Question
Hi,
My name is Lindsey Fletcher and I am a seventh grade student doing an experiment to see if frosting will effect a sunflower's growth. I would like to know what diseases can effect a sunflower and how I can prevent them.Thank you for all of your help. It is deeply appreciated.
       
      Sincerly,
           Lindsey Fletcher

Answer
There are 30 or more known sunflower diseases but nine
diseases are the most commonly seen. Six of the most common
diseases that threaten sunflower yields and are: downy mildew, rust, Sclerotinia, Verticillium wilt, Phoma, and Alternaria spot. Septoria leaf spot, powdery mildew, Rhizopus head rot, and charcoal stem rot are occasionally observed but seldom cause more than very localized yield reduction.
    Fungicidal protection against foliar diseases in sunflower is not normally economical. The exception is when new rust races develop and before resistance genes have been incorporated into commercial varieties. Seed treatment can be economical in areas prone to downy mildew. Growing resistant varieties and using pest
management practices are the best ways to maximize yield.
Disease resistance genes are present in many sunflower hybrids for the following diseases: rust and Verticillium wilt.

As far as your experiment, I do not know what you mean by "frosting" but the best way to find out is try it and record the growth. Good Luck!