White fuzz on plants

I have been bothered for some weeks by something that attacks coleus and impatiens. It is like the whipped egg white we use in meringues. It settles at the axles of the leaves and also mainly on the back of leaves. It seems to suck the life out of the plants and they wilt and die. I tried spraying with an aerosol white oil but this is too harsh for these soft plants and they die anyway. Now I look every day for signs of the white sticky stuff and dip an artists brush in white oil and wipe the spots off. These are mainly indoor plants but some outside also have the same problem. I usually start new cuttings of these plants in a vase and when they root I plant them out thereby having the benefit of the coleus for many months. Now I have this problem, it takes a lot of the fun out of gardening. Going off your descriptions, it sounds to me like either mealy bug, or powdery mildew. Both of these afflictions thrive in warm, damp weather, which we’ve had quite a spell of this summer. Powdery mildew is a fungus which looks like a fuzzy white film on the surface of leaves, first appearing as spots. Mealy bug is a kind of scale that look like tiny fluffy slaters, and leave a spiderweb-like residue in the axles of plants. Neither of these problems can be solved by white oil, and require specific management. To manage powdery mildew you’ll need to remove the worst-affected leaves, and regularly spray a lime-sulfur or bi-carb soda based fungicide on the plants. Fungal spores are spread by water splashing off the leaves, so take care when watering to direct the stream below the leaves, straight to the roots. If your coleus or impatiens aren’t too precious to you, I’d even recommend just replacing them (if powdery mildew is the culprit), to avoid the disease spreading onto other plants. Avoid composting infected plants, as the spores can stick around and spread. Mealy bug can be controlled by either neem oil or soap-based pesticides, which you can purchase from most nurseries or hardware stores. They’re attracted to excess water, fertilizer, and new growth, so if your gardening routines need tweaking that may be something to consider. Do you have a gardening question for Jess? Send your queries to [email protected]

Contents

Mealybugs

Description of mealybugs

Houseplants are prone to a varied assortment of insect pest problems. Some of the most common are scale insects and spider mites. However, one of the easiest to recognize is the mealybug. You’ve probably seen mealybugs at one time or another on the stems or leaves of a houseplant. They look like small white puffs of cotton or fluffy deposits of white powder. They are common on African violets, Ficus, jade gardenia, poinsettia and other indoor plants. The body of each mealybug is oval and about 1/4 inch long. However, the soft, segmented body is concealed by filaments of white wax that cover the insect. The filaments extend out from the periphery of the body and may be up to 1/2 inch long.

Life cycle of mealybugs

The mealybugs found on houseplants lay eggs in a compact, white waxy sac, usually in the axils where the leaves join stems. Three hundred or more yellowish or orange eggs may be deposited by a single female. The eggs hatch into tiny, immature mealybugs called nymphs that move about on the plant searching for a place to settle and eventually insert their beaks into the plant and begin sucking out the sap. As mealybugs feed numerous waxy filaments start forming as white, threadlike projections located along the edge of the body. The filaments grow, curl and tangle until the entire body is covered. Mealybugs usually remain in one place for their entire life span of four to ten weeks.

Damage caused by mealybugs

Mealybugs are related to aphids and scale insects. Like these, the mealybugs feed on the plant’s sap by extracting it through a long slender beak pierced into the plant tissue. Heavily infested plants are weakened from excessive sap loss and may die. Lightly infested plants may only be stunted, yellowed or malformed. The sweet honeydew excreted by these sap feeders provides a substrate for the distracting black fungus called sooty mold.

Management of mealybugs

Mealybugs may be difficult to control and unless the plant is particularly valuable, it may be best to throw away infested plants before the insects spread to other houseplants. The standard, well-known remedies for houseplant pests are often successful if applied with diligence and persistence. Picking off individual mealybugs and egg sacs or dabbing each one with an alcohol–soaked cotton swab may be satisfactory for lightly–infested plants. Similarly, syringing the plants with a forceful spray of lukewarm water may adequately dislodge a light pest infestation.

Insecticide sprays are available for mealybugs and other houseplant pests. Use aerosol or hand pump spray products made just for houseplants. These may contain any of several different ingredients, including insecticidal soaps, pyrethrin, neem, or a synthetic pyrethroid such as permethrin, bifenthrin or resmethrin. Granular insecticides that you add to the soil of infested houseplants may be effective. Use with caution and read and follow all label directions.

Biological control is often used to keep mealybug populations at low levels on large houseplants grown in malls and botanical centers. A specific ladybug called the mealybug destroyer is particularly effective. These ladybugs, originally from Australia, are mass-produced by several companies in the U.S. The predators are purchased from the suppliers and released onto infested plants at regular intervals. The ladybug adults and larvae feed on the mealybug eggs and small nymphs. A very tiny wasp that parasitizes mealybugs is also sometimes used to supplement control by the predators. As attractive as this option seems, it is unlikely to be practical for homeowners with a few, relatively small plants or with a limited infestation of mealybugs.

Additional information on mealybugs and other common, houseplant pests is available in pamphlet Pm–1595, Houseplant Insect Control. Check at your local county extension offices or online at https://store.extension.iastate.edu/Product/pm1595-pdf.

How to Manage Pests

Pests of Homes, Structures, People, and Pets

Mealybugs

Published 3/16

In this Guideline:


  • Identification and life cycle
  • Damage
  • Management
  • About Pest Notes
  • Publication
  • Glossary

Mealybugs, such as these obscure mealybugs, are usually found in groups feeding in protected areas.

