If you have never heard of scale, this refers to a common type of houseplant pest. There are actually thousands of different species of scale insects, and they can be difficult to identify or be incorrectly identified if you don't know exactly what to look for. Scale, just like any other houseplant pest, is important to try to catch early and treat quickly so that the infestation does not kill your plant or spread to other plants in your home. So, let's discuss scale on plants, how to get rid of scale on plants, what scale looks like, how to prevent scale infestations, and more!
What Is Scale on Plants?
Scale insects are part of a large and diverse group of around 8,000 different species. They are part of the Coccoidea family and are closely related to aphids, mealybugs, and whiteflies. Due to the fact that there are 8,000 different types of scale, they vary greatly in size, shape, and color. In general though, scale insects can be categorized as either hard scale or soft scale.
Hard scale, sometimes called armored scale, have a hard shell that protects them. This can make hard scale more difficult to treat, as pesticides can have a difficult time penetrating this hard outer shell. Armored scale actually become immobile once they reach maturity, fastening themselves to one spot on a plant and remaining there throughout the entirety of their lifecycle. The offspring of the adult insects are mobile and spread throughout the rest of the plant until they find a spot to attach themselves to where they also become immobile and begin to reproduce.
Soft scale, as one could imagine, do not have this protective shell. Instead, they are covered with a waxy protective coating. While this coating can repel certain pest control products, soft scale bugs are much easier to kill than armored scale. Mealybugs are actually one of the most common and well-known types of soft scale, and are not uncommon as a houseplant pest. For the purpose of this blog, we will be primarily addressing hard scale or armored scale, since this is often what people are referring to when discussing how to get rid of scale on plants.
What Does Scale Look Like on Plants?
Knowing how scale insects look is the first step in correctly identifying this houseplant pest. So, what does scale look like on plants? As we said above, they do have varying sizes and appearances due to the large number of species of this insect. Hard scale, however, are often rounded and look like a small bump on the stems or leaves of a plant. They are most often green or brown in color and are almost always spotted in clusters. It is very rare to see just one scale by itself, which can make this type of houseplant pest easier to spot. If you are unsure if a small bump or blemish on your plant is scale or not, try gently scratching at the bump. If the bump comes off, it is likely scale. If the bump does not come off, it is likely just a blemish.
How To Get Rid of Scale on Plants
Because of the shell of armored scale and the way they firmly attach themselves to the plant they are feeding on, these houseplant pests can be difficult to get rid of. Scale eggs remain under the protection of the mother's shell until they hatch and enter the "crawler stage." It is during this stage that the scale insects are most vulnerable, but this stage is short-lived. Making sure you use the right products and employ an adequate treatment schedule will be necessary if you want to successfully treat a plant that is infested with scale. So, here are the steps one should take for how to get rid of scale on plants.
How To Treat Scale on Plants
STEP 1: PROPERLY IDENTIFY THE INSECT
If you notice something out of the ordinary on your plant, the first and most important step is always to properly identify the issue. Given the above information, if you feel confident that scale has infested your plant, then move on to the next step. If you are unsure, you can do a scratch test on any questionable bumps. A single scale insect will rarely appear by itself, so also look for other clusters of insects throughout your plant, under the leaves, or down the stems. You can also send us pictures of your plant or bring your plant in for us to inspect and diagnose.
STEP 2: THOROUGHLY INSPECT YOUR PLANT
After identifying the presence of this houseplant pest on your plant, you should thoroughly inspect the entirety of your plant. It is also a good idea to thoroughly inspect any other plants that were near the infected plant just in case. If you catch scale early enough, it is not uncommon for them to be more or less confined to one area of your plant. In this case, you can prune off that branch or portion of the plant for quick and easy disposal of the pests. If it is not realistic to prune off all the infested parts of your plant, move on to treatment of the plant. Even if you do decide to prune off the infested portion of the plant, you should still treat the rest of the plant in the event that nymphs in their "crawler stage" were simply missed.
