Abstract
Resistance of PTB, a variety of periwinkle [Catharanthus roseus (L.) G. Don], to dieback disease (caused by Pythium aphanidermatum) gave protection equivalent to 5. 76 kg ha-1 of the fungicide captafol on a susceptible variety WH 12. When protected with captafol, PTB suffered less (75%) plant mortality and gave higher leaf (146%) and root (200%) yields than unprotected WH 12.