editor’s note

Some weeds are harder to hate than others. The Find out about the prospects for biocontrol of Chinese for instance - they're almost too tasty to condemn. privet (Ligustrum sinense) in the Southeast on page 17, and jelly, guava jam, guava shakes.... Read about guava's gas- saddle up for the wildly-successful "Great Air Potato tronomical attributes and astronomical spread in two articles RoundUp" on page 20. Too bad air potatoes aren't as tasty in this issue. Ken Langeland and David Hall detail two spe- as guavas. But then again, "Dioscorea shake" doesn't exactly cies ( guajava and P. cattleianum) in Florida (below) have an appealing ring. -Amy Ferriter and Charles Wikler describes strawberry guava (P. cattleianum) in Hawaii where researchers are hoping to in- troduce South American biocontrol agents soon.

Common guava ()

Exotic Guavas in Florida: so delicious but— By Ken Langeland and cattleianum Sabine [P. littorale Raddi] fresh and used in jellies, jams, drinks, David Hall (Schroeder 1946, Wunderlin 1998), and pies, ice cream, etc. Cultivars of P. Costa Rican guava, Psidium guajava are grown commercially for The guavas belong to the friedrichsthalianum (O. Berg) Niedenzu, their fruit. Common guava, and straw- Psidium (, Myrtle Family), occur in Florida as landscape berry guava are known to have es- which comes from the Greek, mean- (Dehgan 1998). Psidium longipes (O. caped cultivation and included on the ing edible fruit. Psidium is a tropical Berg.) McVaugh, mangrove berry, is "Florida Exotic Pest Council's American genus with approximately native to Florida. The guava fruit, es- (FLEPPC) 1999 List of Invasive Spe- 100 species of evergreen and pecially that of Psidium guajava culti- cies". Both are listed under Category I, , some with edible berries. vars that have been developed with which means they are considered by Common guava, Psidium guajava L., superior taste qualities, is highly re- FLEPPC as invasive exotics that are strawberry or Cattley guava, Psidium garded for its edible qualities, eaten altering native plant communities.

4 SUMMER 2000 Strawberry guava has characteristic gray-brown to reddish bark that peels off in irregular patterns.

Common Guava Common guava (Psidium guajava L.) Psidium cattleianum, is a or small , usually under 15 feet tall (rarely to 30 feet), with scaly bark. Branches are 4-angled and hairy. Deliciously dangerous in The opposite have a short stalk/ petiole and elliptic to oblong leathery blades. The lower blade surface is cov- Hawaii By Charles Wikler ered with soft hairs, contains numer- Eating the delicious red or yellow once confined to a small region but now ous glandular dots and has very no- fruits of strawberry guava (Psidium a widespread problem throughout the ticeable riblike lateral veins. Inflores- cattleianum) we would never imagine tropics and subtropics. cences are usually 1-flowered in how big the problem caused by these From the beginning, studies about axils. The five sepals are united. The plants is in many tropical regions. This this plant generated considerable de- five petals are white, showy, rounded species is invading extensive areas, dis- bate over which scientific name was and just under 1 inch long. Stamens are persing into important natural habitats, published correctly for Psidium numerous. The ovary is imbedded be- ecologically disrupting them. In addi- cattleianum. Sabine (1821) named the low the rest of the flower parts (infe- tion, this plant is host to several species plant in honor of William Cattley, the rior). The usually dull yellow fruits are of fruit flies. first person to successfully cultivate the Introduced to Hawaii about 1825, species in Britain. Some authors con- rounded or pear-shaped, manyseeded strawberry guava quickly escaped from sidered Raddi as the first to describe berries about 1 to 2 1/2 inches long cultivation. It has become the most im- the plant, also in 1821, but in the lit- with pink or yellowish flesh. Repro- portant forest weed in Hawaii (Smith, erature search, Raddi’s description re- duction is by seeds. Blooming occurs 1985) due to suitable soil and climatic fers to the plant as Psidium littorale in all year. factors, the absence of natural enemies, 1823. Thus, the name Psidium littorale Common guava has been cultivated and effective dispersal by several differ- is usually considered a junior syn- and distributed by man and animals ent agents. Initially, birds disseminated onym, as the original descriptions of for so long that it is difficult to be cer- seeds. Feral pigs, relatively recent invad- both represent the same species. tain of its place of origin but it is be- ers of the Hawaiian ecosystem, have According to Fosberg (1941) in since become the most important dis- Ellshoff et al. (1995), the common name lieved to be from an area extending persal agent of strawberry guava seeds used for strawberry guava is "araca" in from southern Mexico into or through (Diong, 1982). Brazil, “waiwai” in Hawaii, and Central America (Morton 1987). It is Strawberry guava possesses several "Cattley guava" among some Ameri- now cultivated and escaped through- of the characteristics of an opportunist can horticulturists. Strawberry guava out the New and Old World tropics. invasive species, but it seems that its abil- is also mentioned in the literature as In addition to its value for edible fruit, ity to grow clonally is the main reason “goiave de L'Afrique”, in the Domini- the wood is valued in some parts of for its successful invasion and domina- can Republic, “araca-saiyu” and the world, tannin is extracted for use tion of intact native forests in the Hawai- “guayabo amarillo” in Argentina, in tanning and for dyes and, in addi ian archipelago (Huenneke, 1991). This “araza” in Uruguay, "Calcutta-guava" plant is an excellent example of a plant in India, "china-guava" for the British,

