Ken I use a product called ACTINOVATE. Begin by doing a soil drench when the soil reaches 50 degrees. I use one of those instant read meat themometers that you can buy at the grocery store. Happy Yardening, Nancy
Ken, you can buy Actinovate on the internet here: https:/www.amazon.com/dp/B0026KSLG2/?tag=yardener-20. Also many seed catalogs sell it. Begin by using it as a soil drench. The Temperature of the soil needs to be 50 degrees. Then spray the plants every 10 days. A $10 should treat 200 plants one time. The $20 packet will treat 500. It does have a shelf live so don't plan on stocking up on it. Best And Happy Yardening, Nancy.