VIEW ARTICLE

Influence of Benzimidazole Fungicides on Phymatotrichum omnivorum and Phymatotrichum Root Rot of Cotton. Stuart D. Lyda, Associate Professor of Plant Pathology, Department of Plant Sciences, Texas A&M University, College Station 77843; Earl Burnett, Research Soil Scientist, USDA, ARS, Blackland Conservation Research Center, Temple, Texas 76501 Phytopathology 60:726-728. Accepted for publication 30 November 1969. DOI: 10.1094/Phyto-60-726.

Two benzimidazole fungicides, Thiabendazole [2-(4- thiazolyl) benzimidazole] and Benlate [methyl 1-(butyl carbamoyl-) 2-benzimidazole carbamate], applied as drenches around stems of 1-month-old cotton plants at rates of 2 lb. in 15 gal water/acre, proved effective in controlling Phymatotrichum root rot of cotton in greenhouse experiments. Control was based on inhibition of root lesions above the zone of lateral root formation. Benlate was better than Thiabendazole when applied at equivalent wt of active ingredient. Both chemicals were extremely toxic to growth of Phymatotrichum omnivorum when added to a synthetic culture medium; Benlate completely suppressed growth at 50 µm /liter, and Thiabendazole at the same concentration reduced growth 90% during a 50-day test. Neither chemical at fungitoxic levels influenced the respiration of germinating Phymatotrichum sclerotia.