Here is the situation. A lawn has been treated by one of the "bigboys" for a number of years. They did an adequate job, but the last few years the back yard was damaged by grubs. This is not total destruction, but many small to medium patches all over the cback yard.<p>I picked up the treatments this year, a bit later than a normal start, and I put down Dimension in the late spring. <p>Now, the lawn is looking better, but the bare areas that were damaged by grubs are now filling in with crabgrass and some annual weeds. The lawn is a rye/fine fescue mix, with very little bluegrass. (BTW I saw this same situation on a lawn next to a customer, however this lawn is blue, and has crept in very nicely since the spring.)<p>I know that there is a post emergent crabgrass liquid, have never used it, and don't plan to on this lawn, at least it is now green, not brown.<p>My question is: Would it be beneficial to put down a pre-emergent late in the fall, and again in the spring, considering that this lawn has a fairly severe crabgrass problem? I feel fairly confident that I will retain the customer next season, so I am not too worried about the money investment, but don't want to apply unnecessary pesticides?<p>BTW- The grubs will be taken care of this season, so that the damage does not hapen again.