Australian Journal of Entomology (2005) 44, 77–82

Laboratory life history and field observations of Poliopaschia lithochlora (Lower) (: ), a potential biological control agent for Melaleuca quinquenervia (Myrtaceae)

Kylie E Galway1 and Matthew F Purcell2*

1Ecology and Entomology, Lincoln University, Canterbury, New Zealand. 2USDA-ARS Australian Biological Control Laboratory, C/- CSIRO Entomology, Long Pocket Laboratories, 120 Meiers Road, Indooroopilly, Qld 4068, Australia.

Abstract Melaleuca quinquenervia (Cav.) S.T. Blake, Australian broad-leaved paperbark, has become a serious weed in southern Florida. Poliopaschia lithochlora (Lower) is a promising candidate as a potential biological control agent, and this study describes laboratory and field observations of the life history of this moth. Eggs are laid in small batches, mainly on the surface of leaves, and larvae are voracious leaf feeders, concealed in tubes that are usually found in small colonies attached to leaves and stems. Larvae move from these tubes to feed on surrounding leaves, and saplings and suckers are frequently defoliated. Prepupae form sealed bulbs in the larval tubes in which they pupate. Adult females are mainly active and oviposit at night. Development from egg to adult occurs in approximately 80 d. Field populations appear to be regulated by several egg and larval parasites. Because this moth severely damages saplings and suckers of M. quinquenervia, prefers low-lying humid sites, and can be suc- cessfully mass reared, it is rated highly for its potential as a biological control agent. Key words broad-leaved paperbark tree, classical biological control, .

INTRODUCTION (Bodle et al. 1994; Laroche 1994). Attempts to control M. quinquenervia have proven costly, environmentally Australian broad-leaved paperbark, Melaleuca quinquenervia inappropriate, and generally ineffective (Balciunas & Center (Cav.) S.T. Blake (Myrtaceae), is native to the eastern coast of 1991). Herbicidal treatments have been the most practical and Australia, and is found along streams and in swamps (Holliday economically feasible control method (Bodle et al. 1994), 1989), or in seasonally inundated, low-lying areas (Rayamajhi though they are still expensive and can cause damage to non- et al. 2002). In the early 1900s it was introduced into Florida target plant species. Mechanical removal is expensive and not as an ornamental and as a means to dry up sections of the practical in wetland areas. Physical tactics usually involve Everglades for development (Laroche & Ferriter 1992; Bodle control by fire, but M. quinquenervia is well adapted to fire et al. 1994; Laroche 1994). due to its thick protective bark, serotinous capsules, and The spread of M. quinquenervia in Florida has been adventitious buds (Hofstetter 1991). Therefore, control of described as explosive, averaging 2850 ha per year over the M. quinquenervia in Florida will probably depend on the suc- last century (Laroche & Ferriter 1992; Center et al. 2000) with cess of biological control agents introduced from Australia the rate still accelerating (Bodle et al. 1994). In the process it (Laroche 1994). has caused extensive environmental and economic damage Since 1986, surveys have been conducted in Australia to (Laroche 1994; Balciunas et al. 1995). Impacts include a find potential biological control agents of M. quinquenervia, reduction in native wildlife populations, a loss of native veg- and more than 450 herbivores have been collected etation, additional stress placed onto rare, threatened and (Balciunas et al. 1994). Two species have been released in endangered species, increased fire hazard (Balciunas & Center Florida. A foliage-feeding weevil, Oxyops vitiosa Pascoe 1991; Timmer & Teague 1991), increased skin and respiratory (Coleoptera: Curculionidae), was released in 1997 (Center allergic reactions (Diamond et al. 1991), and reduced fishing, et al. 2000) and a sap-sucking psyllid, Boreioglycaspis mela- hunting and air boating activities (Balciunas & Center 1991). leucae (Hemiptera: Psyllidae), was released in 2002 (Wood & In 1992, M. quinquenervia was added to the United States Flores 2002). Both have established (Pratt et al. 2003) Department of Agriculture’s Federal Noxious Weed List and are having a serious impact on the weed, although more agents will be required. Species of Pyralidae are the most common Lepidoptera *Author to whom correspondence should be addressed (email: used in biological control of weeds (Julien & Griffiths [email protected]). 1998). Poliopaschia (formerly Epipaschia) lithochlora

78 K E Galway and M F Purcell

Fig. 1. Field colony of Poliopaschia lithochlora with larvae concealed in tubes webbed to branches and leaves of Melaleuca quinquenervia.

