BLACKGRASS germination seems more prolonged in second wheats than earlier drilled first wheats, which could make growers consider different control strategies, says DuPont’s Alistair McRobbie.

“First wheats had moisture early enough, so there was a good flush of blackgrass. It is important to get something on before the application window closes.” That window is closing fast as the likelihood of getting a spray day declines, and as it gets cold, blackgrass stops growing, so efficacy decreases.

Second wheats, in contrast, were drilled in poorer conditions, and the wetter conditions may have pushed blackgrass back into dormancy, says Mr McRobbie. “Germination stops when soil temperatures dip below 8C. When it warms up, blackgrass might come up.” That would push growers to a more contact type programme, he adds.