While our gardens are full of bad insects that bite us and eat our plants, many of the bugs in our garden are not only helpful and beneficial but responsible for much of the food we eat. Many of our valuable pollinators are on the decline due to habitat loss and overuse of pesticides by both commercial farmers and home gardeners. Since pesticides cannot tell the difference between a good bug and a bad one, it is best to not use them at all.
Here in our garden, we use a variety of different methods for insect control. We have chickens, ducks, and guineas that roam free-range throughout the day eating every bug they see. Since introducing chickens to our garden, we have seen a significant decrease in Japanese Beetle damage. Guineas love to eat ticks, I am told. And ducks just eat every bug within reach. Since I have read that geese eat snails, I am entertaining the thought of getting a goose for my garden. (Don't tell my husband.)
Aphids will usually be taken care of by Ladybugs, if you haven't killed them all with pesticides. If you don't have a good Ladybug population, you can order them online from Gardens Alive. Be sure to follow their instructions when you release them. Its really the Ladybug larva that devours the most aphids.
If you can't wait for the Ladybugs to do their job, use the safest insecticide you can, insecticidal soap. You can purchase it ready made or make your own (1 or 2 Tablespoons of pure liquid soap like Castile, not detergent, to 1 quart of water.) Spray on the undersides of leaves and only where you see aphids.
For Japanese Beetles, mix up a cup of soapy water and add a little vegetable oil. Take it outside and as you see a Japanese Beetle, knock it into the soapy water. The oil will prevent its being able to climb out. This is a good job for your little boy, if you have one.
For many plant pests like squash bugs and tomato hornworms, the best method of control is to simply pick them off by hand. Since I don't like to touch bugs and caterpillars, I use my pruners to knock them off. You can then mash them, or if you have chickens, knock the bug on the ground for them to fight over. It's been years since I've seen a grasshopper in the garden here. Our chickens used to fight over them. It was fun to watch.
For ticks and fleas, here is an excellent recipe for homemade repellent.