VIEW ARTICLE

Systemic Fungistatic Activity of 1,1,1-Tricholoro-3-nitro-2-propanol Against Smut Fungi in Grasses. John R. Hardison, Research Plant Pathologist, Crops Research Division, ARS, USDA, and Department of Botany and Plant Pathology, Oregon Agricultural Experiment Station, Corvallis 97331; Phytopathology 61:936-939. Accepted for publication 5 March 1971. DOI: 10.1094/Phyto-61-936.

Systemic fungistatic activity against several smut fungi was noted for 1,1,1-trichloro-3-nitro-2-propanol (TCNP) after soil application and root uptake in several grasses. TCNP applied at 5-30 mg/600 ml soil (about 5-30 lb./acre) in the root zone of infected plants temporarily eliminated disease symptoms and prevented sporulation of Ustilago striiformis (stripe smut) in Poa pratensis, Dactylis glomerata, and Agrostis palustris, and of Urocystis agropyri (flag smut) in P. pratensis for 8-19 weeks. During suppression of the pathogens, plants regained normal color and leaf form, growth rate was restored, and root growth was increased. The pathogens were not killed, however, and sporulation and disease symptoms reappeared 8-19 weeks after TCNP was applied. Loose smut (Ustilago nuda) was controlled in Larker barley by TCNP applied at 15-30 mg/600 ml soil 10 days after seeds were planted. Lower dosages (5-10 mg) resulted in incomplete control, but TCNP prevented usual destruction of spikes in which sporulation of U. nuda was restricted. U. bullata in Bromus marginatus and Tilletia caries in Triticum aestivum were not controlled by treating soil around infected plants. TCNP was ineffective against Puccinia striiformis and Helminthosporium vagans in P. pratensis.