This level is a little more difficult than the first. You need to light up all 4 before they are removed. Not just two this time. And you find when you have falling crops, it unlights them which is really annoying. So the best piece of advice would be to work on the bottom flies first, then when you have them open or lit, do the same to the top ones.
To take a shortcut, you could make one or more lit, open the wings of the others then use shovels to light your remaining ones. Saves risking them getting caught by more crops.
Once you have the flies, make your rows on the grass to get extra points. If you work again at the bottom of the screen, you have more chance of falling crops making rows all by themselves.