Orchid Pests, Diseases, and Cultural Issues

It can be heartbreaking to watch helplessly as long-awaited orchid buds brown, die and drop instead of becoming those much-anticipated flowers. Bud blast, when buds wither and fall from an otherwise healthy plant, may occur through any of a number of causes. Buds are the most sensitive part of an orchid, and are easily affected by unsuitable conditions in the growing environment. Cattleyas, Phalaenopsis and Dendrobiums seem particularly susceptible to this problem. The most frequent reasons for this are as follows.

Blister like swellings on leaves, which can be green to brown, becoming corky with time.

Nutrient deficiencies can be diagnosed by leaf symptoms, from general chlorosis (nitrogen), necrotic damage to newly forming growths (calcium) and magnesium (excessive leaf yellowing on older leaves).

Excess salts in water supplies and excess fertilizer applications can result in salt toxicity, often manifested by black leaf tips.

Your hands, cutting tools and repotting surfaces can all be contaminated by orchid disease organisms and viruses so proper sanitation is required to prevent their spread.

Many growers summer their orchids outdoors to take advantage of the sun and fresh air unavailable to them inside a greenhouse or home. Before bringing plants back inside their winter growing area, check them thoroughly for hitchhikers — plant and insect pests that may ride into the growing area on the returning plants.