For avid gardeners who care about the earth, the issue of pests can be vexing. On the one hand, they desire to grow their plants to maturity, maintaining them intact from would-be predators. At the same time, they recognize that some of the most effective pesticides do collateral damage to crops, soil and groundwater.
Happily, there are numerous substances that repel and repulse insects and other creeping plant-eaters while leaving the surrounding ecosystem unmarred. Many of these lethal repellants are easily found and procured. With a little research and experimentation, growers will discover the best organic pesticides for vegetable gardens.
1. Pyrethrin
Found in many breeds of chrysanthemum, pyrethrins are naturally lethal to many insects. Just after blooming, the plant’s flowers undergo drying, grinding or oil extraction by means of solvent. The yielded dust contains pyrethrin compounds that kill insects on contact. Effective against beetles, cockroaches, mosquitoes and flies, pyrethrins also protect agricultural and horticultural crops from natural pests.
In addition, they eliminate ticks and fleas from pet hair. Like chemical insecticides, pyrethrins attack the pest’s central nervous system. Important to note is that the administered dose must be sufficient to kill the insects. Many will fall to paralysis upon contact, yet then recover and survive. Some synthetic compounds also incorporate pyrethrin so gardeners do well to confirm the organic nature of any pyrethrin product.
2. Lime-Sulfur
Organic pesticides for vegetable gardens impact the environment less than their chemical counterparts. Still, that does not mean they do not pack a punch. A good example of this is lime-sulfur. Composed of calcium hydroxide and sulfur (simply boil lime and sulfur together), this compound is a very strong insecticide. Thus, gardeners should take care in its application.
Lime-sulfur burns foliage severely so growers do best to apply it in early spring before budding. Additional treatments can take place in late autumn after leaves fall. Lime-sulfur not only kills insects, but neutralizes their eggs as well. Like many other organic pesticides, lime-sulfur comes in synthetic versions. If you purchase it at a nursery or garden center, a careful check of the ingredients is warranted.
3. Sabadilla
A proven terminator of squash bugs, chinch bugs, harlequin bugs and stink bugs, sabadilla pesticide is derived from the ground seeds of the sabadilla plant. It kills by both contact and ingestion, making it one of the most lethal organic pesticides for vegetable gardens. Since sabadilla dust can also adversely affect human respiration, its use is carefully regulated by the U.S. Environmental Protection Agency (EPA).
Presently, EPA permits sabadilla use for cucumbers, squash, melons, beans, turnips and potatoes, among other crops. Gardeners should nevertheless wear masks when using this very effective pesticide. If a conveniently located nursery does not carry sabadilla, consumers will find several mail-order suppliers and online retailers that make it available.
4. Garlic and Onions
It should surprise no one that the same things that inhibit human interaction can likewise impede insect activity. As garlic and onions have ruined many a job interview and romantic aspiration, these herbs efficiently dispatch a wide variety of destructive bugs. Most vegetable growers employ garlic and onions in the form of a spray.
Each component contains sulfur compounds that emit strong odors that are obnoxious to many insect species. Simply liquefying the herbs in a blender with water is all it takes to produce a potent spray. Alternatively, garlic and onion powders can substitute for fresh ingredients. Ready availability makes garlic and onions attractive organic pesticides for vegetable gardens.
5. Ryania
The Ryania tree is a toxic South American flora, the roots and stems of which are often employed against rapacious pests and insects. Ryania contains alkaloids, i.e. chemical compounds rich in basic nitrogen. A killer of corn borers and related caterpillars and moths, ryania also produces toxic reactions in dogs and humans. This serves as another reminder that “organic” may still require safety considerations. That said, this substance does minimal damage to plants and wild mammals.
6. Tomato Leaves
Like ryania, tomato foliage is chock full of alkaloids. Chopping up tomato leaves and soaking them in water overnight causes the liquid to assume the alkaloid properties of the leaves. Straining the leaves and further diluting the water makes spray-able organic pesticides for vegetable gardens. This solution is a successful weapon against aphids, in particular, and it attracts beneficial insects to the garden.
These include aphid midges, damsel bugs and lacewings, all of which feed on aphids. Because of its potency, tomato leaf spray mandates direct contact on the offending pest exclusively. Furthermore, vegetables should be thoroughly washed before eating, as you would to remove synthetic pesticides.
7. Cayenne Pepper
Hot pepper—Cayenne Pepper as a shining example—is a successful neutralizer of cabbage looper larvae and of spider mites. While the capsaicin in hot peppers is in no way poisonous to plants, animals or soil, its acrid properties make life very unpleasant for onion flies and spiny bollworms, to cite two more examples. Cayenne powder in a quart of water for one hour yields a powerful insect repellent that is easy to make and easy on the environment.
Adding some dish soap to the solution helps it to cling. Since its purpose is prophylactic, Cayenne pepper spray applications are not on a schedule. Treat plants as needed. The same elements that fend off muggers and mashers will repulse plundering pests, the primary reason to use organic pesticides for vegetable gardens.
Summing Up
A practical lesson of horticultural science is that the very properties that make certain plants dangerous to insects are themselves useful when protecting other plants. The more we learn about what helps some flora survive in the wild, the better equipped we are to fortify our gardens against their natural enemies.
Time and again, low tech proves to be most deadly. When all is said and done, gardeners have more and better choices as they select the best organic pesticides for vegetable gardens.
