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Guavas Gone Global

Wildland WeedsSUMMER 2000

2 SUMMER 2000

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WILDLAND WEEDS 3

Wildland WeedsWildland WeedsSUMMER 2000, Volume 3, Number 3

Wildland Weeds (ISSN 1524-9786) is a quarterly publication of the FloridaExotic Pest Plant Council (EPPC)

Wildland Weeds is published to provide a focus for the issues and con-cerns regarding exotic pest plant biology, distribution and control. To be-come a member of the Florida EPPC and receive the Council newsletterand Wildland Weeds Magazine, contact the Treasurer.

FLORIDA EXOTIC PEST PLANT COUNCIL

The Florida Exotic Pest Plant Council has not tested any of the products advertised or re-ferred to in this publication, nor has it verified any of the statements made in any of theadvertisements or articles. The Council does not warrant, expressly or implied, the fitnessof any product, advertised or the suitability of any advice or statements contained herein.

Direct editorial inquiriesto Amy Ferriter, EditorWildland Weeds Magazine:3301 Gun Club Rd.West Palm Beach, FL 33406aferrite@sfwmd.gov

Editorial BoardMike BodleJim CudaRoger HammerKen LangelandSteve ManningDan Thayer

For advertisinginformation contact:Outdoor Tech, Inc.6791 Proctor Rd.Tallahassee, FL 32308Phone 850 668-2353Fax 850 668-2664Debra Tarver

Officers

Tony Pernas, ChairmanP.O. Box 279Homestead, Florida 33030(305) 242-7846tony_pernas@nps.gov

Ken LangelandChair Elect7922 NW 71st StreetGainesville, FL 32606(352) 392-9614kal@gnv.ifas.ufl.edu

Jackie Smith, Secretary3111-B13 Fortune WayWellington, FL 33414(561) 791-4720Smithj1@mail.state.fl.us

Dan Thayer, TreasurerPO Box 24680West Palm Beach, FL 33416(561) 682-6129dthayer@sfwmd.gov

Amy Ferriter, EditorP.O. Box 24680West Palm Bch, FL 33416-4680(561) 682-6097aferrite@sfwmd.gov

Directors

Mike BodleP.O. Box 24680West Palm Bch, FL 33416(561) 682-6132 mbodle@sfwmd.gov

Keith Bradley22601 SW 152nd AveMiami, Florida 33170(305) 247-6547 bradley2@gate.net

Hillary CherryP.O. Box 118526Gainesville, FL 32609(352) 336-2623hcherry@ufl.edu

Dan Clark800 Dunlop Rd.Sanibel, Fl 33957(941) 472-3700dclark@peganet.com

Ed FreemanP.O. Box 8Sarasota, Fl 34230(941) 378-6142efreema@co.sarasota.fl.us

Doria GordonP.O. Box 118526Gainesville, FL 32611(352) 392-5949dgordon@botany.ufl.edu

Francois LarocheP.O. Box 24680West Palm Bch., FL 33461(561) 682-6193flaroche@sfwmd.gov

Brian Nelson2379 Broad StreetBrooksville, Fl 34609(352) 796-7211brian.nelson@SWFNMD.state.fl.us

Committee Chairs

By-LawsFrancois LarocheP.O. Box 24680West Palm Bch., FL 33461(561) 682-6193flaroche@sfwmd.gov

EditorialAmy FerriterP.O. Box 24680West Palm Bch., FL 33416(561) 682-6097aferrite@sfwmd.gov

Legislativevacant

MembershipBrian Nelson2379 S. Broad St.Brooksville, FL 34009(352) 796-7211

MerchandiseJackie Smith3111-B13 Fortune WayWellington, FL 33414(561) 791-4720791-4722Smithj1@mail.state.fl.us

Plant ListDan Austin/Kathy BurksFlorida Atlantic UniveristyDepartment of BiologicalSciencesBoca Raton, FL 33431(561) 297-3327daustin@fau.edukathy.burks@dep.state.fl.us

PublicationsKen Langeland7922 NW 71st StreetGainesville, FL 32606(352) 392-9614kal@gnv.ifas.ufl.edu

ProgramKen Langeland7922 NW 71st StreetGainesville, FL 32606(352) 392-9614kal@gnv.ifas.ufl.edu

SymposiumTony PernasP.O. Box 279Homestead, Florida 33030(305) 242-7846tony_pernas@nps.gov

ResearchJohn Volin2912 College Ave.Davie, FL 33314(954) 236-1115jvolin@fau.edu

EducationJim DuquesnelP.O. Box 487Key Largo, FL 33037(305) 451-1202jpcrsp@reefnet.com

VendorsPhil Waller6651 Englelake Dr.Lakeland, FL 33813(941) 619-6255phil_waller@py.cyanamid.com

Task Forces

Brazilian PepperDean Barber5882 South Semoran Blvd.Orlando, FL 32822(407) 275-4004barber1@mail.state.fl.us

LygodiumAmy Ferriter andTom Fucigna3301 Gun Club Rd.West Palm Bch., FL 33416(561) 682-6097aferrite@sfwmd.gov

CarrotwoodEd FreemanP.O. Box 8Sarasota, FL 34230(941) 378-6142Fax 378-6136efreema@co.sarasota.fl.us

VinesMike BodleP.O. Box 24680West Palm Bch, FL 33416(561) 682-6132mbodle@sfwmd.gov

Exotic GrassesJoe Maguire22200 Sw 137th AvenueGoulds, FL 33170(305) 257-0933flameabl@shadow.net

Skunk VineSheryl Bowman andBrian Nelson10940 McMullen Rd.Riverview, FL 33569(813) 672-7876resmgmt@scfn.thpl.lib.fl.us

Chinese TallowGreg Jubinsky3915 Commonwealth Blvd.MS710Tallahassee, FL 32399(850) 487-2600greg_jubinsky@dep.state.fl.us

MelaleucaFrancois LarocheP.O. Box 24680West Palm Bch., FL 33461(561) 682-6193flaroche@sfwmd.gov

Visit these websites:

Florida EPPC’s: www.fleppc.orgTennessee EPPC’s: www.webriver.com/tn-eppc

California EPPC’s : www.caleppc.org

Table of Contents

4 Editor's Note

4 Exotic Guavas in Florida: So delicious but–by Ken Langeland and David Hall

5 Psidium catleianum, Deliciously dangerous inHawaiby Charles Wikler

12 Herbicide Screening Results for Two CommonExotic Grass Species in Floridaby Dan Thayer

17 Chinese privet, Ligustrum sinense: Prospects forClassical Biological Control in theSoutheastern United Statesby J.P. Cuda and M.C. Zeller

20 The Great Air Potato Round Upby Steven Vann

22 Internodes

About the cover:The yellow varietyof strawberry guava(Psidiumcattleianum) formsdense thickets alongthe Little ManateeRiver in Florida andis considered one ofHawaii's worstweeds.

4 SUMMER 2000

editor’s noteSome weeds are harder to hate than others. The guavas

for instance - they're almost too tasty to condemn. Guavajelly, guava jam, guava shakes.... Read about guava's gas-tronomical attributes and astronomical spread in two articlesin this issue. Ken Langeland and David Hall detail two spe-cies (Psidium guajava and P. cattleianum) in Florida (below)and Charles Wikler describes strawberry guava (P.cattleianum) in Hawaii where researchers are hoping to in-troduce South American biocontrol agents soon.