Grape mealybug egg mass pulled apart to expose orange eggs and yellow crawlers.

First-instar nymphs of the grape mealybug and honeydew.

Five parasitic wasps, Acerophagus notativentris, have emerged from the parasitized and mummified grape mealybug at right.

Adult mealybug destroyer lady beetle and its waxy white larva feed within a colony of mealybug nymphs.

Mealybugs are soft, oval, wax-covered insects that feed on many plants in garden, landscape, and indoor settings. Usually found in colonies, they are piercing-sucking insects closely related to soft scales but lack the scale covers. Like soft scales, they can produce abundant honeydew and are often associated with black sooty mold. Mealybugs are favored by warm weather and thrive in areas without cold winters or on indoor plants.

IDENTIFICATION AND LIFE CYCLE

Mealybugs are in the insect family Pseudococcidae, part of the superfamily Coccoidea, which also includes armored scales, soft scales, and cottony cushion scale.

Mealybug bodies are distinctly segmented and usually covered with wax. Older individuals may have wax filaments around their body margins. In some species the filaments are longer in the rear and can be used to help distinguish between different species.

Mealybugs are usually found feeding in colonies in somewhat protected areas such as between two touching fruits, in the crown of a plant, in branch crotches, on stems near soil, or between the stem and touching leaves. A few mealybug species feed on roots.

While adult females are wingless and similar in shape to nymphs, adult male mealybugs, which are rarely seen, are tiny two-winged insects with two long tail filaments. Many mealybug species can reproduce asexually without mating.

Life cycles vary somewhat by species. Adult females of most mealybugs lay 100-200 or more eggs in cottony egg sacs over a 10- to 20-day period. Egg sacs may be attached to crowns, leaves, bark, fruit, or twigs. An exception is the longtailed mealybug, which produces eggs that remain within the female until they hatch.

Newly hatched mealybug nymphs (called crawlers) are yellow to orangish or pink, lack wax, and are quite mobile, but they begin to excrete a waxy covering soon after settling down to feed. Although older nymphs and adults have legs and can move, they don’t move very far or very rapidly. Nymphs molt through several instars before becoming adults.

Depending on species and environment, mealybugs may have two to six generations a year. Where climates are warm or plants are growing indoors, all stages may be present throughout the year. On deciduous plants such as grapevines, mealybugs may overwinter on or under bark as eggs (within egg sacs) or as first-stage nymphs.

Mealybugs are sometimes confused with other pests that produce waxy coatings, honeydew, and black sooty mold, including the cottony cushion scale, woolly aphids, and even some soft scales and whiteflies. Be sure to carefully examine the insect beneath the wax to identify it properly.

Over 170 species of mealybugs occur in California. Only a few have become major pests. Some of the most common problem species are pictured and described in Table 1.

DAMAGE

Mealybugs suck sap from plant phloem, reducing plant vigor, and they excrete sticky honeydew and wax, which reduces plant and fruit quality, especially when black sooty mold grows on the honeydew. Large accumulations of mealybugs, their egg sacs, and wax can be unattractive. High populations feeding on foliage or stems can slow plant growth and cause leaf drop; however, healthy plants can tolerate low populations without significant damage. Ground mealybugs, which are not very common in landscapes and gardens, feed on roots and can cause plant decline but are generally not seen until plants are dug up and roots are exposed.

Many types of perennial plants are affected by mealybugs. Among fruit trees, citrus has the most problems, but mealybugs may sometimes be found on stone fruits or pome fruits, although rarely at damaging levels. Mealybugs can build up in grapes, especially the vine mealybug, a new invader that attacks roots as well as aboveground parts, but the grape, obscure, and longtailed mealybugs also occur.

Many woody ornamental plants and some herbaceous perennials can be infested including cactus, coral bells (Heuchera), figs (Ficus), flax grasses (Phormium), fuchsia, gardenia, hibiscus, jasmine, mimosa, Miscanthus grasses, and oleander. The cypress bark mealybug can be a serious pest on Monterey cypress in urban areas and also attacks other species of cypress, cedar, and juniper.

Plants growing indoors or in greenhouses are especially vulnerable because year-round mild temperatures favor mealybug populations, and indoor plants are usually not exposed to the natural enemies that often keep mealybugs under control outdoors. Among houseplants, aglaonema, coleus, cactus, dracaena, ferns, ficus, hoya, jade, orchids, palms, philodendron, schefflera, poinsettia, and various herbs including rosemary and sage often have problems with aboveground mealybugs. Ground mealybug infestations are most often reported on African violet and gardenias.

Some mealybugs, such as those infesting grapevines, can transmit viruses, but these aren’t usually a major problem in gardens and landscapes. The pink hibiscus mealybug, Maconellicoccus hirsutus, which currently is only established in Imperial County in California, has saliva that is especially toxic to plants.

