House Plants
Common Diseases and Pests

House Plants Common Diseases: With diseases and insects a constant threat, find our best tips for getting rid of aphids and our natural spider mite control.

Most often, if plants are given plenty of fresh air and not crowded together, insects should not cause serious trouble.

No matter how many steps in caring for house plants one may take, house plant bugs/diseases are almost certain to put in an appearance, and steps to fight them must be taken immediately. Remember, though, that the best remedy is prevention, and the best prevention is to have good strong healthy house plants.

House Plants Common Diseases

Perhaps the most common of house plant problems is neither insects nor disease. It is sour, soggy soil.

Sour soil is the result of improper drainage conditions, too much water, or both. It causes the leaves to turn yellow and stunts new growth. Correcting the harmful conditions will usually renew the health of the plant, but in bad cases it will be far better to remove the soil, wash the soil from the roots, carefully clean the pot (if the same one is to be used) and repot in good porous fresh potting soil. And make sure the pot is draining well. Keep on the dry side until growth is resumed. More on container drainage here.

As a rule, insects do much more damage to house plants than is caused by diseases. One characteristic of nearly all plant insects (which will surprise most gardeners), is the speed in which they multiply.

One today, and tomorrow a million!! No exaggeration.

Never let the bugs get a start. If you get to them in time, they're easy: if not, you've got a very difficult task on your hands!!

House Plant Problems/House Plant Pests

Aphids/ House Plants Common Diseases


Aphid Photo

Photo Credit: Mike E. Talbot

Aphids or green plant lice is the most commonly encountered of any house plant pest. It used to be dreaded, but now can be readily and effectively exterminated. There are several forms and colors of these pests. If you have attempted plant-growing, you are undoubtedly familiar with them.

In the house, shaded places, crowded plants, poor ventilation, dry plants...all are environments favorable to the development of aphids. Change these conditions at once!!

Getting rid of aphids can be done by spraying them off with water, or even submerging the plant under water. (A great natural aphid control)

Insecticidal soap is a great method as well. Bought from a hardware store, etc. this method gives good results.

An insecticide spray noted for use with aphids can also be used, but some are not recommended for home use...use caution.

For more info on Aphids and another form of removal, click here.

Red Spider Mites/ House Plants Common Diseases

Red Spider Mite

Red Spider Mite

This very serious pest is about the size and color of a grain of red pepper...although sometimes appearing brown or dull red. To make himself inconspicuous, he works on the under side of the leaves and behind a tiny web. He makes himself known by the leaves on which he lives. They first turn light green, then show small yellow spots, turn yellow and finally drop off.

Red mites are very hard to get rid of when he is allowed time to become well established. The best weapon to use against him, where it can be done, is clear cold water with as much force as possible against the under side of the foliage. Damp atmosphere helps in the work; so keep the air damp, and be on a sharp lookout. Evaporated sulphur, or flowers of sulphur dusted upon the leaves will also help.

Where the collection of plants is not too large, the quickest and easiest spider mite control is to dip the top of each plant quickly two or three times into hot water (140°F to 165°F). Although uncomfortable to the hand, water of this temperature will not injure the tenderest plant. Of our house plant tips, this one is effective against Aphids and mealy bug, as well as against the spider mite.

For more house plants common diseases info and more methods of extermination click here.

Mealy Bug/ House Plants Common Diseases

The mealy bug inhabits a white, cottony looking mass, which is easily seen. Remove this covering and the real intruder is there. It is most fond of the soft-wooded plants, such as coleus and fuchsias. They thrive in a hot, dry atmosphere, and will keep out of sight, in a mass of leaves or under some branch axis, until there are a large number.

If they are discovered before multiplying to any great extent, exterminate them with a fine brush or cotton ball dipped in alcohol.... if applied directly to them, this will kill them on the spot.

Scale/ House Plants Common Diseases

The scales that infest house plants are of two kinds. The more common is the brown scale, which has a hard, slightly convex, circular shell, one-quarter of an inch or so in diameter. The white scale is much smaller, and soon forms quite dense colonies. Both attack the thick-leaved, smooth-barked plants, such as palms, ferns, lemons, and abutilons. They do not appear to be doing any damage, but invisibly suck the juices of the plant. They should be destroyed at once. This is accomplished by the use of insecticidal soaps applied with a sprayer.

Alcohol soaked cloths can be used to dab onto the scales, which is very effective but only for scales which are visible. Oftentimes, many homeowners will discard the plant rather than risk the spreading of these insects.

Thrips/ House Plants Common Diseases

These do not often appear in the house, but may where plants are crowded in a shady place. They eat the substance of the leaves, leaving only the skeleton structure. They are small, about a quarter of an inch long, and brown or black. , pyrethrins, neem oil, etc. will keep them quiet.

Root Aphids/ House Plants Common Diseases

Sometimes the leaves of a healthy plant will begin to look sickly with no apparent cause. It may be found upon examination that the blue root Aphids is at work, clinging in clusters to the rootlets. Remove and wash away the soil, and then wash the roots in insecticidal soap suds, and repot in fresh soil.

Soil Worms/ House Plants Common Diseases The common earthworm will sometimes find it's way into a pot, and while they don't seem to bother the roots, they render the soil next to useless, especially in small pots. Another worm, or actually larva, sometimes to be found is very small and hatches into a small white fly. If numerous, they do a great deal of damage. The treatment recommended for root Aphids will get rid of them; or you could use lime water (slake a piece of fresh lime the size of an apple in a pail of water, drawing off the water after settling). If used freely it will kill them.

House Plant Diseases

There are but two plant diseases likely to attack plants in the house: house plant fungus and mildew. The first seems to be a sort of decomposition of the leaf, leaving a black, powdery residue. It's fought by spraying with bordeaux. Bordeaux can be found in paste or powder form, which for small quantities is much better than to try to mix it yourself.

The house plant disease of mildew causes the tenderest leaves to curl up and some of them seem to be covered with a white powder. Flowers of sulphur, dusted over the plants while the foliage is damp, is a good remedy.

For easy reference of house plant information, use this simple table of plant insects and diseases.

House Plants Common Diseases Reference Chart




Aphids, green and black Shade; poor ventilation; thick foliage Spray off with Water; Insecticidal Soap
Aphids, blue Stunted Growth; lack of water Insecticidal Soap; repotting; tobacco tea applied to roots
Thrips, 1/4 inch long, brown or black Shaded places; crowded plants Neem Oil;
Mealy Bugs Other Scale insects Corners; close, dry air Brush off; Alcohol Soaked Cottonball
Red Spider Hot, dry atmosphere Moisture, sulphur, hot water
Rose Beetle Hank Picking; wood ashes
White Flies (Aleyrodes) Dry Foliage Kerosene Emulsion
Slugs Dark Corners; dampness; decaying wood Air-slaked lime, sweetened bran
Ants Insect Powder; molasses traps
Angleworm Dampness; heavy soil Lime; lime water; tobacco tea and tobacco dust washed into soil
White Grub Destroy
Fungous Leaf Spot Bordeaux
Mildew Flowers of sulphur

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