STEP 3: PURCHASE A PEST CONTROL PRODUCT
Scale must be treated with specific pest control products. Not all products will effectively kill these insects. Our two most highly recommended products are Bonide Neem Oil and Bonide All Seasons Horticultural Oil. These oils work by coating the insects and suffocating them. If you notice scale on your plants, purchase one of these pest control products from your local Garden Center in Fort Collins immediately! Systemic houseplant pest control products are also effective, poisoning the pests as soon as they feed on your plant. It is always recommended to have some of these pest control products on hand, as pests can spread quickly and immediate treatment is always ideal. There are many other different types of pest control products that are also effective at dealing with scale, so you can look into those options as well! Some of these other options include Bonide Rose Rx and Bonide Tree & Shrub Insect Control.
STEP 4: TREAT YOUR PLANT
Treatment of your plant is relatively simple. Spray down the entirety of your plant thoroughly, focusing especially on spots where scale bugs have congregated. It is also recommended to spray the surface of the soil thoroughly in the event that any juvenile scale insects have fallen into the soil. Many pest control products aimed at killing scale work immediately, killing the bugs on contact. However, even after the bugs are dead, they will remain on your plant unless you wipe them off since they attach themselves to the stems and leaves of your plant. So, after treating your plant, we recommend wiping down the leaves and stems of the plant with hydrogen peroxide until no sign of the scale infestation remains. Wiping the leaves with hydrogen peroxide will help to kill off any insects or larvae that may have somehow escaped the suffocating spray.
STEP 5: DEVELOP A TREATMENT SCHEDULE
When dealing with houseplant pests, it is always recommended to repeat treatment every couple of days for 3-4 more treatments and then to cut back to a once-per-week treatment for several weeks. This will help to ensure that any surviving insects do not have a chance to repopulate and infest your plant once again. Nothing is more discouraging than thinking you've successfully treated a houseplant pest infestation, just to see the same bugs sucking the life out of your plant another month or two down the road. After a month or two of sticking to this treatment schedule, do a thorough inspection of your plant. If no pests are visible, it is safe to say you have successfully handled the infestation. However, this does not mean that you should just leave your plant to fend for itself until the next pest comes along. Preventative maintenance is an important part of houseplant care, especially if you have a lot of houseplants!
How To Prevent Scale on Plants
While avoiding houseplant pests altogether is unlikely, there are a few things you can do to avoid serious infestations that could kill your plants, catch infestations early, and curb pests before they are able to fully infest a plant. Let's talk about how to prevent scale on plants.
Be Aware Of Your Plants and Inspect Them Regularly
Awareness is key! Houseplant pests are usually small and disguise themselves to blend in, so unless you are aware of your plants and take the time to inspect them regularly, you could completely miss the signs of houseplant pests. Any infestation that is not caught early is likely to spread to your other plants and can often lead to some plants becoming so plagued by the infestation that they are unable to recover. So, be aware of your plants, look at their leaves when watering them, and be conscious of any signs your plant may display in the event that they are being attacked.
Incorporate Treatments Into Your Regular Maintenance
Incorporating periodic treatments into your regular houseplant maintenance is a preventative measure that can save you a lot of work down the road, especially when it comes to plants that are more susceptible to pests. So, just like your monthly fertilizing or your quarterly leaf dusting, consider spraying down your plants with the pest control product of your choice monthly or every other month. Many pest control products work to treat the most common houseplant pests, so using one can prevent a number of different infestations.
Thoroughly Inspect New Plants and Pretreat
Whenever you bring home a new plant, we highly suggest quarantining it and treating it as if it did have pests. Even if you thoroughly inspect the plant, there is always the chance that pests could be hiding in the foliage or in the soil of the plant. It is always so frustrating to bring home a new plant you are excited about, only to realize months or weeks down the road that it is home to an infestation of life-sucking bugs. And even more frustrating is when this one plant spreads these unwanted guests to the rest of your healthy plants. So, no matter what, always treat new plants for pests before giving them a home among the rest of your plants. The same goes for any plants that are placed outdoors during the warm months. Plants are much more likely to contract insects when they are outdoors, and treating them before they are brought back inside is a preventative measure that should never be overlooked.