Table 1. Common Pest Mealybugs in California

SPECIES DESCRIPTION SPECIES DESCRIPTION
Obscure mealybug
Pseudococcus affinis
Distinct filaments around the body, covered with powdery wax. Vine mealybug
Planococcus ficus
Similar to citrus mealybug with shorter filaments than other mealybugs in grapes . Has a dark stripe on its back. May be found on roots as well as aboveground.
Hosts: Many hosts, primarily outdoor plants. Hosts: Mostly grapes in California, although its potential hosts include other fruits and ornamental trees.
Longtailed mealybug
Pseudococcus longispinus
Two tail filaments that are longer than its body. Gives birth to live nymphs and produces no egg masses. Cypress bark mealybug
Ehrhornia cupressi
Round, bright orange or red and surrounded with a ring of wax. Found beneath bark plates.
Hosts: Citrus, grapes, nursery stock, and indoor ornamentals. Hosts: Monterey cypress, other cypress, cedar and juniper.
Grape mealybug
Pseudococcus maritimus
Almost identical in appearance to obscure mealybug. If poked (not punctured), it will release a reddish orange defensive secretion. Obscure mealybug secretion would be clear. Ground mealybugs
Rhizoecus spp.
No obvious filaments. Live in soil.
Hosts: Grapes, pears, pomegranate, and other fruit trees. Hosts: Many plants, but mostly damaging on potted plants such as African violets.
Citrus mealybug
Planococcus citri
Short, equal-length waxy filaments around the body. A dark stripe may be visible down its back.
Hosts: Citrus, several landscape shrubs . Most common mealybug on indoor ornamentals.

MANAGEMENT

Mealybugs are very difficult to manage with insecticides. Fortunately most species have natural enemies that keep their populations below damaging levels in outdoor systems such as landscapes and gardens. The best approach to managing mealybugs is to choose plants known to be less prone to problems, inspect plants for mealybugs before bringing them onto your property, and rely on biological control and cultural practices to keep mealybug numbers in check.

Cultural Practices

Mealybugs are often introduced into landscapes (and especially into indoor areas) on new plants or on tools or pots. Because adult females can’t fly and mealybugs can’t crawl very fast, they don’t rapidly disperse in the garden on their own. Inspect any new plants thoroughly for mealybugs before installing them. If you can’t remove all the mealybugs present, discard and destroy the plant or, if possible, take it back to the source.

Regularly inspect mealybug-prone plant species in your landscape or indoor plantings for mealybugs. If you find an infestation, physically remove the insects by handpicking or prune them out. Toss out older “grandmother” plants that may be a source of infestation for new plants. Check pots, stakes, and other materials for mealybugs and their egg sacs and dispose of any infested items.

If mealybugs are somewhat exposed, it may be possible to reduce populations on sturdy plants with a high-pressure or forcible spray of water. Repeat applications at several-day intervals may be necessary.

Avoid unnecessary applications of nitrogen fertilizer on plants with mealybugs. High rates of nitrogen coupled with regular irrigation may stimulate tender new plant growth as well as mealybug egg production.

If your landscape or interiorscape has a history of serious mealybug problems, consider using only plant species that are not prone to mealybugs for at least a year or two to reduce mealybug density and harborage potential.

Ground mealybugs are even more difficult to control than those that feed aboveground. Prevent introduction of ground mealybugs and quickly dispose of infested plants before the pests can move onto clean plants.

Biological Control

Many natural enemies feed on and kill mealybugs on fruit trees and woody ornamental plants in the landscape. These beneficial insects generally can be relied upon to keep numbers at tolerable levels. Natural enemies include a number of species of parasitic wasps that lay their eggs in or on developing mealybugs. Common parasites (or “parasitoids”) include species in the genera Coccophagus, Leptomastix, Allotropa, Pseudaphycus, and Acerophagus. Look for parasite pupae within mealybug colonies, or emergence holes in mummified mealybugs. Leptomastix dactylopii is sold commercially for release in greenhouses, citrus groves, and interiorscapes, but it kills only the citrus mealybug.

Naturally occurring predators of mealybugs include lady beetles, green and brown lacewings, spiders, minute pirate bugs, and larvae of predaceous midges. The mealybug destroyer lady beetle, Cryptolaemus montrouzieri, is the most important of these predators in many areas. It does not tolerate cold winters, so it is more common in southern California and in coastal areas.

The mealybug destroyer can be purchased for augmentative release and is often released in greenhouses and interiorscapes or in citrus orchards after a cold winter has killed off native populations. Adult beetles are bicolored with reddish-brown heads and hind ends and black in the middle; older mealybug destroyer larvae are covered with white wax, which makes them look somewhat like large mealybugs. When releasing mealybug destroyers, focus on periods when there are many mealybug egg sacs, because the lady beetles require mealybug eggs as food to stimulate their own reproduction. There is little point in releasing them when mealybug numbers are low or when they are not reproducing.

Operators of greenhouses or interiorscapes with regular mealybug problems can establish their own mealybug destroyer colonies for self-release. The lady beetle can be reared in wide-mouth jars on mealybugs grown on sprouted potatoes or other hosts. A ring of petroleum or other sticky material smeared inside jars around the top will prevent the flightless mealybugs from crawling out but allows the lady beetles to fly out into the greenhouse.

Preserve naturally occurring biological control agents by avoiding use of broad-spectrum insecticides for any pests in the area. Also keep ants out of mealybug-infested areas and plants because ants protect mealybugs from their natural enemies.

Chemical Treatment

Nonchemical methods usually provide sufficient control for outdoor plantings in gardens and landscapes. Home and garden insecticides are not very effective for mealybugs, especially on larger plants. The mealybugs’ waxy coating repels most contact insecticides, and their habit of aggregating in hidden locations makes them hard to reach.

For houseplants, greenhouses, and interiorscapes where it is not physically possible to remove mealybugs and where biological control may not be feasible, spot treatment may be used to suppress populations of aboveground feeding mealybugs.