WILDLAND WEEDS 5 “goyavier of St. Martin” in Guadeloupe, dispersed. Although present, it is not too unmistakable in the places where it is "goyavier fraise" for the French, frequent in the first plateau. The species found. Its crown is round and quite "goyavier prune" in Martinique and occurs in humid soils, in small woods dense. The fruits are yellow, as well as "purple-guava" in Jamaica. (capoeiras), and the border of creeks and the endocarp that ranges from light yel- Hoehne (1946) mentioned that the semi-devastated forests. It is also quite fre- low to white. In Parana State it is dis- diKerentiahon between the species be- quent in the coastal swampy fields along tributed along the coast, and on the first comes complicated for what is called the littoral zone of the southern states of and second plateaus. "araca." Although the exact origin of the and Rio Grande do Sul. It type specimen is not known, it seems can be found in and around the southern that the plant was cultivated in Asia and plateau, occurring in the ciliary forests, as America. However, the type locality of well as in disturbed fields (Reitz, Klein & P. Iittorale is cited by Raddi (1823) as the Reis, 1983). coasts of Brazil. Two botanical forms of strawberry Morpholog of the varieties of guava tree are recognized based on fruit color. They are the red fruit P. cattleianum Psidium cattleianum f. cattleianum (P. Iittorale var. Iongipes) and According to Wikler (1999), the main the yellow fruit P. cattleianum f. Iucidum differences between the yellow and red (P. Iittorale var. Iucidum). forms of strawberry guava are: • P. cattleianum var. Iucidum (yellow form) Geographical distribution in It is commonly a shrub in the coast, as part of a vegetation formation called Psidium cattleianum var. Iucidum the area of origin "restinga", where a wide variety of plants In Brazil, the genus Psidium is repre- grow on the sandy substrate with a high • P. cattleianum var. cattleianum (red sented by 9 species, including P. water table. The climate in the coast is hot form) cattleianum. The plant occurs from the and humid with temperatures between 18 The red form is a tree, with heights South of Espirito Santo State in Brazil to and 22°C and annual rainfall between from 2.5 meters up to 20 meters. Its trunk Uruguay, (from 20° and 32° S). Straw- 1430-2450 mm. Its height varies between has the same color of the yellow form al- berry guava is a characteristic bush of 2.5 and 4 meters, rarely exceeding 5 m high. though it differs in shape being straight the “restinga,” typical vegetation of the The trunk is tortuous and with very char- and cylindrical with a larger diameter. Its Atlantic Rain Forest, where it is widely acteristic grayish-brown coloration, being crown is slightly elongated and quite dense. Its fruit and its endocarp are red colored. In the Araucaria Forest it is found inside the woods but exclusively in the first plateau, ranging from 6501100 m. The climate is hot and humid, with temperature between 15 - 19 °C and 1250 - 2500 mm annual rainfall.

