I have attached a photo of a weed that has rapidly become a major issue. My Lawn is 90% Centipede with a small area of St Augustine. The weed has invaded both areas. Lawn was treated with a commercial pre-emergent and fertilizer prior to greening, has since been treated with a post emergent. As grass has greened this weed is now rapidly spreading despite attempts of early intervention. Sprayed small area with Ortho Weed B Gone for Southern Lawns, which killed the weed but also severly burned the grass. Does anyone know what this is and have suggestions for a course of action. Thank you.