Investigations on chemical control of common bunt of wheat. 1

Abstract

Field trials were conducted at five sites in Victoria and one in South Australia in 1963-64 and 1965-66 to test a number of chemicals alone and in combination for the control of common bunt of wheat (Tilletia caries (DC.) Tul. and T. foetida (Wallr.) Liro) using mixed populations of the species as inoculum. On seed-borne bunt, fentin hydroxide and ziram were sufficiently active to warrant further testing. The chlorobenzenes hexachlorobenzene (HCB) and 2, 3, 5, 6 tetrachloronitroanisole had a strong selective action : they gave excellent control of T . caries, but HCB, especially, failed to control T . foetida. In contrast, the dithiocarbamates tested tended to be more effective on T. foetida. None of the chemicals tested, including HCB, controlled soil-borne bunt. The available evidence suggests that an hitherto unknown race of T. foetida had been used which has a high degree of field tolerance to HCB. A combination seed dressing of phenylmercuric acetate and CCC ('Cycocel') gave good control of seedborne bunt, but did not promote tillering or yield.