Find out about the prospects for biocontrol of Chineseprivet (Ligustrum sinense) in the Southeast on page 17, andsaddle up for the wildly-successful "Great Air PotatoRoundUp" on page 20. Too bad air potatoes aren't as tastyas guavas. But then again, "Dioscorea shake" doesn't exactlyhave an appealing ring. -Amy Ferriter

By Ken Langeland andDavid Hall

The guavas belong to the genusPsidium (Myrtaceae, Myrtle Family),which comes from the Greek, mean-ing edible fruit. Psidium is a tropicalAmerican genus with approximately100 species of evergreen trees andshrubs, some with edible berries.Common guava, Psidium guajava L.,strawberry or Cattley guava, Psidium

Exotic Guavas in Florida:so delicious but—

cattleianum Sabine [P. littorale Raddi](Schroeder 1946, Wunderlin 1998), andCosta Rican guava, Psidiumfriedrichsthalianum (O. Berg) Niedenzu,occur in Florida as landscape plants(Dehgan 1998). Psidium longipes (O.Berg.) McVaugh, mangrove berry, isnative to Florida. The guava fruit, es-pecially that of Psidium guajava culti-vars that have been developed withsuperior taste qualities, is highly re-garded for its edible qualities, eaten

fresh and used in jellies, jams, drinks,pies, ice cream, etc. Cultivars of P.guajava are grown commercially fortheir fruit. Common guava, and straw-berry guava are known to have es-caped cultivation and included on the"Florida Exotic Pest Plant Council's(FLEPPC) 1999 List of Invasive Spe-cies". Both are listed under Category I,which means they are considered byFLEPPC as invasive exotics that arealtering native plant communities.

Common guava (Psidium guajava)

WILDLAND WEEDS 5

Common GuavaCommon guava (Psidium guajava L.)

is a shrub or small tree, usually under15 feet tall (rarely to 30 feet), with scalybark. Branches are 4-angled and hairy.The opposite leaves have a short stalk/petiole and elliptic to oblong leatheryblades. The lower blade surface is cov-ered with soft hairs, contains numer-ous glandular dots and has very no-ticeable riblike lateral veins. Inflores-cences are usually 1-flowered in leafaxils. The five sepals are united. Thefive petals are white, showy, roundedand just under 1 inch long. Stamens arenumerous. The ovary is imbedded be-low the rest of the flower parts (infe-rior). The usually dull yellow fruits arerounded or pear-shaped, manyseededberries about 1 to 2 1/2 inches longwith pink or yellowish flesh. Repro-duction is by seeds. Blooming occursall year.

Common guava has been cultivatedand distributed by man and animalsfor so long that it is difficult to be cer-tain of its place of origin but it is be-lieved to be from an area extendingfrom southern Mexico into or throughCentral America (Morton 1987). It isnow cultivated and escaped through-out the New and Old World tropics.In addition to its value for edible fruit,the wood is valued in some parts ofthe world, tannin is extracted for usein tanning and for dyes and, in addi

Psidium cattleianum,Deliciously dangerous inHawaii By Charles Wikler

Eating the delicious red or yellowfruits of strawberry guava (Psidiumcattleianum) we would never imaginehow big the problem caused by theseplants is in many tropical regions. Thisspecies is invading extensive areas, dis-persing into important natural habitats,ecologically disrupting them. In addi-tion, this plant is host to several speciesof fruit flies.

Introduced to Hawaii about 1825,strawberry guava quickly escaped fromcultivation. It has become the most im-portant forest weed in Hawaii (Smith,1985) due to suitable soil and climaticfactors, the absence of natural enemies,and effective dispersal by several differ-ent agents. Initially, birds disseminatedseeds. Feral pigs, relatively recent invad-ers of the Hawaiian ecosystem, havesince become the most important dis-persal agent of strawberry guava seeds(Diong, 1982).

Strawberry guava possesses severalof the characteristics of an opportunistinvasive species, but it seems that its abil-ity to grow clonally is the main reasonfor its successful invasion and domina-tion of intact native forests in the Hawai-ian archipelago (Huenneke, 1991). Thisplant is an excellent example of a plant

once confined to a small region but nowa widespread problem throughout thetropics and subtropics.

From the beginning, studies aboutthis plant generated considerable de-bate over which scientific name waspublished correctly for Psidiumcattleianum. Sabine (1821) named theplant in honor of William Cattley, thefirst person to successfully cultivate thespecies in Britain. Some authors con-sidered Raddi as the first to describethe plant, also in 1821, but in the lit-erature search, Raddi’s description re-fers to the plant as Psidium littorale in1823. Thus, the name Psidium littoraleis usually considered a junior syn-onym, as the original descriptions ofboth represent the same species.

According to Fosberg (1941) inEllshoff et al. (1995), the common nameused for strawberry guava is "araca" inBrazil, “waiwai” in Hawaii, and"Cattley guava" among some Ameri-can horticulturists. Strawberry guavais also mentioned in the literature as“goiave de L'Afrique”, in the Domini-can Republic, “araca-saiyu” and“guayabo amarillo” in Argentina,“araza” in Uruguay, "Calcutta-guava"in India, "china-guava" for the British,

Strawberry guava hascharacteristic gray-brown toreddish bark that peels off inirregular patterns.

6 SUMMER 2000

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WILDLAND WEEDS 7

Psidium cattleianum var. Iucidum

• P. cattleianum var. cattleianum (redform)The red form is a tree, with heights

from 2.5 meters up to 20 meters. Its trunkhas the same color of the yellow form al-though it differs in shape being straightand cylindrical with a larger diameter. Itscrown is slightly elongated and quitedense. Its fruit and its endocarp are redcolored. In the Araucaria Forest it isfound inside the woods but exclusivelyin the first plateau, ranging from 6501100m. The climate is hot and humid, withtemperature between 15 - 19 °C and 1250- 2500 mm annual rainfall.

Psidium cattleianum var. cattleianum

Biocontrol in HawaiiUnable to control strawberry guava

by mechanical and chemical means inHawaii, the U.S. National Park Serviceinitiated efforts to find biological controlagents against this weed. A cooperativeprogram between the Cooperative Na-tional Park Resources Studies Unit, Uni-versity of Hawaii at Manoa, and theParana Forest Research Foundation andthe Federal University of Parana was es-tablished in March 1991.

“goyavier of St. Martin” in Guadeloupe,"goyavier fraise" for the French,"goyavier prune" in Martinique and"purple-guava" in Jamaica.

Hoehne (1946) mentioned that thediKerentiahon between the species be-comes complicated for what is called"araca." Although the exact origin of thetype specimen is not known, it seemsthat the plant was cultivated in Asia andAmerica. However, the type locality ofP. Iittorale is cited by Raddi (1823) as thecoasts of Brazil.

Two botanical forms of strawberryguava tree are recognized based on fruitcolor. They are the red fruit P. cattleianumf. cattleianum (P. Iittorale var. Iongipes) andthe yellow fruit P. cattleianum f. Iucidum(P. Iittorale var. Iucidum).

Geographical distribution inthe area of origin

In Brazil, the genus Psidium is repre-sented by 9 species, including P.cattleianum. The plant occurs from theSouth of Espirito Santo State in Brazil toUruguay, (from 20° and 32° S). Straw-berry guava is a characteristic bush ofthe “restinga,” typical vegetation of theAtlantic Rain Forest, where it is widely

dispersed. Although present, it is not toofrequent in the first plateau. The speciesoccurs in humid soils, in small woods(capoeiras), and the border of creeks andsemi-devastated forests. It is also quite fre-quent in the coastal swampy fields alongthe littoral zone of the southern states ofSanta Catarina and Rio Grande do Sul. Itcan be found in and around the southernplateau, occurring in the ciliary forests, aswell as in disturbed fields (Reitz, Klein &Reis, 1983).