Spot Treatment with Isopropyl Alcohol

On small infestations on houseplants, a 70% or less solution of isopropyl (rubbing) alcohol in water may be dabbed directly on mealybugs with a cotton swab to kill them or remove them. Test the solution out on a small part of the plant 1 to 2 days beforehand to make sure it does not cause leaf burn (phytotoxicity). In some cases, a much more diluted solution may be advisable. Where infestations are extensive, a 10-25% solution of isopropyl alcohol can be applied with a spray bottle. You will need to repeat this procedure every week until the infestation is gone.

Insecticides

Insecticidal soaps, horticultural oil, or neem oil insecticides applied directly on mealybugs can provide some suppression, especially against younger nymphs that have less wax accumulation. Be sure to test for phytotoxicity of these materials prior to treatment as well.

Products containing the systemic insecticide dinotefuran may reduce mealybug numbers on some landscape plants, and plant spikes or granules containing the related insecticide imidacloprid may reduce mealybug crawler numbers on houseplants. These neonicotinoid products are less reliable against mealybugs than against other piercing-sucking insects in many situations. Their use should be avoided when possible, especially on flowering plants, because of potential negative impacts on natural enemies and pollinators.

Other insecticides, including pyrethroids, are also labeled for some situations but may not be much more effective than soaps and oils and can be devastating to natural enemies. Be aware that none of the available insecticides will likely provide complete control of all individuals, and that you will need to monitor and treat again as needed. When infestations become severe, consider discarding houseplants rather than repeatedly treating them with insecticides. On outdoor plants, cultural practices and biological control should be adequate for suppressing mealybugs in most situations.

WARNING ON THE USE OF PESTICIDES

Cloyd, R. A. 2011. Mealybug Management in Greenhouses and Interiorscapes (PDF). Kansas State University AES and CE Bulletin MF3001. 4pp.

Dreistadt, S. H. 2001. Integrated Pest Management for Floriculture and Nurseries. UC ANR Publication 3402, Oakland, CA.

Dreistadt, S. H. 2016. Pests of Landscape Trees and Shrubs: An Integrated Pest Management Guide, 3rd edition. UC ANR Publication 3359, Oakland, CA.

PUBLICATION INFORMATION

Pest Notes: Mealybugs

UC ANR Publication 74174

Author: M. L. Flint, Extension Entomologist Emerita, Department of Entomology, UC Davis.

Produced by University of California Statewide IPM Program

PDF: To display a PDF document, you may need to use a PDF reader.

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Mealybugs – Houseplants


Mealybugs on potted cycad

  • Mealy bugs are covered with a powdery wax and the body tapers towards the tail.
  • They may have waxy tufts around the body margin and several tails at the rear end.
  • Mealybugs may be found at rest or slowly crawling on the undersides of leaves, on stems in flowers or even on the outside of the pot.
  • Cottony white wax is usually the first sign of their presence.
  • Mealybugs damage plants by sucking sap and their feeding can result in yellowing leaves, stunting, dieback or death of the plants.
  • They secrete honeydew that supports the growth of black sooty mold on plant parts.

Management

  • Check plants on a regular basis for the presence of mealybugs. Mealybugs that have been parasitized will be darker in color and exit holes may be visible where the parasite emerged.
  • Mealybugs are very difficult to control. Heavily infested plants should be discarded.
  • Isolate infected plants so the infestation does not spread.
  • Dipping a cotton swab in household alcohol and dabbing it on the individual mealybugs can control light infestations. Mealybugs treated with alcohol will turn light brown in color. Be careful not to get the alcohol on the leaves of the plants as they may be damaged.
  • For heavy infestations, spray the plants thoroughly with insecticidal soap for houseplants or a registered houseplant spray. Be sure to follow all directions carefully and make sure that the plant or pest are on the label. Multiple applications will most likely be necessary.
  • The other option, is using a systemic houseplant insecticide that is watered in around the roots.
  • After treating monitor the plant for mealybugs each time you water. Retreatment may be necessary.


Mealybugs on cactus


Dieback on Paphiopedilum (slipper) orchid


Mealybugs on flower of shrimp plant. They
conceal themselves very well making them
difficult to control


Close-up of a mealybug under a waxy coating


Mealybugs on coleus

Facts, Identification & Control

Scientific Name

Family Pseudococcidae

Appearance

What do they look like?

Mealybugs are very small, soft-bodied, oval-shaped insects that are covered with a white, powdery wax coating.

In addition, many mealybug species have projections extending from their body, giving them the appearance of having many legs on the side and rear of the body.

When seen on plants, they look like very small spots of cotton.

Mealybugs move slowly, but when they find a suitable location on the plant, they often become immobile and form clusters on the plant.

How Did I Get Mealybugs?

Both indoor and outdoor plants attract mealybugs. The pests will attack a wide range of vegetation, including fruit trees, gardenias, African violets, and more. Mealybugs hide beneath leaves and flower petals, making their tiny bodies even harder to spot.

People with houseplants, gardens, and flower beds often encounter these pests. The mealybug thrives during the warm months of spring and summer.

How Serious Are Mealybugs?

These pests harm plants by piercing the plant’s leaves and stems and drinking their sap, which leads to wilting and yellowed leaves. Mealybug honeydew, the pests’ sticky waste, also causes mold growth on plants and attracts other insect pests. Mealybugs do not bite or spread disease to humans.

How Do You Get Rid of Them?

If you suspect you have mealybugs infesting your plants, contact your local Orkin branch office for an inspection and to prepare an integrated mealybug treatment plan to effectively and efficiently resolve the problem.

