[Zippy]

Is it safe to put mowings into the compost bin from a lawn which has had weed and feed on it? Does it biodegrade?

If not, could i use the mowings as mulch around fruit bushes where I dont want weeds or other plants to grow anyway?

[fatcat1955]

All the weed and feed packets i have read say discard the first mowings.

[DD.]

fatcat1955 has nailed it.
 
Read what it says on the pack of what you've got there. You can't give "coverall all" advice when it comes to chemicals.