Doveweed (Murdannia and nudiflora) has become a very aggressive and difficult to control weed in warm season turf. It is a summer annual with a grass-like appearance. It has parallel veins and the leaves are narrow and lance-shaped. It flowers throughout the summer (blue and purple clusters). It tends to germinate much later than other summer annual weeds such as crabgrass.
A good pre-emerge program is key. Pre-emergent herbicides should be applied when soil temperatures at 4" depth approach 70 degrees F. If doveweed is the only target, application timing is delayed slightly due to later germination. If doveweed and other summer annuals are the target, a good approach would be a split application, combined with a post-emergent program.
Contact your local Target Specialty Products representative for specific product recommendations for your area. ALWAYS read and follow all label instructions.