I also love the book Carrots Love Tomatoes as mentioned above. We use it every year.

3 cloves garlic, finely crushed (or equivalent in garlic oil or juice)
1 Tablespoon vegetable oil, any kind will do
3 Tablespoons Tabasco or other hot pepper sauce (the hotter the better)
4 cups water
1 teaspoon plain liquid dishwashing soap, such as Ivory

1.Combine the crushed garlic, cooking oil and hot sauce and let stand overnight.
2.Strain and add the water.
3.Add the dishwashing soap and stir gently.

Pour into a hand sprayer and spray the tops and especially the undersides of the leaves weekly or as needed.

Store in a closed container in the refrigerator.

Tobacco Spray for Insect Control
Nicotine is extremely toxic to insects but it’s effect is short-lived, only a few hours. This makes it a low hazard to your good insects such as bees and lady bugs.

This is a good defense against aphids, fungus gnats, immature scale, leafhoppers, thrips, leaf miners, and asparagus beetle larvae.

4 cups water
1/4 teaspoon plain liquid dishwashing soap
1/4 cup dried crushed or chewing tobacco or cigarette butts

1.Add the soap to the water and stir to dissolve
2.Soak the tobacco or cigarette butts in the water and soap mixture for 1 hour.
3.Strain through cheesecloth or other fine strainer to remove particles that would clogg your sprayer
Pour into a hand sprayer and spray directly onto pests and undersides of leaves. Use weekly.

Store in tightly closed container. Will keep several weeks.

Note: nicotine can be absorbed into the plant leaves and remain for several weeks. To be safe,
do not use on vegetables and fruits plants sooner than one month before harvest.
Do not use on eggplant, peppers or tomatoes, as these plant suffer from many of the same diseases which tobacco may carry.