I would have thought the old (current?) AHDB advice on spraying thresholds would be appropriate in these situations.If plenty of shotholing and you don’t apply an insecticide will this not make larvae problems worse later on?.
I realise you can go back later for larvae which are slightly more vulnerable if correctly timed.
Can anybody advise?.
From AHDB Information Sheet 24
Consider applying a spray if:
– Adults have eaten over 25% of leaf area at the cotyledon–2 true leaf growth stage
– Adults have eaten over 50% of the leaf area at the 3–4 true leaf stage
– The crop is growing more slowly than it is being destroyed.