Organic Garden Pesticides

Organic pesticides can be mixed up at home for use in the garden.

With all the focus on organic gardening, you may be wondering how you can effectively control pests at home without using harmful synthetic pesticides. Fortunately, many organic pesticides can be used in the home garden, many of which are composed of ingredients that can be purchased from a grocery store or pharmacy. Additionally, several commercially-prepared varieties derived from natural sources are available from garden stores.

Detergents

One popular organic pesticide involves spraying liquid dishwashing detergent on plants. This treatment is very effective at deterring white flies, spider mites, and aphids. It will also work for a host of other pests common on carrots, celery, cucumbers, eggplants, peppers and other vegetables. The most basic formula is made by mixing detergent, vegetable oil, and water.

Sulfurs

Pure sulfur can be dusted or sprayed on plants. It is particularly good for combating powdery mildews, rusts, leaf blights, and fruit rots, but can also be somewhat successful at controlling spider mites, psyllids, and thrips. It is best used on fruits and vegetables. Lime sulfur, which is made by mixing both lime and sulfur, is also organic and can be effective when sprayed on fruit trees. Both kinds are best used in cooler climates, as they can be damaging to plants when used in temperatures over 80 degrees Fahrenheit.

Pyrethin, Sabadilla, and Neem

Pyrethin is a natural pesticide derived from chrysanthemum plants. It is particularly effective on flying insects. Another organic insecticide, sabadilla, is a natural pesticide derived from the seeds of the sabadilla lily. It is very effective against caterpillars, leaf hoppers, thrips, stinkbugs and squash bugs, and can be used on vegetables. Unfortunately, however, sabadilla can be very irritating if inhaled. Neem is an insecticide and fungicide that comes from the neem tree, a native to India. Commercial preparations can be used to control gypsy moths, leaf miners, sweet potato whiteflies, western flower thrips, loopers, caterpillars and mealy bugs. Neem is not suitable for vegetables, fruits, herbs, or any plants that will be eaten, however.

Tobacco

Tobacco can be used in two forms to kill a host of pests. For fungus gnats, symphylids, centipedes, root lice, and other underground pests, a solution of tobacco mixed into water is particularly effective. The mixture is deadly if ingested, however. Additionally, snuff tobacco can be dusted on the surface of plants to kill flies and worms. However, if tobacco is used on tomatoes, peppers, and eggplants, they can become infected with a disease called tobacco virus. Additionally, tobacco is the source of nicotine sulfate, a commercially-prepared pesticide. It is extremely dangerous to humans and animals when absorbed through the skin, however. It works best at ridding plants of aphids, thrips, and spider mites. It works well on many plants but can damage roses.

Hot Pepper

Crushed hot pepper or hot sauce can be dusted or sprayed, respectively, on plants to discourage snails, cats, dogs, and any other pests that eat foliage.

Spearmint Spray

Spearmint, mixed with green onions, water, and hot pepper, is an excellent defense against a host of chewing insects. Small plants are dipped whole into the solution, whereas larger plants can be sprayed with the strained liquid.

Petroleum Oil Sprays

Sprays derived naturally from petroleum can be helpful in protecting hearty woody plants. Dormant oils are used in winter (before the first buds), and summer oils only in summertime, when the plant is not dormant.

References

• Mother Earth News: Guide to Organic Pesticides
• Colorado State University Cooperative Extension: Some Pesticides Permitted in Organic Gardening

Resources

• University of California Agriculture and Natural Resources: How to Manage Pests