If you could post a picture of your plants for us, that would help a lot.
Fungus on the soil surface really shouldn't be affecting the plants much. You can spray your plants with a solution of 1/2tsp. baking soda to a quart spray bottle for a few days if you think it's a problem and that will slow down or stop the fungal growth.
Edible plants should never be sprayed with "fly spray" because these are plants that produce food. You need to always use non-toxic controls for insects (and fungus) on all edibles. (think of this as a "big picture" moment, not just your science fair project that you don't care if they survive and bear or not). In fact you should include this info in your science fair report. It's all about the learning.
For flying insects a spray of 1/2 tsp dish soap to a quart of water will usually knock down any annoying bugs. But if what you have are fungus gnats, you may need to water your plants with a mild solution of hydrogen peroxide. You can get it at the drug store, and dilute it 1oz. to 2 cups of water. The peroxide douse will not hurt the plants at all and breaks down to oxygen and water very quickly, so again it is non-toxic.
Looking forward to seeing your pictures!