The complexity of mealybug treatment is situational.

Depending on the number of plants that are infested and the location of the infested plants, the appropriate treatment plan may range from very simple prevention and control to somewhat more complex and widespread treatment techniques.

For the homeowner, mealybug control may not be expensive, but can be very time consuming since success depends upon a very careful inspection process. The easiest solution for the homeowner may simply be tossing out infested plants.

If disposal is not an option, the homeowner can “quarantine” plants for 10-14 days as a way to ensure infested plants are not brought home.

Mealybug Infestations

One of the easiest ways to manage mealybug infestations is to prevent introduction of infested plants into the house’s interior. The homeowner can carefully inspect any plants that are purchased before bringing them home for interior use or exterior landscape planting. If the plants appear to be free of mealybugs, it is a good idea to “quarantine” the plants for about two weeks. Another method to prevent mealybug damage is to cut out or cull infested leaves or stems so there is no opportunity for mealybugs to further expand the population on the infested plant. As a last resort, the most efficient method to prevent damage can be to simply dispose of infested plants to keep mealybugs from spreading to other, non-infested plants.

If a minor mealybug infestation is discovered, treating the infested plant(s) may require using alcohol-soaked cotton swabs to treat the insects; removing mealybugs by exposing infested plants to running water; and/or washing the plants with soapy water.

If the mealybug infestation is widespread, the treatment plan may require a product to treat not only mealybugs, but also to treat ants that are feeding on the honeydew produced by the mealybugs. This is important since ants protect mealybugs from predators and may move mealybugs from one plant to another, thus increasing the number of infested plants. If the treatment plan requires using a product, it is usually best to let your pest management professional apply it since his/her experience and knowledge ensures the product’s labeled-use directions are followed and adhered to strictly.

Behavior, Diet & Habits

What do they eat?

Mealybugs feed by sucking plant juices which weakens the plant and causes the plant’s leaves to turn yellow, wilt and drop. The insects also produce honeydew, a sticky substance that increases mold growth on plants and attracts feeding ants. If the mealybug infestation is not eliminated, the plant will probably die.

Mealybugs & Ants

Mealybugs attract ants by excreting honeydew, a sticky, sweet substance that the ants feed on. Plants infested with mealybugs usually have leaves that turn yellow and wilt, and if the infestation is not eliminated, the plant may eventually die.

Where do they live?

Mealybugs are plant feeders and will infest most parts of their host plant. They normally are located on the underside of plant leaves and stems, and populate many outdoor plants such annuals, bushes and shrubs. Mealybugs will heavily infest almost any plants in greenhouses, homes or businesses. They feed by forcing their needle-like piercing mouthparts into the plant and use a sucking action to remove the plant juices.

Most people want to know – How To Get Rid of Mealybugs – after they have seen mealybugs on their indoor plants or on other ornamental plants in the landscape.

If you have noticed what looks like small pieces of cotton or blotches of powder all over the leaves, those small, fuzzy, tiny white bugs on plants are probably mealybugs.

If you’ve seen them, naturally, mealybug control will be a priority.

What Do Mealybugs Look Like And Why Control is Necessary?

Mealybugs are white, soft-bodied, cottony-looking insects with a protective waxy coating, and equipped with piercing/sucking mouth parts under order hemiptera.

They are like plant scale insects and aphids in that they suck the fluids from green leaves and stems, robbing plants of essential nutrients.

Mealybugs excrete large amounts of honeydew, this makes an excellent “growing soil” for a black fungus called sooty mold. Some of the known species of mealybugs that are likely to infest your home and garden include:

  • Pink hibiscus mealybug (Maconellicoccus hirsutus)
  • Vine mealybug
  • Citrus mealybug (Planococcus citri)
  • Grape mealybug
  • Longtailed mealybug (Pseudococcus longispinus)
  • Pineapple mealybug
  • Obscure mealybug (Pseudococcus viburni)

Sooty mold is unattractive and interferes with photosynthesis, it can also retard the growth of the plant.

This can also make the leaves and floors sticky. Sooty mold usually whithers away after removing the mealybug.

Related: Organic Natural Pest Control Without Pesticides

Watch For Ants Feeding On Mealybug Honeydew

Where do mealybugs come from?

Ants feed on the honeydew when you find ants crawling around your plants indoors or out or observed making a nice trail from a plant.

Take some time to examine your houseplants closely for these sucking pests.

These annoying white bugs on plants do well indoors – they love and live very well in warm, dry environments. These pests have a life cycle of about 30 days.

These crawlers normally call home and adult females deposit their eggs where leaves join stems or along leaf veins. When the eggs hatch, their feeding will cause leaves to turn yellow and drop.

Damaged plants look withered and may have a sticky sap on the leaves or stems.

Mealybugs On Houseplants – What Plants Get Them On The Most?

Some of the indoor plants most commonly affected by mealybugs include:

  • The African violets pests include root and foliar mealybug
  • Aglaonema
  • Cactus and Succulent pests
  • Dracaena plants
  • Ferns
  • Palms
  • Ficus – weeping fig
  • Pothos plants – Green Jade, Golden & Marble Queen
  • Philodendron
  • Norfolk Island Pine – Araucaria Plant
  • Schefflera
  • Jade succulent with yellow leaves falling off
  • Spineless Yucca Elephantipes

How To Get Rid Of And Control Mealybugs On Plants

Here’s how to kill mealybugs.

As with soft scale insects, an easy method of control is to apply alcohol with cotton swabs directly on the mealybug.

