Effects of cyazofamid against Plasmodiophora brassicae Woronin on Chinese cabbage

Abstract

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 x 60 x 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.

A comparison of clubroot development and management on canola and Brassica vegetables

“…However, a drench application of quintozene (trade name Terraclor) has a long history of efficacy against clubroot on cole crops (Finlayson & Campbell, 1971) and it is registered in Canada for use on cole crop transplants. Soil drenches with three relatively new fungicides, fluazinam, cyazofamid and flusulfamide, have also been used to reduce clubroot severity in vegetable crops (Mitani et al, 2003;Gossen et al, 2012b;Kowata-Dresch & May-De Mio, 2012).…”

Assessment of the impact of resistant and susceptible canola on Plasmodiophora brassicae inoculum potential

“…Amendment with lime to increase soil pH (Donald & Porter, 2009), and application of fungicides (Shimotori et al, 1996;Donald et al, 2001;Mitani et al, 2003) and soil amendment products are recommended for clubroot management in vegetable production. However, these options are not practical or cost effective for the production of extensive field crops, because of the enormous quantities required to reduce clubroot severity in even a single field (Myers & Campbell, 1985;Webster & Dixon, 1991;Murakami et al, 2002).…”

Control of Potato Late Blight by Cyazofamid

“…Cyazofamid, 4-chloro-2-cyano-N,N-dimethyl-5-p-tolylimidazole-1-sulfonamide, IKF-916 (development code), Ranman ® is a novel fungicide highly active against fungi of Oomycetes 2-6) and Plasmodiophora. 7) We previously reported that cyazofamid at 80 g active ingredient (a.i. )/ha with 300 liters/ha of application volume, which corresponds to 67 mg a.i./ml with 1200 liters/ha of application volume, exhibited excellent activity against potato late blight in the field.…”