Pest Controls for Orchids-Part 3

By Steven A. Frowine, December 5, 2017

Editor's Note: This is the fifth of a 10 part series of articles about orchids. These articles are written by Steven Frowine, who collaborated with National Gardening Association and Wiley & Sons to produce the highly popular book Orchids for Dummies. We hope you enjoy this series of articles! 

Here are more insect controls. Refer back to earlier posts for pictures and descriptions of these creatures.


Neem is quite an effective, low toxicity insecticide that is frequently used by organic gardeners. For more info on this material go to this link:

One supplier of Neem is below:



Insecticidal Soap

Some folks use dilute liquid dish washing detergent, but be careful. Some soaps are phytotoxic (burn the leaves).


Superior or All-Seasons Horticultural Oil

DO NOT use DORMANT OIL SPRAYS on your orchids. They are a much thicker oil than the superior or all season oils and will severely damage your orchids. They are intended to be used on dormant fruit trees and outdoor ornamental plants, not actively growing plants with leaves.


If you have a particularly bad or persistently problem with these guys you might want to try Talstar.


Isopropyl alcohol

Use on cotton swab and wipe across the armored shell of this insect. Make sure that you penetrate or break the shell of this insect.


 Insecticidal Soap, Neem or Superior Horticultural Oils   See above for more details and suppliers.
This is a difficult pest to eradicate. You will have to apply controls repeatedly to get rid of it. Before I spray, I usually try to rub off the armored shells of the scale with my fingers then wash the leaf with mild soapy water. Then I spray with my chosen control.

For particularly bad infestations I have sometimes  had to resort to a stronger systemic material like Orthene (Acephate).

If you decide to use Orthene, try to purchase it in the form like the container pictured below. This material is mixed with water so will not be as harsh to the orchid leaves as an oil based is.

Spider Mites

I hate these tiny guys. It is amazing how fast they can reproduce, especially in hot, dry weather. They can do a lot of damage.

To prevent mite infestations keep your orchid properly watered and in a growing area that is not too hot.

First: Wash off with strong stream of warm soapy water.

Then spray with Insecticidal Soap and/or All Season Horticultural Oil

See above for supplier.

If  the infestation has gotten way out of hand you may need to use a stronger material like Orthene (Acephate). This can also be combined with the All Season Oil to be even more effective. Even with this material you may have to spray every 7 to 10 days for a total of three applications to wipe these guys out.

Snails and Slugs

Old beer. The yeast in beer is a strong attractant to snails and slugs. Put out a shallow platter, about ½" deep, of beer and wait for these creatures to belly up to the bar at nightfall. The next day you will find them drowned in the brew.

Another control: Put out pieces of lettuce in the evening that will attract slugs and snails. This lettuce, with attached feeding slugs, can be removed and discarded in the morning.

Sluggo® If you use baits, be sure that they are harmless to pets. Sluggo® is safe.

It is iron phosphate, which is a material commonly used in fertilizers.


Snap Traps

Good old snap traps still do the job. Peanut butter is effective bait. I do not recommend using poison baits. They could harm your pets and the mice that die from this poison frequently end up in the walls of your house and the sickening smell takes weeks to dissipate.

Live Traps

If you can't stomach the idea of killing these creatures, you can use live traps and release them into your neighbor's yard. Just kidding. Unless, you really don't like your neighbors.

Of course, a cat is also a possibility!


Roach aerosol sprays can ONLY be used on the floor, NOT directly on plants. The oil carrier in these aerosols can severely damage your orchid's leaves.

Orange Oil both repels and kills roaches. And it smells good!

Also, a light dusting of Boric Acid works and is safe and odorless.

Fungus Gnats and other insect buried in the orchid media.

For any pests that are in the potting media, like fungus gnats, a simple, safe and effective control is to drown the buggers by submerging the pot and media for an hour or so in water. Before dunking the pot in the water, wrap the top of it with a cloth to prevent the bark or other potting media from floating out of the container when submerged.

General Info Chemical Controls

Many of the chemical controls for insects and diseases can damage the plants to which they are applied if misused. To be on the safe side, always read the pesticide label to see if orchids are listed as a plant that this chemical should not be used upon. And when applying the pesticide, never use more than the dosage recommended. Apply it in the cool of the early morning and make sure that the potting media is damp. Pesticides can much more easily damage a moisture stressed orchid.
To find more technical information on orchid pests and their controls, I highly recommend the excellent booklet published by the American Orchid Society titled Orchid Pest and Diseases.

Some Pesticide Notes and Reminders

  1. Don't spray household aerosol insect controls, such as those designed for killing ants, roaches, and wasps on your orchid plants. These are intended to be used to kill insects outdoors and in the kitchen, and contain petroleum distillates that if sprayed directly on your orchid plants, can cause serious plant tissue damage.

  2. All horticultural oils are not the same. Use the ones called "superior" oils; do not use dormant oils. The superior oils are much thinner and more refined and are meant to be used when the plants are actively growing.

  3. Respond quickly to signs of insect problems. Miniature plants have small leaf areas so can very quickly become infested and seriously damaged.

  4. Apply the chemical where the bugs are---usually under the leaves and on new growth.

  5. In most cases repeated sprays will be necessary to gain control of the pest—usually once every 7 to 10 days for a total of three to four sprayings. The reason for this is that many of the eggs of the insects are resistant to the sprays used so will hatch out after spraying.

  6. Always use the least poisonous solution. Read the label and it will tell you its relative toxicity. These are the signal words to look for on the label and are in order from the least to most toxic.


means the pesticide product is slightly toxic if eaten, absorbed through the skin, inhaled, or it causes slight eye or skin irritation. 


indicates the pesticide product is moderately toxic if eaten, absorbed through the skin, inhaled, or it causes moderate eye or skin irritation.


means that the pesticide product is highly toxic by at least one route of exposure. It may be corrosive, causing irreversible damage to the skin or eyes. Alternatively, it may be highly toxic if eaten, absorbed through the skin, or inhaled. If this is the case, then the word "POISON" must also be included in red letters on the front panel of the product label.

You should not have to use any material more toxic than "Warning" and try first those that only have a "Caution" signal word.

For the next article we will switch gears and talk about Lady's Slippers!

This useful reference, Orchids for Dummies, which has been popular for both beginner and experienced orchid lovers, is available on and in book stores around the country.

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Comments and discussion:
Thread Title Last Reply Replies
Ground Squirrel Deterrent? by AbiWoodbridg Jan 19, 2019 10:26 PM 0
Controlling mealy bugs on orchids by sam739is Jan 19, 2019 12:12 PM 0
Untitled by ctcarol Jan 11, 2019 8:59 PM 0
No Neem please ! by CarolineScott Dec 7, 2017 10:56 AM 0
Great Advice by ctcarol Dec 5, 2017 8:00 PM 2

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