Morpholog of the varieties ofPsidium cattleianum

According to Wikler (1999), the maindifferences between the yellow and redforms of strawberry guava are:• P. cattleianum var. Iucidum (yellow form)

It is commonly a shrub in the coast, aspart of a vegetation formation called"restinga", where a wide variety of plantsgrow on the sandy substrate with a highwater table. The climate in the coast is hotand humid with temperatures between 18and 22°C and annual rainfall between1430-2450 mm. Its height varies between2.5 and 4 meters, rarely exceeding 5 m high.The trunk is tortuous and with very char-acteristic grayish-brown coloration, being

unmistakable in the places where it isfound. Its crown is round and quitedense. The fruits are yellow, as well asthe endocarp that ranges from light yel-low to white. In Parana State it is dis-tributed along the coast, and on the firstand second plateaus.

8 SUMMER 2000

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“Nautique”

WILDLAND WEEDS 9

tion to other medicinal uses, theroots, bark, leaves and immature fruitsare used to halt gastroenteritis, diar-rhea and dysentery throughout thetropics (Morton 1987). In Mexico, thetree may be parasitized by mistletoethat causes rosette-like formationscalled wood flowers, which are sold asornamental curiosities (Morton 1987).

According to P. W. Reasoner, com-mon guava was introduced to Floridafrom Cuba in 1847 (Popenoe 1920).However, it was already reported asnaturalized in 1765 (DeBrahm 1773).The 1887-1888 Catalog and Price Listfor Royal Palm Nurseries states: “Theguava has become a necessity to SouthFlorida; is to South Florida what thepeach is to Georgia”. It has been grownsuccessfully as far north as the Pinellaspeninsula [sic] on the west coast andCape Canaveral on the east coast(Popenoe 1920) and was grown com-mercially at Palma Sola, Punta Gorda,Opalacha, Indiantown, and other lo-calities (Barrett 1956). Three cultivarsare now grown commercially, Home-stead and two private selections.About 225 acres are in production inDade (90%), Lee, Broward, and PalmBeach Counties (Jonathan Crane, per-sonal communication). This acreagehas been expanding since 1992 and hasgreater potential due to expandingAsian and Latin markets. The crop isworth in excess of $3,000,000 annually.In Hawaii, 7,000 acres are grown.While available in the horticulturaltrade, common guava is relatively in-significant in the current ornamentalgrower and landscape market and aphase-out of production and sale byFlorida ornamental growers is encour-aged by an agreement between theFLEPPC and the Florida Nurserymenand Growers Association (Aylsworth1999).

Common guava grows and fruitsunder unfavorable conditions, spreadsrapidly by seeds and has become aweed in many areas (Popenoe 1920).In fact, it is present as a weed in 27countries and considered a common toserious pest in nine of these (Holm _aL 1979). It forms thickets and has aserious impact on native forests andopen woodlands (Cronk and Fuller1995). Small, in 1933, reported it inhammocks, roadsides, pinelands, and

old fields of peninsular Florida and theKeys, and it was further reportedspreading into hammocks andpinelands in 1971 (Long and Lakela).It now ranges from Pinellas andBrevard Counties south to the Keys(Nelson 1994) and has been reportedfrom Florida parks and preserves inBroward, Collier, Dade, Highlands,Lee, Martin, Osceola, Palm Beach, andSarasota Counties (FLEPPC 2000). InJonathon Dickinson and SeabranchState Parks alone 1,163 stems weretreated in 1998-99 (Florida Park Ser-vice). Trees are controlled by basal barkapplications of Garlon 4, cut stumpapplications of Garlon 4 or 3A, andhand pulling of seedlings.

Strawberry GuavaStrawberry guava [P. cattleianum

Sabine] is a shrub or small tree to 25feet tall with smooth, gray-brown toreddish bark that is inclined to peel offin irregular patterns. The slick,leathery, evergreen, opposite leaves areelliptic to somewhat broader towardsthe tip and up to 3 inches long with ashort stalk/peti-ole. The lateralnerves in theblades are as-cending andcurve forwardwithout forminga distinct mar-ginal nerve. Theinflorescence isstalked and 1-flowered fromthe leaf axils.Flowers havefive united se-pals. The five pet-als are white,showy, roundedand about 1 inchwide. Stamensare numerousand anthers areattached in thecenter and splitlongitudinally.The ovary is im-bedded belowthe rest of theflower parts (infe-rior). The red-purple or yellowfruits are almost

A survey identified potential bio-logical control agents from which theimpacts of seven insect species andtheir effects on Psidium cattleianumare discussed by Wickler et al. (1999):a lead gall produced by Tectococcusovatus (Homoptera, Eriococcidae),bud galls formed in response toDasineura gigantea (Diptera,Cecidomyiidae), a shoot gall pro-duced by Eurytoma sp. (Hy-menoptera, Eurytomidae), a seed gallinduced by Sycophilia sp. (Hy-menoptera, Eurytomidae), anotherleaf gall formed in response to an un-known species of Psyllidae, the saw-fly, Haplostegus epimelas (Hy-menoptera, Pergidae), and the chry-somelid Lamprosoma azureum (Co-leoptera, Chrysomelidae).

The author gratefully acknowl-edges Dr. Clifford W. Smith for all hisassistance since the beginning ofthese studies, Dr. Simon Elliot andMilton Mendonça Jr. for their help-ful comments in the draft manuscriptand Dr. J.H. Pedrosa-Macedo and theBiological Control of Weeds groupfrom the Laboratory of Forest Protec-tion of UFPR for their further assis-tance. Funding from the U.S. Na-

10 SUMMER 2000

round, many-seeded berries about 1and 1/ 2 inches long with white flesh.Reproduction is by seeds. Bloomingusually occurs in early summer. Nativeto southeastern Brazil, it is planted inthe subtropics and tropics. Strawberryguava can survive temperatures as lowas 22 F (Morton 1987) and is grown asfar north as Alachua County.

P. cattleianum occurs as two distinctbotanical varieties. The commonredfruited variety is called Cattleyguava or strawberry guava, P.cattleianum Sabine var. cattleianum [P.littorale Raddi var. longipes (O. Berg)Fosberg] (Fosberg 1941). This varietyis a small dense tree. It makes a niceornamental with the copious array ofdark shiny green leaves and bright redfruits. The fruit is sweet and obviouslyeaten and spread by wildlife and cattle.As an escape, strawberry guava hasbeen found on floodplains and in oakhammocks and cattle pens fromOsceola County south into Lee County(Wunderlin et al. 1995). The commonname, strawberry guava, comes fromthe flavor of the fruit, which tastes likea strawberry. The fruits are eaten freshor used for making jelly, drinks andother culinary uses, however, it is notgrown commercially for its fruit inFlorida. It is an attractive dooryardtree, presenting “________ an almostexotic or Japanese picture as an accent"and used as a hedge (Stressau 1986).

The less frequent yellow-fruitedvariety is called yellow Cattley guavaor yellow strawberry guava, P.cattleianum Sabine var. lucidum Hort. [P.littorale Raddi var. lucidum (Degener)Fosberg] (Fosberg 1941). This varietyis a loosely branched small tree said tobe useful for reforestation (Staff,Hortus Third 1976). The fruit is sul-phur-yellow, translucent and some-what acid when ripe. Yellow Straw-berry guava forms dense thicketsalong the margin of the Little ManateeRiver in Hillsborough County. Thisvariety has also been listed [sic] as P.lucidum Hort., P. chinense Lodd. exLodd. and P. sinense (not a valid name,probably a misspelling of chinense)(Popenoe 1920).

Strawberry guava forms thicketsand shades out native vegetation inforests and open woodlands (Cronkand Fuller 1995). It has had cata-

strophic effects on native habitats ofMauritius, and it is considered amongthe worst pest plants in Hawaii (seeWikler, this issue), where it has in-vaded a variety of natural areas (Cronkand Fuller 1995). It has become domi-nant in native forests of Hawaii, in-cluding in two national parks, whereits clonal spread is enhanced by activi-ties of feral pigs (Huenneke andVitousek 1990).