Wiping down the foliage regularly and helping plants clean will help keep these white fuzzy bugs in check.

For a mealy bug insecticide, if a plant becomes severely infested consider using safe natural organic neem oil sprays to control the pest or make your own homemade insecticidal soap or possibly horticultural oils.

Neem can be found at your local garden center. Always read the pesticide label and wear appropriate safety equipment when applying any chemical.

For heavy infestations of mealy bugs that are hard to reach, try spraying directly on the insects a mixture of 10 percent rubbing alcohol and 90 percent water. Repeat applications weekly until the bugs are gone.

Always test any insecticidal soap and alcohol mixtures on a small portion of the plant prior to full application as some plants may be sensitive to soap or alcohol. Systemic insecticides are another possibility, although I try to avoid them.

How To Get Rid Of Mealybugs On Orchids?

Here’s how to get rid of mealy bugs.

Mealy Bug feeding on the buds of Phalaenopsis moth orchid

Prevention is the best way to get rid of mealy bugs on orchids. These pests can come from a number of sources, such as:

  • Plants that have been allowed to spend time outside during the warm months
  • Fresh produce or flowers (either purchased or brought in from outdoors)
  • Put in place by ants seeking to set up a “farm” to harvest honeydew
  • New plants introduced to your collection
  • Use of contaminated potting medium

Whenever you purchase a new plant, bring plants or produce in from outdoors, inspect thoroughly for mealybugs and ants!

Quarantine new plants for a couple of weeks to avoid introducing pests to your orchids and other houseplants.

Kill The Mealybugs When You See Them

Luckily, mealybugs are susceptible to many non-toxic home remedies so you do not have to use toxic pesticides in your home to get mealybugs off your orchids.

One of the simplest and most popular treatments is simply to use a cotton swab dipped in rubbing alcohol on these pests when you see them. Rubbing alcohol will kill them on contact.

Don’t just treat the obvious ones, though. Inspect the entire orchid to find any that may be lurking in the leaf joints, under leaves, in the substrate or in crevices in the container.

To eliminate mealybugs check frequently and treat repeatedly to be certain of killing them all.

Treat Mealybugs On Orchids With Homemade Insecticidal Soaps

Make an effective mealybug treatment (insecticidal soap) using a mild spray mix using a liter of distilled water and a teaspoonful of organic liquid castile soap. Doctor Bronner’s makes a good product.

Check Out our Homemade Recipe For Insecticidal Soap

You can also make a liter of orchid-safe mealy bug spray by combining distilled water and isopropyl alcohol 50/50 along with a teaspoonful of liquid castile soap in a spray bottle.

Spraying alcohol will help kill off mealybug eggs.

Spray on the plant (orchids) lightly, early in the day. Be sure they are in an area that has bright, indirect light and good air circulation so that the water and spray will dry thoroughly.

You don’t want your orchid leaves to stay damp for an extended period of time.

Heavily infected orchids can be rinsed in a castile soap and water solution, rinsed and allowed to dry thoroughly.

It is not a good idea to spray or rinse blossoms or buds. If mealybugs infest an orchid in bloom, it’s best to sacrifice the blossoms by pruning them to save the plant.

Neither rubbing alcohol or mild insecticidal soap have residual effects, so you will need to treat repeatedly over several days to eradicate all the pests.

Check back daily to be sure the job is complete.

Neem Oil Has A Residual Effect

A mild solution of organic neem oil is also safe to use on orchids.

This natural pest control product is very versatile, and you are sure to find lots of uses for it on all your houseplants and in your garden.

Be sure to follow packaging directions carefully when using the concentrate to make foliar sprays and soil drench solutions.

Even with its residual effects, neem oil should be applied several times for best results.

8 Step Process For Orchid Mealybug Control And Eradication

Follow these eight steps to get rid of mealybugs and keep them away:

#1 – Be vigilant! Examine all plants and their containers thoroughly for mealybugs on a regular basis.

#2 – Inspect all of your plants and treat as needed.

#3 – When you see mealybugs, act immediately.

  • Wash heavily infested orchids with a mild insecticidal soap solution.
  • Use a cotton swab with alcohol to treat mild infestations.
  • Change container and substrate if necessary.
  • Prune blossoms if necessary.

#4 – Wash down your plant area using a strong solution of soapy water. Finish up by spraying the area with rubbing alcohol and wiping it down again.

You can add a little neem oil to the alcohol spray for added residual effect.

#5 – Quarantine affected plants – make sure they are not touching any other plants and treat with neem oil spray.

#6 – Carefully observe the affected orchid. Check it every day and use a cotton swab dipped in isopropyl alcohol to kill off any mealybugs that may reappear.

#7 – If you still see mealybugs after a week, treat with neem oil spray again.

#8 – Keep the orchid in quarantine for several weeks. When you no longer see any sign of mealybugs, you can put it back in your collection.

Keep A Clean Plant Area

Mealybugs are able to hide in crevices and remain alive in a dormant state even when plants are not present.

Be sure to move your plant collection and wipe down all surfaces with soap and water and rubbing alcohol on a regular basis.

Check and wipe down the bottoms of containers and saucers and all equipment used to care for your orchids and other houseplants.

Mealybugs can hide out in orchid potting medium and regular potting soil.

If they are a recurring problem, you may need to repot orchids and other plants with fresh, new substrate.

When you repot orchids, be sure to clean and treat the roots with a mild insecticidal soap solution. Rinse thoroughly before placing the plant in its new substrate.

