Q: All of a sudden, half my lawn grass died. It’s mostly on the sunny side, with some in the shade. This doesn’t look like the grass has simply gone dormant with the usual hot, dry summer weather. When I pull up on the grass, it just comes off by the handful without the roots. Any ideas on what happened and what to do next? The lawn is many years old, and this hasn’t happened before. A: As I tell people all the time, there are three things that affect plants: insects, disease, and everything else. Insects tend to leave evidence of their presence. In this case, grubs could have eaten the roots and killed the grass, but in general, when grubs damage roots, they don’t eat them all and the grass becomes like fresh sod with a smaller root system that can be watered. As the new roots grow, …