Strawberry guava first appeared inthe horticulture trade in Florida in the1887-1888 Catalog and Price List forRoyal Palm Nurseries. However, it wasnot included in southeastern flora bySmall (1933). It was noted as "often grow-ing wild" in 1956 by Barrett (1956). It hasbeen reported in Florida parks and pre-serves in Pinellas, Hillsborough, Martin,and Palm Beach Counties (FLEPPC1996). In Jonathan Dickinson State Parkand Seabranch Preserve alone, 2,087Strawberry guava stems were controlledin 1998-99 (Florida Park Service). Wherepossible, stems are cut and treated withGarlon 3A. In Jonathan Dickinson StatePark, it was necessary for DEP to bull-doze and restore a three acre site (Rich-ard Roberts, personal communication).At Seabranch, up to seven guava plantsper square meter occur and 5-15% ofvegetation has consisted of Strawberryquava in various sites in 35 acres JohnGriner, personal communication).Twenty acres have been restored by se-lective removal of this pest plant andplanting of native vegetation.

In summary, the guavas have pro-vided us with delicious desserts, orna-mental plantings, and commercial in-come. On the other hand, common andStrawberry guavas have escaped cul-tivation and are weeds in natural areasrequiring expenditure of public fundsto protect native plant communites.This is an example of the dilemma weface with many introduced plants thatare both commercially valuable andnatural area weeds.

AcknowledgementsThanks to Hillary Cherry for library

assistance and Bob Pemberton for sup-plying information from the RoyalPalm Nursery catalogue.

Ken Langeland is a Professor at theUniversity of Florida's Center for Aquatic

tional Park Services and the Univer-sity of Hawaii (CA80xx2-9004) sup-ported this study.

Charles Wikler is a Forester at theParaná Forest Research Foundation andholds an M.S. and Ph.D. in BiologicalControl of Insects and Weeds RuaTheresa P. Moura, 70 - Pilarzinho 82100-440 - Curitiba - Paraná - Brazil. E-mail:cwickler@bbs2.sul.com.br

ReferencesDiong, C.H. 1982. Population biology and

management of the feral pig (Susscrofa) in Kipahulu Valley, Maui. Un-published Ph.D. dissertation, Univer-sity of Hawaii, Honolulu.

Ellshoff, Z.E. Gardner, D.E., Wikler, C., & SmithC.W. 1995. Annotated bibliography of thegenus Psidium, with emphasis of P.cattleianum (strawberry guava) and P. guajava(common guava), forest weeds in Hawai’i.Technical Report No. 95. Cooperative NationalPark resources Studies Unit, Botany Dept.,University of Hawaii, Honolulu.

Hoehne, F.C.; 1946. Frutas Indígenas.Instituto de Botânica, Publição da série“D”, São Paulo. 88 p.

Huenneke, L.F. 1991. Population biologyof an invading tree, Psidium cattleianum,in Hawai’i Volcanoes National Park. Pp.177-188, In: Center, T.D., R.F. Doren, R.L.

Hofstetter, R.L. Meyers, and L.D. Whiteaker(eds.) Proceedings of the Symposium onExotic Pest Plants; U.S. Department of theInterior, National Park Service; Novem-ber 2-4, 1988; Miami, Florida.

Reitz, P.R., Klein, R.M. & Reis, A. 1983.Flora Catarinense (Psidium). (Flora ofSanta Catarina (Psidium).) Sellowia35:684-715.

Sabine, J. 1821. Psidium cattleianum. Trans.Roy. Hort. Soc. 4:315. Pl. 11.

Smith, C.W. 1985. Impace of alient plants onHawaii’s native biota. In: Stone, C.O., andJ.M. Scott (eds.), Hawaii’s Terrestrial Eco-systems: Preservation and Management.Cooperative National Park Resources Stud-ies Unit, University of Hawaii, Honolulu.

Wikler, C. 1999. Distribuição geográficamundial de Psidium cattleianum Sabine(Myrtacea) e um cecidógeno compossibilidades de utilização emcontrole biológico.

Post-Graduation Forestry Course.Universidade Federal do Paraná. Doc-toral thesis. 135 p.

Wikler, C., Pedrosa-Macedo, J.H., Vitorino,M.D., Caxambú, M.G. & Smith, C.W.1999. Strawberry Guava (Psidiumcattleianum) – Prospects for BiologicalControl. Program and abstracts of the XInternational Symposium on BiologicalControl of Weeds, P128, pp. 138. N.Spencer and R. Nowierski (eds.) 04-14July, Bozeman, Montana, USA. MontanaState University.

WILDLAND WEEDS 11

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ReferencesAylsworth, J.D. 1999. Invasive is Out. Orna-

mental Outlook. 8(8):40,42.

Barrett, M.F. 1956. Common Exotic Trees of SouthFlorida. Univ. of Florida Press, Gainesville.pp. 298-299.

Florida Park Service. Undated. 1998-99Resource Management Annual Report - July1, 1998-June 30, 1999.

Cronk, Q.C.B., and J.L. Fuller. 1995. Plant Invad-ers. Chapman and Hall, London. pp. 111-114.

DeBrahm, W.G. 1773. DeBrahm's Report of theGeneral Survey in the Southern District ofNorth America. Tricentennial edition (L.DeVorsey, Jr., ed.), No. 3, 1971. Univ. of So.Carolina Press, Columbia. 325 pp. As cited in:Austin, D.E 1978. Exotic plants and their ef-fects in southeastern Florida. Env. Conserv.5:25-34.

Dehgan, B. 1998. Landscape Plants for Subtropi-cal Climates. Univ. Press of Florida, Gaines-ville. p. 480.

FLEPPC. 2000. Florida Exotic Pest Plant Counciloccurrence data base. Unpublished. Dataavailable by requests via Web site: http://www.fleppc.org/.

Fosberg, ER. 1941. Varieties of the Strawberry

Guava. Proc. Biol. Soc. Wash. 54:179-180.

Holm, L., J.V. Pancho, J.R Herberger, and D.L.Plucknett. 1979. A Geographical Atlas ofWorld Weeds. John Wiley & Sons, New York.pp. 297-298.

Huenneke, L.E, and P.M. Vitousek. 1990. Seed-ling and clonal recruitment of the invasivetree Psidium cattleianum: Implications formanagement of native Hawaiian forests. Biol.Cons. 53:199-211.

Long, R.W., and O. Lakela. 1971. A Flora of Tropi-cal Florida. University of Miami Press. CoralGables, FL. pp. 642-643

Morton J.E 1987. Fruits of Warm Climates.Published by the author, Miami, FL.pp.356-367.

Nelson, G. 1994. The Trees of Florida. PineapplePress Inc., Sarasota, FL. pp. 104-105, 241-242.

Popenoe, W. 1920. Manual of Tropical andSubtropicalFruits. MacmillanCo. pp.272-283.(Facsimile reprint 1974, Hafner Press, NewYork.).

Schroeder, C.A. 1946. Priority of the SpeciesPsidium cattleianum Sabine. Jour. ArnoldArboretum. 27:314-315.

Small, J.K. 1933. Manual of the SoutheasternFlora. Univ. of No. Carolina Press, ChapelHill. p. 937.

The Staff of the Liberty Hyde Bailey Hortorium.1976. Hortus Third. Macmillan PublishingCo., New York. p. 923.

Stressau, EB. 1986. Florida, MyEden. FloridaClassics Library, Port Salerno, FL. p. 102.

Wunderlin, R.P. 1998. Guide to the VascularPlants of Florida. Univ. Press of Florida,Gainesville. p. 454.

Wunderlin, R.P., B.E Hansen, and E.L. Bridges.1995 (updated May 1996). Atlas of FloridaVascular Plants. Web site: http://www.usf.edu/ ~isb/projects/hb-atlas.html.

