Lobate Lac Scale and Melaleuca:

A Devastating Insect Aidedby an Invasive Tree

This brochure was produced by TAME Melaleuca (TheAreawide Management Evaluation of Melaleuca quinquen-ervia), a multi-agency project promoting the long-term,areawide management of melaleuca. TAME Melaleuca isfunded and coordinated by the USDA’s AgriculturalResearch Service, and cooperators include the SouthFlorida Water Management District and the University ofFlorida’s Institute of Food and Agricultural Sciences. Formore information, visit our Web site athttp://tame.ifas.ufl.edu.

Unintended Consequences and Accidental IntroductionsFrom the end of the last ice age up to the time of Spanish settlement in 1500, the number ofspecies in Florida remained relatively constant. However, when the Spanish arrived, new organisms from disease-causing microbes to feral hogs became established, and over the next 500years humans continued to introduce new species. Some introductions have been intentional,while others were accidental. Some have had enormous impacts, while others have had none.From house flies and cat fleas to rabies, West Nile virus, house mice, dandelions, melaleuca, andlobate lac scale, hundreds of species have been introduced in the last five centuries. We struggleto maintain fragments of something we call the real Florida, but it is a difficult battle. Melaleucahas overtaken thousand of acres of natural areas, but with an aggressive approach we may win thebattle. The lobate lac scale is a different story. This alarming pest is killing trees and shrubs acrossSouth Florida, and the effects will ripple across ecosystems and compromise habitat quality for allwildlife. This tiny insect does not discriminate between natural vegetation, landscaped shrubs, orcommercial fruit trees. Please help us control lobate lac scale, melaleuca, and all invasive species.

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The InvaderLike a hurricane in slow motion, this invader isspreading across south Florida and destroying all kindsof trees and shrubs in its wake. It congregates in large

numbers andcloaks itselfand its victimsin black sootymold. Nolarger than apinhead, thisinsect has thepotential tocreate big trou-ble–perhapsthe most sig-nificant trou-ble yet for

gardeners and natural areas alike in South Florida. Itis the lobate lac scale.

The lobate lac scale is a relatively new insect pest inFlorida, but it already has an enormous presence.Native to India and Sri Lanka, it was first found inBroward County in 1999 and some of the heaviestinfestations remain in this county. By 2002, it hadspread north to Lake Worth, south to Homestead, andwest into the Everglades. Lobate lac scale also occursin the Bahamas, where a recent survey found thattwo-thirds of plant species examined were infestedwith lobate lac scale.

The lobate lac scale does not discriminate widely in itshost plants, and it has been found on over 150 speciesin Florida. Many important plants are highly suscepti-ble, including native species such as wax myrtle, cocoplum, red bay, wild coffee, and strangler fig, and com-mercially important species such as mango, ficus,lychee, and star-fruit. This widespread choice of hostsis what makes lobate lac scale particularly troubling.Evidence of their sap-sucking destruction includesblackened leaves and branches, branch dieback, andfor susceptible species of shrubs and trees, death.

Double Trouble: Melaleuca and theLobate Lac ScaleMelaleuca (MEL-ah-LUKE-ah) is an invasive weedthat spreads into valuable wetlands and other naturalareas in Florida. It easily outcompetes native vegeta-tion and severely diminishes wildlife habitat quality.Melaleuca has infested hundreds of thousands of acresand has cost millions in control efforts. It is on theFederal Noxious Weed List and is illegal to possess inFlorida. Furthermore, melaleuca serves as a particu-larly good host for the lobate lac scale. Residentialmelaleucas infested with the lobate lac scale can act assource populations where large numbers of lac scalelarvae are free to spread onto valued landscape andnative plants.

Melaleuca and other invasive weeds should beremoved in order to protect Florida’s natural areas andto avoid or control a lobate lac scale infestation.Contact your county’s cooperative extension office forguidance on the removal of melaleuca.

