had been noted that certain snails, slugs, beetles, and insect larvae eat rusted areas of bean and other leaves in preference to healthy leaves. Leaves of pinto bean (Phaseolus vulgaris), 12 days after being infected with rust (Uromyces phaseoli), had 10 times the pantothenic acid content of healthy leaves. No clear differences between healthy and rusted leaves were found for thiamin, riboflavin, folic acid, or niacin. Snails (Helix aspera) fed only on healthy leaves gained less than snails fed only on rusted leaves. Rats with their pantothenic acid stores depleted lost weight on a diet of dried healthy leaves, but gained on dried rusted leaves. Diobrotica beetles choose rusty over healthy leaves in a ratio of 3:1. The pantothenic acid would seem to be concentrated in the rust mycelium and spores.