Vegetable Garden Insecticides

Beetles can be a nuisance in your vegetable garden.

Regardless of how well managed a vegetable garden is, there are instances when certain insects get out of control. The best management practice in the vegetable garden is to use a combination of strategies, including mechanical, biological and the cultural control methods. Nonchemical methods are the safest choice for vegetable gardens. Alabama A&M and Auburn Universities Extension suggests using insecticides only as a last resort because this can kill the beneficial insects as well.

Insecticidal Soap

Insecticidal soap is a recommended insecticide for the control of aphids, adelgids, scale, thrips, whitefly, earwigs, wooly aphids and other insects. According to the University of New Hampshire Extension website, insecticidal soaps are one of safest choices for vegetable gardens. Besides vegetables, insecticidal soaps can be used on flowers, houseplants, roses and shrubs. Insecticidal soaps do not burn the plant foliage and do not stay for long in the environment. In vegetable gardens they are safe to be used up to the day of the harvest. The main ingredients in most insecticidal soaps are potassium salts of fatty acids derived from plants.

Neem Oil

Insecticides made with the extract from the seeds of the tropical neem tree are highly effective, 100 percent organic pesticides. The derivative from the seeds is the primary ingredient in these insecticides, even though some other oils and ingredients in the solution also contain effective insecticidal properties. Neem oil is nontoxic and kills insects in the early stages of development. The greatest efficacy of neem oil insecticides is against whiteflies, thrips and aphids. Neem oil does not work instantly but leads to a steady decline in the number of pests within a week of application. Active ingredients in neem oil are like the hormones that insects produce. These inhibit the real hormones in the insects to function properly.

Pyrethrins

Pyrethrins are among the most important natural insecticides and are derived from the painted daisy, Chrysanthemum cinerariifolium. Pyrethrins affect insects upon contact and disturb their nervous systems, which leads to convulsions and death. Pyrethrins based insecticides break down rapidly in the sun and become nontoxic within a couple of days. Pyretrins are highly effective against such resilient pests as squash beetles, tarnished plant bugs and beetles. Since pure pyrethrins just stuns insects and does not kill them, they are usually combined with a synergist called piperonyl butoxide. Pyrethrins are minimally toxic for people and do not harm birds and other wildlife.

References

• Alabama, A&M and Auburn Universities Extension: Garden Bugs
• University of New Hampshire Cooperative Extension: Using Insecticidal Soap in Your Garden
• Discover Neem: About Neem Oil and Insects
• University of Rhode Island Extension: Least Toxic Pesticides