A giant soft scale species known as tuliptree scale can infest landscape trees such as poplar, magnolia, and tulip poplar.
As female tuliptree scales develop, they grow spherical and can give the appearance of warts on limbs. They also attract black sooty mold and produce a lot of honeydew.
To reduce immature scales that overwinter, you can use a dormant oil in the winter. To control crawlers when they emerge, you can apply a targeted pesticide spray. Or, you can use a systemic solution.
There have been reports of tuliptree scale attacking poplar, linden, redbud, and magnolia trees.
Scale insects are “sucking pests,” which means they siphon plant juices with a mouth resembling a needle. Scales from tuliptrees belong to the “soft scale group,” which means they don’t make a waxy covering for their bodies. It is well known that soft scales can generate a lot of honeydew. These insects likewise excrete this sugar water-like fluid in their feces because they process and eat sugary sap all day long. Shiny and sticky honeydew accumulations can attract the black sooty mold fungus, which consumes honeydew and can blanket branches and trunks. In addition to causing twig dieback and canopy thinning, scale feeding can also do so.
A 3/8″ long mature female tuliptree scale might be grey, yellow, orange, pink, or black in hue. This species’ immature scales are noticeably black in hue. These soft scales will likewise be slightly spherical in shape, with a raised profile. Because of this, tuliptree scale infestations frequently cause the tree’s twigs to seem warty and rough.
Immature scales from tuliptrees overwinter. The year following their birth, these immature scales will start eating again and continuing to grow until the summer. Males develop into winged insects that mate with motionless females as they get older. Up to 3000 new scales can be produced by each female tuliptree scale. Around August, the eggs begin to hatch, and the young crawlers either remain on the same tree as their parents or may be scattered by birds or the wind. Before overwintering, the young generation will eat briefly. Every year, there is one generation.
Scales frequently flourish on stressed plants. Plant health will be aided by adhering to the specified watering and fertility schedules. But excessive fertilization encourages scale accumulation. If possible, make improvements to plant locations to lower stress and encourage development. You can cut out individual infestations to try to solve the problem, or you can cut out specific areas of a larger issue to make chemical management more practical.
When managing scales, there are two pesticide options: treating the crawlers directly or administering a systemic treatment. Regardless of your decision, management may require several growing seasons of repeated treatments.
You can apply a systemic treatment of imidacloprid (Bayer Tree & Shrub is one potential brand name) or dinotefuran to combat soft scale species like the tuliptree scale (Orthro Tree & Shrub is one possible trade name). You can have control without having to rely on broad-spectrum sprays on the plant thanks to a systemic pesticide. This makes it easier to ensure that the product will harm the pests you are trying to control and keeps insecticide residues inside the plant you want to protect. When deciding to employ a systemic product, timing is crucial. An application submitted in the spring (April–May) ought to give 12 months of management.
The stage of a scale insect’s life that is most vulnerable to control is when it is a crawler. You must keep an eye out for the crawlers’ emergence in order to cure them. In August, you can visually look for tuliptreescale crawlers. The crawlers can also be treated after the initial discovery by placing pieces of double-sided or black electrical tape (sticky side out) next to scale concentrations.
Horticultural oils can kill an insect by suffocating it or by getting inside of its overwintering stages. As a result, they might not work in areas where multiple scale layers have built up. Long chain fatty acids found in insecticidal soaps directly kill vulnerable insects when they come into touch with them. Similar to horticultural oils, they demand full protection. Since soap doesn’t leave a residue, some bugs can require many treatments. Check the package for information on the plant species you intend to treat as these treatments may burn the leaf of delicate plants, such as Japanese maple.
Products used on trees during their dormant season are known as dormant oils. They will burn the plant and kill bugs if they are applied to green plant tissue. On keep the nymphs under control, dormant oils can be put to tuliptree scales in the winter.
Scale crawlers can be controlled on landscaping trees and shrubs by spraying a variety of natural and synthetic insecticides. Although these compounds often have a longer residual life than oils and soaps, the timing, coverage, and safety measures regarding damage to particular plant species are quite similar to those for oils and soaps.
There are a few things to look for in order to determine whether control measures were successful or not.
When crushed, live scales should “bleed” when squashed; dead scales won’t be wet and won’t.
Once the scale weight has been lifted, the new leaves should appear healthier. When compared to when the plant was infested, buds should open a little quicker, and the enlarged leaves should have normal color and turgor.
CAUTION! This publication’s pesticide recommendations are only authorized for use in Kentucky, USA. Some goods’ use might not be permitted in your state or nation. Before applying any pesticide indicated in this publication, kindly check with your local county agent or regulatory official.
