Unintended Consequences and Accidental IntroductionsFrom the last ice age up to the time of Spanish settlement, the number of species in Floridaremained relatively constant. However, when the Spanish arrived, new organisms from disease-causing microbes to feral hogs became established, and over the next 500 years humans con-tinued to introduce new species. Some introductions have had enormous impacts, others havehad none. Some introductions are accidental, and some have had unintended consequences.From fleas to flies, rabies to rodents and, more recently, melaleuca and the lobate lac scale,hundreds of species have been introduced in the last five centuries. We struggle to maintainfragments of something we call the real Florida, but it is a difficult battle. Melaleuca has overtaken thousand of acres of natural areas, but with an aggressive approach we might winthat battle. The lobate lac scale is another alarming invasive pest that is killing trees and shrubsacross South Florida. This tiny insect does not discriminate between natural vegetation, land-scaped shrubs, or commercial fruit trees. If left unchecked, the effects of lobate lac scale, likethose of melaleuca, will ripple across ecosystems and compromise habitat quality for all wildlife.

For more information on melaleuca and its management, visit the TAME Melaleuca Web site

http://tame.ifas.ufl.edu

Project Coordinator: Cressida SilversUSDA-ARS Invasive Plant Research Laboratory

Ft. Lauderdale, FL(954) 475-0541

USDA-ARS is an equal opportunity employer. February 2004

Lobate Lac Scaleand Melaleuca:

A Devastating Insect Aidedby an Invasive Tree

http://tame.ifas.ufl.edu

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The InvaderLike a hurricane in slow motion, the lobate lacscale is spreading across South Florida anddestroying a variety of trees and shrubs in itswake. It congregates in large numbers and cloaksitself and its victims in black sooty mold. No larger

than a pin-head, thisinsect ispoised tocreate bigtrouble –perhaps themost signifi-cant troubleyet for gar-dens andnaturalareas inSouthFlorida.

The lobate lac scale is a relatively new insect pestin Florida, but it already has an enormous pres-ence. Native to India and Sri Lanka, it was firstfound in Broward County in 1999 and some of theheaviest infestations remain in that county. By2002, it had spread north to Lake Worth, south toHomestead, and west into the Everglades. Lobatelac scale also occurs in the Bahamas, where arecent survey found that two-thirds of plant speciesexamined were infested with lobate lac scale. Thisinvasive pest has been found on over 200 speciesin Florida. Many important plants are highly sus-ceptible, including native species such as wax myr-tle, coco plum, red bay, wild coffee, and stranglerfig, and commercially important species such asmango, ficus, lychee, and star-fruit. This wide-spread choice of hosts is what makes lobate lacscale particularly troubling. Evidence of their sap-sucking destruction includes blackened leaves andbranches, branch dieback, and for susceptiblespecies of shrubs and trees, death.

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

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 whilethe true lac scale has been used since ancienttimes to produce shellac, the lobate lac scale hasno commercial value. Lobate lac scales are darkbrown but oftenappear dull blackdue to a coveringof sooty mold.This mold alsogrows on theleaves of infestedand nearby unin-fested plants,feeding on thesugary waste(honeydew)excreted by thelobate lac scale.Measuring about1/16 inch across,the adult lobate lac scale is visible to the nakedeye, and looks like a tiny, four-lobed bump of bark.These hardshelled adults are usually surrounded

by dozens of othersuch bumps. Theyare found primarilyon thin woodybranches less than1 inch in diameter.

Adults are immobile,but the red-coloredlarvae are not; it isat this stage of theirlife cycle that infes-tations spread. Thelarvae, sometimescalled crawlers,often move or fall tonew sites on theirhost plants ornearby plants. Whiletheir spread is often

aided by strong winds, much of their long-distancedispersal results from the actions of people, suchas when a plant owner moves an infested plantfrom one location to another. You can help by nottransporting any plants or plant material that yoususpect of harboring lobate lac scale. Nurseriesinfested with lobate lac scale are quarantined untilthey are free of the pest.

Double Trouble: Melaleuca and theLobate Lac ScaleMelaleuca (MEL-ah-LUKE-ah) is an invasive weedthat spreads into valuable wetlands and other nat-ural areas in Florida. It easily outcompetes nativevegetation and severely diminishes wildlife habitatquality. Melaleuca has infested hundreds of thou-sands of acres and has cost millions of dollars incontrol efforts. It is on the Federal Noxious WeedList and is illegal to possess in Florida.Furthermore, melaleuca serves as a good host forthe lobate lac scale. Melaleuca trees infested withthe lobate lac scale can act as a breeding groundwhere large numbers of larvae are free to spreadonto valued landscape and native plants.

Melaleuca and other invasive weeds should beremoved in order to protect Florida’s natural areasand to help avoid or control lobate lac scale infestations. Contact your county’s CooperativeExtension office for guidance on the removal ofmelaleuca.

The TreatmentBecause lobate lac scale is a relatively new pest,little research about it has been published. Evenso, certain insecticides are effective in controllinglobate lac scale on ficus trees but are not currentlylegal to use on most fruit trees. Horticultural oilsare generally effective on scale insects, and workis underway to determine their effectivenessagainst lobate lac scale.

The best long-term solution for controlling thelobate lac scale is using its natural enemies – aconcept known as biological control. When plantsor animals are introduced beyond their naturalrange, they are often without the associated

complex of insects and diseases that normallycontrols their numbers.

Biological control involves determining what organ-isms attack the pest in its native range, and thenreleasing these agents into the non-native range.For the lobate lac scale in Asia, some natural ene-mies are tiny non-stinging wasps. The wasps hashave a very narrow diet, but before these natural

enemies can beused in Florida,research mustconfirm that theyeat nothing but thelobate lac scale.Researchers withthe USDAAgriculturalResearch Service,the University ofFlorida, and theFlorida Depart-ment of Agricultureand ConsumerServices are working with col-leagues in Indiaand Thailand toacquire and studythese natural enemies.

Residents wishingto treat lobate lac

scale infestations may contact their county’sCooperative Extension office (seehttp://extension.ifas.ufl.edu) for more guidance(including publication #EENY-276). The state hasalso posted three lobate lac scale circulars onlineat

http://edis.ifas.ufl.edu/IN471,

http://creatures.ifas.ufl.edu/orn/scales/lobate_lac.htm,

http://www.doacs.state.fl.us/~pi/enpp/ento/parat-achardina.html.

Bumps on the stems and sooty moldon the leaves of this wax myrtle indicate a lobate lac scale infestation.

Wax myrtles are perhaps the mostsusceptible of all trees to lobatelac scale. Unfortunately, wax myr-tles are one of the most importantberry-producing trees for birds inSouth Florida.

Lobate lac scale usually infests twigsand small branches that are lessthan 3/4 inch in diameter. It has notbeen observed on foliage.

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