Do not use herbicides that use 2,4-D, mecoprop, or dicamba to prevent damage but look for products that contain atrazine for St. Augustine grass.Part of the triazine class, atrazine is an herbicide that is used to stop broadleaf weeds from growing in corn crops and turfs like residential lawns and golf courses. Atrazine is one of the most widely used and most controversial herbicides in the world. "The grower using less atrazine is trying to make up for reduced weed control with row cultivation. Atrazine, when combined with emulsifiable agricultural oil and water is effective against post-emergent weeds. Williams' team estimates that over one-half of sweet corn fields are losing yield due to incompletely controlled weeds, even with atrazine and tillage.Atrazine is the main weapon against weeds in sweet corn, with few alternatives"If the regulatory decision is that we can't use atrazine in ways that ensures protection of the environment and human health, then growers will need immediate, economically viable weed management alternatives", Williams said. So, how long does it take for atrazine to work? 27 It has an average half-life in soil of around 60-75 days. "We ran a simple scenario to see what it would cost for growers to switch from using atrazine to broad-spectrum broadleaf herbicide mesotrione and found that it would cost an additional $9.2 million, taking into account all of the sweet corn acreage, not just the 175 fields in the study. "There are several benefits to reduced tillage, but very little sweet corn is grown in no-till. He noted that there is progress in using other physical and alternative weed control tactics such as flaming, mechanical weeding, and crop varieties that suppress weeds, but use of such tactics requires more management than spraying an herbicide.Williams believes the data from the study can help with long-term planning. Here is a video with professional lawn care tips:Weeds start dying after a few weeks but grass is fine» What is the Best Weed Killer for St. Augustine Grass?Ortho RTS Weed B Gon Weed Killer for St. AugustinegrassOne application takes care of most of the weedsTakes a few weeks and a couple of rains to get the weeds to dieWith a concentrated formula, Image Herbicide has an easy and fast application that kills bothersome weeds on contact and will cover over 3,000 square feet. This means it will kill existing weeds and those that have yet to spring up from the ground. However, for the control of weeds from seeds, rainfall or watering is necessary within 7 to 10 days after treatment Consistently feeding your lawn with Scotts Turf Builder will give it the nutrients it needs to look its best while also helps it to withstand the stress of weeds. These include morning glory, cocklebur, jimsonweed, lamb's quarters, pigweed, ragweed, various mustard weeds, buckwheat, purslane, amaranth, Spanish needle, velvetleaf and most grasses. When using atrazine, you should expect about 3 to 4 weeks to kill off the weeds in your yard. The rate of kill will vary with the type of grass, but atrazine has about a 75 percent success ratio when killing fescue. Farmers, lawn care workers and gardeners use atrazine both to prevent broadleaf weeds from establishing before they emerge from the ground and to kill weeds that have emerged. St. Augustine grass can also be sensitive to specific herbicides that contain 2,4-dichlorophenoxyacetic acid, or 2,4-D.Works great on lawns that are a mix of grass typesWhen you are looking to kill and prevent tough weeds in your St. Augustine grass, the Image Herbicide for St. Augustine Grass is an easy-to-use concentrate that will starve your weeds to death. "The U.S. Environmental Protection Agency completed re-registration of atrazine in 2006, but due to controversy over human health and environmental safety concerns, launched a special review and re-evaluation of atrazine last November. "When growers didn't use atrazine, they used more row cultivation.