Chemical treatments inhibiting germination of wheat rust, clover anthracnose, canola blackleg and rice blast spores

Abstract

In vitro studies were undertaken to determine the effects of five chemical fungicide/disinfectant treatments [Tilt 250 EC (propiconazole), Amistar 250 SC (azoxystrobin), Sporekill, (didecyl dimethyl ammonium chloride), Farmcleanse (Alkali metal salts of alkylbenzene sulfonic acid and coconut diethanolamide) and Virkon S (potassium peroxymonosulfate)] in preventing spore germination of Puccinia graminis f. sp. tritici, Kabatiella caulivora, Leptosphaeria maculans and Magnaporthe oryzae. Germination was inhibited by all fungicides and disinfectants. Maximum reductions in spore germination were obtained at manufacturer’s recommended concentration and concentrations above, while concentrations below were less effective than the recommended concentration. Overall, Amistar and Tilt were the most effective of the chemicals tested, reducing germination of M. oryzae L. maculans and P. graminis f. sp. tritici spores by >75%. However, the extent to which germination of fungal spores was inhibited was dependent on the pathogen. Sporekill was the least effective, inhibiting spore germination across all the pathogens by <15%. Additional studies undertaken to define the effectiveness of the same fungicides/disinfectants for the same pathogens inoculated on five common carrier materials, metal, fabric, wood, paper, and rubber, also showed Amistar and Tilt the most effective. Results highlight a necessity for re-evaluating the requirement for decontamination procedures for carrier materials that have perhaps long been mistakenly considered of low biosecurity risk in regards to the movement of exotic fungal plant pathogens and their races