1.   This pest is a grassy weed rather than a broadleaf type.

2.   What can I do to kill the grassy weeds without harming the St. Augustine?

3.   You might check the herbicide labels at a garden center to see if there is one that targets this grassy weed.

4.   You can control annual bluegrass with a pre-emergent or post-emergent herbicide that targets grassy weeds.