12 SUMMER 2000

Herbicide Screening Results forTwo Common Exotic Grass Species

in Florida

by Dan Thayer

Two invasive exotic grass speciesare abundant and unwanted featuresof the 21,875 acre DuPuis Reserve, justeast of Lake Okeechobee in SouthFlorida. They are torpedograss (Pani-cum repens) and bahiagrass(Paspalum notatum). In the past de-cade, there has been an increasingnumber of products marketed as grassspecific herbicides. The purpose of thescreening was to evaluate these newproducts, along with a few standard

HERBICIDE TREATMENTS:

Treatment Rate (oz.) Rate (oz.)

Number Herbicide Acre Plot Surfactant Acre Plot

1 Envoy 34 2.55 SunWet 4 .3

2 Envoy 17 1.27 SunWet 4 .3

3 Arsenal 40 3.0 Dynamic 6.7 .5

4 Rodeo 128 9.6 Dynamic 6.7 .5

5 Roundup Pro 128 9.6 Cohere 6.7 .5

6 Poast 40 3.0 SunWet 4 .3

7 Poast 80 6.0 SunWet 4 .3

8 Fusilade 24 1.8 Dynamic 6.7 .5

9 Plateau 8 .6 Dynamic 6.7 .5

10 Plateau 12 .9 Dynamic 6.7 .5

11 Vantage 46.3 3.47 Dynamic 13.3 1.0

grass herbicides, for efficacy againstthese grasses and selectivity for thenative flora at three test sites within theDuPuis Reserve. The herbicide rates,and the adjuvants used in this study,were recommended by the manufac-turer or their local distributor. Thesepreliminary tests will be used to short-list products for further study.

METHODS: Torpedograss plotswere established in a seasonal wetlanddominated by torpedograss, and in

anassociated drainage ditch heavilyinvaded with torpedograss. Thetorpedograss marsh and ditch weredry at the time of herbicide application.Surrounding the torpedograss invadedwetland is an established stand ofbahiagrass. Bahiagrass plots wereplaced adjacent to the torpedograsstest site. The torpedograss marsh plotswere virtually a 100% cover oftorpedograss. Scattered throughoutwas a light cover of pickerelweed(Pontederia sp.) and broom grass

WILDLAND WEEDS 13

Treatment Bahiagrass

Number Herbicide Effect Comments

1 Envoy No Effect

2 Envoy No Effect

3 Arsenal 100% Kill 100% on all other vegetation.

4 Rodeo 80% Kill Minor effect on pickerelweed.

5 Roundup Pro 20% Kill Minor effect on pickerelweed.

6 Poast No Effect

7 Poast No Effect

8 Fusilade No Effect

*9 Plateau No Effect

*10 Plateau No Effect

11 Vantage No Effect

*In ditch plots, Plateau at both rates killed pickerelweed but had no effect on maidencare.

American CyanimidPRODUCTPORTFOLIO

ArsenalImazapic ApplicatorsConcentrate(Plateau)

StalkerSahara

Pendulum

PRODUCT USES• Exotic Control • Brush Control •Bareground•Turf Management • Seed Head Suppression•Basal Applications • Pre-emergent Control

• Aquatic EUP •

For InformationCall Phil C. Waller(941) 619-6255

Fax (941) 701-8287

6651 ENGLELAKE DRIVE, LAKELAND,FLORIDA 33813

Torpedograss Marsh PlotsSix-Months Post-Treatment

14 SUMMER 2000

Bahiagrass Plots. Pre-treatment, Plot #5

Bahiagrass Plots. 6-months Post-treatment' Plot #5.

(Andropogon virginicus). The ditch plotswere a mix of torpedograss,maidencane (Panicum hemitomon), andpickerelweed. In the ditch plots,torpedograss was not consistentthroughout, so evaluations focused ontreatment effects to native species. Thebahiagrass plots contained broomgrass and yellow-eyed grass (Xyrissp.). With the exception of the ditchsite, the test plots were burned on June15th, 1999. Herbicide applications weremade on August 2nd, 1999. Fire wasused to reduce the existing thatch andto break apical dormancy. Previousstudies indicate an increase in efficacyfor herbicides applied to perennialgrasses following fire.

Torpedograss marsh plots andbahiagrass plots were applied from anATV using an electric powered sprayerwith a boom arrangement of flat-fannozzles (6505s). The ditch plots weresprayed with the same ATV and aBoom Buster nozzle which delivered1.5 GPM. All herbicides were appliedat a total spray volume of 40 gallonsper acre. Each plot was 0.075 acres insize. Permanent photo locations wereestablished to monitor each treatment

plot through time. Visualratings of herbicide effi-cacy were conducted atthree and six months post-treatment. Where appli-cable, visual ratings weremade for nontarget veg-etation treatment effects.The Six month evaluationsare presented here. Theweather conditions onAugust 2nd, at 1200, wereclear to partly cloudyskies, 94°F, 66% RH, andwinds from the west at 3mph.

Many thanks to TraceWolfe, Bo O'Neal, JackieSmith and Steve Smith fortheir help with this trial.

Dan Thayer is the Direc-tor of the Vegetation Man-agement Division at theSouth Florida Water Man-agement District. He can bereached at (561) 682-6097,dthayer@siwmd.gov.

WILDLAND WEEDS 15

Vegetation management programs and control products for Aquatics,Forestry and Roadway/Utility Rights of Way.

SOLUTIONS - SERVICE - SATISFACTION

FLORIDA OFFICE3705-10 S.W. 42nd Ave.Gainesville, FL 32608

(352) 375-2601 (O)(352) 375-3123 (FAX)

Enterprises, Inc.

Renewing the Environment

CORPORATE OFFICEP.O. Box 557

Monticello, AR 71655(870) 367-8561

Treatment Bahiagrass

Number Herbicide Effect Comments

1 Envoy No Effect

2 Envoy No Effect

3 Arsenal 100% Kill 100% Kill of pickerelweed.

4 Rodeo 95% Kill No effect on yellow-eyed grass.

5 Roundup Pro 99% Kill No effect on yellow-eyed grass.

6 Poast No Effect

7 Poast No Effect

8 Fusilade No Effect

9 Plateau 100% Kill No effect on broomgrass.

10 Plateau 100% Kill No effect on broomgrass.

11 Vantage Indeterminable

Bahiagrass PlotsSix-Months Post-Treatment

16 SUMMER 2000

Dow AgroSciences Ad

WILDLAND WEEDS 17

Figure 1. Chinese privet growing in aconservation area in north Florida.

By J. P. Cuda and M. C. Zeller

Chinese or hedge privet, Ligustrumsinense (Oleaceae), is a semi-deciduousshrub or small tree of Asiatic origin thatis commercially available from thenursery industry as an omamental orborder plant (PlantFinder 1999). Afterits introduction into the United Statesin 1852 (Dirr 1983), this woody shrubeventually escaped cultivation, and by1932 had become naturalized across thesoutheastern United States (Small1933). It is now considered an invasiveweed in many areas of the Southeast(Dirr 1983, Nelson 1996).

In its introduced range, Chineseprivet is a common component of theunderstory vegetation of forests innorth Florida (Fig. 1), Alabama, Geor-gia (Godfrey 1988), Kentucky, Northand South Carolina (Radford et al.1968), Mississippi (Goddard 1992),Oklahoma (Taylor et al. 1996), Tennes-see (Radford et al. 1968, Faulkner et al.1989) and Texas (Correll and Johnston1970). This woody shrub also is an in-vasive weed in Australia (Burrows andKohen 1986) and Argentina (Montaldo1993). While primarily a woody in-vader of abandoned or disturbed areas(Godfrey 1988), Chinese privet readilyinvades natural areas adjacent to dis-turbed sites, and is especially abundantalong stream banks. The present dis-tribution of naturalized populations ofChinese privet in Florida is shown inFig. 2 (Wunderlin et al. 1995).

