Plant-Safe Insecticide for a Houseplant

Eradicating houseplant pests, like aphids, sometimes requires insecticide treatment.

Mites, scale insects, fungus gnats and whiteflies can afflict indoor plants, harming the plant and sometimes creating an unsightly mess. Houseplant pests often arrive on new plants, infest plants being temporarily kept outside, or enter through open windows and screens. Although washing and hand-picking pests often bring bugs under control, you sometimes need to resort to an insecticide. When choosing an insecticide, always read the label carefully to ensure the product's safety for your houseplants. If you don't see your plant listed on the label, don't use the product.

Before You Spray

Before using an insecticide on your plant, you should correctly identify not only the insect but also the plant. Incorrect identification of the pest can lead to time and money wasted on ineffective treatments, while incorrect identification of the plant species can cause inadvertent application of a harmful product. Removing pests by hand, swabbing individual pests with alcohol, and washing plants with a strong jet of water can treat problems without the need for an insecticide.

Natural Insecticides

Before you turn to the hard stuff, consider using a few natural, less toxic insecticides to bring pests under control. Insecticidal soaps disrupt the insect's ability to regulate the movement of water in and out of its body and kill many common pests with minimal risk to the plant. For maximum safety, use formulations specified for insect control rather than mixing your own. Horticultural oils block the pores insects use to breathe, inhibit their normal metabolism and interfere with feeding. Both insecticidal soaps and horticultural oils pose few risks to beneficial insects, people and pets.

Chemical Options

Several active ingredients form chemical insecticides effective against houseplant pests, including pyrethins, bifenthrin, permethrin, resmethrin, imidacloprid and disulfoton. According to the University of Minnesota Extension, finding approved chemical insecticides for houseplants can be tough. If your plant can withstand living outdoors for a few weeks, moving it outside lets you use insecticides approved for outdoor use. Read the label carefully to confirm the product's safety for your plant.

Avoiding Insecticide Damage

You've identified the pest and determined that you can use the insecticide on your houseplant. A few extra steps will ensure that your plant will wind up better off after the treatment. First, water the plant properly leading up the treatment; never treat water-stressed plants with insecticide. Mix only the insecticide you intend to use that day and, if you don't use it all, properly dispose of it according to the directions on the label. Always spray plants in a well-ventilated area. If you want to better assure the product's safety for your plant, try it on a single leaf first to see what happens.

References

• University of Minnesota Extension: Houseplant Insect Control
• Colorado State University Extension: Insect Control -- Soaps and Detergents
• Colorado State University Extension: Insect Control -- Horticultural Oils
• University of Delaware Cooperative Extension: Insect Pests of House Plants