Quali-Pro Prodiamine, Pre-Emergent Herbicide, 5 lbs, Yellow Granules. Prodiamine 65 WDG is a pre-emergent herbicide used to control a wide variety of broadleaf and grassy weeds. Not only is it extremely broad-spectrum, it is also one of the most cost effective pre-emergent herbicides on the market. This product can be used in both the spring and fall so that you are able control unsightly weeds all year long. Weeds controlled (but not limited to) include: Annual Bluegrass (Poa Annua) Chickweed Crabrass Foxtail Goosegrass Henbit Knotweed Spurge.