How to Care for Houseplants | Get Rid of Insects & Bugs

Mid-winter is when insects often show up on indoor plants. Most of them have been in residence since the plants came inside, but late January is the time when their numbers explode. Suddenly we have large flights of tiny black fruit flies buzzing around us. We notice that the floor or table under a particular plant is sticky, or that a plant is unexpectedly covered with tiny, cotton-like debris. Here we’ll explore how to care for houseplants that are suffering from an invasion of bugs or insects. Most insect problems get worse in the winter because of a combination of warm indoor temperatures, low humidity, and less air circulation. Add to this a complete lack of the predators that keep these pests in check outside, and you have an insect problem that balloons quickly. How you combat these pests depends on which one is attacking your plants.

HOW TO CARE FOR HOUSEPLANTS | GET RID OF INSECTS & BUGS

FUNGUS GNATS

The tiny black fruit flies that often come in soil are fungus gnats. The larvae of these small insects eat the roots and other organic matter in pots, and then hatch into tiny, annoying but harmless gnats. There are three ways to control this insect effectively. Most garden centers sell yellow sticky cards that are often labeled as “white fly traps.” Because insects, including the fungus gnats, are attracted to the color yellow they will gravitate to these cards and be trapped on the sticky surface. The gnat larvae in the soil can be treated with any product that contains spinosad, which is an organic bacteria. The spinosad needs to be added to the can every time you water the plants for at least a month. Together, the yellow sticky cards and the spinosad control all but the worst fungus gnat infestations. If a particularly heavy outbreak of this pest isn’t managed with those organic treatments, a systemic product can be used. Most garden centers sell a systemic insecticide for houseplants and they should be applied according to directions. [text_ad]

WHITEFLY, SCALE, APHIDS & MEALYBUG

Insects are divided into two types depending on their mouthparts. There are insects that chew plants for their food, and those that suck juices from plants for their daily meals. Most of the critters that are problematic on houseplants have sucking mouthparts. They stick their teeny-tiny soda straw into the plant’s leaf and pull out the sugar-rich sap. The other most common pests on houseplants have such sucking mouthparts. Whitefly, scale, aphids and mealybug are the typical insects that plague indoor greenery. You’ll know that your plants have one of these if the foliage, stems or area underneath the plant feels sticky. The sap the insects excrete is rich in sugar, resulting in extreme tackiness. Over time a grey mold will also form on these excretions. Treat these pests as soon as they or the stickiness is discovered. Wipe as many off manually as possible, or spray them away with a hard stream of water. Follow this with a coating of insecticidal soap or horticultural oil. Because new generations of insects will continue to hatch, this treatment will need to be repeated at least three times, every ten days, or according to directions. On a particularly warm winter day (above 45 degrees) it’s often most practical to take the plant outside for treatment. Apply the soap or oil thoroughly, let it drip outside for thirty minutes, and bring the plant back indoors. If a plant is sentimental, older and an impressive specimen it’s worth combatting the insects with the methods above. But some plants can be so infested that it’s not worth jumping through the hoops necessary in order to save them. Sometimes the hardest part of learning how to care for houseplants is admitting when you can’t. If an infested houseplant isn’t special, it might be best to say, “Thanks for all the great times!” and toss it in the compost, bugs and all. Have any tips for how to care for houseplants that are suffering from an invasion of bugs or insects? Let us know! This post was first published in 2017 and has been updated. 

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