Activity of carbendazim, dimethachlon, iprodione, procymidone and boscalid against Sclerotinia stem rot in Jiangsu Province of China

Abstract

Carbendazim (MBC) was widely used to control Sclerotinia stem rot routinely during the 1980s in China, but development of MBC resistance in the causal agent Sclerotinia sclerotiorum led to control failures of this disease. In this study it was found that the MBC resistance in S. sclerotiorum populations was widespread throughout Jiangsu Province with a resistance frequency of 29.54% in the 1786 collected isolates during the growing seasons of 2006 to 2008. The resistance frequencies differed among sampled cities, ranging from 3.1% to 54.9%. The field MBCresistant isolates showed comparable mycelial growth, sclerotia production and pathogenicity to the wild-type sensitive isolates, which suggested that the field MBC-resistant isolates might have sufficient parasitic fitness to compete with the field MBC-sensitive isolates in the field. In the in vitro sensitivity test, boscalid showed greater activity against S. sclerotiorum than dicarboximide fungicides (dimethachlon, iprodione and procymidone).The treatment 50% boscalid (WG) 125 g a.i. ha −1 was comparable in efficacy to the treatment 50% iprodione (WP) 600 g a.i. ha −1 , and better than other treatments of 6% dimethachlon (WP) 690 g a.i. ha −1 and 50% procymidone (WP) 337.5 g a.i. ha −1 , whereas MBC failed to control Sclerotinia stem rot (control efficacy only 16.0%). The most active agent for controlling Sclerotinia stem rot was boscalid in our study.

Susceptibility of winter rape cultivars to fungal diseases and their response to fungicide application

“…During our research, fungicide application also significantly reduced the incidence of sclerotinia stem rot; however, its efficacy during the season with high disease pressure was insufficient. As was suggested by other researchers, control of the diseases caused by S. sclerotiorum is complicated (Bardin and Huang, 2001;Ma et al, 2009). …”

Control of plant sap-sucking insects using entomopathogenic fungi Isaria fumosorosea strain (Ifu13a)

“…In France, the preventative chemical control of Sclerotinia stem rot at the beginning of flowering has led to the occurrence of resistance of S. sclerotiorum to benzimidazole fungicides (MBC). Resistance of S. sclerotiorum strains to carbendazim, which is used to be sprayed because of its effectiveness and its cheapness, is widespread in most oilseed rape cropping areas from central to north-eastern parts of France (Penaud et al 2003) and also in China, where carbendazim has been used to control this fungal disease since the 1980s (Ma et al 2009;Xu et al 2015). Resistant populations of S. sclerotiorum against benomyl, which belongs to the same fungicidal class, have been detected in Canada (Gossen et al 2001).…”

Control of white mold of dry bean and residual activity of fungicides applied by chemigation

“…Unlike fluazinam, procymidone can be used as both a preventive and curative fungicide, with moderate systemic activity (Chen et al, 2010). Procymidone in the soil may be absorbed by roots, and translocated to leaves and flowers (Chen et al, 2010), which makes it particularly effective (Ma et al, 2009). The target site of this fungicide is cytochrome c of the mitochondrial oxidative pathway.…”