Chemical Exposure Warning Be aware that this herbicide might produce moderate irritation to the respiratory tract and the skin, and you should wash contaminated skin with soap and water.Click to see full answer. Correspondingly, is Casoron harmful to pets?Answer: If Casoron 4G Herbicide is applied according to the label it will not be harmful to your pet. According to the product label, do not enter or allow persons or pets to enter the treated area until granules are thoroughly watered in and treated soil has dried.Similarly, what is the difference between preen and Casoron? Both Casoron and Preen are pre-emergents, meaning that they work to kill seedlings before they sprout. This means they will not eliminate weeds that have already broken through the soil surface and are growing above ground. Casoron is persistent in both soil and water (i.e., it hangs around). Just so, does Casoron kill existing weeds? Casoron is a nonselective herbicide that eradicates just about anything that crosses its path, including grass, plants and shrubs. You should only spray it directly on weeds you want to control; however, Roundup does not destroy most plants or grasses when they accidentally exposed to it in small amounts.When should I spread Casoron?Apply CASORON 4G either in early spring before seeds of annual weeds germinate or after cultivation has removed the growing weeds. Distribute granules uniformly over the soil sur- face. If treatment is followed by application of 1⁄2 to 1 inch of water by overhead irrigation, the lower rates are recommended.