Missouri is a transitional zone for both Warm Season Grasses and Cool Season Grasses.
The best control for crabgrass is to have a thick healthy lawn that prevents most crabgrass seeds from germinating. If that's not possible or you want to make sure your crabgrass is undercontroll, then a pre-emergent crabgrass preventative should be applied. Timing is critical for this application. Once the seeds have germinated, pre-emergent controls are not effective.
Every year at the University of Missouri Turfgrass Research Center, crabgrass control chemicals are tested. There are several products that perform consistently. Top ranked materials include Ronstar (oxadiazon), Dimension (dithiopyr) and Barricade (prodiamine). These products give excellent full season control. Using these products, you can not seed new grass in the spring. If seeding is anticipated in the spring control crabgrass with Tupersan (siduron), the only product available that can be applied at the time of seeding.
Crabgrass prevention happens in the spring prior to seed germination. In southern Missouri, applications should be down no later than April 1, and in the north around April 15.
Promoting healthy growth and avoiding conditions that cause stress to your turfgrass is the best way to prevent a severe disease outbreak. Stressed lawns are an open invitation for a lawn disease to gain a foothold. Optimal maintenance practices are the best way of avoiding stressed turfgrass.
Even if a pathogen is present in the soil, infection will not occur unless the environmental conditions are conducive to disease development. Once turf diseases have become active, they can cause heavy damage if not treated properly. Here is a list of common diseases to Missouri lawns:
Professional lawn care associations: the Missouri Turfgrass and Ornamental Council that was created to provide turfgrass research and educationsl findings for turfgrass managers.
Missouri Hardiness Zones: 4 - 7