It’s the last chance to control blackgrass, experts are warning. “Mow too early and blackgrass won’t die, it’ll just re-tiller from the bottom and produce heads later,” says ADAS, senior research scientist and arable weed specialist, Dr Sarah Cook. “Once it starts producing seed it stops thinking about producing new tillers and concentrates on producing seeds, that’s the time to take it out – usually the first two weeks in June. Nick Sanderson of Northumberland-based Tynegrain agronomy highlights the importance of taking measures beyond those plants you can see above the crop. “If you’re spraying off a patch and can…