(Lower) (Lepidoptera: Pyralidae: Epipaschiinae) (Solis Establishment of laboratory colony 1992) is one of the most damaging moths observed on Colonies of P. lithochlora were collected from M. quinquenervia. The tube-dwelling larvae form small col- M. quinquenervia in the field over a wide geographical range onies consisting of a system of tubes and small branches from Peregian (26∞30.37¢S 153∞05.47¢E), 129 km north of bound together (Burrows et al. 1996) (Fig. 1). The tubes Brisbane in south-eastern Queensland, to Woodburn consist of webbing and faecal matter and only one larva (29∞27.8¢S 153∞15.4¢E), 62 km north of Grafton in New South occupies each tube. Sizeable field populations of Wales. Colonies, including webbed leaves and stems, were P. lithochlora have been observed at several locations in removed from M. quinquenervia trees and taken back to the Queensland and New South Wales, often defoliating whole laboratory for processing. Individual tubes were separated and saplings and suckers and damaging larger trees. placed into clear plastic punnets (8 cm2 base ¥ 5 cm high) This paper describes laboratory and field observations on lined with paper towelling, and sealed with a clear plastic lid. the life history of this insect in the context of its potential as Larvae were fed twice weekly with fresh M. quinquenervia a biological control agent of M. quinquenervia. leaf material collected from ornamental trees in Brisbane, and paper towelling was replaced weekly. The prepupal stage is reached when the larva forms a complete bulb at the entrance MATERIALS AND METHODS to the tube. Pupae were removed from these bulbs and placed collectively into punnets. Life history studies were conducted at the United States Oviposition chambers consisted of clear plastic cylinders Department of Agriculture, Agricultural Research Service (20 cm diam. and 60 cm high) with the lid containing a gauze (USDA-ARS), Australian Biological Control Laboratory ventilation hole (10 cm diam.). Our previous laboratory stud- (ABCL) in Brisbane during 1997–2003. All laboratory studies ies revealed that females had higher oviposition and increased were carried out at 20–25∞C. longevity in these chambers than in aluminium-framed, gauze

