SENSITIVITY OF CRINIPELLIS-PERNICIOSA TO PROCYANIDINS FROM THEOBROMA-CACAO L

Basidiospores from four geographic isolates of Crinipellis perniciosa (Stahel) Singer, the pathogen causing witches' broom disease in various members of the Sterculiaceae, Solanaceae and Bixaceae, were exposed to different concentrations of partially-purified oligomeric procyanidins (condensed tannins), (-)-epicatechin/(+)-catechin, and anthocyanins extracted from cocoa seeds. The effectiveness of the test compounds for inhibiting basidiospore germination and germ tube elongation was: a mixture of procyanidins with 5-8 monomeric units (n = 3-5) > a mixture of procyanidins with 3-5 monomeric units (n = 3-5) > a mixture of the B2 dimer of (-)-epicatechin and the B5 dimer of (-)-epicatechin and (+)-catechin > (-)-epicatechin/(+)-catechin greater than or equal to anthocyanins. Sensitivity to test compounds also varied among isolates, and could be used as a criterion to distinguish the isolates. A total procyanidin fraction had little or no effect on the growth rates of dikaryotic (saprophytic) mycelial cultures.