Hymenoptera: Argidae) on Miconia Calvescens DC (Melastomataceae)

Biological Control 43 (2007) 95–101 www.elsevier.com/locate/ybcon Ecology, host specificity and impact of Atomacera petroa Smith (Hymenoptera: Argidae) on Miconia calvescens DC (Melastomataceae) Francisco R. Badenes-Perez a,*, M. Tracy Johnson b a Pacific Cooperative Studies Unit, University of Hawaii at Manoa, Honolulu, HI 96822, USA b Institute of Pacific Islands Forestry, USDA Forest Service, Pacific Southwest Research Station, Volcano, HI 96785, USA Received 16 March 2007; accepted 15 May 2007 Available online 25 May 2007 Abstract Miconia calvescens DC (Melastomataceae) is an invasive tree considered to be the greatest threat to natural ecosystems of Hawaii and other Pacific islands. The potential of the sawfly Atomacera petroa Smith (Hymenoptera: Argidae) as a biological control agent of M. calvescens was evaluated in field and laboratory studies in its native range in Brazil. At two field sites, 31.1% and 15.3% of the M. calvescens leaves sampled presented rasping damage by A. petroa larvae, affecting 2.0–66.7% (16.8% on average) of the area of each attacked leaf. Damage by A. petroa was significantly more frequent among older leaves (81.2% affected) than younger leaves (18.8% affected), and percentage of leaves damaged declined significantly with increasing stem diameter. Damage by individual A. petroa larvae feeding as first through sixth instars ranged from 304 to 924 mm2 (663 mm2 on average) of M. calvescens leaf material in the field. In the laboratory, A. petroa developed through the final three larval instars in 2.1, 2.5 and 3.1 d on average, respectively, pupated for 5–10 d, and survived as adults for 5–8 d. No feeding damage by A. petroa was observed on plant species associated with M. calvescens at field sites, including three other species of Melastomataceae, or on test plants exposed to A. petroa larvae in the laboratory, indicating that A. petroa has a narrow host range. Host specificity, foliar impact, and the likely absence of specialized natural enemies in Hawaii appear to justify further study of A. petroa as a biological control agent of M. calvescens. Ó 2007 Elsevier Inc. All rights reserved. Keywords: Miconia calvescens; Atomacera petroa; Sawfly; Weed management; Leaf area; Host specificity 1. Introduction the main methods used to contain the spread of M. calvescens, but control is difficult and costly, especially in remote The velvet tree, Miconia calvescens DC (Melastomata- areas. Biological control is considered an essential tool for ceae), is a small tree native to Central and South America long-term management of M. calvescens (Smith, 2002). that is considered a serious threat to natural ecosystems in Argidae (Hymenoptera) is one of the most diverse fam- Hawaii and other Pacific islands because of its ability to ilies of sawflies in the neotropics, with 30 genera and invade intact native forests (Medeiros et al., 1997; Meyer, approximately 300 species described (Smith, 1969, 2006). 1998). M. calvescens can outcompete the native vegetation The subfamily Atomacerinae includes only the genus Ato- of these islands and has displaced over 65% of the native macera and is restricted to the western hemisphere, mainly forest in Tahiti since its introduction in 1937 (Meyer and the eastern part of the Americas, from southeastern Can- Florence, 1996). Herbicides and mechanical removal are ada to northern Argentina (Smith, 1992, 2006). Most larvae of Argidae feed externally on foliage, and several species are economically important defoliators (Cahoon and Stevenson, 1986; Smith and Middlekauff, 1987; Boyd * Corresponding author. Present address: Department of Entomology, Max Planck Institute for Chemical Ecology, Hans-Knoell-Str. 8, D-07745 and Cheatham, 2004). Two species of Argidae, Schizocerel- Jena, Germany. Fax: +49 03641 57 1502. la pilicornis (Holmgren) (Gorske et al., 1977; Norris, 1997) E-mail address: [email protected] (F.R. Badenes-Perez). and Arge humeralis (Beauvois) (Regas-Williams and 1049-9644/$ - see front matter Ó 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.biocontrol.2007.05.011 96 F.R. Badenes-Perez, M.T. Johnson / Biological Control 43 (2007) 95–101 Habeck, 1979) have been considered for biological control Larvae were transferred successfully to rearing containers of purslane and poison ivy, respectively. in the laboratory by carefully cutting the M. calvescens Larvae of Atomacera spp. have been found feeding on leaf approximately 2 mm around each larva without plant species in the families Convolvulaceae, Fabaceae, detaching it from the leaf surface. To study the life cycle Melastomataceae and Malvaceae (Lindquist and Trinnell, of A. petroa on M. calvescens, 25 field-collected 3rd 1965; Boyd and Cheatham, 2004; Smith, 2006). Larvae of instars were placed individually in plastic food storage the sawfly Atomacera petroa Smith rasp the upper surface containers (30 · 15 · 10 cm) with one M. calvescens leaf of