Insecticide For Potted Plants

Homeowners must make sure that the plants in their homes receive proper care and a pesticide may be called for to deal with bugs attacking the potted plants. Potted plants can be kept pest-free with a well-timed insecticide application. While most household insecticides are too strong for potted plants, certain organic pesticides are well suited for killing aphids, mites and other pests that commonly attack the roots and leaves of houseplants.

Insecticide For Potted Plants

Major Pests

Aphids: Aphids are small, soft-bodied, pear-shaped insects about ¹/₁₆– to ⅛-inch long. They are usually green but may be pink, brown, black, or yellow. Some aphids have a woolly or powdery appearance because of a waxy coat. Adults may or may not have wings.

Aphids are usually found feeding on new growth or the undersides of leaves. Some feed on roots. They suck plant sap, resulting in yellowing and misshapen leaves. In addition, growth may be stunted, and new buds deformed. As aphids feed, they excrete a sugary material, called honeydew, which makes leaves shiny and sticky. Sooty mold fungi may grow on the honeydew, producing unsightly dark splotches on the plant’s surfaces.

Control: With minor infestations, handpicking, spraying with water, or wiping the insects with a cotton swab dipped in rubbing alcohol may be practical. Insecticidal soap spray may also be used. In most cases, the treatment will have to be repeated multiple times. For houseplants that are taken outdoors, spray with insecticidal soap, neem oil extract, pyrethrins, imidacloprid, cyfluthrin, deltamethrin, or lambda cyhalothrin to control aphids. See Table 1 for examples of brands and products. Imidacloprid granules put onto the soil will also control aphids. See footnote on Table 1 about spraying houseplants outdoors. Follow label directions for safe use.

Mealybugs: Mealybugs are small, pale insects related to scales. They are about ⅛ to ¼ inch long and move very sluggishly. The adult females cover themselves and their eggs with a white, waxy material, making them look cottony. Some have waxy filaments that extend beyond their bodies.

Nymphs (immature forms) hatch from the eggs. Once they begin to feed, the waxy coating starts to form. Nymphs look like adults, only smaller. The wax on mealybugs helps repel pesticides and makes them somewhat difficult to control. Mealybugs are most commonly found on the lower surfaces of leaves and in leaf axils (where the leaf attaches to the stem). One species feeds on the roots. They suck plant sap, causing stunted and distorted growth and sometimes plant death. Like aphids, mealybugs excrete honeydew, providing the opportunity for the growth of sooty mold fungi.

Control: Light infestations can be controlled by removing individual mealybugs by hand or by wiping each insect with a cotton swab dipped in rubbing alcohol. An insecticidal soap spray may also be used. With a heavy infestation, it may be necessary to discard the plant. For houseplants that are outdoors, spray with neem oil extract, pyrethrins, acetamiprid, imidacloprid, cyfluthrin, deltamethrin, or lambda cyhalothrin to control mealybugs. Imidacloprid granules put onto the soil will also control mealybugs. See Table 1 for examples of brands and products. See footnote on Table 1 about spraying houseplants outdoors. Follow label directions for safe use.

Spider Mites: Mites are not insects but are more closely related to spiders. Since they are extremely small, plant damage is typically the first sign of their presence. A silky web is often seen with heavier infestations.

Both spider mite adults and their immature forms damage plants by sucking plant sap. Damage includes light-colored speckling on the upper surface of leaves and results in a plant with an overall faded look. If the mites are left unchecked, leaves become bronzed or yellowed, and the plant dies. Spider mites are usually more of a problem on houseplants that remain indoors year-round, especially palms and English ivy.

Control: Spray sturdy plants forcefully with water, including the undersides of leaves, to dislodge mites and break up their webs. Plants also can be sprayed with insecticidal soap. For houseplants that are outdoors, spray with insecticidal soap, neem oil extract, or an insecticide containing sulfur. It is often necessary to spray once a week for several weeks to control mites. See Table 1 for examples of brands and products. See footnote on Table 1 about spraying houseplants outdoors. Follow label directions for safe use.

Plants placed outdoors during summer may have a reduced problem with spider mites. Be sure to place all houseplants initially in mostly shade, as even plants that grow well in more sun might be burned until they have adapted to the higher light levels.

Fungus Gnats: Adult fungus gnats are delicate in appearance and about 1/8-inch long. Often they can be seen running across or flying near the soil surface under a houseplant. They are weak flyers and are attracted to light.

The adults do not feed on houseplants but can be a nuisance to people. In severe infestations, they are often seen in large numbers on nearby windows.

The whitish larvae (immature forms) of fungus gnats have shiny black heads and can grow as large as ¼-inch. The larvae generally feed on decaying organic material or fungi growing in the soil. The larvae of some species will also feed on roots. This feeding is especially damaging to very young plants. With older, established plants, the initial sign of an infestation is that the plant loses its normal healthy appearance. A heavily infested plant may lose leaves because of the feeding of larvae on its roots.