How to Get Rid Of Mealy Bugs On Succulents?

Mealybugs are susceptible to all sorts of pesticides and homemade pest control solutions, but one of the simplest and most affordable for use with succulents is 70% isopropyl alcohol.

These pests can be killed on contact with a little rubbing alcohol on a cotton swab, or you can simply spray your succulents with straight rubbing alcohol to kill off both the pests and their eggs.

In cases of heavy infestation, you can even use straight rubbing alcohol as a soil drench to kill the bugs and their eggs in the soil surrounding the plant.

Quarantine Affected Plants

When you see mealybugs on one of your succulents, be sure to remove or separate it from your collection. It is helpful to give plants a good drenching and keep it apart for a couple of weeks.

Check every day and treat for mealybugs as needed by spraying. Check all parts of the plant and its pot for any bugs that may be hiding in crevices.

Take special care to inspect the base of the stem as these bugs like to hide in the soil surrounding the plant. Spray or drench this area liberally.

It’s also a good idea to clean up your plant area with a strong solution of detergent and water and treat other members of your succulent collection with rubbing alcohol.

It won’t hurt them, and it may help prevent a major infestation. Many enthusiasts simply keep a sprayer bottle of isopropyl alcohol close at hand for regular treatments.

For more details read our Mealybugs on Succulent Plants article.

Is Straight Rubbing Alcohol Really Safe For Succulents?

For succulents, regular use of rubbing alcohol does not seem to be harmful. It kills the pests on contact and then it evaporates quickly, so it doesn’t have a chance to damage plants or roots.

Most succulent enthusiasts agree that isopropyl alcohol is the most affordable and simplest solution for getting rid of mealy bugs on succulents.

However, if you don’t want to use alcohol or don’t have it on hand, try adding a teaspoonful of dish soap to a quart of water to make a spray.

If you have an outdoor succulent garden, be sure to keep a healthy population of natural predators, such as Lady Bugs.

Vigilance Is Key To Defeating Mealybugs

If you can catch mealybugs before they have a chance to reproduce much, you should be able to keep them under control or even eradicate them with the rubbing alcohol method.

Just be sure to treat infestations repeatedly until you see no more mealybugs. Continue to spray and perform preventative measures on a regular basis.

https://www.succulentsandsunshine.com/kill-mealybugs-on-succulents/

All Natural Mealy Bug Control With Beneficial Insects

Using beneficial insects or natural enemies for biological control of mealybugs is another option.

For example, one mealy bug killer is the beneficial insect also known as the “Mealybug Destroyer” or Cryptolaemus montrouzieri technically and as “Crypts” for short.

They, like the excellent garden friend the ladybug, Cryptolaemus montrouzieri are lady beetles. Unlike the ladybug, these beneficial insects hang around after release and do not disappear.

Leptomastix dactylopii makes another natural enemy of mealybugs. They are parasitic wasps that attack the citrus mealybugs.

You can also go for other mealybug destroyers that also go after nymphs, aphids, spider mites, fungus gnats, and more.Image: Forest and Kim Starr | puuikibeach

Have you ever found something on a houseplant that you first thought was a tiny piece of cotton, but then you realized was a living thing? Mealybugs can ruin the appearance of your indoor and outdoor plants and can cause a significant amount of damage. When left unchecked, mealybugs can eventually kill a plant. For such small creatures, mealybugs can be surprisingly hard to remove. They are found in warm, moist climates and can be introduced to your home and yard by new plants, tools or other materials.

Mealybugs: A Complete Guide To This Lawn Pest

In this post, we will tell you everything you need to know about mealybugs, including what they look like, their favorite hiding spots, their impact on our green spaces and, perhaps most importantly, what you can do if you find them feasting on your plants.

Tiny White Bugs On Plants Can Be Harmful

Those tiny white bugs you noticed while watering your plants might actually be a mealybug infestation. These tiny pests are typically white in color, which comes from a wax produced by special glands on the top and sides of their bodies. Mealybugs are related to aphids, which are also covered with waxy secretions, so these two insects are often confused.

Mealybugs are tiny creatures—sometimes only half a millimeter long—which often congregate on the part of the plant where the leaves attach to the plant’s stem. Aphids are more likely to leave behind residue in patterns on the backside of leaves or in a coating on a plant’s stem. Although it’s difficult to catch mealybugs on the move, you can sometimes notice active adults making their way across a plant’s leaves or stem. Do mealybugs fly? Only the adult males. Both insects can cause similar damage to your plants, and you can use some of the same tactics to control these pests.

All plant species are at risk for damage from a mealybug infestation. In warmer parts of the country, citrus and ornamental plants are more severely impacted by this lawn pest. Tropical plants, woody trees, shrubs, perennials and annuals can also be attacked by this pest. Mealybugs feed by sucking sap from plant roots, crowns, stems, twigs, flowers, fruit and leaves and leaving behind a honeydew-like residue which attracts ants. The sticky substance provides the perfect conditions for a sooty-colored mold to develop on the plant.

Mealybugs are experts at hiding on roots, in crevices and under lips and pots and planters. There are many species of mealybugs, all of which are very tiny. Some have longer tiny needle-like rods which look like tails, while others have longer rods extending around their bodies. Some species are more pink, yellow or light green in color, but most are white.

Where Do Mealybugs Come From?