Life history of Poliopaschia lithochlora 79 cages (45 cm2 by 90 cm) (unpubl. data 1997). A honey and number of larval instars, 849 larvae randomly selected from water solution was smeared onto the inside of the chamber and the laboratory colony were preserved in 70% ethanol. We a potted M. quinquenervia sapling (approximately 60 cm high, measured the head capsule widths of each specimen using a in a 150 mm diam. pot) was placed inside the cylinder. When graticule scale in a binocular microscope set at 35 times mag- P. lithochlora adults emerged, 1–3 pairs (male/female) were nification. The durations of larval instars were determined by released into oviposition chambers. Saplings were searched recording the development of 60 neonate larvae daily until daily and replaced if eggs were found. After emergence, larvae pupation. A change of instar was recorded when the head were left on the saplings for approximately 2 weeks before capsule was shed. being transferred individually into square plastic punnets, both to prevent cannibalism and for space efficiency. When prepu- Pupae pae developed bulbs, each immature was checked daily by making a small observation hole in the bulb using forceps, so Characters were determined to separate male from female that pupation could be recorded. Pupae were removed from pupae. The sex of pupae was determined by viewing the ven- bulbs and placed into punnets for emergence. First-generation tral surface of the ninth abdominal segment. Male pupae pos- (F1) laboratory-reared adults were used in all life-history sess two, raised, oval structures, whereas the female pupae studies. possess a slit, situated perpendicular to the abdominal segment bands. Pupal dimensions were determined by recording the Life-history studies lengths and widths of 50 second-generation pupae using a graticule scale in a binocular microscope set at 8 times mag- Development of immatures nification. We also measured 100 first-generation pupae (sex The development time of all immature stages of P. lithochlora not determined) and 50 second-generation pupae (25 pupae was determined in two studies using newly laid eggs obtained from both sexes) to compare laboratory generations. The pro- from the laboratory colony. portion that survived the pupal stage was determined for 150 In the first study, 300 eggs were monitored daily for randomly selected pupae from the first-generation laboratory eclosion to determine the egg development duration. We colony. transferred larvae 2 weeks after they had emerged from M. quinquenervia saplings to cut foliage in rearing punnets. Adults The punnets were lined with paper towelling, replaced weekly, General observations were made on the size and colour of and the cut foliage was replaced twice weekly. Immatures adults. Newly emerged adults were sexed using the form of were checked daily and pupation, adult emergence and sex the antennae. Males have large pronounced plumose setae were recorded. The development duration from egg to adult that are curved back over the head and attached to the pedi- was calculated for both males and females. Development cle of the antennae; these are absent in females. To observe times for immatures that died in rearing were discarded. daily activity and determine the pre-oviposition period, In the second study, the development of immatures was fecundity and adult longevity, oviposition chambers were set monitored on whole saplings for comparison with develop- up as for the laboratory colony. One female and two males ment recorded on cut foliage. Approximately 300 eggs were that were <12 h old were placed into individual oviposition left on saplings for the immatures to develop. New saplings chambers and monitored every 12 h for oviposition. Males were provided as needed when most of the leaf material had that died were replaced. If oviposition occurred, the sapling been consumed. Pupal bulbs were removed from the plant and was removed, searched, and all eggs were counted. A new placed into punnets and adult emergence was recorded every plant was added to the chamber. Pre-ovipositional period, 24 h to determine the development time from egg to adult. The oviposition per female per day (n = 84) and fecundity durations of the egg, larval and pupal stages were not recorded. (n = 20) were recorded. The adult longevity was determined for 62 males and 48 females. Deaths were recorded every Eggs 24 h. Observations were made on the shape, colour and leaf position of eggs in the laboratory colony and other studies. The number Parasites of eggs per batch and the number of batches per leaf were All parasites emerging from field-collected colonies were pre- recorded for 236 leaves on which oviposition had occurred. served. In all field collections, egg parasites were collected The dimensions of 64 eggs were also measured using a grati- only from one field site, as eggs were difficult to locate. There- cule scale in a binocular microscope set at 8 times magnifica- fore, we placed small potted saplings of M. quinquenervia tion. The proportions of infertile eggs and of viable eggs that with newly oviposited eggs at two field sites, Morayfield hatched were recorded for 700 randomly selected eggs. (27∞07.05¢S 152∞58.08¢E), 45 km NNW of Brisbane, and Nudgee (27∞22.61¢S 153∞05.60¢E), 12.5 km NNE of Brisbane. Larvae These sites were selected as they were known to contain larval/ Observations were made on the colour and markings of many pupal parasites of P. lithochlora. At Morayfield, six potted larvae in the laboratory colony and studies. To determine the saplings with 132 eggs in total were placed in large trays filled

80 K E Galway and M F Purcell

Table 1 Developmental duration of each immature life stage of Poliopaschia lithochlora reared in punnets on Melaleuca quin- quenervia in the laboratory

