Low-drift fungicide application technology for sclerotinia stem rot control in canola

Five methods of fungicide application were made to canola (Brassica napus) to determine the effect of nozzle type and pressure on sclerotinia stem rot (Sclerotinia sclerotiorum) infection of canola and crop yield. Benomyl and vinclozolin fungicides were effective in reducing stem rot in treated plots and increasing yield over the unsprayed check in 2 of 3 years. Variation in product performance among years indicated that environmental conditions had a major effect on crop development, sclerotinia stem rot infection, the effect of fungicides and subsequent yield. Overall, conventional flat fan nozzles (TeeJet XR), low-drift venturi nozzles (CFFC TurboDrop) and hollow cone nozzles (TeeJet TXVS-8) were all effective at reducing disease symptoms. Both 275 and 550 kPa provided similar performance although increasing the venturi nozzle pressure to 550 kPa improved disease control slightly. These results indicate that venturi nozzle technology is appropriate for use with foliar fungicides for sclerotinia control in canola provided pressures are adjusted to optimize nozzle performance.