General News

Biocontrol News and Information 33(1), 1N–8N www.cabi.org/BNI General News Oriental Fruit Fly Biocontrol in French Polynesia parasitism had reached 65% on the same three host plants. If M. indica (a seasonal fruit) is included, The ten years’ data analysed in a paper in Biological mean parasitism increased from 47.7% in 2006 to 1 Control by Roger Vargas and co-authors were col- 59.7% in 2009. Fruit fly numbers were also still lected during a programme on the biological control falling: by 2009, numbers of B. dorsalis, B. tryoni and of oriental fruit fly (Bactrocera dorsalis) in French B. kirki emerging from guava fruits had declined Polynesia. As well as providing an account of “the 92.3%, 96.8%, and 99.6%, respectively, from 2003 most successful example of classical biological con- levels. trol of fruit flies in the Pacific outside of Hawaii”, the authors report on investigations on interspecific Following its introduction to Tahiti in 2007, D. long- competition and displacement among B. dorsalis and icaudata was found to be established in early 2008. two other invasive Bactrocera species that had been It is now widespread on the island but numbers accidentally introduced and established in French remain low. Sampling rarely found parasitism levels Polynesia some years earlier: B. kirki (introduced in on an area or host-plant basis exceeding 5%, and it 1928), and B. tryoni (in 1970). During surveys of five was often lower (mean 2.4% for the 11 host plants of the Society Islands of French Polynesia (Tahiti, from which it has been recovered, cf. 43.4% for F. Moorea, Raiatea, Tahaa and Huahine) B. dorsalis arisanus from the same plants), and D. longicaudata was found on 29 host plants. It is commonly reared accounts for less than 10% of the parasitoid guild on from Mango indica (mango), Terminalia catappa Bactrocera spp. on Tahiti. Nonetheless, the new (tropical almond), Inocarpus fagifer (Polynesian introduction has increased total mortality by parasi- chestnut) and Psidium guajava (common guava) toids and these are early days; with time its fruits collected from trees along roadsides (and these populations may increase further. thus became the subject of a monitoring programme on Tahiti), but more significantly from wild P. gua- The observed decreases in numbers of the three Bac- java, which is invasive in the interior. In Hawaii, P. trocera species in absolute terms and relative to each guajava and P. cattleianum (strawberry guava) have other are concluded to be the combination of the proved to be the key hosts; these are invasive and action of the biocontrol agents and competitive inter- often dominate the wild vegetation of the interior, action between the fruit fly species. The fruit flies use although the pest is of more economic importance on different host plants to differing extents, but all use tree fruits along major roadways, where there are common guava, Polynesian chestnut and tropical more residential gardens and commercial orchards. almond, which were extensively sampled on Tahiti during the biocontrol programme. Bactrocera dor- During the programme in French Polynesia, which salis now predominates in mango, common guava began in 2002, three biocontrol agents that had been and tropical almond. While in mango B. dorsalis may introduced to Hawaii during the successful campaign have found an ‘empty’ niche – or one not exploited by against B. dorsalis (1947–53) were considered for B. kirki in particular – it has steadily displaced B. introduction: Fopius arisanus, Diachasmimorpha tryoni and B. kirki on common guava and tropical longicaudata and F. vandenboschi. Given its contri- almond to become the predominant species. It has bution to control in Hawaii, F. arisanus was the thus probably become the dominant fruit fly on many primary candidate for French Polynesia and was of the fruit tree species in French Polynesia. introduced from Hawaii in 2002, with D. longicaudata following in 2007; F. vandenboschi was The authors end by saying that the results add eventually rejected for introduction because it is now weight to arguments for the use of F. arisanus rare in Hawaii, having been largely displaced by F. against B. dorsalis on other islands of French Poly- arisanus. nesia and elsewhere in the Pacific, and further afield against related invasive Bactrocera spp. in Indian This new publication follows an earlier paper in Ocean island countries, Africa and South America. 