Psidium cattleianum var. cattleianum

Biocontrol in Hawaii Unable to control strawberry guava by mechanical and chemical means in Hawaii, the U.S. National Park Service initiated efforts to find biological control agents against this weed. A cooperative program between the Cooperative Na- tional Park Resources Studies Unit, Uni- versity of Hawaii at Manoa, and the Parana Forest Research Foundation and the Federal University of Parana was es- tablished in March 1991.

WILDLAND WEEDS 7 tion to other medicinal uses, the old fields of peninsular Florida and the A survey identified potential bio- roots, bark, leaves and immature fruits Keys, and it was further reported logical control agents from which the are used to halt gastroenteritis, diar- spreading into hammocks and impacts of seven insect species and rhea and dysentery throughout the pinelands in 1971 (Long and Lakela). their effects on Psidium cattleianum tropics (Morton 1987). In Mexico, the It now ranges from Pinellas and are discussed by Wickler et al. (1999): tree may be parasitized by mistletoe Brevard Counties south to the Keys a lead gall produced by Tectococcus that causes rosette-like formations (Nelson 1994) and has been reported ovatus (Homoptera, Eriococcidae), called wood flowers, which are sold as from Florida parks and preserves in bud galls formed in response to ornamental curiosities (Morton 1987). Broward, Collier, Dade, Highlands, Dasineura gigantea (Diptera, Cecidomyiidae), a shoot gall pro- According to P. W. Reasoner, com- Lee, Martin, Osceola, Palm Beach, and duced by Eurytoma sp. (Hy- mon guava was introduced to Florida Sarasota Counties (FLEPPC 2000). In menoptera, Eurytomidae), a seed gall from Cuba in 1847 (Popenoe 1920). Jonathon Dickinson and Seabranch induced by Sycophilia sp. (Hy- However, it was already reported as State Parks alone 1,163 stems were menoptera, Eurytomidae), another naturalized in 1765 (DeBrahm 1773). treated in 1998-99 (Florida Park Ser- leaf gall formed in response to an un- The 1887-1888 Catalog and Price List vice). Trees are controlled by basal bark known species of Psyllidae, the saw- for Royal Palm Nurseries states: “The applications of Garlon 4, cut stump fly, Haplostegus epimelas (Hy- guava has become a necessity to South applications of Garlon 4 or 3A, and menoptera, Pergidae), and the chry- Florida; is to South Florida what the hand pulling of seedlings. somelid Lamprosoma azureum (Co- leoptera, Chrysomelidae). peach is to Georgia”. It has been grown The author gratefully acknowl- successfully as far north as the Pinellas Strawberry Guava edges Dr. Clifford W. Smith for all his peninsula [sic] on the west coast and Strawberry guava [P. cattleianum assistance since the beginning of Cape Canaveral on the east coast Sabine] is a shrub or small tree to 25 these studies, Dr. Simon Elliot and (Popenoe 1920) and was grown com- feet tall with smooth, gray-brown to Milton Mendonça Jr. for their help- mercially at Palma Sola, Punta Gorda, reddish bark that is inclined to peel off ful comments in the draft manuscript Opalacha, Indiantown, and other lo- in irregular patterns. The slick, and Dr. J.H. Pedrosa-Macedo and the Biological Control of Weeds group calities (Barrett 1956). Three cultivars leathery, evergreen, opposite leaves are are now grown commercially, Home- from the Laboratory of Forest Protec- elliptic to somewhat broader towards tion of UFPR for their further assis- stead and two private selections. the tip and up to 3 inches long with a tance. Funding from the U.S. Na- About 225 acres are in production in short stalk/peti- Dade (90%), Lee, Broward, and Palm ole. The lateral Beach Counties (Jonathan Crane, per- nerves in the sonal communication). This acreage blades are as- has been expanding since 1992 and has cending and greater potential due to expanding curve forward Asian and Latin markets. The crop is without forming worth in excess of $3,000,000 