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Insect pests
| Type | Symptoms | Treatment |
|---|---|---|
| Two-spotted spider mites Tetranychus urticae |
Discoloured foliage, fine web appears. Mostly affects Cymbidium. |
See fact sheet. |
|
False spider mites or flat mites Brevipalpus russulus |
Pits on upper leaf surface. | Same treatment as for two-spotted spider mites. See fact sheet. |
| Aphids Cerataphis lataniae |
Spotted or deformed flowers or none at all. Aphids like young shoots and flower spikes. | See fact sheet. |
| Mealybugs, scale insects Pseudococcus longispinus, Diaspis boisdevalii | Powdery white mass in leaf axils; small brownish shells all over the plant. | See fact sheet. |
Diseases
| Type | Symptoms | Treatment |
|---|---|---|
| Botrytis blight Botrytis cinerea |
Black spots on flowers. | See fact sheet |
| Leaf spot Cercospora sp. / Gloeosporium sp. |
Round brown or black spots on the upper or under surface of leaves, sometimes on tips. | Improve air circulation. Wipe off any water remaining on leaves after watering. If possible, remove the worst-affected leaves. |
| Heart rot | Centre of plant turns black and rotten. Leaves pull off easily. | Destroy plant. Disinfect all tools. |
| Bacterial diseases | Slightly damp brown spots on leaf surface. Affect mostly Phalaenopsis and Paphiopedilums. | Remove infected parts. Disinfect all tools. |
| Viral diseases | Mosaic or necrotic rings on leaves, stunted growth and deterioration of the plant, mottled or streaked flowers. | No effective treatment. Destroy plant. Disinfect all tools. |
Physiological problems
| Type | Symptoms | Treatment |
|---|---|---|
| Insufficient light | Dark green leaves. Poor or no flowers. New shoots smaller. | Increase light intensity.. |
| Too much light | Yellowed leaves. Whitish burns on upper surface of leaves. Slow growth. | Decrease light intensity. |
| Insufficient water | Wilted leaves and pseudobulbs. Deformed leaves. | Increase frequency of waterings |
| Too much water | Wilted leaves and pseudobulbs. Leaves turn yellow and drop off. Roots deteriorate. | Decrease frequency of waterings, repot and remove affected parts. |
| Lack of humidity | Wilted leaves. Shrivelled leaves. | Mist leaves. Use a humidifier or place the plant on a bed of gravel in a water-filled saucer. |
| Too much humidity | Leaf spots and black spots on pseudobulbs. | Improve air circulation. Remove affected parts. |
| Sudden drop in temperature | Leaf spots, tips of leaves brown. | Protect from drafts. |
| Mineral deficiency | Yellowed leaves. Slow growth. | Fertilize properly. |
