|My sunflower plants have a black splotch on the end of the leaf, and everyday it travels a little farther up. I thought it might be because I have them in a container with no drainage but now I don't know. I noticed in my raised flower bed they have the same problems. Different types of plants too so do you think this could be caused by humidity or could it be a diease?
|There are several fungal diseases that result in black spots on sunflower leaves, as well as on other plants, and fungi love humidity! Sunflowers need drainage, so that may be weakening the plants' natural defenses further. You can try something to keep the disease from spreading, such as Silka-Ben (available from Gardener's Supply Co., www.gardeners.com, ph# 800-863-1700) or Shield-All Organic Fungicide from Gardens Alive (812-537-8650, [email protected]). Best of luck!|