Biological control agents for the guava moth, Coscinoptycha ...

Biological control agents for the guava moth, Coscinoptycha improbanaSustainable Farming Fund Project L11/145J. J. DymockJuly 2012Co-funded by the following Industry Groups and Regional CouncilsProject Team CompositionProject Manager: Dr J J DymockMember 1: (Chair) Don McKenzie, NRC Biosecurity Senior Programme ManagerMember 2: Tim Harper, Feijoa grower (Maungataroto) and President of NZ Feijoa AssnMember 3: Dr Lisa Jamieson, Plant and Food ResearchMember 4: Dr Mike Butcher, NZ Pipfruit IndustryMember 5: Dr Chris Hale, NZ Summerfruit IndustryMember 6: Bev Worthington, President, NZ Macadamia SocietyGrowers: Jeff Cleghorn, Macadamia Grower (Kerikeri) Murray Redpath, NZ Tree Crops Assn,Peter Albertson, Feijoa Grower (Kerikeri)Regional Councils: Don McKenzie - Northland Regional Council, Jack Craw – AucklandCouncil, Kevin Collins -Waikato Regional Council, John Mather- Environment Bay of Plenty

7 samples11 samples10 samplesMap of Sydney suburbs where samples of lilly pilly were collected.Photo: Magenta lilly pilly (Syzygium paniculatum) incubated in 2L plastic containers.

Photo: Samples of lilly pilly fruit incubated in 2L containers in the laboratory at the University ofSydneyOver the period 23–27 April 2012, the contents of each container were examined. Any insectspresent had emerged from the lilly pilly fruit since the experiment had been set up (20 and 22March). These insects were stored:• dry – Lepidoptera (moths), Curculionidae (weevils), Tephritidae (fruit flies); or• in absolute alcohol (guava moths only); or• in 70% alcohol – all Hymenopteran wasp specimens.Photo: Examining the contents of a 2L container of incubated lilly pilly fruit.

DNA analysis of guava moth populationsEcogene (Landcare Research) sequenced 658 base pairs of the Cytochrome oxidase I (COI) gene fromthe following guava moth specimens:• 10 guava moths from four of the lilly pilly fruit samples collected in and around Sydneyon 20 and 22 March 2012• 10 larvae of guava moth infesting feijoa in Mangonui and Cable Bay (Doubtless Bay,Northland) on 17 May 2012• the leg of one pinned moth specimen from New Caledonia held at L’Institutagronomique néo-CalédonienRESULTS AND DISCUSSIONPheromone trapping of guava mothVery few guava moths have been caught in pheromone traps baited with synthetic guava moth sexpheromone in Australia. Only one moth was trapped in this study, in Bundaberg, QLD, in November2011. It was identified as C. improbana using morphological characters (R. Hoare, pers. comm.). Noguava moths were caught in a pheromone trap placed in a lilly pilly tree from 23–28 April 2012, inStanmore, an inner-west suburb in Sydney. Fruit from this tree had yielded guava moth duringsampling a month earlier.C. improbana has only previously been collected in guava moth sex pheromone trap in Nambour,QLD, in August 2004 (2 moths trapped in 4 days in a derelict guava orchard, Dymock 2004,Northland Regional Council Internal Report). All pheromone traps were baited with DESIRE 2-component synthetic guava moth sex pheromone.Insects reared from lilly pilly fruitFruit was collected from lilly pilly from 28 sites in northern Sydney, Sydney north shore and innerwestsuburbs on 20 and 22 March 2012 (data available as a separate excel file).C. improbana was reared from lilly pilly fruit from 23 of the 28 sites. A total of 680 C. improbanamoths emerged from fruit samples during the study (Table 1).

