Systemic Antifungal Activity of Isobutyl O-Coumarate in Apple

Higher Plant–Lower Plant Interactions: Phytoalexins and Phytotoxins

“…On the assumption that the blue fluorescent com ponents are hydroxycinnamic acid derivatives of some novel type, various synthetic acids (e.g. isobutyl o-coumarate) have successfully been applied as a spray on leaves of suscep tible apple varieties to enhance their resistance to the scab disease (Kirkham and Hunter, 1964). However, in spite of this success, it is clear that much further work is needed to establish whether substances which increase in amount after infection really have a sig nificant role in plant protection.…”

Greenhouse evaluation of chemicals for control of powdery mildews. V. Tests with unsaturated compounds*

“…Two other groups of unsaturated compounds recently reported (Pianka, 1963;Bates, Spencer & Wain, 1963) to be highly toxic to various fungi were also included; compounds in the first group were derived from P-nitrostyrene, and in the second from the simpler nitroalkenes. Although a few esters of cinnamic acid had been tested and found of no value in the first series, the continuing interest in this acid and in the closely related o-coumaric acid, especially as esters, for the systemic control of apple scab (Kirkham & Hunter, 1964), led us to include both these acids and most of the esters tested by Kirkham & Hunter (1965). Most of the compounds used in the second series of mildew tests were also tested for activity against Venturia inaequalis (Cke.)…”