Beware of reading too much into wheat orange blossom midge trap catches, warns ADAS.
Midges lured to the pheromone used in traps will nearly all be males, says entomologist Steve Ellis. But it is the females laying eggs from which the ear-damaging larvae emerge that really matter and against which sprays should be targeted.
“The traps merely tell you that the males are active and that you should be checking crops for egg-laying females.”
Only when the weather favours female flight are crop-damaging midge infestations likely to occur, says Dr Ellis.
At last week’s Boxworth open day many growers reported finding large numbers of the tiny insects in their traps, he notes.
“And at High Mowthorpe, where we began trapping on 31 May, we’d caught just over 1000 in just one by 3 June. That’s a phenomenal number, and it would have been tempting to have sprayed.
“But when we inspected our crops we couldn’t find any at all.”
He suspects that many other growers, too, even those with high trap counts, would not have had any egg-laying taking place.
“Up to last Thursday we suspect conditions just weren’t right for females to fly.
“Much depends on what happens in the next few days. If it stays warm and still in the evenings, then they may start to do so.
“But I suspect quite a few growers may have been confused over what their traps were telling them and maybe sprayed too soon or unnecessarily.”