Stage Duration (d)† Female Range Male Range

Mean ± SEM (min–max) Mean ± SEM (min–max) Frequency (n = 39) (n = 52) Egg 10.41 ± 0.12a 9–11 10.65 ± 0.07a 9–11 Larvae 48.26 ± 0.68a 43–61 44.56 ± 0.37b 39–54 Pupae 16.54 ± 0.18a 15–20 16.40 ± 0.15a 15–20 Head capsule widths (mm) †Means in each row followed by the same letter are not significantly different (unpaired t-test, P < 0.05). Fig. 2. Frequency of head capsule measurements of 849 pre- served Poliopaschia lithochlora larvae. with water to minimise crawling predators at two times in September 1997. At Nudgee, two potted saplings with 687 Table 2 Duration of instars (d) of Poliopaschia lithochlora eggs in total were set into mud next to a large pond in March reared in punnets on cut foliage of Melaleuca quinquenervia in 2003. The plants were retrieved after 1 week from Morayfield the laboratory and after 5 d from Nudgee for observation. Emerging parasites Instar Number Mean ± SEM Range were preserved. 1605.5 ± 0.2 4–10 2375.0 ± 0.4 2–11 3275.1 ± 0.4 4–8 RESULTS 4216.2 ± 0.6 4–10 5186.9 ± 0.5 4–11 Development of immatures 6156.7 ± 0.5 4–12 768.7 ± 0.8 4–11 The mean development time from egg to adult was signifi- 856.2 ± 0.9 3–10 cantly longer for females (mean ± SEM) at 75.21 ± 1.02 d (n = 39, range 68–89 d) than for males, 71.69 ± 0.38 d (n = 52, range 67–82 d) (unpaired t-test, P < 0.01) (Table 1). Survival oviposited on 83% of leaves, and two batches per leaf on 13% from egg to adult was 31.7%. For immatures left on potted of leaves. Up to four batches per leaf have been observed in saplings, the mean development period from egg to adult was the laboratory. Of the eggs observed, 89.5% were viable and significantly longer for both females and males at 81.50 ± less than 1% of these eggs failed to hatch. 0.45 d (n = 94, range 73–93 d) and 78.60 ± 0.58 d (n = 73, range 72–93 d), respectively (unpaired t-test, P < 0.01). Once Larvae again females developed significantly slower than males (unpaired t-test, P < 0.01). Larvae range from grey/brown to pink/brown in colour, with the head and prothoracic shield mottled (yellow, tan and Eggs brown). A cream-coloured dorsal stripe runs along the length of the body. Poliopaschia lithochlora eggs are dorsally flattened, ovate to The number of larval instars could not be determined using elliptical in shape, with entire margins. The surface of the frequencies of head capsule widths, as no distinct clusters chorion is pitted. The eggs are yellow when first oviposited, could be distinguished (Fig. 2). Only five of the 60 larvae with fertile eggs becoming cream-coloured soon after. The monitored for number and duration of instars survived to the development of the embryo is easily seen through the chorion. pupal stage, resulting in a high standard error in results for late The colour of infertile eggs softens to a pale yellow. Eggs are instars (Table 2). We recorded eight larval instars. The com- fixed to the leaf and overlap if laid in batches. Eggs are ovi- bined durations of each larval instar was 50.3 d. This duration posited on the upper or lower surfaces of both young and old is longer than that obtained in Table 1, most likely due to the leaves. They are laid along the margins of leaves, but no daily disturbance of larvae to locate shed exuviae of head consistent pattern was observed with regard to position or capsules. batch size. Only one batch was seen on the stem and another on the midrib of the leaf. The average dimension of 64 eggs Pupae was 1.26 ± 0.01 mm (range 1.07–1.47 mm) long and 0.82 ± 0.02 mm (range 0.53–1.20 mm) wide. Egg batches Male pupae were significantly smaller than females in both contained an average of 6.14 ± 0.24 eggs (n = 264, range 1– length (unpaired t-test, P < 0.01) and width (unpaired t-test, 30 eggs), which did not significantly (unpaired t-test, P = 0.92) P < 0.01) in the second generation. The average dimensions change whether one (n = 180 leaves) or two batches (n = 56 of 25 male pupae was 12.28 ± 0.19 mm long (range 10.13– leaves) were oviposited on the leaf. One batch per leaf was 13.87 mm) by 3.54 ± 0.08 mm wide (range 2.53–4.47 mm) Life history of Poliopaschia lithochlora 81 and the average for 25 female pupae was 14.11 ± 0.09 mm tions. In the laboratory, a colony could be sustained throughout long (range 13.33–14.80 mm) by 4.42 ± 0.07 mm wide the year. Male immatures develop faster than females in both (range 3.87–5.07 mm). There was a significant difference punnets and on whole plants. This can be attributed solely to between first and second generations for both pupal length, a significantly shorter larval stage for males, as the egg and 12.78 ± 0.11 mm (range 9.60–15.07 mm) and pupal durations were not significantly different for the sexes. 