Chinese privet can grow to a heightof 10 m. The plant is characterized byits numerous leafy pubescentbranchlets, and its small, simple, de-ciduous to semi-deciduous leaves areelliptic in shape (Fig. 3). The leaves aregreen (variegated in cultivation), op-posite, have short pubescent petioles,and are attached at right angles to thestems. In bloom, the branchlets bearnumerous, many-flowered panicles.Flowers (Fig. 3) are white and mal-odorous; the corolla tube is shorterthan the spreading lobes, and the sta-mens are exserted. The fruits (Fig. 4)are blue, fleshy drupes that are in-gested by birds (McRae 1980,Buchanan 1989, Montaldo 1993). Newinfestations probably develop frombird-dispersed seeds (Montaldo 1993).

Chinese privet,Ligustrum sinense:Prospects for ClassicalBiological Control in theSoutheastern United States

Figure 2. Current distribution of naturalized populations of Chinese privet and the ligustrum seedweevil Ochyromera ligustrI in Florida. Adapted from Wunderlin etal. (1995).

Figure 3. Branchlet of Chinese privet withleaves and flowers.

18 SUMMER 2000

The Florida Exotic Pest Plant Coun-cil lists Chinese privet as a Category Iinvasive species (FLEPPC 1996). Theshrub disrupts native plant communi-ties in riparian and upland habitats bycompeting for the available light andspace. The federal- and state-listed en-dangered Miccosukee gooseberry,Ribes echinellum, is on the verge of be-ing displaced in Florida by encroach-ing stands of Chinese privet(Langeland and Burks 1998). More-over, nutrient cycling in natural areascan be disrupted by the presence ofChinese privet. Faulkner et al. (1989)observed that dense thickets of Chi-nese privet in Tennessee produce largequantities of litter, and act like umbrel-las by preventing the infiltration of leaflitter from the native tree canopy. Ag-riculture and public health also can beimpacted by the presence of Chineseprivet. Dense stands of this invasiveshrub can serve as alternate host plantsfor the citrus whitefly, Dialeurodes citri(Hicks and Oliver 1987), and are con-ducive to infestations of the hard tickIxodes scapularis, a suspected vector ofLyme disease in the southern UnitedStates (Goddard 1992).

Where it displaces native vegeta-tion, Chinese privet may not have anadverse impact on wildlife popula-tions because of its nutritional value.The plant serves as food source for thebobwhite quail, Colinus virginianus,and the white-tailed deer, Odocoileusvirginianus, when more desirable for-age plants are scarce (McRae 1980,Stromeyer et al. 1998a,b).

From a management perspective,mechanical control methods such as

cutting andp r e s c r i b e dburning are in-e f f e c t i v eagainst Chi-nese privet(Faulkner et al.1989). Theplant resproutsrapidly fromthe cut stumps,and its affinityfor low-lyingdamp areasdoes not allowfire to carrywell. The moistconditions in

the bottom litter layer also reduce theeffectiveness of the fire by not allow-ing temperatures to become hotenough to kill the root crowns.A1though the herbicide glyphosatewill severely damage or kill Chineseprivet, chemical control is impracticaland too expensive for large areas withdense growth (Faulkner et al. 1989).Since conventional methods are inap-propriate for selectively controllinglarge infestations of Chinese privet innatural areas, biological control withnatural enemies from the plant's nativerange should be considered.

Chinese privet would be a good can-didate for classical biological controlbecause the environmental risks asso-ciated with the importation and releaseof host specific natural enemies wouldbe low. There are no native congenersin the genus Ligustrum occurring in theUnited States (Pemberton 1996). There-fore, the level of host specificity re-quired for candidate natural enemiesmay be quite broad yet still not pose arisk to non-target nativeor economically impor-tant plant species. Thenursery industry wouldprobably object to the in-troduction of insects thatfeed on the foliage orgirdle the branches orstems of Chinese privetand would be fearful ofattacks on the widelyused Ligustrumjaponicum (Japaneseprivet) and the alsopopular L. Iucidum (waxprivet). This conflict of

interest could be resolved by selectingonly those insects that attack the plant'sflowers or seeds. According to Harley(1986), suppression of reproduction isimportant for controlling woody weeds(a) that reproduce by seed; (b) whereexisting plantings provide some ben-efit, e.g., ornamental value; and (c)when herbicide applications provideonly temporary control and retreatmentis uneconomical or environmentallydisruptive. Chinese privet meets all ofthese criteria.

Biological control of Chinese privetalready maybe occurring in some ar-eas, although not as a result of anypurposeful introductions. The seedweevil Ochyromera ligustri was recentlyfound attacking Chinese privet in LeonCounty, Florida (Fig. 2) (Cuda andZeller 1998). This immigrant naturalenemy of Ligustrum spp. maybe ca-pable of reducing the spread of Chi-nese privet into new areas and/or thedensities of existing stands. However,field and laboratory studies will be re-quired to determine to what extent thisinsect can control the growth andspread of Chinese privet populationsin natural areas.

Ochyromera ligustri was first discov-ered in 1959 on Japanese privet, L.japonicum, in Wake County, North Caro-lina (Warner 1961, Wray 1961), and isbelieved to have immigrated from theOrient in nursery stock imported into theUnited States. Since then, the weevil hasbeen found in Florida, Georgia, Northand South Carolina, and Virginia, as wellas North and South Dakota (O'Brien andWibmer 1982, Johnson and Lyon 1988).Considering that Leon County is theonly locality in Florida where Japaneseprivet (the principal host plant for O.

Figure 5. Ligustrum seed weevil Ochyromera ligustri, aninsect natural enemy of Chinese privet.

Figure 4. Berry-like fruits of Chinese privet.

WILDLAND WEEDS 19

ReferencesBuchanan, R. A. 1989. Pied

currawongs (Strepera graculina): Their dietand role in weed dispersal in suburbanSydney, New South Wales (Australia). Pro-ceedings of the Linnaen Society of New SouthWales 111: 241-256.

Burrows, E J., and J. Kohen. 1986. Inhibition ofgermination in privet. Plant Protection Qtrly1: 107-108.

Correll, D. S., and M. C. Johnston. 1970. Manualof the vascular plants of Texas.

Texas Research Foundahon, Renner, Texas. 1881pp.

Cuda, J. R, and M. C. Zeller. 1998. First recordof Ochyromera ligustri (Coleoptera:Curculionidae) from Chinese privet inFlorida. Florida Entomologist 81: 582-584.

Dirr, M.A. 1983. Manual of woody landscapeplants, 3rd ed. Stipes Publishing Co.,Champaign, IL. 536 pp.

Faulkner, J. L., E. E. C. Clebsch, and W. L. Sand-ers. 1989. Use of prescribed burning for man-aging natural and historic resources inChickamauga and Chattanooga NationalMilitary Park, USA. Environmental Manage-ment 13: 603-612.

Florida EPPC. 1996. Florida Exotic Pest PlantCouncil occurrence database. URL: http://www.fleppc.org/.

Goddard, J. 1992. Ecological studies of adult Ix-odes scapularis in central Mississippi: queshing activity in relation to time of year, veg-etation type, and meteorologic conditions.Journal of Medical Entomology 29: 501-506.

Godfrey, R. K. 1988. Trees, shrubs and woodyvines of northern Florida and adjacent Geor-gia andAlabama. University of Georgia Press,Athens. 734 pp.

Harley, K. L. S. 1986. Suppression of reproduc-tion of woody weeds using insects whichdestroy flowers or seeds, pp. 749-756. InDelfosse, E.S. (ed.), Proceedings of the VI In-ternational Symposium on Biological Controlof Weeds, 19-25 August 1984, Vancouver,Canada. Agriculture Canada.

Hicks, C. B., and A. D. Oliver.1987. Citrus white-fly preference among four ornamental hostplants. Hortscience 22: 59-60.

