Allotments 4 All

when i went to water my sprouts over the weekend there was a swarm of little flies - can this be carrotfly ?

what should i do -  i try not to use pesticide ?  ???

White ones that fly up in your face or black ones that hang round your ankles?
  :-\

they flew up -  not sure about the colour - was in a hurry so just ignored it, hope it goes away -  will have a better look this weekend

The whitefly are a nuisance but not a real problem... compost type flies down near the ground could be cabbage root fly which are a problem..  :-X