Of course, FOR SAFE USE OF ANY PESTICIDE, ALWAYS READ AND FOLLOW THE LABEL INSTRUCTIONS!
How do you get tree scales off?
Using a flat blade to scrape or pluck the insects off by hand is one method of removing scale from your trees. To remove the scales, place the blade lightly on the branch and draw it over them. To catch the insects and get rid of them later, you can wrap plastic around the tree’s base.
How do you get rid of scale on plants for good?
Since most insecticides are rendered ineffective by scale’s protective layer, treating it can be challenging. The best way to control infestations is through natural or mechanical controls. Try the following techniques if scale insects are present:
Monitor:
Keep an eye out for scale on your plants since once the soft or hard shell has formed, no insecticide will work. When the insects are most vulnerable, in the spring, watch for the initial crawler stage; cleanse the area before applying a spray.
Use water:
Use a mild hose blast to loosen eggs, nymphs, or adults from small infestations. To kill them, dispose of in a bucket of soapy water. Those stems or leaves that have sooty mold should be cleaned.
Use natural predators:
Scale-eating insects provide organic pest control. These include ladybugs, soldier beetles, parasitic wasps, and lacewings. Create habitat to draw and maintain these insects. You can order beneficial insects online or at your local garden center.
Apply horticultural oil:
Neem oil, an organic horticultural oil, works on eggs, nymphs, and adults because it coats and suffocates the insects. Don’t forget to adequately cover the entire plant. Applying oil in the spring before leaves appear will help control insects and overwintering eggs. Multiple applications can be required. Carefully follow the directions since some plants could be sensitive and because applying oils requires a specific range of temperature.
Use insecticidal soap:
Use a store-bought insecticidal soap or make your own. The crawler stage, before the scale develops its protective layer, is when this therapy is most effective. Multiple applications can be required.
How can I get rid of an infestation of large scales?
There are several strategies to manage scale insects in the garden, but the best ones involve preventive or eliminating contaminated plant material before the insects can spread. Even though you might not need to take all of these actions, you could need to combine them in order to get rid of a scale bug infestation.
Prune
If you find the infection when it is still little, pruning diseased branches is frequently the simplest and safest solution. Make sure you have removed all infected stems by carefully inspecting the plant and any nearby plants. Infected plant debris should not be composted; instead, it should be bagged and properly burned or disposed of in the trash.
Treat With Rubbing Alcohol
If there is a light infestation of scale insects, rubbing alcohol can destroy them. The best strategy is to use a cotton swab to apply the rubbing alcohol directly on the scale bugs. However, doing this in an outside garden can be quite time-consuming. As a result, you can also prepare a solution of one part rubbing alcohol to seven parts water and put it in a garden sprayer or spray bottle.
What is horticultural oil?
Most horticultural oils are petroleum-based mineral oils, while some vegetable oils, such cottonseed and soybean oils, also have pest-repelling properties. In order to make oil easier to spray, it is typically emulsified.
Spraying horticultural oil on your plants in the late spring, right before the leaves emerge, is useful. Scale insects have the ability to hibernate as nymphs or eggs hidden in tree bark.
At this stage, spray your plants using a garden sprayer or hose-end sprayer that is loaded with 2 to 5 ounces of oil per gallon of water. The scale will be smothered by this application before the insects can develop their protective coating.
Scale can be found on stems, the undersides of leaves, and along the base of the plant, thus it’s crucial to treat the entire plant. The scale insects are suffocated by the oil, which coats them and obstructs their breathing pores.
Apply Insecticidal Soap
Scale can be killed using insecticidal soaps while they are still larval, but once the insects are attached and foraging inside their protective shells, they are less effective. Use a garden sprayer or spray bottle to apply until all of the leaves are dripping.
Follow the instructions on the container to be sure, but generally speaking, 1 ounce of soap to 1 gallon of water is a reasonable ratio.
These soaps don’t withstand the weather for very long, so multiple applications will be necessary to catch all the larvae, but these organic insecticides won’t leave a risky environmental impact.
Warning
Apply insecticidal soaps only to well-hydrated plants to avoid hurting them. Never use the product on plants that are exposed to direct sunlight or when it is hotter than 90 degrees Fahrenheit.
Apply Neem Oil
Neem oil and other insecticides containing azadirachtin, a fundamental component of neem oil, provide great defense against scale and kill adult insects as well as merely larvae.
Neem oil and water don’t mix well, so you’ll need to add some dish soap to serve as an emulsifier. As a general rule, add 1 to 2 teaspoons of oil and 1 to 2 tablespoons of detergent to each gallon of water. Use a garden sprayer to apply.
