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How To Treat Scales On Plumeria

If you're wondering how to effectively treat your plumeria plant infested with scales, we researched and looked for ways to treat them, and here is what we gathered. 

There are several ways to treat scale infestation. You can: 

  • Manually remove scales from the stem with your fingernails or a soft toothbrush.
  • Use a cotton swab dipped in rubbing alcohol and rub it over the white sticky patch to kill insects hiding behind their outer covering.
  • Scrape off the topsoil and treat the remaining soil with an insecticide. 
  • Spray neem oil or insecticidal soap from the top to the bottom parts of your plant then use paper towels to clean the leaves. 

Keep reading as we discuss how to spot scales on your plumeria plant and the signs of infestation in the next sections. Additionally, we'll cover the types of scales that may attack your plumeria plant, what chemicals to use to effectively remove them, and more.

How To Spot Scales In Your Plumeria Plant?

frangipani flowers are charming with their white color

Scale insects are distinctive and don't initially look like other insects. The term comes from the fact that adult females are stationary and have a waxy coating that mimics a fish or reptile scale. 

Scales can be any color, shape, or size, but they most frequently take the form of small, brown, spherical lumps on the leaves and stems of your plant.

What Are The Two Scale Groups That May Infest On Your Plants?

Scales can be classified as armored or soft-shelled. 

Armored (Hard) Scales

Macro Photography of Scale Insect - Coccidae on Green Leaf

Here are some characteristics of armored scales you should know:

  • Once they start feeding, armored scales normally don't move and don't make honeydew.
  • This type is usually microscopic and unnoticeable. They are typically just 1/16" - 1/8" in length.
  • Since the protective covers frequently look like plant bark, populations may grow significantly before being discovered or a plant exhibiting obvious damage.

Soft-Shelled Scales

Scale insects (Coccidae) on a magnolia in the garden

On the other hand, this is how you can identify soft-shelled scales:

  • A waxy coating is secreted by delicate scales to protect them from the environment. Additionally excreting sweet honeydew, soft scales can travel from branches to leaves throughout their entire cycle.
  • When fully grown, these scales are 1/8" - 1/4" (some can grow up to 1/2") in length, dome-shaped, and spherical to oval. Soft-shelled scales that are still developing eventually turn darker in color.
  • They are typically found under the leaves and on the stems of plants. 
  • Soft-shelled scales are also easier to kill compared to armored scales. 

What Are The Signs That Your Plumeria Plant Is Infested With Scales?

A plant with scale infestations will have slimy drips on its leaves. This fluid produced by aphids, mealybugs, and scale is known as honeydew.

Although honeydew doesn't harm plants in and of itself, the increased humidity it causes around the leaves and stems can lead to fungal issues.

However, be careful when scraping off the scales from your plumeria leaves since it can trigger the release of large amounts of honeydew which causes a sticky slime to form on the leaves of the plant and promotes bacterial and fungal illness.

The presence of ants is also an indication that your plumeria is infested with scales. 

Another sign of scale infestation is the curling and falling off of plumeria leaves. This happens because scales directly suck the sap from the stems and veins of the plant. 

When present in large populations, several species of scale damage plants and limit their growth. Plant sections that are highly affected may perish and infested plants usually look water-stressed.

When Is The Best Time To Treat Scales

The best time to apply narrow-range oil or insecticides to effectively control scales is during the dormant season or in late winter to early summer when scale crawlers become active. 

Additionally, you can use a systemic pesticide to treat some scale issues on large plants and other hosts that are particularly vulnerable to scale damage. 

However, always remember to apply insecticides at night or when the plant is out of direct sunlight. Failure to do so can lead to the burning of your plant. 

What Can Use To Treat Scales?

Unrecognizable female orangery worker taking care of plants spraying leaves with fresh water

There are three types of treatment chemicals you can apply to get rid of scale from your plants. These are horticultural oil sprays, systemic insecticides, and contact insecticides. 

