Orchids are very fascinating and growing orchids can be rewarding. Providing optimum growing conditions make for healthy orchids which are also resistant to diseases. But even healthy orchids get infected by pests and suffer from various diseases. Some of the common orchid
diseases are listed below.
1. Bacterial Leaf Rot – This disease appears as a discoloration and is noted as a spot on the leaf. The spot grows with time and has irregular borders. The infected part turns grey and softens. The remedy for this disease can be cutting the leaf with a sterile instrument or blade and treating the better edge with a bactericidal solution. Sprinkling cinnamon on the leaves is also effective.
2. Bacterial Crown Rot – This disease is similar to leaf rot but affects the uppermost leaves (crown). The remedy can be removal of the infected uppermost leaves and spraying the open area with bactericidal solution.
3. Bacterial Root Rot – This disease manifests in the form of shriveling of the lower leaves. This can be caused by over watering and is a common disease. The remedy can be repotting the plants which will show dark and soft roots. These roots can be removed and the plant repotted followed by less frequent watering.
4. Petal Blight – The flowers develop spots due to fungal infection. This is most often caused by collection and retention of water on the petals. The remedy includes application of fungicide, removal of infected flowers, decreasing humidity levels and increasing the air circulation.
5. Black Rot – The fungal disease blackens plant parts and makes them watery. The disease can be controlled if only the leaf is affected. The leaf should be removed using a sterile cutting tool and the plant treated with a fungicide. The treatment should be repeated until the infection is under control.
6. Basal Rot – This is also known as ‘Southern Blight’ and is often caused due to over watering. The disease starts at the base of the plant and proceeds upward. The disease can be treated if discovered in the early stages. The afflicted part should be cut and the wound treated with sulphur.
7. Botrytis – The fungal disease mainly affects the flowers of phalaenopsis, cattleya, cymbidium and dendrobium. The disease occurs due to poor air circulation and moist conditions. Tiny black spots appear on the petals which grow in size and can even get covered with a grey mold in later stages. Fungicides can be used to fight the disease along with increasing night time temperatures and providing better air circulation.
8. Phalaenopsis Bud Blast – This makes the plant produce buds that do not develop completely and turn yellow or drop off. This is usually caused due to root rot, over fertilizing and watering associated problems.
9. Brown Wet Spot – The bacterial infection commonly occurs in phalaenopsis and is caused by Pseudomonas cattleyae. Plants develop brown-black, soft areas under the leaves, which later travel to the surface as well. It is generally caused by cool temperatures, high humidity and poor air circulation or a combination of all. If the disease is caught early, the infected leaves can be cut with a sterile blade and dusted with sulphur or a fungicide.
10. Orchid Virus – This is a dreaded disease since it can’t be identified in the early stages. The virus kills leaf cells making the plant prone to various other bacterial infections. The orchids can develop black spots on the leaves but appear normal otherwise. There is no definite cure for the disease but it can be prevented by providing suitable growth conditions.
Maintaining clean growing conditions along with frequent inspection for diseases can keep the plants healthy.