annually. a distinct mar- In Hawaii, 7,000 acres are grown. ginal nerve. The While available in the horticultural inflorescence is trade, common guava is relatively in- stalked and 1- significant in the current ornamental flowered from grower and landscape market and a the leaf axils. phase-out of production and sale by Flowers have Florida ornamental growers is encour- five united se- aged by an agreement between the pals. The five pet- FLEPPC and the Florida Nurserymen als are white, and Growers Association (Aylsworth showy, rounded 1999). and about 1 inch Common guava grows and fruits wide. Stamens under unfavorable conditions, spreads are numerous rapidly by seeds and has become a and anthers are weed in many areas (Popenoe 1920). attached in the In fact, it is present as a weed in 27 center and split countries and considered a common to longitudinally. serious pest in nine of these (Holm _ The ovary is im- aL 1979). It forms thickets and has a bedded below serious impact on native forests and the rest of the open woodlands (Cronk and Fuller flower parts (infe- 1995). Small, in 1933, reported it in rior). The red- hammocks, roadsides, pinelands, and purple or yellow fruits are almost WILDLAND WEEDS 9 round, many-seeded berries about 1 strophic effects on native habitats of and 1/ 2 inches long with white flesh. Mauritius, and it is considered among tional Park Services and the Univer- Reproduction is by seeds. Blooming the worst pest plants in Hawaii (see sity of Hawaii (CA80xx2-9004) sup- usually occurs in early summer. Native Wikler, this issue), where it has in- ported this study. Charles Wikler is a Forester at the to southeastern Brazil, it is planted in vaded a variety of natural areas (Cronk Paraná Forest Research Foundation and the subtropics and tropics. Strawberry and Fuller 1995). It has become domi- holds an M.S. and Ph.D. in Biological guava can survive temperatures as low nant in native forests of Hawaii, in- Control of Insects and Weeds Rua as 22 F (Morton 1987) and is grown as cluding in two national parks, where Theresa P. Moura, 70 - Pilarzinho 82100- far north as Alachua County. its clonal spread is enhanced by activi- 440 - Curitiba - Paraná - Brazil. E-mail: P. cattleianum occurs as two distinct ties of feral pigs (Huenneke and [email protected] botanical varieties. The common Vitousek 1990). redfruited variety is called Cattley Strawberry guava first appeared in References guava or strawberry guava, P. the horticulture trade in Florida in the Diong, C.H. 1982. Population biology and cattleianum Sabine var. cattleianum [P. 1887-1888 Catalog and Price List for management of the feral pig (Sus scrofa) in Kipahulu Valley, Maui. Un- littorale Raddi var. longipes (O. Berg) Royal Palm Nurseries. However, it was published Ph.D. dissertation, Univer- Fosberg] (Fosberg 1941). This variety not included in southeastern flora by sity of Hawaii, Honolulu. is a small dense tree. It makes a nice Small (1933). It was noted as "often grow- Ellshoff, Z.E. Gardner, D.E., Wikler, C., & Smith ornamental with the copious array of ing wild" in 1956 by Barrett (1956). It has C.W. 1995. Annotated bibliography of the dark shiny green leaves and bright red been reported in Florida parks and pre- genus Psidium, with emphasis of P. cattleianum (strawberry guava) and P. guajava fruits. The fruit is sweet and obviously serves in Pinellas, Hillsborough, Martin, (common guava), forest weeds in Hawai’i. eaten and spread by wildlife and cattle. and Palm Beach Counties (FLEPPC Technical Report No. 95. Cooperative National As an escape, strawberry guava has 1996). In Jonathan Dickinson State Park Park resources Studies Unit, Botany Dept., been found on floodplains and in oak and Seabranch Preserve alone, 2,087 University of Hawaii, Honolulu. hammocks and cattle pens from Strawberry guava stems were controlled Hoehne, F.C.; 1946. Frutas Indígenas. Instituto de Botânica, Publição da série Osceola County south into Lee County in 1998-99 (Florida Park Service). Where “D”, São Paulo. 