R.C.
I have successfully used neem in the past to get rid of ticks and fleas in my yard. I also use "Mosquito Barrier" to deter mosquitos. It's a super potent garlic spray that you can apply with a hose end spayer. The smell lasts only an hour, but the mosquitos can smell it for a few weeks, depending on the rain. For aphids and other garden pests, I buy ladybugs - much to the great delight of my daughter. It's a wonderful activity for her and we get rid of a few thousand bad bugs!