Diagnosing Issues with Orchids Grown Indoors

Even with the best of care, issues sometimes arise when growing orchids indoors. These issues are typically caused by environmental problems, insects, or diseases.

Environmental Problems

Too Much Light

A common problem when moving them outdoors in the spring
Plants should be a light green in color. They turn yellow-green or sometimes red in too much light
Damage can progress very quickly and will eventually cause white, then brown spots that die
Provide more shade as quickly as possible when symptoms show up
Always transition orchids to new light intensities slowly to prevent leaf scald or other problems

Fertilizer Burn

Too much fertilizer can cause brown/dead root and leaf tips, yellowing of leaves, and salt build-up on the container
Prevent fertilizer burn by watering with plain water, then fertilize after the media has been thoroughly wetted
Flush media regularly and repot orchid with fresh media regularly to reduce salt/fertilizer build-up

Wrinkled or Leathery Leaves

wrinkled leaves on orchid — Wrinkled leaves and pseudobulbs and accordian folded wrinkles are all signs of insufficient water. ⁽¹⁾

Shriveled, misshapen, accordion-folded pleats, limp, and leathery leaves are all symptoms of insufficient water
Evaluate watering frequency and water more often if plants are dry for too long in between waterings. Do not overwater
Evaluate the root system and look for green or white, plump roots in growing media that are still coarse and intact. Brown, shriveled roots are an indication of potential root rot. Rooting media that is compacted or broken into smaller pieces is likely holding too much water promoting root rot. Raise humidity and repot the orchid in fresh media

Insect Issues

Aphids

Common pests that can cause discoloration, distorted growth, and sticky honeydew
Prevention is important – don’t bring in infested plants and isolate them immediately when you see them
Control with a good cleaning, soapy water, insecticidal soap, and/or Neem

Mites

Common in dry conditions
Causes mottled foliage and heavy infestations will have fine silk webbing
Control by regularly wetting/washing foliage and raising the humidity

Scale and Mealybug

mealybug on orchid — Cottony masses with sticky honeydew underneath are both signs of mealybug infestation. ⁽²⁾

Very difficult to control, mealybug is often hiding in the media as well
Infestations should be dealt with swiftly and quickly when first noticed
Cleaning (with rubbing alcohol) can be a good start, follow up with several rounds of insecticides such as Neem, horticultural oil, or insecticidal soap
Persistence is key to control
Toss heavily infected plants to reduce the potential of infecting other plants

Ants

The moist, well-drained media for orchids is an ideal home for ants
They often feed on the honeydew produced by aphids, scale, or mealybug
They don’t cause damage to plants, but are often a sign of another insect issue and are a nuisance
Control by dealing with the primary issue (such as aphids), repotting (and thoroughly washing container and removing the media), or by using baits or traps

Cockroaches

Often live in the media, especially if orchids spend time outside
Can cause damage to growing points and flower buds, along with being a nuisance and human health hazard.
Watch carefully for them (they are nocturnal), keep the growing area clean of leaf debris
Control by repotting or with repellents, baits, sticky traps, or insecticides

orchid with scale — Insect pests like scale can be difficult to control. ⁽³⁾

Disease Issues

Root Rot

A decay and collapse of the plant or pseudobulb near the crown
Almost always because of too much water. Let plants dry out between waterings, change the media if it holds too much water

Leaf Spots

Phyllosticta Leaf Spot

Small, elongated black/purple spots (surrounded by tan or gray) along veins of leaves
Spreads readily in low light and wet conditions
Be sure plants don’t have leaves that stay wet overnight
Remove affected leaves to prevent spores from spreading – repeated applications of fungicides can be used

Black Rot

Caused by a few different species of fungus
Moves very quickly through plants and spreads easily by splashing water to other plants
Avoid wetting leaves and have good air circulation to prevent infections
Remove all infected parts with a sterile knife
Apply a fungicide to the remaining healthy parts

Viruses

More than 25 viruses have been reported to infect orchids. The two most common orchid viruses are cymbidium mosaic virus and odontoglossum ringspot virus.

Symptoms

Virus symptoms in orchids vary by species, virus strain, and environmental conditions such as temperature and light, and infected plants may show no visible signs. Other issues like nutrient imbalance, excess salts, pests, or fungal and bacterial diseases can mimic virus symptoms. Common indicators of viral infection include yellow, brown, or black spots or lines on leaves, often sunken, as well as ringspots or mosaic patterns of yellow and green. Flowers may display brown streaks or color break, which appears as lighter line patterns, though color break can also result from genetic mutations.

Viruses spread between orchids through contaminated tools during division or harvest, via tissue culture, and by insect vectors such as aphids and thrips.

Diagnosis

Each virus does not produce characteristic symptoms on orchids. This makes a precise visual diagnosis virtually impossible. While ringspots or sunken brown spots may suggest a virus, confirmation requires testing. Common diagnostic methods include serology, plant bioassays, and electron microscopy. ELISA test kits, based on serology, are commercially available and can be used by growers or through testing services. Bioassays involve inoculating indicator plants with sap from suspect orchids and observing symptoms, while electron microscopy reveals virus particles but requires specialized training and equipment. These tests can be performed in plant diagnostic labs for a small fee.

Control

Orchid viruses cannot be cured, so infected plants should be discarded, as there are no chemical controls available. Preventing spread is critical and requires strict sanitation. Sterilize tools by dipping them in alcohol or using a 10% bleach solution. Purchase virus-free plants from reputable growers who test their stock and control aphid and thrip infestations to reduce the risk of transmission.

More Information

Photo credits: 1: Aaron Steil; 2: Aaron Steil; 3: Aaron Steil

Authors:

Aaron Steil

Last reviewed:

January 2026