88 p. (Wunderlin et al. 1995). The common possible, stems are cut and treated with Huenneke, L.F. 1991. Population biology name, strawberry guava, comes from Garlon 3A. In Jonathan Dickinson State of an invading tree, Psidium cattleianum, the flavor of the fruit, which tastes like Park, it was necessary for DEP to bull- in Hawai’i Volcanoes National Park. Pp. a strawberry. The fruits are eaten fresh doze and restore a three acre site (Rich- 177-188, In: Center, T.D., R.F. Doren, R.L. or used for making jelly, drinks and ard Roberts, personal communication). Hofstetter, R.L. Meyers, and L.D. Whiteaker other culinary uses, however, it is not At Seabranch, up to seven guava plants (eds.) Proceedings of the Symposium on Exotic Pest Plants; U.S. Department of the grown commercially for its fruit in per square meter occur and 5-15% of Interior, National Park Service; Novem- Florida. It is an attractive dooryard vegetation has consisted of Strawberry ber 2-4, 1988; Miami, Florida. tree, presenting “______an almost quava in various sites in 35 acres John Reitz, P.R., Klein, R.M. & Reis, A. 1983. exotic or Japanese picture as an accent" Griner, personal communication). Flora Catarinense (Psidium). (Flora of and used as a hedge (Stressau 1986). Twenty acres have been restored by se- Santa Catarina (Psidium).) Sellowia 35:684-715. The less frequent yellow-fruited lective removal of this pest plant and Sabine, J. 1821. Psidium cattleianum. Trans. variety is called yellow Cattley guava planting of native vegetation. Roy. Hort. Soc. 4:315. Pl. 11. or yellow strawberry guava, P. In summary, the guavas have pro- Smith, C.W. 1985. Impace of alient plants on cattleianum Sabine var. lucidum Hort. [P. vided us with delicious desserts, orna- Hawaii’s native biota. In: Stone, C.O., and littorale Raddi var. lucidum (Degener) mental plantings, and commercial in- J.M. Scott (eds.), Hawaii’s Terrestrial Eco- Fosberg] (Fosberg 1941). This variety come. On the other hand, common and systems: Preservation and Management. is a loosely branched small tree said to Strawberry guavas have escaped cul- Cooperative National Park Resources Stud- ies Unit, University of Hawaii, Honolulu. be useful for reforestation (Staff, tivation and are weeds in natural areas Wikler, C. 1999. Distribuição geográfica Hortus Third 1976). The fruit is sul- requiring expenditure of public funds mundial de Psidium cattleianum Sabine phur-yellow, translucent and some- to protect native plant communites. (Myrtacea) e um cecidógeno com what acid when ripe. Yellow Straw- This is an example of the dilemma we possibilidades de utilização em berry guava forms dense thickets face with many introduced plants that controle biológico. along the margin of the Little Manatee are both commercially valuable and Post-Graduation Forestry Course. Universidade Federal do Paraná. Doc- River in Hillsborough County. This natural area weeds. toral thesis. 135 p. variety has also been listed [sic] as P. Wikler, C., Pedrosa-Macedo, J.H., Vitorino, lucidum Hort., P. chinense Lodd. ex Acknowledgements M.D., Caxambú, M.G. & Smith, C.W. Lodd. and P. sinense (not a valid name, Thanks to Hillary Cherry for library 1999. Strawberry Guava (Psidium probably a misspelling of chinense) cattleianum) – Prospects for Biological assistance and Bob Pemberton for sup- Control. Program and abstracts of the X (Popenoe 1920). plying information from the Royal International Symposium on Biological Strawberry guava forms thickets Palm Nursery catalogue. Control of Weeds, P128, pp. 138. N. and shades out native vegetation in Spencer and R. Nowierski (eds.) 04-14 forests and open woodlands (Cronk July, Bozeman, Montana, USA. Montana Ken Langeland is a Professor at the State University. and Fuller 1995). It has had cata- University of Florida's Center for Aquatic

