Many a house plant can be saved from an early doom if houseplant owners would bear in mind that keeping plants healthy and trouble-free is largely a matter of prevention and not cure.
Rarely Infested With Pests & Disease
Houseplants rarely become naturally infested with plant pests or diseases as their outdoor brethren do.
The home acts as a protective environment shutting out bugs and blights.
When insects or diseases do show up, you may well be to blame, since many troublemakers can enter homes only by hitching rides on plants or in the potting soil. Actually, the majority of house plant ailments is caused by overzealous doctoring or disregard for environmental and nutritional requirements.
Learn The Plant Pests Danger Signs
Learning to recognize the danger signs on houseplants and inspecting all plants carefully for these signs before OK’ing them to bring into your home should be the first consideration.
A plant that looks clean and healthy at the garden center may actually be carrying the “seeds” of an infestation. The few specks on the underside of a leaf may be the forerunners of thousands of swarming spider mites.
The tiny insignificant scales in a stem crevice may be scale insects that will multiply later into a big ugly mess covering the entire stem. One small brown spot may be the generator of many more spots that will destroy the beauty of the plant and perhaps kill it.
Diagnosing Houseplant Ailments Look For Obvious Culprits
When diagnosing plant ailments, look for the more obvious culprits first – insects, mites and root-knot nematodes. If they are not the cause, then look for the more elusive factors – disease or improper environmental and nutritional conditions.
Practically all the common destructive houseplant pests feed by sucking the sap from foliage or stems.
Among the most obvious are the scale insects. Yet the uninitiated seldom recognize them as house plant pests but think them some scaly growth or disease. But they are insects, doomed to an inactive existence under a protective shield except for a short period following hatching, when they are tiny, flat creatures known as crawlers. Mature scales are threadlike, pear-shaped, oval or hemispherical, depending on the species.
Look for scales on fern, cactus, ivy, palm, rubber plants (Ficus), citrus, camellia, begonia, orchid and croton.
To avoid scale insects, give all new plants a good cleaning and remove any suspicious-looking objects.
Frequent additional baths should prevent any scales that sneaked by from gaining a foothold. Neem tree oil or a safer insecticidal soap is also good to apply before new houseplants move inside and is effective against the crawler stage.
All feeding stages of scales are generally controlled and killed with the chemical Malathon.
Mealy Bugs in The Leaf Axils
Look for mealybugs in leaf axils, bud clusters and wherever there’s a crevice they can squeeze into on African violet, coleus, begonia, fern, fuchsia, gardenia, amaryllis, camellia, cactus, croton, ivy and citrus, and a host of other plants.
The young are very similar to the crawlers of scale insects, but as they grow older, they cover themselves with a protective, powdery white waxy substance. They excrete a sticky honeydew, which harbors a sooty mold, blackening badly infested plants. Prevention and control of mealybugs is the same as for scale insects.
White Flies Most Persistent Houseplant Pest
White flies are perhaps the hardiest and most persistent house plant pest once they have established themselves. The young are pale, inactive spiny creatures that excrete copious amounts of honeydew. The adults are tiny, active, white-winged flies.
Because the young are tough babies and nothing seems to work on them, control must be concentrated on the adults. I always start with a weekly spraying of Neem oil, if Neem does not control malathon is recommended.
Tiny Spider Mites
Spider mites are so tiny that you normally see their damage, a grayish stippling of foliage, before you find the red or yellow 8-legged midgets and their round glistening eggs.
Their shed skins, amidst the fine webbing on leaf undersides, look like white chaff. A long list of plants may harbor spicier mites. Most commonly you will find them on asparagus fern, begonia, cactus, fuchsia, ivy, African violet and dracaena.
A cold-water washing will usually control spider mites. However, in some cases, spraying with malathon or the neem oil insecticide may also be needed.
The cyclamen mite is so small that it cannot be seen with the naked eye, but its injury is easily recognizable. The glassy white or transparent mites produce stunted, cupped or distorted leaves and flowers on African violet, begonia, ivy, crassula, fuchsia, geranium and cyclamen. In African violets, the center growth stays pale and stunted.
Badly infested plants should be destroyed, for this pest is very difficult to control. Make sure that only healthy plants are brought into the house and propagate only from clean stock.
Fungus Gnats and Springtails
The last insects to be considered are springtails and fungus gnats control, slim white jumping insects, not because they are a pest but because so many people notice them and think they are injuring their plants. They live on decaying vegetable matter in the soil and usually appear when they are driven out by watering. Malathon and Neem oil should take care of them.
House Plants and Diseases
Now, on to diseases of house plants. Prevention is the secret of disease-free plants. For most diseases are incurable, and even if a particular disease can be cured, it frequently leaves the plant scrawny and unattractive. To keep plants healthy and prevent the appearance of disease, the average house plant owner needs only practice the following rules:
1. Sterilize all soils used for potting and propagating. Buy bagged potting mixes that have been sterilized.
2. For propagating, use only clean, healthy-looking plant parts from healthy plants.
3. When buying plants, bulbs and corms, inspect them closely and select only those with no blemishes or abnormalities.
4. As soon as a disease is spotted on one of your plants, remove the affected plant parts or else destroy the whole plant together with the soil. Do not leave such a plant around to contaminate other plants.
5. Wash your hands with soap before handling plants and after handling diseased plants.
6. Do not overwater soil.
7. Syringe plants with water no oftener than once a week, and provide adequate ventilation so the leaves will dry off quickly.
8. If a fungus disease is present and uninfected foliage needs to be protected. apply a protective fungicide such as Captan (1 teaspoonful per quart of water) at weekly intervals.
Houseplant Root Rot
The house plant diseases known as root rots, stem rots and wilts are characterized by discoloration and decay of roots or stems and finally wilting.
Almost all house plants are susceptible to some form of rot or wilt, but these diseases most frequently occur in coleus, geranium. cactus, African violet, gloxinia and begonia. The bacteria or fungi responsible are soil born and are encouraged by overwatering, There is no cure – only prevention.
Occasionally, house plants may be infected with virus diseases. Spotted wilt (a brown streaking of stems and leaves) often attacks amaryllis, begonia, geranium and gloxinia; mosaic (yellow and green mottling of leaves), coleus and geranium; and ring spot (rings of yellow tissue on leaves), camellia and peperonia.
However, in many instances, leaf spots, leaf blights (browning and drying up of leaves), leaf discoloration and failure of plants to grow or bloom may be caused not by viruses, bacteria, fungi (or pests) but rather by nutritional or environmental conditions. In fact, the symptoms just named are the most common protest signs of plants growing under unfavorable conditions.
Flower and bud blights caused by fungi occur only under damp conditions and are not common in house plants. But bud blast (dropping of buds) and lack of flowering may be due to improper environment or nutrition.
Knowing and meeting your plants’ requirements and following the preventive measures outlined will normally insure against many of these houseplant troubles.