Herbicide products containing propyzamide can be applied to oilseed rape from October 1 until January 31, providing the crop has at least three leaves
Despite the wide window, Corteva Agriscience advises growers to focus on using the right rate, in the right conditions and at the right time.
Clare Stapley, Corteva's oilseed rape category marketing manager says: "This is to ensure growers get the best efficacy as well as making sure the product stays where we need it - in the field, controlling weeds.
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Temperatures
"Propyzamide works best when applied to cold, moist soils, but this must be balanced with the need to protect water.
"Soils should be at 80 per cent field capacity (1-2.5cm of moisture), soil temperature at 10degC and declining, and an appropriate rate should be selected.
"Only use the maximum rate of 840gai/ha for severe black-grass situations. Rates of 750gai/ha or 500gai/ha are recommended for less severe black-grass or other grasses and broad-leaved weeds. Only use one product containing propyzamide per crop per year."
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Data correlations
The appropriate temperature range for applications is often reached on or after November 5, so growers are advised to be ready but resist the temptation to apply outside of the ideal conditions.
Data demonstrating the correlation between application date, dose rate and black-grass control reaffirms the importance of waiting for the optimum conditions, says Ms Stapley.
