Pre emergence/ no pre -emergence

[Ladybird]

Drilled our first bit of wheat this evening, on an osr stubble drilled with oats and phacelia cover crop. Drilled at 45 kg/ha , ( the cover crop) good in places but not quite sure how to quantify the success of it right now [emoji57][emoji379].
So what I'm wondering is .... Is it worth pre emergence spraying when you have a green cover crop? Would it be better applied peri once cover crops shrivelled up?!

 

[BSH]

Drill throught he green and then spray off with round up instead of a pre em. I have had little benefit from pre ems in DD.