Orchid Pests Control
Southern Ontario Orchid Society‘s March meeting was full of helpful and practical information for orchid growers. Orchid pests control: symptoms, and treatment options for orchid pests! Last summer, my oncidium’s three flower spikes were eaten by slug. By the time I realized it was slug, I was able to save half of the last flower spike. So, this topic was a very much needed knowledge for this summer.
Here are a list of available pest control treatments:
1. Horticultural oil – contains 97% mineral oil, and it’s fast working and effective
2. Neem oil
3. Organophosphate – it kills all bugs, good and bad; and it has 48 hours no enter if used in greenhouse. It should be used as last resort.
4. Pyrethrum – contact insecticide; once it’s dry, there’s no harm
5. Sulphur – use it every 7 days; it lowers pH level, and destroys eggs
6. Silicon Dioxide – organic solution to control insects, no harm to pets, fish, and animals. It controls slugs and snails
7. Insecticidal soap – kills bugs by dehydration
8. Yellow sticky traps – attract mature adults so that no eggs will be reproduced
| Pest | Best Treatment |
| Aphids | Insecticidal soap Shower the plants with cold water in summer outdoor |
| Mealybugs | Horticultural/Neem oil is the best Repeat 3 times Ladybug is effective |
| Thrip | Use insecticidal soap, and horticultural/neem oil spray every 7 days |
| Scale | Horticultural/Neem oil for adults Insecticidal soap when they are small |
| Spider mite | Sulphur powder mix with water at 1 tbsp + 1 litre of water to spray Lower temperature by 5 degrees/increase humidity by 5-10% because they like hot and dry Pyrethrum based spray (Trounce) |
| Slugs | Beer for slugs Damp newspaper for earwigs |
| Fungus gnat | Adult has no harm to orchid, sticky trap is the best |
It’s recommended that you keep track of the application date, and change to a different type of spray after 3 applications because insects tend to develop resistance to the first type of spray you’ve used. Last but not least, if you try all methods, and still no sign of recovery, you can try drowning the orchid in bathtub for 24 hours.
Credit: Spencer Hauck
Featured image credit: American Orchid Society
Next step up would be spraying with insecticidal soap, and if this is repeated once a week, the insects will usually be subdued. Nurseries and hardware stores sell soap sprays, but they are simple to make with this recipe: HORTICULTURAL OIL SPRAY: 1 Tablespoon vegetable oil, I teaspoon liquid soap, and 2 cups water in a spray bottle.