Summer Squash Leaves Have Brown Spots And White Powdery Spots And Are Curling And Yellow With Brown Edges

Question From: S. Knox - Seattle, Washington, United States
Q: My summer squash has been producing and has been beautiful. Now the plants are developing brown spots on the leaves and the early fruit while small develops brown rot at the base. A few leaves are spotted with white possible mildew...I cut off a is hollow, no slime or moisture...not slimy. The leaf is yellow with brown edges and curled. I have pulled off the bad squash fruit. Is this possibly powdery mildew? And how should I treat it?

A: Sharon, Sounds like your summer squash may have more than one problem. Powdery mildew may start as small spots but quickly spreads over the leaves. They look like they have been dusted with powder. They can be sprayed with Actinovate, an OMRI listed biofungicide. The rotted stem ends may be stem rot, another disease. It's terminal. When the fruit rots at the tips when they are small, the cause is lack of pollination. Take a paint brush and take the pollen from a male flower, straight stem and brush it onto a female flower - the stem will be shorter and plumper. Best And Happy Yardening, Nancy.