20072 in which the successful establishment of F. arisanus in French Polynesia (on Tahiti, Moorea, 1Vargas, R. I., Leblanc, L., Putoa, R. and Piñero, J.C. Raiatea, Tahaa and Huahine) was described, (2012) Population dynamics of three Bactrocera spp. together with data indicating the early success of the fruit flies (Diptera: Tephritidae) and two introduced introduction: by 2006 F. arisanus was parasitizing natural enemies, Fopius arisanus (Sonan) and Dia- 51.9% of the invasive Bactrocera spp. infesting chasmimorpha longicaudata (Ashmead) common guava, Polynesian chestnut and tropical (Hymenoptera: Braconidae), after an invasion by almond on Tahiti and was providing significant con- Bactrocera dorsalis (Hendel) in Tahiti. Biological trol; for example, it had reduced numbers of flies Control 60(2), 199–206. emerging from guava fruits by 75.6%, 79.3% and 97.9% for B. dorsalis, B. tryoni, and B. kirki, respec- 2Vargas, R.I., Leblanc, L., Putoa, R. and Eitam, A. tively, compared with 2003 (pre-establishment) (2007) Impact of introduction of Bactrocera dorsalis levels. The data in the new paper indicate that F. (Diptera: Tephritidae) and classical biological control arisanus is having a growing impact. By 2009 mean releases of Fopius arisanus (Hymenoptera: Braco- Are we on your mailing list? Biocontrol News and Information is always pleased to receive news of research, conferences, new products or patents, changes in personnel, collaborative agreements or any other information of interest to other readers. If your organization sends out press releases or newsletters, please let us have a copy. In addition, the editors welcome proposals for review topics. 2N Biocontrol News and Information 33(1) nidae) on economically important fruit flies in During April and May the night temperature is very French Polynesia. Journal of Economic Entomology close (13–14°C) to the optimum temperature 100, 670–679. required for winter rust spore germination and infec- tion. But during these months the environment is Contact: Roger I. Vargas, USDA-ARS, US Pacific relatively dry. Therefore it appears that the climatic Basin Agricultural Research Center, Hilo, Hawaii. conditions of Kathmandu valley are not conducive for Email: [email protected] winter rust to inflict significant damage to Parthe- nium. To date, it is not clear how widespread the rust is in other Parthenium-infested areas of the country. Puccinia abrupta var. partheniicola: a biocontrol Given the heterogeneous climatic conditions across agent of Parthenium hysterophorus new to Nepal Nepal, some areas may be more suitable for winter rust than Kathmandu valley. Puccinia abrupta var. partheniicola, also called 1 parthenium winter rust, is one of two fungal patho- Dhileepan, K. and Strathie, L. (2009) Parthenium gens that have been used as biocontrol agents hysterophorus. In: Muniappan, R., Reddy, D.V.P. and against the noxious invasive weed Parthenium hys- Raman, A. (eds) Weed Biological Control with terophorus. Parthenium, a native of Central and Arthropods in the Tropics: Towards Sustainability. South America, is an invasive weed of global signifi- Cambridge University Press, Cambridge, UK, pp. cance which has been rapidly expanding in urban, 272–316. agricultural and grazing lands of Australia, Asia, 2 Africa and the Pacific causing serious environ- Shrestha, B.B., Poudel, A., Khatri-Chhetri, J., mental, economic, human and animal health Karki, D., Gautam R.D. and Jha, P.K. (2010) Fortui- problems. Though Parthenium was first encountered tous biological control of Parthenium hysterophorus in Nepal in 1967, the population explosion of this by Zygogramma bicolorata in Nepal. Journal of Nat- weed has been occurring since the 1990s throughout ural History Museum 25, 332–337. the southern part of the country; along the road net- works, it has been expanding to higher elevations in By: Bharat Babu Shrestha, PhD, the Mid Hills of Nepal. Central Department of Botany, Tribhuvan University, Kathmandu, Nepal. Winter rust is naturally found in Argentina, Bolivia, Email: [email protected] Brazil, Central America and Mexico. As a part of a biocontrol programme, rust collected from Mexico was first introduced into Australia between 1991 and Australia Releases First Biocontrol Agent 1995. In other parts of the world, the rust has not against Madeira Vine been introduced intentionally, but it has been reported from a number of countries including The release of a chrysomelid leaf-feeding beetle in China, India, Ethiopia, Kenya, Mauritius and South the Australian state of Queensland in May 2011 Africa1. In Nepal Parthenium infected by winter rust marked the first release worldwide of a biocontrol was observed in May 2011 on the campus of Trib- agent against the weed Anredera cordifolia, or huvan University at Kirtipur (27° 40’ 42.6” N, 85° 17’ Madeira vine. Native to South America, Madeira 7.2” E, 1324 m above mean sea level) in Kathmandu vine was introduced as an ornamental and has valley, and at a few other sites in the valley. This is become a serious environmental weed in several the first report of the winter rust from Nepal. Its countries, including South Africa and Australia. It identification was confirmed by Dr Marion K. Seier spreads rapidly via tubers produced on its stems and and Dr Harry C. Evans at CABI at Egham in the UK. its vigorous mat-like growth smothers native vegeta- Herbarium specimens of Parthenium with leaves tion, including trees, especially in moist and riparian infected by this rust have been deposited in the Her- areas.

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