What’s On My Plant? - Mealybugs
Mealybugs, pesky invaders of our indoor and outdoor green spaces, are among the most common and persistent pests that gardeners and plant enthusiasts encounter. Despite their diminutive size, these tiny insects can wreak havoc on our beloved plants if left unchecked. They can impede plant growth and cause leaf discoloration. They can also cause leaves, fruits, vegetables, and flower buds to prematurely drop.
As they feed, mealybugs excrete honeydew, a sugary waste substance that attracts ants, yellow jackets, and other insects. The sticky liquid drips on foliage, hardscape, outdoor furniture, and cars. Subsequently, the fungal disease sooty mold grows on the honeydew and creates dark blotchy marks on foliage and branches.
Mealybugs, members of the Pseudococcidae family, are soft-bodied insects typically found in warm and humid climates. The females are small, ranging from 1/20 to 1/5 of an inch in length, with a distinctive cottony or mealy wax covering that gives them their name. This white, powdery substance often obscures their actual body, making them appear fuzzy or fluffy. The males are short lived, tiny, winged, fly like insects that never feed and therefore are inconsequential (well, at least on this page).
Where they come from:
How these pests spread around the garden or appear in your house is somewhat of a mystery; mealybugs are essentially immobile. In the garden, they fall from a trees and blow about, are carried in on birds or clothing, or hide within improperly composted mulch. Inside the home, they can blow in through an open window, hitch a ride in on your clothing, or come as a passenger on a pet.
Let’s not forget ants. Ants are very industrious and will actually “farm” them, moving them about the home and garden, as they intentionally harvest the honeydew to feed the colony.
Favorite Plants:
Mealybugs are not particularly picky eaters and can infest a wide variety of plants, both indoors and outdoors. However, they do show preferences for certain species, including succulents, citrus trees, orchids, ferns, and various houseplants. These pests thrive in plants with tender foliage or new growth. They are primarily found in colonies on perennials, woody shrubs, citrus, and indoor plants. Mealybugs especially like tender new growth and are often found in protected areas between closely hanging fruit, leaf and stem joints, plant crowns, and trunk forks.
Cultural Controls:
Prevention is key when it comes to managing mealybug infestations. Below are some practices that can keep these pests out of your home and garden.
Regularly inspect plants for signs of infestation, such as the presence of white cottony masses or sticky honeydew residue, to catch outbreaks early.
Quarantine newly acquired plants to prevent introducing mealybugs to your existing collection.
Practice good plant hygiene by removing debris and dead foliage to deter mealybugs from establishing colonies.
Avoid using high nitrogen fertilizers as they can cause excessive, soft new growth that will be more susceptible to infestation.
Biological and Mechanical Controls:
Several biologic control methods can be employed to manage mealybug populations without resorting to chemical pesticides.
Introduce natural predators such as ladybugs, lacewings, and parasitic wasps to keep mealybug populations in check.
Mechanical controls can be effective on a small infestation.
Hose down your plants in the early morning with a strong stream of water to knock mealybugs off the plant and to the ground, effectively killing them. We carry The Bug Blaster which can be effective in dislodging adults, larva, and eggs.
Chemical Controls:
For severe infestations or when other methods prove ineffective, chemical pesticides may be necessary as a last resort.
Natural/Organic: Horticultural oils and insecticidal soaps are effective in suffocating and disrupting mealybug colonies when applied directly to infected plants. Additionally, a solution of rubbing alcohol and water can be used to spot-treat heavily infested areas.
Master Nursery’s Horticultural Oil, Fertilome’s Neem Oil and Spinosad, or Bonide’s Insecticidal Soap are treatments that we normally recommend. Each of these products and other similar products can be photo-toxic to certain types of plants, so check with us for advice.
Chemical/Synthetic: Insecticides containing active ingredients such as imidacloprid or acetamiprid can be used to target mealybugs. However, it's essential to carefully follow the manufacturer's instructions and avoid using broad-spectrum pesticides that may harm beneficial insects and other non-target organisms.
In conclusion, while mealybugs may seem like formidable foes, with vigilance and a combination of cultural, organic, and, when necessary, chemical controls, their impact can be minimized, allowing our plants to thrive in peace. By understanding their behavior and implementing appropriate management strategies, we can protect our green spaces from these unwanted guests.
