Cymbidium orchids are a popular choice for many orchid enthusiasts, but they can be susceptible to scale infestations. Scale insects can severely damage your plants by sucking sap and leaving behind a sticky residue. Addressing a scale problem quickly and effectively is crucial for maintaining the health of your Cymbidium orchids.
Signs of Scale Infestation
Symptoms
- Soft Scale: Damages the plant by sucking sap, leaving behind a sticky excretion called honeydew.
- Hard Scale: Does not leave behind the honeydew excretion.
- Male Infestation: Appears powdery and white in large numbers.
- Female Scales: Create larger scales that protect their eggs.
Inspection
Regularly inspect your Cymbidium orchids, paying close attention to the undersides of leaves, along the stems, and in the roots and rhizomes. Early detection is key to preventing a full-blown scale infestation.
Treatment Methods
Isopropyl (Rubbing) Alcohol
- Swabbing: Use a cotton bud or ball dipped in isopropyl alcohol to swab and daub the affected areas of the plant. Avoid using other alcohols like ethanol or methanol, as they can damage plant tissues.
- Spraying: Mix a 50:50 solution of isopropyl alcohol and water, adding a few drops of mild liquid dish detergent and 1/2 to 1 teaspoon of neem oil, horticultural oil, or mineral oil. Thoroughly spray the entire plant, focusing on the midribs, veins, and leaf edges.
Horticultural Oil
Apply horticultural oil liberally to the Cymbidium orchid, ensuring all surfaces are covered. The oil works by smothering the scale insects, so any uncovered areas will not be effectively treated.
Insecticides
Use insecticides labeled for use on ornamental plants, such as Malathion or Imidacloprid. Follow the product instructions carefully.
Additional Care Tips
- Quarantine: Isolate new orchids for two weeks before adding them to your collection to prevent the spread of scale.
- Regular Inspection: Check all plants in your collection regularly for signs of scale and remove any affected specimens immediately.
- Separation: Keep your Cymbidium orchids separated and do not allow the leaves of different plants to touch each other.
- Repotting: If the infestation is severe, repot the plant in a new, clean container with fresh growing media.
Frequency of Treatment
Scale management often requires repeated treatments every 2-5 weeks, depending on the life cycle of the particular scale species affecting your Cymbidium orchids.
Precautions
- Chilling: Be cautious of rapid evaporation of alcohol, which can chill the plant tissues. Wipe away excess alcohol or avoid using it on warm days.
- Toxicity: Some common household chemicals can be toxic to humans, pets, and plants, even in diluted forms. Use caution and follow all safety instructions.
By following these steps and precautions, you can effectively treat scale infestations on your Cymbidium orchids and maintain a healthy, thriving collection.
References:
– Eva Orchids. (n.d.). Scale Insects on Orchids. Retrieved from https://www.evaorchids.co.nz/how-to-grow-your-orchids/pest-and-disease/scale-insects-on-orchids
– St. Augustine Orchid Society. (n.d.). Scale Insects on Orchids. Retrieved from https://www.staugorchidsociety.org/PDF/ScaleInsectsonOrchids.pdf
– Reddit. (2019). Outdoor cymbidium covered with scale. Salvageable or a goner? Retrieved from https://www.reddit.com/r/orchids/comments/ctp8ac/outdoor_cymbidium_covered_with_scale_salvageable/
– Orchid Tree. (2020). Pest: Scales on Orchids | How to get rid of orchid scales? | Series 8. Retrieved from https://www.orchid-tree.com/blogs/orchid-pests-and-diseases/pest-scales-on-orchids-how-to-get-rid-of-orchid-scales-series-8
– Orchid Plant Care. (n.d.). How to Get Rid of Orchid Scale. Retrieved from https://www.orchidplantcare.info/orchids-scale/