Johnson, W. T., and H. H. Lyon. 1988. Insects thatfeed on trees and shrubs,2nd ed. Comell Uni-versity Press, Ithaca. 556 pp.

Langeland, K. A., and K. C. Burks. 1998. Identifi-cation and biology of non-native plants inFlorida's natural areas. University of Florida,Gainesville. 165 pp.

McCrae, W. A. 1980. Unusual bobwhite foods onabandoned Piedmont farmlands, Georgia,USA. Georgia Journal of Science 38: 49-54.

Montaldo, N. H. 1993. Avian dispersal and re-productive success of two species ofLigustrum (Oleaceae) in a forest relict in Ar-gentina. Revista Chilena de Historia Natural66: 75-85.

Nelson, G. 1996. The shrubs and woody vines ofFlorida. Pineapple Press, Sarasota. 391 pp.

O'Brien, C. W., and G. J. Wibmer. 1982. Anno-tated checklist of the weevils (Curculionidaesensu lato) of North America, Central America,and West Indies (Coleoptera:Curculionoidea). Memoirs of the AmericanEntomological Institute 34: 116.

Pemberton, R. W. 1996. The potential of biologi-cal control for the suppression of invasiveweeds of southem environments. Castanea61: 313-319.

PlantFinder. 1999. PlantFinderwholesaleguide tofoliage and omamental plants, October, p.165.

Radford, A. E., H. E. Ahles, and C. R. Bell. 1968.Manual of the vascular flora of the Carolinas.University of North Carolina Press, ChapelHill. 1183 pp.

Small, J. K. 1933. Manual of the southeastem flora,part one and two. University of North Caro-lina Press, Chapel Hill. 1554 pp. (facsimilereprint 1972, Hafner Publishing, New York.).

Stromayer, K. A. K, R. J. Warren, and T. B.Harrington. 1998b. Managing Chinese privetfor white-tailed deer. SouthemJournal of Ap-plied Forestry 22: 227-230.

Stromayer, K. A. K, R. J. Warren, A. S. Johnson, RE. Hale, C. L. Rogers, and C. L. Tucker.1998a.Chinese privet and the feeding ecology ofwhite-tailed deer: The role of an exotic plant.Journal of Wildlife Management 62: 13211329.

Taylor, E. S., L. K. Magrath, R Folley, R Buck, andS. Carpenter. 1996. Oklahoma vascular plants:Additions and distributional comments. Pro-ceedings of the Oklahoma Academy of Sci-ences 76: 31-34.

Warner, R. E. 1961. The genus Ochyromera newto the western hemisphere, with a new spe-cies and additions to the Junk-SchenklingColeopterorum Catalogus (Curculionidae:Prionomerinae, Endaeini). Coleopterists' Bul-letin 15: 121-124.

Wray, D. L. 1961. Biology and life history of theligustrum weevil (Curculionidae). Coleopter-ists' Bulletin 15: 119-120.

Wunderlin, R. R, B. F. Hansen, and E. L. Bridges.1995 (updated Dec 1998). Atlas of Floridavascular plants. University of South Florida,Institute for Systematic Botany. URL: http:// www.usf.edu/ ~isb /projects /atlas /maps/ ligusine.gif. & ligujapo.gif.

ligustri) is documented as naturalized(Wunderlin et al. 1995), it is not surpris-ing that the weevil has adapted to Chi-nese privet in this region of north Floridawhere the two species of Ligustrum haveoverlapping distributions. The weevilalso has been collected from wax-leafligustrum, L. Iucidum, common privet,L. amurense, lilac, Syringa spp., and grape,Vitis spp., in North Carolina (Warner1961, Wray 1961). However, it is not clearfrom the literature whether lilac or grapeare legitimate host plants in that they arecapable of supporting complete devel-opment of the weevil.

The biology of O. Iigustri on Japaneseprivet was reviewed by Johnson andLyon (1988). The weevil is 3-5 mm longand is shiny brown with golden yellowhair like scales (Fig. 5). The adults feedon the foliage by making small perfora-tions in the interior of the leaf blade, anddrop to the ground when disturbed. InNorth Carolina, adults are active fromlate June to early July. Females deposittheir eggs in the seed or in the maturefleshy fruits. The larvae (Fig. 6) feed in-side the fruits and destroy the seeds asthey complete their development to theadult stage. New adults emerge from theseeds (one weevil per seed) in mid-May,and there is only one generation per year.

We thank M. C. Thomas for identify-ing the insect, J. F. Butler and K. C. Burksfor the photographs of the insect andplant, respectively, and J.H. Frank andN.C. Coile for reviewing the manuscript.Florida Agricultural Experiment StationJournal Series No. N-01574.

Jim Cuda is an Assistant Professor inthe Entomology and Nematology Depart-

ment, University ofFlorida, P.O. Box110620, Gainesville,Florida 32611-0620

Mark Zeller is a Bi-ologist in the Bureau ofInvasive Plant Manage-ment, Florida Depart-ment of EnvironmentalProtection, 3917 Com-monwealth Boulevard,M.S. 710, Tallahassee,Florida 32399-3000

Figure 6. Mature larva of the ligustrum seed weevil O. ligustri.

20 SUMMER 2000

By Steven VannThe Great Air Potato RoundUp was an invasive nonna-

tive plant awareness festival held by the City of Gainesville,Florida's Nature Operations Division on February 5th, 2000.The focus of the event was to help the public recognize thatthey play an integral role in the management of their localnature parks. An educated public is one of the most effectiveand powerful tools for a land manager. Most of our parkshave residential borders and are connected to other neigh-borhoods by the many creeks that flow through Gainesville.For the last eighteen months, the City has been developing apublic education campaign to help people understand howlandscaping decisions they make at home can affect the natu-ral communities in their parks.

The initial campaign consisted of nativescape workshops,a corresponding brochure, and guided nature waLks. The pro-gram enjoyed limited success. Our message was gettingthrough, but we often had low attendance, and many of theparticipants were already aware of the problems of non-na-tive invasive plants. We were failing to attract a large portionof our target audience - the public who had little or no knowl-edge of the issue. Then one afternoon, while brainstorming inthe office, it came to us. We needed to have one large, full-scaleeducation event, disguised as a volunteer exotic plant removalday and celebration. To make the event fun for everyone, wedecided to have prizes, competitions, and of course, a free Tshirtfor participants, the "lure." Once we came up with a catchyname, The Great Air Potato RoundUp was on its way.

Why Air Potato?We chose air potato (Dioscorea bulbifera) for three reasons.

First, air potato's prevalence in Gainesville helped volunteersrecognize the plant during and after the event. The plant haslarge populations established along most of Gainesville'screeks; it is a menace to both public nature parks and privatelandowners. Second, picking up tubers that resemble bakingpotatoes involved little training for volunteers. Having a oneday event did not allow time to train volunteers in plant iden-tification, mechanical removal, and herbicide application.

Lastly, air potato tuber removal allowed us better sched-uling opportunities. The spring and fall in Gainesville arebooked with festivals, plant sales, and football games andthe summer is just too hot to attract many people outside.That left winter, when the plant is dormant and most of thetubers have descended, blanketing the ground...perfect.

OrganizationThe Great Air Potato RoundUp was modeled after popular

litter cleanups, with participants collecting tubers instead oftrash. We targeted areas in nature parks or properties that havedirect creek connections to nature parks. Prospective volun-teers were asked to call prior to the event to pre-register. Thevolunteers were assigned sites and asked to meet their siteleader at the site on the morning of the event. The site leaderswere key. In addition to orientating and supervising volun-teers, they had the most important task of the day, education.We asked persons who were knowledgeable in ecology,Florida's Natural Communities, and invasive nonnative plantecology to volunteer as site leaders. Armed with pressed plantsamples, line drawings, photos, maps, and fact sheets, our siteleaders gave short presentations prior to letting the volunteersloose to collect tubers. To encourage participation and increasemotivation, recognition was given to the individual and groupwith most tubers collected, the largest tuber collected, and themost unusual tuber collected. These awards were presented atthe celebration following the event. The celebration also of-fered educational displays, food, and live music from the localacoustic duo Trail Ridge, who performed their new tune, AirPotatoville. The event culminated with a prize drawing for sev-eral great prizes, including a new mountain bike (another greatlure).

