Are you seeing spots of small white fuzz on the leaves of your garden tomatoes and need to identify the problem? Or already know those little cottony dots are mealybugs and want to treat the problem? In either case, let’s talk about getting rid of mealybugs, one of the most common pests on indoor and outdoor plants.
There are many ways to control mealybugs, both natural and chemical. Whether you remove insects by hand, spray plants with neem oil, or use an insecticide is a personal choice. You can pick the best for your situation by learning the different options.
What are Mealybugs?
Mealybugs are small oval insects with soft bodies covered with white fuzzy material with a waxy coating. This fluffy cotton-like material protects the unarmored bugs from excess heat and resulting moisture loss. They prefer warmer temperatures and grow one-quarter to one-inch long at maturity. You typically find them in protected areas like under leaves or branch junctions.
9 Ways to Control Mealybugs
Mealybugs are difficult to control indoors or outside because they reproduce so quickly and often hide in plant crevices that are hard to see. Because of this, it’s essential to treat a problem soon to reduce numbers. Remember that you may need to implement more than one control method and use them repeatedly.
1. Quarantine All Affected Plants
The first step in fighting mealybugs is to move an infested plant away from other unaffected neighbors. Obviously, this is easier for indoor plants, but you can quarantine outdoor plants by placing them in a transparent plastic bag. Separating them from the others keeps the multiplying mealybugs from jumping from one plant to the next.
2. Fight a Small Infestation By Hand
To head off an early problem, you can remove the mealybugs by hand. This process is time-consuming but incredibly effective. Wipe all the leaves with a clean, damp cloth to knock off most of the bugs. Then pick the remaining adults and eggs from the spots where the leaves attach to the branches and stems.
3. Use Water Pressure to Your Advantage
One of the quickest ways to lower mealybug numbers for indoor and outdoor plants is to spray them with water. Use your garden hose and spray water directly at your plants to knock the bugs off. Make sure there is plenty of pressure in the water stream, but not enough to damage plants.
4. Dab Them with Rubbing Alcohol
Another way to control wingless insects is to spot-treat them using rubbing alcohol. Dunk a cotton ball or swab in rubbing alcohol and then use it to saturate insects and eggs. The rubbing alcohol dissolves the outer coating and acts as a desiccant, drying out interior cells and causing death. Before starting, test to see if it damages the foliage.
5. Turn to Insecticidal Soap
Insecticidal or horticultural soaps are commonly used by gardeners to treat insect pests on indoor and outdoor plants. These products contain fatty acids that suffocate small, soft-bodied insects. You can purchase a premade product or make your own using “pure” liquid soap and water. Always spray the entire play, paying close attention to the bottom of the leaves.
6. Rely on a Naturally Occurring Pesticide
Neem oil is a natural product that controls mealybugs and other insect pests made by pressing seeds of neem trees. The clarified hydrophobic oil suffocates insects when sprayed on them. Azadirachtin can also be extracted from the oil and used in commercial products as a feeding deterrent or insect growth interrupter that halts the progression of life stages.
7. Bring in Predators to Curb an Infestation
If your mealybug problem is in garden plants, one biological control method is to bring in predators that feed on them. This low-effort solution works best with lady beetles, brown and green lacewings, and some types of predacious midges. There is even a type of small lady beetle commonly called the mealybug destroyer (Cryptolaemus montrouzieri) that can destroy 250 mealybugs per larvae.
8. Controlling Mealybugs with Chemical Pesticides
One of the most common ways gardeners treat plant insect problems is to spray chemical pesticides. Different insecticide products effectively control mealybugs but typically reduce beneficial insect populations. If you opt for chemical control, always read the product label carefully to see if it will harm your target plant.
9. Proactively Preventing an Infestation
Preventing mealybugs is the best method of control. While it might not stop them completely, it may reduce problems considerably, making an issue easier to manage. In turn, you’ll see less plant damage. The following are some of the best cultural practices you can implement to prevent mealybugs—and other nuisance pests—from bothering your plants.
- Do not overwater your plants, and avoid overhead watering.
- Plant lavender, thyme, oregano, lantana, or anise around your garden to naturally repel mealybugs.
- Use a garlic spray around susceptible plants as a deterrent.
- Regularly inspect your plants for signs of an infestation.
Mealybug Life Cycle
A mealybug takes six to twelve weeks to complete an entire life cycle, depending on its species and the local climate. The challenge with controlling a problem is multiple generations occur with overlapping lifecycles, so populations grow exponentially once they attack a plant. Often they aren’t noticed until populations get large.
- Adult females lay approximately 600 eggs over five to ten days and then die after the process. These eggs are deposited in fluffy white cotton masses on the bottoms of leaves and the crooks where branches meet stems.
- Eggs take approximately five to ten days to hatch after laying, and the immature nymphs immediately begin searching for feeding sites. At this point, both sexes are wingless and look alike.
- Females go through four instars, or developmental phases, before reaching maturity and are constantly mobile. They will invade and feed on plants throughout their life, looking for a suitable place to lay eggs.
- Males have one purpose in life, and that is mating. Once they find a feeding site, they quickly settle and spin a white waxy cocoon. Before maturation, they’ll go through five instars but only feed in the first two. Adult males have wings and look more like wasps but don’t have functional mouthparts, so they cannot feed. They’ll only live a day or two.
Identifying Mealybug Damage
Mealybug damage is similar to that of other sap-sucking insects. They insert a feeding tube through the leaf cuticle to access the vascular system, which results in yellowing leaves, reduced plant vigor, stunted growth, and dieback. A large number of pests on a plant can result in death. You will also see a shiny sticky sap known as honeydew on the leaves.
Honeydew itself isn’t damaging, but when the sugary substance is excreted and collects on the foliage, it encourages black sooty mold growth. It also attracts ants to your plants, which compounds your pest problem.
Are Some Plants Prone to Mealybug Infestations?
Some plants are more prone to mealybugs. Since they are sap-sucking pests, they are typically attracted to plants with high sap content. Outdoors they are highly attracted to citrus trees, fruit crops, and hibiscus. These tropical insects especially like perennial foliage plants because they can house generation after generation, so houseplants like succulents are highly susceptible.