13.19 ± 0.17 mm (range 10.13–14.80 mm), respectively Development of immatures is characterised by a long larval (unpaired t-test, P = 0.02), and pupal width, 3.81 ± 0.05 mm stage with at least eight larval instars. Female adults can live (range 2.80–4.93 mm) and 3.98 ± 0.08 mm (range 2.53– for up to 2 weeks and oviposit large numbers of eggs. 5.07 mm), respectively (unpaired t-test, P = 0.03). Of the first- Eggs are difficult to find in the field, and the impact of generation pupae, 98% emerged successfully. Trichogrammatidae parasites on field populations could not be determined. Carcelia sp. flies and ichneumonid wasps are very Adults common parasites of P. lithochlora in the field. The potential of P. lithochlora as a biological control agent will at least Adults were light brown in colour with darker brown markings partly depend on whether endemic parasites significantly reg- on the fore wings. They varied in size, with females and males ulate the immature stages of this moth if released in the USA. having a wingspan of up to 28 mm and 24 mm, respectively. Its tube-dwelling habit and additional cover from webbed Adults were inactive during the day, and became very active leaves and branches may offer some protection for the larvae at dusk. Females were able to produce fertile eggs within 12 h and pupae from natural enemies. The absence of ‘specialist’ of emergence. They rarely oviposited during the day. The parasites may allow substantial populations to develop and average oviposition per day per female was 26.11 ± 3.45 eggs inflict significant damage on the exotic stands of (range 1–183 eggs) and the average total fecundity was M. quinquenervia, especially seedlings and suckers. Our field 95.65 ± 14.29 eggs (range 3–224 eggs). There was no signif- observations (unpubl. data 1997) in Australia indicate that this icant difference between adult life expectancy for males moth prefers low-lying wet or grassy habitats with high 6.98 ± 0.33 d (range 3–12) and females 7.31 ± 0.36 d (range humidity. Therefore, P. lithochlora may adapt very well to the 2–14) (unpaired t-test, P = 0.51). wetland areas of southern Florida where M. quinquenervia is a problem, particularly the Florida Everglades. Parasites Mass rearing of this agent for quarantine host testing Three unidentified species of Ichneumonidae (Hymenoptera) could be performed on live saplings or on cut foliage. Polio- and one species of Braconidae (Hymenoptera) were reared paschia lithochlora develop faster on cut foliage in punnets, from P. lithochlora larvae collected in south-eastern Queen- though maintaining a colony in this fashion is labour inten- sland. An undetermined Carcelia sp. (Diptera: Tachinidae) sive. If quarantine space is not limited, rearing larvae on parasitised both field-collected larvae and pupae in both whole plants is better. Second-generation pupae were signifi- northern and south-eastern Queensland. An undescribed cantly larger than first-generation pupae, indicating that mass Trichogramma sp. (Hymenoptera: Trichogrammatidae) was rearing techniques are suitable. This factor combined with reared from P. lithochlora eggs collected at Daintree high fecundity, high viability of eggs and moderate survival (16∞13.24¢S 145∞25.16¢E), 86.6 km NNW of Cairns, where from egg to the adult stage indicates that large numbers could 56% of eggs (n = 25) were parasitised. This species is a known be generated for quarantine testing or field releases in the parasite of Spodoptera spp. and undetermined Noctuidae, Hes- USA. periidae and Pieridae, and has been collected in Queensland, Further research on the field and laboratory host-specificity, Northern Territory and Western Australia (J Pinto pers. comm. seasonality and distribution of this insect are underway. The 2003). No parasites were reared from the eggs on six potted results of these studies will determine whether P. lithochlora saplings placed at Morayfield. However, 2.3% of the 687 eggs is shipped to quarantine facilities in the USA for final host- on potted saplings placed at Nudgee were parasitised by specificity and pre-release evaluations. Trichogrammatoidea bactrae Nagaraja (Hymenoptera: Tri- chogrammatidae). This is the most common species of Trichogrammatoidea in Queensland and occurs throughout the ACKNOWLEDGEMENTS Australasian region (J Pinto pers. comm. 2003). We thank Bradley Brown, Jeffery Makinson and Dalio Mira (USDA-ARS) for assisting with laboratory studies and field DISCUSSION collection of larvae. We also thank Dr Alma Solis (USDA- ARS Systematic Entomology Laboratory), the Queensland Poliopaschia lithochlora larvae can severely damage young Museum, and the Commonwealth Scientific and Industrial M. quinquenervia plants and complete defoliation of saplings Research Organisation Australian National Insect Collection and suckers has been observed at several field sites in south- for identifications and specimen records. This work was finan- eastern Queensland. In the laboratory, its life cycle is com- cially supported by the USDA-ARS, the South Florida Water pleted within 2–3 months, and 4–5 generations per year could Management District, US Army Corps of Engineers, and the potentially develop in the field, depending on seasonal varia- Florida Department of Environmental Protection. 82 K E Galway and M F Purcell