Mealybugs are so small that they can come in undetected from a variety of sources: potting soil, other plants, fresh produce from the grocery store or farmers market. You are more likely to find mealybugs inside, but you can also find them outdoors. The pink hibiscus mealybug is a native of India and was first reported in Egypt in 1920. It spread to the Caribbean in 1993 and then quickly spread through the islands and up to Florida from there.

Other states such as Alabama, Arizona, California, Georgia, Louisiana, Mississippi, New Mexico, North Carolina, South Carolina and Texas also suffer economic losses because of the infestation of mealybugs on crops and ornamental plants in nurseries.

If you are wondering what attracts mealybugs, understanding that these pests prefer plants with high levels of nitrogen can lead you to be more judicious in applying fertilizer and water. Homeowners who overfertilize plants or keep plants moist may be unknowingly making their plants more vulnerable to an infestation.

Where to Find Mealybugs

Mealybugs can look like little pieces of cotton on your plant. They like to hide in hard-to-see areas like under the leaves and in crooks and crevices of plants like the leaf and stem axis. However, they will infest any area of the plant. When you just have one or two females, they can be harder to spot. However, once they start laying their egg sac or the eggs hatch, then they are much easier to spot because they tend to cover more areas of your infected plant.

Are Mealybugs Harmful to Humans?

Some mealybugs can spread viruses, but this is uncommon and primarily occurs with species which prefer grapevines. Mealybugs do not bite humans, although coming into contact with these creatures can sometimes cause skin irritation. The sticky residue mealybugs leave behind can be hard to remove from clothing. Wash your hands and clothing after coming into contact with mealybugs to avoid any potential impact.

The biggest threat mealybugs pose is to humans is economic. Damage from these pests to agricultural crops can be significant and homeowners may be forced to discard impacted plants in cases of an infestation.

Mealybugs on Succulents

These troublesome pests can be a major headache for succulent owners. Mealybugs are notorious for hiding in the plant crevices and sucking them dry, especially once the egg sacs hatch. Removing dead areas of the plant can help take away their hiding spots, as well as reduce the occurrence of mold on your plant.

Mealybug Life Cycle

Mealybugs start out as eggs and then move into larval and adult stages. Females lay up to 500 eggs in a cottony egg sac attached to plants, fruit, bark or twigs. After about 10 days, the egg sac hatches and the babies quickly spread out over the plant looking for feeding sites.

Adult male mealybugs are tiny two-winged insects are born without the ability to feed and die quickly. Their sole meaning for existence is to fertilize the females. In warmer climates, mealybugs can produce up to 8 generations in a single year. In more temperate areas, mealybugs only produce one or two generations annually.

Mealybugs in Florida

Pink hibiscus mealybugs, which are reddish-brown or pink with no noticeable filaments or stripes, were discovered in Florida in 2001. This species attacks many of Florida’s crops and plants, such as citrus, avocado, fig, guava, mango, sugarcane, asparagus, beans, beets, cabbage, peanuts, cucumber, lettuce, pepper, pumpkin, tomato, bougainvillea, hibiscus, palm and oleander.

This pest’s impact on agriculture is so significant that a professor from the University of Florida wrote a whitepaper about it, stating that, “The overall annual cost of control and damages to the US economy from PHM have been estimated to be US $700 million, with the global total being about $5 billion.”

In Florida, we mainly see the long-tailed, citrus, madeira, solanum, striped, solenopsis, papaya, Granara de Willink, Jack Beardsley and pink hibiscus mealybugs, according to the University of Florida.

Prevention

Before introducing a new plant inside or into your garden, inspect it for mealybugs and other insects. They can be found hiding in protected, hard-to-see areas of the plant, like the underside of leaves, stems, touching leaves and leaf axils. Remember to check everything before introducing it into your house or garden: the soil, leaves, stems, fresh produce and garden tools.

If you catch a mealybug infestation early, you can usually cut off the infected parts of the plant to prevent it from spreading.

As we mentioned earlier, mealybugs are attracted to high nitrogen levels, so don’t overwater or over fertilize your plants.

Mealybug Removal Tips

Mealybugs are notorious for being some of the most difficult to remove pests for homes and greenhouses. If you can catch them before the infestation grows, your likelihood of success is higher. Here are some tips for trying to rid your plants of mealybugs:

  • Be sure to remove any infected plant away from healthy plants as soon as possible.
  • Many people recommend putting alcohol on a Q-tip and applying it to infected areas. We’ve also heard of people putting the alcohol in a spray bottle and spraying that on the plant. If you try this, be judicious about how much you spray, so that you don’t damage the plant.
  • Spraying your plants with high-powered water can also remove these pests.
  • Ladybugs eat mealybugs. By introducing beneficial insects, including lacewings, syrphid flies and small parasitic wasps, you can help reduce mealybugs on your outdoor plants.
  • Insecticidal soaps and dish soap have also been known to get rid of small infestations.
  • Pruning infected leaves or stems can also help rid them from your plant.
  • Introducing the Cryptolaemus montrouzieri is another way to combat these pests, since this beetle is known to feed on mealybugs.
  • Throwing away the infected plant.

ABC Will Help Protect Your Plants

Since mealybugs are so tiny, prolific and expert hiders, an infestation can crop up quickly. If you experience an infestation or have trouble handling the problem on your own, the professionals at ABC Home & Commercial Services can help devise a plan to treat the mealybugs, as well as the ants that are attracted to the sticky residue they leave behind. The earlier you schedule service, the quicker the experts at ABC can help rid your plants of these pests before they destroy your plants and garden.

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