Tiny wingless insects, mealybugs are only 1/5 inch long and have a waxy, gray or white appearance. The pests form sticky clusters on plant stems, flowers and leaves and if not controlled can cause stunted growth, leaf loss and fruit loss. If you notice a mealybug infestation, take control of the situation and eradicate the problem with home remedies.
Encourage Natural Predators
In most cases, natural predators provide enough control for mealybugs, keeping the population at levels too low to cause lasting damage to your plants. But mealybug populations may surge if enough natural predators don't visit your yard.
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Parasitic wasps are the main mealybug predators. There are many types of parasitic wasps, all of which you can attract with the right plants.
- Marigold (Tagetes spp_._) is an annual flower known for its vibrant yellow or orange flowers. It requires full sun and well-draining soil and grow anywhere from 6 inches to 24 inches tall, depending on the variety.
- Rosemary (Rosmarinus officinalis, U.S. Department of Agriculture plant hardiness zones 8 through 10) grows as tall as 6 feet and needs dry, well-draining soil. It does best in full sun but can tolerate some light shade.
- Fennel (Foeniculum vulgare, USDA zones 4 through 9) attracts beneficial parasitic wasps and also butterflies. Its feathery leaves grow as tall as 6 feet with yellow flowers making it an attractive addition to the garden.
- White clover (Trifolium repens, USDA zones 3 through 10) creeps along the ground, growing no taller than 6 inches with globe-shaped white flowers. White clover prefers moist soil in light shade but can also survive in dry soils in full sun. Because it grows aggressively, this plant may sometimes turn invasive, so check before planting if it's a problem in your area.
Mealybugs excrete a sticky substance, called honeydew. The honeydew attracts ants to the area, and the ants may prevent natural predators from getting at the mealybugs effectively. Additionally, ants often pick up mealybugs and carry them to other plants, spreading the pest problem.
Control ants and you help to control and eradicate mealybugs while also stopping the mealybugs from spreading to currently uninfected plants. There are many ways to control ants naturally and effectively:
- Hose down the affected plants with water. This rinses away the honeydew and may help to keep ants from being attracted to the mealybugs.
- Pour boiling water onto the ant hill. This collapses the ant nest and scalds the ants to death. If ant activity resumes, repeat the boiling water application. It may take several attempts.
- Sprinkle diatomaceous earth in a circle around the base of the plants. Ants die after crawling over and through diatomaceous earth. Replenish the dust whenever it rains, as rain can rinse away the diatomaceous earth.
Kill Mealybugs Directly
If attracting natural predators and reducing ant activity doesn't solve the mealybug crisis, turn to direct controls to kill mealybugs directly.
Individual Plant Infestations
For individual plants, hose them down with a strong blast of water from a garden hose. This is often enough to knock off the mealybugs and keep their populations low.
Alternatively, dip a cotton swab in rubbing alcohol and dab the clusters of mealybugs on your plant's foliage, stems and fruit. The alcohol zaps and kills the pests.
Multiple Plant Infestations
For more widespread mealybug infestations, make a homemade insecticide spray. Homemade sprays eradicate and kill mealybugs and many other soft-bodied pests, including aphids and whiteflies.
Pour 4 teaspoons of liquid dish soap into a spray bottle.
Add 1 quart of tap water.
Spritz the soapy insecticide directly onto mealybugs. The soap kills on contact. Coat all affected parts of your infected plants.
Rinse the plant with fresh water after a couple of hours.
Repeat the spray application if you notice resumed mealybug activity.