Indoors, fungus gnats are most often a problem when potting soil that is rich in organic matter, such as peat moss, is used to grow plants. It is especially a problem when overwatering occurs.

Control: For plants that can tolerate it (i.e., most houseplants, especially during winter), allow the soil to dry between watering. Dry conditions will kill the larvae. Do not allow water to stand in the saucer beneath houseplant containers, and invert saucers beneath plants outside to not collect rainwater. Products that contain strains of the biological control agent Bacillus thuringiensis subspecies israelensis can be applied to the soil of houseplants and watered into the soil for control. See Table 1 for examples of brands and products. Follow label directions for safe use.

Root Ball Pests: Houseplants taken outdoors during the summer may have their root balls infested with pillbugs, millipedes, and slugs. These houseplant pests may cause minor feeding damage to root systems. They are generally found along the exterior of the root ball in small cavities carved from the potting mix. Ants may also make nests within the potting soil of houseplants while outside.

Control: The plant container can be gently removed to inspect for pillbugs, millipedes, and slugs, which simply can be scraped away. Ant colonies in the container may be killed by soil drenches of products containing cyfluthrin or lambda cyhalothrin. Mix insecticide concentrates at the same rate as for spraying, and pour the solution through the soil in the container. Allow pots to thoroughly drain and dry before bringing indoors. See Table 1 for examples of brands and products. See footnote on Table 1 about spraying houseplants outdoors. Follow label directions for safe use.

Scales: Several species of scales are pests on houseplants. Scale insects can be divided into two groups: armored scales and soft scales. An armored scale secretes a waxy covering that is not an integral part of its body. The covering can be scraped off to locate the insect living beneath it. In contrast, the waxy covering that a soft scale secretes is an integral part of its body.

Scales are unusual insects in appearance. Adults are small and immobile with no visible legs. Scales vary in appearance depending on age, sex, and species. Some are flat and appear like fish scales stuck to a plant. Others look like waxy, colored masses. They range in size from ¹/₁₆– to ½-inch in diameter. They are usually found on stems and the undersides of leaves but may be found on upper surfaces as well. Scales feed by sucking plant sap.

Their immature forms, called crawlers, are mobile, and they also feed by sucking plant sap. Like mealybugs, the soft scale insects excrete honeydew (which results in black sooty mold problems on foliage and stems). Armored scales do not excrete honeydew.

Control: Early infestations of scales can be removed by scraping with a fingernail. Adult scales are relatively protected from insecticides by their waxy covering. However, for houseplants outdoors, sprays with products containing neem oil extract or canola oil help control adult scale insects by smothering. Their crawlers are susceptible to many insecticides, such as insecticidal soap, neem oil extract, canola oil, pyrethrins, acetamiprid, imidacloprid, cyfluthrin, deltamethrin, or lambda cyhalothrin. See Table 1 for examples of brands and products. See footnote on Table 1 about spraying houseplants outdoors. Follow label directions for safe use.

Whiteflies: Whiteflies are not true flies but are more closely related to scales, mealybugs, and aphids. They are very small, about ¹/₁₀– to ¹/₁₆ -inch long. They have a powdery white appearance and resemble tiny moths. When at rest, the wings are held at an angle, roof-like over the body. The immature stage is scale-like and does not move.

Both the adults and their immature forms feed by sucking plant sap. The damage that they cause is similar to that caused by aphids. The infested plant may be stunted. Leaves turn yellow and die. Like aphids, whiteflies excrete honeydew, which makes leaves shiny and sticky and encourages the growth of sooty mold fungi. When plants that are infested with whiteflies are disturbed, the whiteflies flutter around for a while before settling again.

Control: Wash the plant. Spray the plant thoroughly with insecticidal soap, especially the lower leaf surfaces. Imidacloprid granules put onto the soil will also control whiteflies. For houseplants that are taken outdoors, spray with insecticidal soap, neem oil extract, acetamiprid, imidacloprid, cyfluthrin, deltamethrin, or lambda cyhalothrin to control whiteflies. See Table 1 for examples of brands and products. See footnote on Table 1 about spraying houseplants outdoors. Follow label directions for safe use.

Insecticide For Potted Plants

Insecticide for potted plants should be used as a preventative measure. There are many factors that can contribute to the development of insects in your garden. The ideal time to use an insecticide is before you see any signs of infestation. This will help prevent further damage to your plants.

The most common types of insects that affect potted plants are aphids, whiteflies, mites, mealybugs and scale. Aphids are small insects that are found on the undersides of leaves or stems and produce honeydew which attracts ants and other insects. Whiteflies are tiny white insects that live on the undersides of leaves and suck sap from plants causing them to die off prematurely. Mites feed on plant tissue and can cause yellowing or brown spots on leaves. Mealybugs look like tiny cotton balls with legs at first glance but once you get closer you’ll see how much damage they can do! Lastly, scale insects look like little bumps on plant stems or leaves but they too can cause quite a bit of damage!

List Of Insecticide For Potted Plants