Getting rid of mealybugs takes patience, because you may have to repeat treatment for several weeks depending on the size of the infestation. These little pests look like your plant was covered in white fluffy cotton.
These bugs can come from anywhere, including new plants or contaminated soil. They can even come from produce or flowers brought from the grocery store or brought indoors from the garden. Ants can also bring these bugs to a houseplant because they want to feed off the honeydew residue in the bugs.
What are Mealybugs?
There are hundreds of insect species that are known as mealybugs. These bugs vary in sizes between 1/20 to 1/5 of an inch long. They belong to the Pseudococcidae family and are related to other kinds of scale bugs. Since they are warm weather insects, they are more of a problem in the tropics where they can affect entire crops. Those that live in colder climates can find this pest in greenhouses and house plants.
These pests are soft-bodied insects that have a cotton-like coating. In reality their bodies are pink and purple, but they appear white or light gray because of the cotton covering. This covering makes them look like they have many legs coming out of their oval shaped bodies, as well as the illusion of tails or antennae projecting at the end of their bodies.
Covers are actually made from honeydew or undigested sap which they suck from your plants. This cover protects them against predators and control products. The sap they suck out of the
stems and leaves from the plant will stun their growth, make their leaves turn yellow and drop. They are commonly found on new growth, especially at leaf joints, but they can appear anywhere in the plant.
Mealybug damage is not as strong or quick as spider mites, but they can kill your plant in the long run.
It is easy to confuse mealybugs with fungus or mildew. White flies also look similar, however these will fly when the plant is disturbed. Other than the cotton-like appearance, it is possible to identify mealybug damage if you smell sweet honeydew which is secreted by the bugs. Plants may also have black sooty mold fungus.
How to Mealybugs Reproduce
The life cycle of these pests varies between seven to ten weeks. Eggs will hatch into nymphs in one to two weeks. Then it will take another six to nine weeks for nymphs to turn into adults. Immature bugs are cream or brown and are waxy instead of fluffy.
Generations of mealybugs can overlap, so your plant may have several generations of pests and once they get started they will grow in numbers quickly. Females lay between 200-600 eggs in a 20 day period. Most people won’t even realize they have a problem since eggs and nymphs are too small to be noticeable. Once the population explodes it is impossible to ignore.
How to Prevent Mealybug Infestations
Separate any infected plant from the rest, since these pests can spread. Also make sure to wash your hands before touching any other plant after treating your plant. These bugs do not pose any danger to humans.
Some species live in the soil and attack the roots of the plant. The only way to recognize the problem is by seeing yellow leaves and wilting growth. Get rid of the soil to eliminate these bugs. Make sure to have fresh sterile soil before planting.
Don’t add too much fertilizer to your plants since this will create the perfect environment for these bugs to reproduce since they love nitrogen rich soil. They may also appear if you over-water your plants.
Do Mealybugs have Predators?
Yes, thankfully many predators love eating these bugs. Introducing these beneficial insects is a good option for outdoor or greenhouse control. You can buy them from online retailers or plant species that attract them naturally. Lacewings, lacebugs, ladybugs, parastic wasps (Leptomastix dactylopii) and a type of beetle (Cryptolaemus montrouzieri) are great controllers.
How to Kill Mealybugs
Don’t use chemicals to kill mealybugs since they can build resistance and they are toxic to humans and pets.
Mealybugs crawl and move to other areas of your house. They can live for a long time without having a host plant. And just when you thought you had conquered the problem, they can come back and re-infest your plant. Check for them around your plant, pot and tray.
Be patient and persistent when trying to kill mealybugs. Try a combination of the following methods for best results.
Those with a small infection can try washing them off with a steady stream of water. Use a garden hose for outdoor plants and the shower or sink for houseplants. Repeat as needed. This may not eliminate the problem, but it can help to control the population.
Liquid soap solution helps kill mealybugs. Fill a spray bottle with 1 quart lukewarm water and a teaspoon of a gentle liquid or organic dishwasher soap (free of perfumes and additives) so it does not harm your plant. This will coat the bugs and break down the wax. You can also add neem oil to this mixture since it is an excellent natural pesticide. Neem can kill mealybugs on contact and is especially useful in their nymph stage. Horticultural oil is another option to use.
Make your own insecticide spray by combining one small onion, one garlic bulb and one teaspoon of cayenne pepper in a blender. Make a paste out of this and mix it in one quart of water. Let it steep for an hour and strain with a cheesecloth. Add one tablespoon of liquid dish soap and spray on plants. This mix can be stored in the refrigerator for a week. You can also buy hot pepper wax spray.
70% rubbing alcohol kills many houseplant pests on contact. Alcohol dissolves the protective layer, killing the bugs and their eggs. To get rid of mealybugs simply dip a cotton swab in alcohol and apply directly to pests. It is also possible to make a killer spray with one cup of alcohol to one quart of water. Test to make sure the spray does not damage your plant. Repeat the treatment weekly until the problem is gone. Clean the pot with alcohol and replace the soil.