Since honey bees and the majority of other helpful insects are not poisonous, neem oil and other treatments containing azadirachtin are recognized as organic insecticides. It is possible for other plant-based insecticides to be effective.
Use Beneficial Insects
Scale insects can be effectively controlled by beneficial insects including lady beetles, soldier beetles, and parasitic wasps. By giving these natural predators food and shelter, you can encourage them. Additionally, you can order helpful insects via mail to release in your garden.
In the fight against scale, synthetic chemical pesticides ought to be the absolute last option. Neoicotinoids (acetamiprid, dinotefuran, imidacloprid, and thiamethoxam), which are present in systemic insecticides and can be used with some success, are increasingly recognized as a severe threat to honey bees and other pollinators. A chemical pesticide should only be used when all other options have failed.
Controlling Scale on Indoor Plants
Scale insects will proliferate even more quickly indoors than they do outdoors because there are no natural predators there. When scale infests indoor plants, you will need to be incredibly meticulous about controlling or removing it.
Pruning out the infected stems could solve the issue if you find it early enough. For a few weeks, keep a close eye on the plant to make sure no new scales develop. Throw away the pruned stems right away.
Gently brush existing scale off of indoor plants using a cotton swab or facial-quality sponge coated in rubbing alcohol. The scale should be killed by the alcohol on its own, but the dead insects will stay on your plants and make it challenging for you to look for fresh infestations. The small facial sponges in the cosmetics section are small and soft enough to use without damaging the plant stems, but they are abrasive. Make sure to choose plain sponges free of lotion or cleansers. A limited area should always be tested first because certain plants are more sensitive than others.
Can you remove scale?
These sap-sucking bugs cling to host plants’ twigs, leaves, branches, and fruits. Learn about the least-toxic ways to control the scale here.
Over 1,000 species of scale insects are found in North America, and they are frequently seen on houseplants, ornamental shrubs, backyard trees, and greenhouse plants. They are so strangely formed, stationary pests that they frequently resemble bumps, not insects. In many instances, severe infestations develop undetected before plants start to experience damage. It’s possible for large populations to cause poor growth, diminished vigor, and chlorotic (yellowed) leaves. A host that has been infected could die if the infestation is not stopped.
Identification
There are two categories of scale insects:
Armored (Hard)
secrete a tough, non-body-attached coating (1/8 inch long) to protect themselves. Under this spherical armor, the hard scale feeds and lives, but it does not move around the plant. No honeydew is secreted by them.
A waxy film, up to 1/2 inch long, that is a component of the body is called SoftSecrete. They frequently have the ability to travel small distances (though they do so infrequently) and make a ton of honeydew. Soft scales can be flat or nearly spherical in form.
Life Cycle
Under their protective covering, adult females lay eggs that take one to three weeks to hatch. The newly hatched nymphs (known as crawlers) emerge from this covering and travel around the plant until they find an appropriate eating place. Young nymphs pierce the plant with their mouthparts and start to feed. As they get older and become immovable adults, they eventually construct their own armor. They do not pupate and, especially in greenhouses, may have numerous overlapping generations per year.
It should be noted that many species’ males grow wings as adults and resemble little gnat-like insects. They don’t eat vegetation and are rarely spotted. Females frequently procreate without sex.
Control
- Pruning and discarding infected branches, twigs, and leaves will help get rid of scale insects.
- When scale counts are low, they can be manually rubbed or plucked from plants.
- When infestations are mild, dabbing individual pests with a cotton swab dipped in alcohol or a leaf shine containing neem will also work.
- Ladybugs and lacewings, two helpful insects that are sold commercially, are predators of the immature larval or “crawler stage.”
- The larvae can also be eliminated with natural insecticides such as d-Limonene and insecticidal soap. The environment does not retain these compounds very well, thus many treatments throughout egg hatching will be necessary for efficient control.
- The main insecticidal component of neem oil, azadirachtin, may be found in Azamax. With its numerous modes of action and organic approval, this concentrated spray essentially eliminates the possibility of pest resistance growing. The best part is that it doesn’t harm honey bees or many other useful insects.
- All pest life phases, including adults that are shielded from most other pesticides by their armor coats, are controlled with horticultural oils and other safe, oil-based insecticides.
- As a last option, quick-acting natural pesticides should be utilized. These natural insecticides, which are derived from plants with insecticidal qualities, have less negative side effects than synthetic chemicals and degrade more quickly in the environment.
Advice: Ants will defend these pests from their natural predators and eat on the honeydew that sucking insects produce. To naturally get rid of ants, apply Tanglefoot Pest Barrier to the trunks of trees or the stalks of woody plants.