Question
Hi i live in staugustine florida I have white splotches all over the leaves on my yellow squash plants 1 plant produce two squash and the other ones bloom they don't produce I'm trying to figure out what is the problem thank you and look forward to hearing from you

Answer
Shawn, your plants have been infected with powdery mildew, a fungus disease that is especially prevalent in wet and/or humid conditions.

To combat this disease, it is best to order seeds that are resistant to this disease. Most seed catalogs such as Park Seed and Burpee list the various diseases which the hybrids were bred to resist. Also, never water in the evening as this lends to this disease due to the water not evaporating as quickly in the evening. It is always best to water in the morning.

Once the plants are infected, you must use a copper based fungicide. I use a product called Soap Shield, and it works great. But it is best to start spraying in early summer to prevent the disease, because once the plant is infected, powdery mildew is extremely difficult to cure. Attached is a link to this product if you are interested. Your local garden center also has fungicides that control this condition.

http://www.gardensalive.com/product.asp?pn=8066

I hope this answered your question. Good luck, and please write again if I can ever be of assistance.
  
Regards,    

Mike