Pheromone traps for detecting orange wheat blossom midge in susceptible wheat crops need to be laid in crops as soon as possible, ADAS entomologist Jon Oakley has warned.

“I’m expecting a lot of blossom midge activity from next Friday [2 June] through to Monday, if the current weather forecast is right.”

But setting traps at the weekend would be too late, he said. “They need to be out now.”

That was particularly important if growers wanted to use the pyrethroid insecticide Hallmark Zeon (lamda-cyhalothrin), which needs applying to coincide with peak adult midge flight periods for optimum activity.

“You’d spray because you’ve a lot of midges in pheromone traps,” he said.

The alternative option, chlorpyrifos, had a longer application window, which allowed growers to use the traditional threshold of one midge per three wheat feed wheat ears or one per six milling wheat ears.