Horticultural Oil Sprays

This is the most secure and efficient method of controlling scale. The oil covers the scale bugs and blocks their respiration holes when combined and applied to an infected plant.

Rather than being destroyed by a harmful substance, the insects suffocate. Oils put to egg masses similarly prevent oxygen intake and reduce the likelihood of successful hatching.

If at all feasible, time spraying to match with the scale crawler period, when all insecticides are most effective.

Horticultural oils are normally used by the majority of landscaping professionals from late fall to early spring, usually when the temperature is between 45 and 85 degrees Fahrenheit and the relative humidity is below 90%.

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Systemic Insecticides

Systemic pesticides are another control method. These pesticides are applied externally to the plant's trunks or roots and then internalized to the leaves and other sections of the plant.

These are often used when the temperature is not ideal for horticultural oil spray. 

Use a trunk spray or a soil treatment when dispensing systemic pesticide wherever possible. An efficient systemic pesticide applied by trunk can offer comparatively quick control. The interval between soil treatment and pesticide action is longer.

The mix-and-pour technique makes it simple to drench some household chemicals into the soil surrounding the tree trunk.

Products with dinotefuran are effective in controlling scale bugs. 

Contact Insecticides

Contact insecticides can only control scale crawlers because they are likely to rebound off the hard shell of armored scales.

Safety and timing are crucial when applying this one. For information on the safety gear and clothing that should be worn, consult the product label.

How To Properly Apply Neem Oil To Plumeria Leaves With Scales

Neem oil is an effective naturally occurring pesticide. When mixed with dish soap and water, it creates a spray that works wonders on plumerias, killing pests and preventing fungal infection.

Before a full-blown application, you must first test it on a leaf or two for 24 hours. This ensures that the mixture will not harm your plant. 

After checking that you got the right mixture, spray it from top to bottom. 

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How Often Should You Apply Neem Oil To Your Scale-Infested Plumeria?

You can apply neem oil every two weeks as a prophylactic measure. Neem oil should be applied to your plants once a week if you're attempting to control an active pest infestation.

Remember, pure neem oil shouldn't be applied straight to plumeria leaves; instead, you should dilute it or wash the oil off once it has finished working.

How Do You Separate A Scale-Infested Plumeria From Others?

Semboja (Plumeria) is a group of plants in the genus Plumeria, How To Treat Scales On Plumeria

While the injured plant heals, keep it away from the rest of your other plants for 2-3 weeks. Be very careful to make sure that none of its leaves touch those of any other plants. Once the scale bugs have stopped reproducing, repeat this treatment every 7 to 10 days.

Make sure to periodically and carefully inspect all plants as a preventative measure. Dusting leaves and checking for pests are excellent additions to regular plant upkeep.

The best course of action in cases of severe infestation or ineffective treatment may be to remove the entire plant.

Do Ants Help In Controlling The Scale Infestation On Your Plumeria?

Small black ants farming brown Scale bugs on a plant stem, Cape Town, South Africa

It's actually the other way around. Ants will defend scale insects that produce honeydew from helpful predator insects that often aid in controlling scales.

By taking care of ant problems as well, you will be better able to take care of the scale infestation.

If you want to use biological control to eliminate scales from your plumeria, you can use parasitic wasps.  The tiny wasp larvae, which resemble maggots, eat inside or on each scale where the female wasp deposits one or more eggs. 

In Summary

There are several ways to treat scale infestation on plumeria. You can manually remove them by rubbing alcohol-soaked Q-tips or scraping them with your fingernails. 

If you want a more natural approach to spraying them with insecticides, you can use horticultural oil sprays to eliminate them. Just make sure to follow the product's guidelines in applying them. 

You can also treat the trunk or soil of your plant with systemic insecticides. However, it might be best to consult an expert pesticide sprayer when you decide to use this method. 

If you enjoyed this post, you can check out our other articles here: 

What's The Best Neem Oil For Indoor Plants 

What Is The Best Soil For Plumeria?