How to Identify the Scales on Plants
Identification of scales is the first step before you understand how to get rid of scales on plants. Scale insects are small, sap-sucking pests that often appear immobile. They look like round or oval bumps on plant stem or leaves, range from 1/16 to 1/8 inches long, and come in different colors such as brown, gray or black. Unlike other insects, scales have a hard or waxy outer shell that makes them difficult to spot as living organisms.
Types of Scale Insects:
Scale insects are divided into two main types:
Soft Scales:
These scales excrete a sticky substance called honeydew. It can attract ants and lead to sooty mold growth. Examples include the cottony cushion scale and the brown soft scale. Soft scales are typically larger and have a smooth, waxy coating. They feed directly on plant sap, which depletes the plant’s nutrients and weakens them over time.
Hard Scales (Armored Scales):
Unlike soft scales, armored scales do not produce honeydew. They have a tough, protective shell that makes them more challenging to remove. Examples include the San Jose scale and the oyster shell scale. These scales are smaller and can appear as tiny and flat disks firmly attached to the plant’s surface. They feed by inserting their styles into plant tissue, which causes severe damage to soft scales.
Signs of Scale Infestation
Identifying scale infestations early is very important. Here are some common signs that can help you spot scales on your plants:
- Sticky residue, which is the honeydew on leaves. They always appear in clusters.
- Yellowing or wilting leaves.
- Brown or black bumps on plant stems and leaves.
- Stunted growth or branch dieback.
- Sooty mold developing on honeydew deposits.
If you notice these symptoms, inspect your plants closely for scales.
What Damage Does Scale Cause
Scale insects feed on the sap of plants and deprive them of vital nutrients. This can weaken the plant by causing leaves to turn yellow, reducing the overall growth of your plant. Severe infestations can lead to branch dieback or even plant death. For fruiting plants, scales can reduce yield and quality.
When to Take Action Against Scale
The best time to act is during the crawler stage. When young scales are more vulnerable, this stage usually occurs in early spring or late summer, depending on the species. Regularly monitoring your plants for signs of scales will help you time your treatments effectively.
How to Get Rid of Scales
You can remove the scales naturally by pruning the plant or physically removing them. But, it may not completely help you get rid of the problem, and they might come back. Here are some of the effective ways by which you can get rid of them permanently:
Horticulture Oil:
Horticulture oil is a specially formulated petroleum-based or plant-derived oil used to control pests like scale insects. Horticulture oil suffocates scales by coating their bodies and blocking their breathing pores. Avoid applying horticulture oil in extreme temperatures (below 40°F or above 85°F) to prevent plant damage.
To use horticulture oil effectively -
- In a water can, mix 2 to 5 ounces of oil per water can of water to dilute the oil.
- Spray it evenly on all plant surfaces, including the upper and lower parts of leaves, stems and branches.
- Use it during the dormant or growing season, depending on the product’s recommendations.
Avoid using very young plants or those with tender leaves.
Insecticidal Soap:
Insecticidal soap works by breaking down the protective outer layer of scales. It starts dehydrating the scales, resulting in killing them. Mix one ounce of insecticidal soap with a gallon of water or check the package for directions. Use a garden hose and spray the soap solution directly on infested areas to ensure good coverage. Avoid using insecticidal soap on plants in direct sunlight or during high heat (above 90°F) to prevent leaf burn.
Use garden hand gloves while using insecticidal soap to avoid direct contact between your skin and the soap.
Organic Pesticide:
Organic pesticides are a safe and eco-friendly option for controlling scales. These products target pests while being gentle on beneficial insects and the environment. To use organic pesticides:
- Shake the bottle well before use.
- Spray directly onto the affected areas of the plant, ensuring thorough coverage.
- Repeat the application as recommended on the product label for optimal results.
- Follow all label instructions carefully to ensure effective and safe application.
Neem Oil:
Neem oil disrupts the life cycle of scales by acting as an insect growth regulator. Spray neem oil on all parts of the plant, including stems and leaves, to ensure good coverage. Apply neem oil in the evening or early morning to avoid harming beneficial insects and to prevent leaf burn in direct sunlight.
Natural methods like physical removal scales can be effective for small infestations. But they may not fully eliminate the problem. The products mentioned above provide targeted and reliable solutions for scale control. For the best results, follow the application instructions carefully. Also, these treatments should be used as part of a comprehensive plant care routine.
Controlling Scales on Indoor Plants
Indoor plants are not immune to scale infestations. Keep an eye on houseplants and isolate affected ones to prevent the spread of scales. Using the treatments above in a controlled indoor environment can help effectively manage infestations. Ensure proper ventilation and avoid overwatering. Stressed plants are more susceptible to pests and insects like scales.
Once you learn how to get rid of scale on plants, it becomes easier to spot and address them quickly and efficiently.
FAQs
1. Can scales come back after treatment?
Yes, scales can return if the infestation is not fully addressed. Regular monitoring and repeat treatments during the crawler stage can prevent re-infestation.
2. Are these treatments safe for all plants?
Always check the product label to ensure it is safe for the specific plants you are treating.
3. Can I use these products on edible plants?
Many of these products are safe for edible plants. But ensure you follow the pre-harvest interval (PHI) instructions provided on the label.
4. How do you get rid of scale on plants naturally?
Physically remove them using a soft cloth, toothbrush or cotton swab dipped in rubbing alcohol. This method works best for small infestations. Additionally, prune heavily infested branches. Ensure proper plant care to strengthen the plant’s natural defenses.