REFERENCES Plants, University of Miami, Florida, 2–4 November 1988 (eds TD Center, RF Doren, RL Hofstetter, RL Myers & LD Whiteaker), pp. 159–177. United States Department of the Interior, National Parks Balciunas JK & Center TD. 1991. Biological control of Melaleuca quin- Service, Denver, USA. quenervia: prospects and conflicts. In: Proceedings of the Symposium Holliday I. 1989. A Field Guide to Melaleucas. Hamlyn, Melbourne, on Exotic Pest Plants, University of Miami, Florida, 2–4 November Australia. 1988 (eds TD Center, RF Doren, RL Hofstetter, RL Myers & LD Julien MH & Griffiths MW. 1998. Biological Control of Weeds: A World Whiteaker), pp. 1–23. United States Department of the Interior, Catalogue of Agents and Their Target Weeds, 4th edn. CAB Interna- National Parks Service, Denver, USA. tional, Wallingford, UK. Balciunas JK, Burrows DW & Purcell MP. 1994. Insects to control mela- Laroche FB. 1994. Melaleuca Management Plan for Florida. Exotic Pest leuca I: status of research in Australia. Aquatics 16, 10–13. Plant Council, Delray Beach, USA. Balciunas JK, Burrows DW & Purcell MP. 1995. Australian insects for Laroche FB & Ferriter AP. 1992. The rate of expansion of Melaleuca the biological control of the paperbark tree, Melaleuca quinquen- quinquenervia in South Florida. Journal of Aquatic Plant Manage- ervia, a serious pest of Florida, USA, Wetlands. In: Proceedings of ment. 30, 62–65. the VIII International Symposium on Biological Control of Weeds, Pratt PD, Slone DH, Rayamajhi MB, Van TK & Center TD. 2003. Geo- Lincoln University, Canterbury, New Zealand, 2–7 February 1992 graphic distribution and dispersal rate of Oxyops vitiosa (Coleoptera: (eds ES Delfosse & RR Scott), pp. 247–267. DSIR/CSIRO, Mel- Curculionidae), a biological control agent of the invasive tree Mela- bourne, Australia. leuca quinquenervia in South Florida. Environmental Entomology 32, Bodle MJ, Ferriter AP & Thayer DD. 1994. The biology, distribution and 397–406. ecological consequences of Melaleuca quinquenervia in the Ever- Rayamajhi MB, Purcell MF, Van TK, Center TD, Pratt PD & Buckingham glades. In: Everglades: The Ecosystem and Its Restoration (eds SM GR. 2002. Australian paperbark tree (Melaleuca). In: Biological Davis & JC Ogden), pp. 341–357. St Lucie Press, Delray Beach, Control of Invasive Plants in the Eastern United States, Section II: USA. Weeds of Wetlands (eds R Van Driesche, B Blossey, M Hoddle & Burrows DW, Balciunas JK & Edwards ED. 1996. Herbivorous insects R Reardon), pp. 117–130. USDA Forest Service Publication FHTET- associated with the paperbark Melaleuca quinquenervia and its allies: 2002-04. V. Pyralidae and other Lepidoptera. Australian Entomologist 23, 7– Solis AM. 1992. Check list of the Old World Epipaschiinae and the related 16. New World genera Macalla and Epipaschia (Pyralidae). Journal of Center TD, Van TK, Rayachhetry M et al. 2000. Field colonization of the the Lepidopterists Society 46, 280–297. melaleuca snout beetle (Oxyops vitiosa) in south Florida. Biological Timmer EC & Teague SS. 1991. Melaleuca eradication program: assess- Control 19, 112–123. ment of methodology and efficacy. In: Proceedings of the Symposium Diamond C, Davis D & Schmits DC. 1991. Economic impact statement: on Exotic Pest Plants, University of Miami, Florida 2–4 November the addition of Melaleuca quinquenervia to the Florida Prohibited 1988 (eds TD Center, RF Doren, RL Hofstetter, RL Myers & LD Aquatic Plant List. In: Proceedings of the Symposium on Exotic Pest Whiteaker), pp. 339–357. United States Department of the Interior, Plants, University of Miami, Florida, 2–4 November 1988 (eds TD National Parks Service, Denver, USA. Center, RF Doren, RL Hofstetter, RL Myers & LD Whiteaker), pp. Wood M & Flores A. 2002. Sap-sucking psyllid pesters pushy plant. 87–111. United States Department of the Interior, National Parks Agricultural Research 50, 18–19. Service, Denver, USA. Hofstetter RH. 1991. The current status of Melaleuca quinquenervia in Southern Florida. In: Proceedings of the Symposium on Exotic Pest Accepted for publication 26 February 2004.