White leaf spot (WLS), caused by Neopseudocercosporella capsellae, is an economically important disease of many Brassicaceae genera and species in Australia, Europe, and North America. It is concerning that its pathogenicity is increasing in Australia. In Western Australia, triazine and glyphosate are routinely applied to triazine-tolerant (TT) and glyphosate-resistant (RR) canola varieties, respectively, within the first two months of crop development, often corresponding with the period of most severe WLS disease. As atrazine and glyphosate application is known to affect WLS incidence and severity, studies are being undertaken to define exactly how atrazine and glyphosate application at various timings before and after N. capsellae infection affects white leaf spot development on canola varieties of different resistance to WLS. We found that the extent of suppression of WLS by atrazine application was substantial, that it varied with cultivar susceptibility and application timing, and that there was a strong interaction of cultivar x application timing. However, for glyphosate, while glyphosate applied prior to the main WLS infection period increased disease severity, withholding glyphosate applications until WLS infections are well established minimised this predisposition to WLS. These studies highlight potential opportunities for farmers to improve the management of WLS by exploiting better cultivar choices in conjunction with manipulating the timing of atrazine and glyphosate application to minimise WLS and maximise the consequent canola yield.