10 SUMMER 2000 and Invasive Plants in Gainesville, FL. Guava. Proc. Biol. Soc. Wash. 54:179-180. Wunderlin, R.P. 1998. Guide to the Vascular Plants of Florida. Univ. Press of Florida, EMail: [email protected]. ufl.edu Holm, L., J.V. Pancho, J.R Herberger, and D.L. Plucknett. 1979. A Geographical Atlas of Gainesville. p. 454. World Weeds. John Wiley & Sons, New York. Wunderlin, R.P., B.E Hansen, and E.L. Bridges. David W. Hall is President of Hall Con- pp. 297-298. 1995 (updated May 1996). Atlas of Florida sultant, Inc. in Gainesville, FL. Vascular Plants. Web site: http:// Huenneke, L.E, and P.M. Vitousek. 1990. Seed- ling and clonal recruitment of the invasive www.usf.edu/ ~isb/projects/hb-atlas.html. References tree Psidium cattleianum: Implications for Aylsworth, J.D. 1999. Invasive is Out. Orna- management of native Hawaiian forests. Biol. mental Outlook. 8(8):40,42. Cons. 53:199-211. Barrett, M.F. 1956. Common Exotic Trees of South Long, R.W., and O. Lakela. 1971. A Flora of Tropi- Wildland Florida. Univ. of Florida Press, Gainesville. cal Florida. University of Miami Press. Coral pp. 298-299. Gables, FL. pp. 642-643 Florida Park Service. Undated. 1998-99 Morton J.E 1987. Fruits of Warm Climates. Resource Management Annual Report - July Published by the author, Miami, FL. 1, 1998-June 30, 1999. pp.356-367. WEEDS Cronk, Q.C.B., and J.L. Fuller. 1995. Plant Invad- Nelson, G. 1994. The Trees of Florida. Pineapple ers. Chapman and Hall, London. pp. 111-114. Press Inc., Sarasota, FL. pp. 104-105, 241-242. DeBrahm, W.G. 1773. DeBrahm's Report of the Popenoe, W. 1920. Manual of Tropical and Charter Advertisers General Survey in the Southern District of SubtropicalFruits. MacmillanCo. pp.272-283. North America. Tricentennial edition (L. (Facsimile reprint 1974, Hafner Press, New SePRO DeVorsey, Jr., ed.), No. 3, 1971. Univ. of So. York.). Griffin Carolina Press, Columbia. 325 pp. As cited in: Schroeder, C.A. 1946. Priority of the Species Austin, D.E 1978. Exotic plants and their ef- Psidium cattleianum Sabine. Jour. Arnold DowAgrosciences fects in southeastern Florida. Env. Conserv. Arboretum. 27:314-315. 5:25-34. Riverdale Small, J.K. 1933. Manual of the Southeastern Dehgan, B. 1998. Landscape Plants for Subtropi- Flora. Univ. of No. Carolina Press, Chapel Invasive Plant Control cal Climates. Univ. Press of Florida, Gaines- Hill. p. 937. ville. p. 480. Brewer International The Staff of the Liberty Hyde Bailey Hortorium. FLEPPC. 2000. Florida Exotic Pest Plant Council 1976. Hortus Third. Macmillan Publishing Timberland Enterprises, Inc. occurrence data base. Unpublished. Data Co., New York. p. 923. available by requests via Web site: http:// American Cyanamid www.fleppc.org/. Stressau, EB. 1986. Florida, MyEden. Florida Classics Library, Port Salerno, FL. p. 102. Helena Fosberg, ER. 1941. Varieties of the Strawberry

New Name! Growing Commitment!

AgroDistribution LLC. dba Prosource One ProSource One formerly Terra Professional Products has a new name with a growing commitment to our customers. ProSource One is the exclusive source for all of your aquatic vegetation management needs. We offer the right products, reliable advice and dependable services to help make your aquatic program successful. Talk to your ProSource One aquatics vegetation management specialist.

Aquatic Specialists Western Florida Polly Ellinor 1-888-813-0562 Eastern Florida Paul Mason 1-800-207-1408

WILDLAND WEEDS 11