Home Brews

• To create homemade garlic insecticides, Rodale's "Ultimate Encyclopedia of Organic Gardening" suggests preparing either a water or mineral oil formula. For the former, blend six to 10 garlic cloves in 1 qt. water, then strain the garlic pulp from the liquid. Put the garlic-infused water in a clean spray bottle. To create the oil-based blend, soak 10 to 15 chopped garlic cloves in 1 pt. mineral oil for one day. Strain the chopped garlic pulp. To use the formula at full strength, pour the mixture into a spray bottle. Alternatively, dilute it by mixing equal parts garlic mineral oil and water before adding it to a spray bottle.
  
  

Commercial Products

• Garlic is listed as a main ingredient or part of a botanical blend in some commercial products, especially those which are geared to organic gardeners. Some garlic sprays claim to target specific insect pests or plant diseases, while others are broad-spectrum repellents or fungicides. Look for sprays which specifically mention the pests bothering your plants, if you are able to identify them. Alternatively, focus on multi-insect repellents which mention the kind of plant you are trying to protect, such roses, lawns or vegetables.
  
  

Affected Insects

• Clemson's Cooperative Extension service notes that garlic and hot pepper sprays target many of the same insect pests which attack garden plants as well as houseplants. Among the insects which may be controlled with garlic spray are aphids, lace bugs, leaf hoppers, spider mites, thrips and whiteflies. But the Clemson program notes that garlic spray may also repel beneficial insects, suggesting gardeners practice limited or targeted applications instead of preemptive spraying of large areas of the garden. Experiments conducted at Ohio State University found that weekly sprays of garlic-based insecticide increased the yield of market beans by discouraging bean beetles and potato leaf hoppers. The garlic spray was more effective than pepper spray, row covers and plain water, but not as effective as chemical sprays, researchers noted.
  
  

Alternatives

• Hot pepper spray generally addresses the same garden pests as garden spray, notes the Rodale encyclopedia. Make your own home insecticide by blending and straining 1/2 cup chili peppers with 2 cups water. The Clemson Cooperative Extension program notes that garden centers also offer pepper sprays, sometimes known as capsaicin spray. Neam leaf sprays additionally address a long list of "bad" bugs, while citrus oils target fleas, ticks, roaches and mosquitoes. Pyrethrum powder, derived from chrysanthemums, must be applied directly to pests and are designed to paralyze or kill the insects. Clove essential oil is another broad-spectrum botanical found in both commercial products and home remedies.