House Plant Bugs

Beautiful houseplants can be a gardener's delight, yet, they can also be one of the greatest frustrations when there's an infestation of bugs. The key is knowing how to identify houseplant bugs and how to get rid of them before they cause damage to your plants.

Common Houseplant Bugs

An infestation of bugs on a house plant.

Although there are dozens of different kinds of houseplant bugs, there are six kinds that are most commonly found in house plants. These include aphids, mealy bugs, spider mites, white flies, fungus gnats and millipedes. Each of these bugs can quickly become an infestation if left unattended, an they will eventually kill your plants.

Identification

Leaves have marks that can be telltale signs of bug infestations

As a regular scheduled regime to your plant care, you should look for signs of bugs and bug infestation. Check the undersides of leaves for any hidden bugs or eggs, new shoots or buds for cloudy residue and all leaves and stems for spotting, streaking, discoloration, wilting or deformation. It's especially necessary to check out the plants in the nursery before you buy them because they could be exposed to other plants that are infested and may have early stages of bug infestation that is not noticeable to the naked eye.

Pruning

Houseplant bugs feed off new buds and shoots.

Most often house plant bugs will feed off the new shoots and buds first before they move to the older parts of the plant. This is because new growth is easier to penetrate and the bugs can more easily suck the plant juices from them. Since the bugs may be inside the new shoots or buds, you need to prune them back to the first joint or set of leaves that have not been infected by the bugs. New growth will continue once the plant is free of the infestation and has regained its strength.

Any damaged leaves should be removed immediately as they will not regain their strength even after the bugs are gone. As well, any leaves that are laden with eggs should be removed. Healthy leaves that have a few eggs or bugs do not need to be taken off as the invaders can be removed through washing the plant and the leaves. However, it will not harm the plant if you do remove them.

Washing and Spraying

While infestations may be on the underside, the top of the leaves may seem clean.

You can wash plants that are primarily foliage with large leaves with warm, soapy water and a cloth. More complex plants with smaller leaves can be sprayed with insecticidal soap which can be purchased at any garden nursery. This type of plant would include those with blooms or buds that are still healthy. Although both are good methods, the insecticidal spray soap is most effective because it can get into the smaller areas of the plant that could be missed from hand washing. To use the spray, turn the plant upside down and first spray all the underside of the leaves and then turn it back and spray the tops. For larger plants, you'll need to keep them upright and begin with the undersides of the lower leaves and branches and work your way upwards.

Follow-Up

Spraying plants with insecticidal soap is a good preventative measure.

Once the plant is cleansed of all the infestation, follow the instructions on the insecticidal label for a follow-up dose of spray. For very heavy infestations, you can purchase an insecticide that contains resmethrin, tetramethrin or allethrin from the garden nursery, which will get rid of the bugs. Afterward, as a scheduled procedure, you can spray the insecticidal soap on the plant as a preventative measure.

Follow-up

References

• Alberta Agriculture and Rural Development: Houseplants: Insects and Related Pests

Resources

• University of Guelph: Scale Insects & Mealy Bugs on Houseplants