To compare the level of herbicide tolerance in SP1333 (a new genotype with improved tolerance to Group C herbicides) against PBA Hallmark XT to pre- and post-emergent applications of ‘Gp C’ at various rates. 

• Key Messages: SP1333 and PBA Hallmark XT showed little to no signs of herbicide damage at x0.25 gai/ha and 376 gai/ha. At higher herbicide rates SP1333 showed lower herbicide damage than PBA Hallmark XT, but grain yield results were unreliable due to shattering in SP1333.
• Establishment and Plant Growth: Application of ‘Gp C’ PSPE had little or no impact on emergence and early plant growth. Lentils had optimum establishment and growth as a result of adequate soil moisture at sowing and favourable conditions during the rest of the season. Growth, development and yield were not affected by the few frost events, which occurred in the spring.
• Herbicide Damage: Both varieties did not show symptoms of herbicide damage at lower rates (x0.25 and x0.5 gai/ha) irrespective of the time of application (Table 1). However, at higher rates (x1 and x2 gai/ha) the new variety SP1333 showed less damage than PBA Hallmark XT. At x2 gai/ha, PSPE damaged SP1333 more whereas application at 4 node stage was more detrimental for PBA Hallmark XT.
• Number of weeds: Better control of weeds were achieved when ‘Gp C’ was applied as PSPE or 4 node applications at rates above x0.5 gai/ha (Table 2). Almost full weed control was seen in the x1 gai/ha and above for both PSPE and 4 node treatments. Weed densities were not different between varieties.
• Biomass at flowering: At flowering varieties were not significantly different in biomass. In PBA Hallmark XT biomass improved when low rates (x0.25 and x0.5 gai/ha) were applied as PSPE spray but decreased at the highest ‘Gp C’ rate (x2 gai/ha) applied as PSPE or 4 node stage spray, compared to the plants which did not receive herbicides (Table 3). This indicates that application of ‘Gp C’ at lower rates as PSPE sprays in PBA Hallmark XT can effectively control weeds without the crop damage or biomass loss, as oppose to higher rates. However, rates or times of herbicide application did not cause any biomass change in SP1333.