Chemical and biological approaches to control of Pythium root rot of poinsettia.
Excellent control of P. irregulare and P. debaryanum root rot of the Euphorbia pulcherrima cv. Annette Hegg Dark Red was given by pyroxychlor, etridiazole and fenaminosulph. A mixture of Bacillus isolates gave no control and the addition of Glomus fasciculatus failed to reduce the disease to an acceptable level. In a 2nd experiment the best results were again given by fungicides (etridiazole + thiophanate methyl, fenaminosulph + benomyl, metalaxyl or propamocarb) while G. fasciculatus, G. mosseae or Trichoderma harzianum had little effect.