Identification of Lobate Lac ScaleScientific name: Paratachardina lobata lobata

The best known member of the lac scale family(Kerriidae) is the true lac scale of Asia, and while thetrue lac scale has been used since ancient times to pro-duce shellac, the lobate lac scale has no commercialvalue. Lobate lac scales are dark brown but oftenappear dull black due to a covering of sooty mold.This mold also grows on the leaves of infested andnearby uninfested plants, feeding on the excreted sug-ary waste (honeydew) secreted by the lobate lac scale.Measuring about 2 mm (1/16 inch) across, the adultlobate lac scale is visible to the naked eye, and lookslike a tiny, four-lobed bump of bark. These hard-

shelled adults areusually sur-rounded bydozens of othersuch bumps. Theyare found prima-rily on thinwoody branchesless than 2 cm (1 inch) in diameter.

Adults are immobile, but the red-colored larvae arenot; it is at this stage of their life cycle that mostplants become infested. The larvae, sometimes calledcrawlers, often crawl or fall to new sites on their host

plants or nearbyplants. While theirspread is often aidedby strong winds, muchof their long-distancedispersal results fromthe actions of people,such as when a plantowner moves aninfested plant fromone location toanother. Please help usby not transportingany plants or plantmaterial that you sus-pect of harboringlobate lac scale.

The TreatmentBecause lobate lacscale is a relatively newpest, little researchabout it has been published. Even so,

University of Florida researchers have found that theinsecticide imidacloprid is effective in controllinglobate lac scale on ficus trees. Imidacloprid is probablyeffective on other trees, but it is not currently legal touse on most fruit trees. As with any pesticide applica-tion, the applicator must read the label closely andfollow the directions. Imidacloprid is widely availableand sold under the brand names Merit (for profes-sional applicators) and Bayer Advanced Care Tree andShrub Insect Control (for homeowners). Horticulturaloils are generally effective on scale insects, and work isunderway to determine their effectiveness againstlobate lac scale.

The best long-term solution for controlling the lobatelac scale is using its natural enemies–a concept knownas biological control. When plants or animals areintroduced beyond their natural range, they are oftenwithout the associated complex of insects and diseasesthat normally controls their numbers. Biological

control involvesdetermining whatattacks the pest inits natural range,and then releasingthese agents intothe newly intro-duced range. Forthe lobate lac scalein India, one natu-ral enemy is a tinynonstinging wasp.The wasp has avery narrow dietand eats only lacscales, but beforethese natural ene-mies can be used inFlorida, researchmust confirm thatthey eat nothingbut the lobate lacscale. Researchers with the USDA AgriculturalResearch Service, the University of Florida, and theFlorida Department of Agriculture and ConsumerServices (FDACS) are working with colleagues inIndia and Thailand to acquire and study these naturalenemies.

Nurseries infested with lobate lac scale are quaran-tined as required by FDACS until they are free of thescale. Residents wishing to treat lobate lac scale infes-tations may contact their county’s extension office(see http://extension.ifas.ufl.edu) for more guidance(including publication #EENY-276). The state hasalso posted three lobate lac scale circulars online athttp://edis.ifas.ufl.edu/IN471,http://creatures.ifas.ufl.edu/orn/scales/lobate_lac.htm,and http://www.doacs.state.fl.us/~pi/enpp/ento/parat-achardina.html.

Lobate lac scales are small, even next to thelead in a mechanical pencil, yet they lead todeath in trees that are highly susceptible tothis pest.

A combination of bumps on the stems andsooty mold on the leaves of this wax myr-tle means a lobate lac scale infestation.

Wax myrtles are perhaps the mostsusceptible of all trees to lobate lacscale. Unfortunately, wax myrtlesare one of the most importantberry-producing trees for birds inSouth Florida. A blue backdropwas used in this photograph so thedamage could more easily be seen.

Lobate lac scale usually infests thewoody portions of twigs and smallbranches that are less than 2 cm indiameter (3/4 inch). It has not beenobserved on foliage.

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