Tacoma Orchid Society
Tacoma Orchid Society
Tacoma Orchid Society
Tacoma Orchid Society
Tacoma Orchid Society
Tacoma Orchid Society
Tacoma Orchid Society
Tacoma Orchid Society
Tacoma Orchid Society
Tacoma Orchid Society
Tacoma Orchid Society
Tacoma Orchid Society
Tacoma Orchid Society

Orchid Pets and Diseases


General Prevention Methods
Orchids don't usually have problems with insects and diseases when they are provided with the proper amount of light, water and air movement. Sterilize the cutting instruments you use in your orchids in between each plant. Only use an insecticide labeled for ornamental plants. When using oils, soaps and insecticides, be thorough, change formulation and do not use the minimum concentration of mixture. Never use chemicals prophylactically. Isolate a new orchid for at least two weeks. Checking your orchid plants regularly for the following insects and diseases may prevent a serious outbreak:

Aphids
Aphids are insects that may be green, black or brown with pear-shaped bodies. They form colonies or clumps on the undersides of the leaves and particularly on new growth. They reproduce rapidly.

Methods of Control:
  1. Touch the insect with a cotton swab soaked in rubbing alcohol.
  2. Use Neem Oil by Dyna-Grow.
  3. Strong mint tea sprayed onto the plant. 1 part mint to 4 parts water steeped and strained.
  4. Lady bugs.


White Flies
White flies are insects that look triangular and have a white body. You can find them on the under sides of the leaves or in swarms around the plant when it is disturbed.

Methods of Control:
  1. Use yellow sticky traps.
  2. Use Neem Oil by Dyna-Grow.
  3. Remove and destroy all leaves that have more than 50% damage.


Spider Mites
Spider Mites are very tiny insects that can only be seen with a magnifying glass. They are the most difficult to eradicate. The leaves may curl or drop and the growth may be stunted. Look for the webs and rust colored specks on the undersides of leaves. There are two kinds of spider mites, the false spider mite and the red spider mite. The red spider mite is the most common.

Methods of Control:
  1. Quarantine the plant that is infested!
  2. Spray the plant with rhubarb tea.
  3. Alcohol spray: 4 parts water to 3 parts rubbing alcohol.


Mealy Bugs
Mealy bugs are insects that are white and hairy looking. They move and mature very slowly. They live in colonies and stems of joints. They suck fluid from the plant, which causes pale foliage, leaf drop and stunted growth. Mealy bugs also carry fungus and diseases.

Methods of Control:
  1. Manual removal works well if there are just a few.
  2. Touch the insect with a Q-tip soaked in rubbing alcohol.
  3. Insecticidal soaps kill mealy bugs in a day or two.


Scale
Scale is an insect that may be white, yellow, brown, gray or black. The mature female scale are typical rounded and light colored while the males are have a cottony appearance. It looks like a hard-shelled lump on the stems and leaves. It is so tightly attached that it sometimes appears to be a part of the plant. The Foliage will turn yellow and the leaves will drop.

Methods of Control:
  1. Quarantine the plant that is infested!
  2. Manual removal works well for small populations. Use a knife to scrape them off.
  3. Touch the insect with a Q-tip soaked in rubbing alcohol.
  4. Insecticidal soaps kill scale in a day or two. Spray the plant at ten day intervals.
  5. Alcohol spray: 4 parts water to 3 parts rubbing alcohol.
  6. Regardless of the method or chemical used, you must remain vigilant and expect to make at least 2-3 applications ten days apart.
  7. An extreme infestation will require replacing the potting material. The potting material can contain scale eggs. This potting material will need to be destroyed.


Slugs and Snails
Slugs and snails are molluscs and if you live in the Pacific Northwest you know these guys. If you grow you orchids in a green house or outdoors during the summers you will have these unwanted visitors. They will eat the newly planted seedlings or the new growth over night.

Methods of Control:
  1. Manual removal of slugs and snails.
  2. Tray of Beer near the plants.


Brown Spot
This disease is caused by the bacterium Pseudomonas cattleyae. This occurs particularly in phalaenopsis and paphiopedilums. The early sign of the infection is a soft watery area on the surface of the leaf. If left untreated it will rapidly spread and turn brown.

Methods of Control:
  1. Quarantine the plant that is infested!
  2. Cut off the infected area and dust the cut surface with Orthocide.
  3. When large number of plants are infected, they should be sprayed with a solution of natriphene.
  4. All infected plants should be soaked in nathriphene or Physan for 1 hour.


Viral Diseases
No orchid grower wants to here the word virus. Symptoms will vary according to the orchids' genus and the virus. The flowers can have irregular stripes and blotches of different colors in either the petals or sepals about 1 week after opening. However, do not assume every malformed flower or marked leaf is caused by a virus.

Methods of Control:
  1. Isolate the suspected flower and watch the flowers open. If they are malformed, it is almost certain a virus.
  2. The only treatment for an infected orchid plant is to burn it.
  3. If you have any questions about this topic please contact the Tacoma Orchid Society for more information.