Effects of cyazofamid against Plasmodiophora brassicae Woronin on Chinese cabbage
Cyazofamid (4-chloro-2-cyano-N,N-dimethyl-5-p-tolylimidazole-1-sulfonamide) is a novel fungicide with high levels of activity against Oomycetes fungi and Plasmodiophora brassicae Woronin. The effects of cyazofamid were investigated against P brassicae, the causal agent of clubroot disease in Chinese cabbage. Cyazofamid at 0.3 mg litre-1 inhibited resting spore germination of this pathogen by about 80%. Cyazofamid at 3–10 mg litre-1 exhibited fungicidal activity to resting spores of P brassicae 1–10 days after treatment. When cyazofamid was applied to infested soil, both root-hair infections and club formation caused by P brassicae were strongly inhibited at 1–3 mg kg-1 dry soil. These results suggest that cyazofamid directly inhibits resting spore germination, thereby leading to the inhibition of root-hair infection and club formation. Cyazofamid at 3 mg kg-1 dry soil also exhibited complete control of clubroot disease. The effect of broadcast soil application using a dust formulation at 2 kg AI ha-1 (equivalent to 1.3 mg AI kg-1 dry soil), and plug seedling tray application by a suspension concentrate formulation at 200 and 400 mg AI tray-1 (30 × 60 × 4 cm3) against P brassicae was also evaluated. Cyazofamid exhibited good efficacy against the pathogen. The sequential treatment including plug seedling tray application with cyazofamid and pre-plant broadcast soil application with the fungicide fluazinam also exhibited excellent levels of control. These results indicate that cyazofamid has a high potential to be an effective fungicide for the control of clubroot disease.
© 2003 Society of Chemical Industry
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Document Type: Research Article
Publication date: 2003-03-01
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