SponsorshipPrior to the event, one of our goals was to obtain sponsors.

The more money we had, the more we could do. We sent outseveral letters to businesses and organizations, and followedup with phone calls. Whenever the opportunity presented it-self, we took our show on the road, and gave several presenta-

To encourage participation and increase motivation, recognition wasgiven to the individual and group with most tubers collected, the largesttuber collected, and the most unusual tuber collected.

TheGreat

AirPotatoRoundUp

To encourage participation and increase motivation, recognition was given to the individual andgroup with most tubers collected, the largest tuber collected, and the most unusual tuber collected.

WILDLAND WEEDS 21

tions about the event. The old saying, "persistence does payoff," is true. The donations came pouring in. The FloridaExotic Pest Plant Council (EPPC) and the Payne's PrairieChapter of the Florida Native Plant Society (FNPS) enthu-siastically supported us. They were followed by donationsfrom Dow Agrosciences, Brewer International, Monsanto,and Water and Air Research. In addition to monetary spon-sorships, several sponsors donated services or products. FullCircle Solutions helped us with the logistics of disposing ofthe tubers once collected, and a localbicycle shop, SpinCycle, donated a mountain bike for the raffle. In addition,many local businesses donated several prizes that includedmovie and restaurant gift certificates, birdhouses, nativeplants, gym memberships, and much more.

The Power of AdvertisingNow we had to get volunteers. Instead of depending on

a single advertising method, we developed a multi-mediaapproach. A radio ad ran twenty times in the week prior tothe event, posters were put up in business windows aroundtown, small signs were placed at strategic intersections, andwe bought ad space on the side of two buses from the localpublic transit. We also took advantage of several free ad-vertising sources. The local public radio station played pub-lic service announcements daily about the event, and localnewspapers ran articles before and after. We put listings inlocal volunteer announcements, and wrote articles for sev-eral local newsletters. We then began targeting groups suchas local clubs and organizations, Boy Scout and Girl Scouttroops, neighborhood associations, and two great volun-teer resources in Gainesville, The University of Florida and

Santa Fe Community College. We used the same persistentapproach as obtaining sponsors; starting with letters, fol-lowed by phone calls, more phone calls, and then a travel-ing slide show to meetings.

Success!Thanks to a creative idea, aggressive advertising, and

generous sponsors the event was a success. When first dis-cussing the idea, we imagined getting 150 volunteers anddecided to shoot for 300. Then the phone began to ring non-stop, and two weeks prior to the event we topped the 300person goal. We added new sites daily to handle the increas-ing number of people. The final tally on the day after theevent was staggering. 675 volunteers participated at 21 sitesaround Gainesville, collecting a total of 11,748 pounds oftubers, almost 6 tons! The success went well beyond thenumbers. The event included knowledgeable volunteers, (thechoir) and the general public. This mix had volunteers learn-ing from other volunteers. An article in the local studentnewspaper, The Alligator, captured the real success of theevent. The article quoted a mother explaining how she andher children were headed home to remove air potato in theiryard, and a teacher who was saving some tubers to show toher class on Monday morning. We are still receiving callsfrom people who are removing air potato form their yards,and from others that are organizing small roundups withtheir neighborhood associations. These types of results aretoo valuable to measure.

Steven Vann is with the Nature Operations Division, City ofGainesville, Station 66, PO Box 490 Gainesville, FL 32602 (352)334-2227. vanns@gru.net

Helena Ad 1/2 page 2/c

22 SUMMER 2000

Biological control on the WebSo, you say your favorite filth is in-

fested with filth flies? Is your green-house so loaded with Lygus bugs thatyour specimen plants are witheringaway? What's to be done, especially ifyou'd like to avoid using chemical con-trol methods? Sounds like biologicalcontrol's for you. And there's more tobiological control than you mightthink. Many question the soundness ofbiological control, some argue its effec-tiveness, and others may just want totry and save their filth. A little bit ofsurfing may well settle all these issues.

Several websites might need visit-ing before you'll be able care and feedfor some biological controls like filthfly parasites or pathogens of Lygusbugs. The National Biological ControlInstitute is run by USDA and theirwebsite (www.aphis.usda.gov /nbci. /noci. html) provides some general in-formation on biological control. Mostof its information, though, has to dowith the agency, their mission, etc., notbiological control itself. But it does pro-vide links to sites that truly informabout the subject.

If you want to be theoretical, thewebsite (www.ruwpa.st-and.ac.uk/projects/other/locust.html) of the ap-plied mathematicians at St. AndrewsUniversity (Scotland) offer things likespatially-modeled grasshopper patho-

gen interactions. Their model illus-trates what might happen when abiocontrol agent induces change in thepopulation of a pest. Their work illus-trates population interactions and thecomplexities affecting whetherbiocontrol initiatives will succeed.

Sometimes websites disappoint, likeone maintained by the Association ofNatural Biocontrol Producers(www.anbp.org). It provides onlythumbnails sketches of biological con-trol information and doesn't really liveup to its stated intent of sharing pro-ducers of natural biocontrols in themarketplace. When you click on the"hotspots" for sources of specific con-trol agents, none appear for any of theagents listed. Maybe the site is simplyunder development.

So, government websites sometimeslose their focus, private sector sitesmay not have resources available toconstruct a really complete website.Yet, biological control is really well rep-resented by at least one website, calledthe Biological Control Virtual ~forma-tion Center (lpmwww.ncsu.edu/biocontrol/ biocontrol.html). Ento-mologists and others at North CarolinaState University took the time to pro-vide very instructive text on wide-ranging examples of biocontrol alongwith links to other useful biocontrolsites.

Mark YourCalendar

Third lnternational Weed Sci-ence Congress. Foz do lguassu,Parana, Brazil. June 6-11, 2000.Contact: P. J. Eventos 55/41/372-1177, pj@datasoft. com.br.

International Meeting for the So-ciety of Conservation Biology. Uni-versity of Montana, Missoula. June9-12, 2000. Contact Fred Allendorf406/243-4184, darwin@se]way.umt.edu, www.umt.edu/scb2000.

The Urban Forestry Institute:The Wildland-Urban Interface, Bal-ancing Growth with Natural Re-source Management and Conserva-tion. The Plaza Hotel, DaytonaBeach, FL. June 25-30, 2000. Con-tact: Mary Vuryea 352/846-0896,mld@ gnv.ifas.ufl.edu.

40th Annual and InternationalMeeting, Aquatic Plant Manage-ment Society. Hanclerly Hotel andResort, San Diego CA. July 16-20,2000. Contact Jim Schmidt 800/5585106, jimschmidt@appliedbiochemists.com.

American Society of Horticul-tural Scientists, Building a BrightFuture for Horticulture. CoronadoSprings Resort, Orlando FL. July23-26, 2000. Contact: www.asks.org

85th Annual Meeting of the Eco-logical Society of America. Snow-bird Utah. August 6-l0, 2000. Con-tact ESA 202/833-8773,esahq@esa.org.

International Conference of theSociety for Ecologial Restoraton.Liverpool England. September 4-9, 2000. Contact: SER 608/265-8557,ser@macc.wisc.edu, www.ser.org.

27th Annual Natural Areas Con-ference. Regal Riverfront Hotel, St.Louis, MO. October 16-20, 2000.

Join the Florida Exotic Pest Plant Council!

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