verticillium wilt

Hi! I'm still relatively new in gardening. A couple of weeks ago, I planted a blackberry bush in my garden. All went well until the past few days when I suddenly noticed that the lower leaves were turning yellow and withering. The other leaves were also developing black contours on their edges...

Hi! I'm still relatively new in gardening. A couple of weeks ago, I planted a blackberry bush in my garden. All went well until the past few days when I suddenly noticed that the lower leaves were turning yellow and withering. The other leaves were also developing black contours on their edges...