M. calvescens foliage causing abundant scars and reduc- (approximately 30 · 15 cm) with the adaxial side facing ing photosynthetic tissue (Picanço et al., 2005; Smith, upwards. Observations were made every 24 h and larvae 2006). The original description of A. petroa only included were transferred to a fresh leaf every 48 h until they morphological descriptions of the adults (Smith, 1992). pupated. Pupae were held in the same containers and Here, we study the biology, host specificity and impact of were examined every 48 h. Emerging adults were offered A. petroa under laboratory conditions and in the natural a food source of 10% sugar solution in a 50 ml Erlen- habitat of the insect in Brazil to evaluate its potential as meyer flask plugged with cotton. To study pupating a biological control agent of M. calvescens. behavior, five 6th instar larvae were placed on the leaves of an 80-cm tall 3-year-old plant grown in a 15 cm pot 2. Materials and methods that was placed in a cylindrical plastic garbage can (1.0 m height · 0.5 m diameter). The container was sealed This study was conducted at two field sites with native at the top with cheese cloth that had a mesh small enough populations of M. calvescens, Viçosa and Dionisio, in the (<0.5 mm) to prevent entrance of natural enemies. Obser- state of Minas Gerais, Brazil. Both areas were in secondary vations were made 48 h later. Atlantic forest heavily disturbed by adjacent agricultural activity and eucalyptus plantations. The Viçosa site, at 2.2. Host specificity of A. petroa 20°4501400S and 42°5205300W and 645 m above sea level, and the Dionisio site, at 19°5003400S and 42°4603600W and Plant species growing near A. petroa-infested M. calves- 345 m above sea level, lay approximately 150 km apart. cens were examined for A. petroa larvae and feeding dam- Laboratory studies were conducted on the campus of age in June 2006 (measurements taken as presence/ the Universidade Federal de Viçosa in a room exposed to absence). Inspected plants were located within a 10 m ambient daylight, temperature and humidity. During the radius of each of five randomly selected M. calvescens period of this study, from April to September 2006, the lab- plants at each field site. Plant species occurring in associa- oratory experienced a photoperiod of approximately 11– tion with the native M. calvescens (monocolored) included 12 h:13–12 h light:dark, 22 ± 8 °C and 85 ± 10% RH. Cli- outplanted M. calvescens from Hawaii (bicolored type with matic data for Viçosa were obtained from the Department purple abaxial side of leaves), Miconia prasina (Sw.) DC, of Agricultural Sciences of the Universidade Federal de Clidemia hirta (L.) D. Don, and Tibouchina granulosa Viçosa. Climatic data for Dionisio were provided by the Cogn. (Melastomataceae); Ricinus sp. (Euphorbiaceae); ‘‘Estaçaõ Meteorolo´gica de Ponte Alta’’ belonging to Desmodium sp. (Fabaceae); Ficus sp. (Moraceae); Musa CAF Santa Ba´rbara Ltda. paradisiaca L. (Musaceae); Eucalyptus sp. and Psidium guajava L. (Myrtaceae); Piper sp. (Piperaceae); Rubus sp. 2.1. Biology of A. petroa (Rosaceae); Coffea arabica L. (Rubiaceae); and Citrus sp. (Rutaceae). At least three plants of each species were A total of 20 M. calvescens plants were randomly examined. selected and examined for presence of eggs, larvae, pupae No-choice and two-choice experiments were conducted and adults of A. petroa every four weeks from April to Sep- in the laboratory to compare survival of A. petroa larvae tember 2006 in each of two locations (Viçosa and Dioni- on a control of local M. calvescens vs. bicolored M. calves- sio). A minimum of one-third of the area of leaves and cens from Hawaii as well as lettuce, Lactuca sativa L. stems of each plant was examined if it was not possible (Asteraceae), collards, Brassica oleracea L. var. acephala to inspect the whole plant because of its location and/or (Brassicaceae), and watercress, Nasturtium officinale Ait. large size. A correction factor was applied to calculate F. (Brassicaceae). The latter three plant species were cho- insect density per plant according to the approximate pro- sen because they are agricultural crops commonly grown portion of each plant sampled (e.g., if only 50% of a plant in both Brazil and Hawaii and because they were readily could be inspected, the total number of insects for the plant available and allowed us to evaluate host range for two was determined as those in the 50% inspected multiplied by additional plant families, Asteraceae and Brassicaceae. two). Approximately, equal quantities of leaves (in terms of total Although larvae were easily collected in the field by leaf area) of each plant type were placed with the adaxial removing the entire leaf where they were feeding, they side facing upwards in plastic containers 30 · 15 · 10 cm. were very sensitive to manipulation, and detaching them Field-collected larvae ranging from 3rd to 6th instars, five from the leaf resulted in their death within a few days.

Load more