Diseases in houseplants can be controlled with preventative measures, since houseplants grown under ideal conditions are not as likely to develop or contract a disease. A plant that shows signs of a disease is easy to treat when action is taken promptly. Knowing the symptoms and monitoring the plants will assist with regulating problems and disease.
Fungal diseases in houseplants include fungal leaf spots, root and stem rot and powdery mildew. A fungal infection produces brown spots with a yellow edge on the leaf. Plant tissue that dies presents small black dots. To treat, remove infected areas of the plant.
Root and stem rot in a plant produces a black ring around the base of the plant, eventually causing wilting. The root becomes soft in texture. Treatment of rot requires removing infected root sections and re-potting the remaining plant in sterilized soil.
Powdery mildew is a fungus that produces a white powder appearance and brown spots on the leaf. Treatment requires removal of infected leaves.
A bacterial leaf spot infection presents water spots with a yellow ring on the leaf and oozes a sticky substance. The spots merge under wet conditions and turn reddish brown under dry conditions. Treat a bacterial infection by removing infected areas of the plant.
Environmental Induced Disease
Oedema, or corky scab, results when a plant receives excess water under poor lighting conditions, most commonly during the winter. The leaves turn yellow and fall from the plant when the disease is present. Re-potting the plant to improve drainage and supplying the proper light will control the condition.
Viral diseases do not present single symptoms for diagnosis. Associated symptoms include deformed leaves and buds, stunted growth and white-colored streaks on the flowers. The leaves develop yellow spots in some cases. Insects are the main carrier of viral diseases. A viral disease is not curable and the plant should be disposed of. Disinfect the pot if it is being reused.
Prevention practices control houseplants diseases. Always clean and disinfect pots and planting utensils before use with a solution of nine parts water to one part bleach. Cleaning prevents spreading the disease to new plants. Carefully water plants and monitor the soil saturation levels. Water by submerging the bottom of the pot in water to prevent splashing on the leaves or getting them wet. Prune houseplants to provide air circulation and prevent fungus growth.