Photo: Specimens of Ichneumonoidea reared from Syzygium paniculatum collected from 16McKenzie St, Lavender Bay, north of Sydney Harbour Bridge.Other Hymenopteran wasps reared from the samples were Anselmella miltoni (Hymenoptera:Eulophidae) from 13 sites, and Megastigmus sp. (Hymenoptera: Torymidae), from ten sites. Boththese species are known as seed feeders. Megastigmus sp. is thought to be associated commensallywith A. miltoni (Juniper and Britton, 2010). These two species are too small (

It is possible that the presence of these weevil larvae in fruit could deter guava moth fromovipositing on fruit and/or guava moth larvae successfully developing within fruit. There was norelationship between the number of Sigastus spp. weevils and the number of guava moths emergingfrom fruit samples in this study (R 2 =0.062, t=1.25, 23 df). At least 95% of fruit from S. paniculatumcollected in Kerikeri in May 2012 and from Awanui in June 2011 were infested by an unnamedweevil larva. Attempts to rear this weevil for identification have so far proven unsuccessful.However, in New Zealand, this weevil could be excluding guava moth from the fruit as no guavamoth larvae have been found either infesting S. paniculatum fruit or co-habiting with these weevillarvae inside the fruit.Other moths (Tortricidae)Eight leafroller moths (Lepidoptera: Tortricidae) in total were reared from seven sites. They are alsopotential non-target hosts of the Ichneumonoidea wasps found in this study.Fruit fly (Tephritidae)A total of 36 adult Tephritidae fruit flies (Bactrocera sp., probably jarvisi) were reared from fruitcollected at nine of the lilly pilly collection sites. The presence of Tephritid larvae in fruit samplesmay deter guava moth oviposition or have a detrimental effect on guava moth larval survival withinfruit, but again there was no relationship between the number of Tephritid flies and the number ofguava moths emerging from fruit samples (R 2 = 0.097, t=1.6, 23 df). No wasp specimens of the genusDiachasmimorpha (which parasitise Tephritidae in Australia), were reared from any of the samples.DNA analysis of guava moth populationsEcogene sequenced 658 base pairs of the Cytochrome oxidase I (COI) gene from 10 larval specimensof guava moth from Doubtless Bay, New Zealand, and 10 moth specimens from Sydney, Australia.Unfortunately, there was insufficient DNA material obtained from New Caledonian guava mothmaterial (only a leg) to sequence DNA to determine the taxonomic status of New Caledonia guavamoth species.Of the ten New Zealand specimens:• nine were identical, with the same three base pairs different from the Sydney specimens• one New Zealand specimen clustered with two Sydney specimens.Therefore, from the guava moth samples analysed, there are two haplotypes present in NewZealand, with one haplotype appearing unique with respect to Sydney specimens.

Key to collection sitesNZ – 10 larvae collected from feijoa in Cable Bay and Mangonui, Doubtless Bay, 17 May 2012AUSMorgan – 2 moths that emerged from Syzygium australe hybrid – corner of Morgan St andLivingstone Rd, Marrickville, inner-west SydneyAUSChurch –3 moths that emerged from Syzygium paniculatum – corner of Pittwater and BakerRds, Church Point, Northern Beaches 33 km NE Sydney CBDAUSBigola – 2 moths that emerged from Syzygium paniculatum – Bigola suburb, Northern Beaches,33 km NE Sydney CBDAUSGrace – 3 moths that emerged from Syzygium paniculatum – 11 Grace Ave, Frenchs Forest,North Shore Sydney

Existing data for C. improbana analysed by Dr Andrew Mitchell, Australia Museum, Sydney, using theBarcode of Life Database (BOLD), showed very little variation in the COI gene in the 14 specimenssequenced so far, collected inland from Canberra to Orange, and Sydney to the QLD border on thecoast.Neither lilly pilly nor acmena fruit have been recorded as hosts of guava moth in Northland (LisaJamieson pers. comm. and pers. obs.), despite being readily available to guava moth. Fruit ofmacadamia (Ruth Huwer, pers. comm.), feijoa and loquat and have not been recorded as hosts ofguava moth in Australia – including fruit from four feijoa trees in Sydney examined during this study(Table 2). The most common insect infesting macadamia nuts in Queensland is the macadamia nutborer, Cryptophlebia ombrodelta (Lepidoptera: Torticidae), which may be excluding guava mothfrom infesting macadamia nuts.Table 2. Host fruit of guava moth common to Australia, New Zealand and Norfolk Island+ host- present, but not a host? present, but not known if a hostSpecies PlantFamilyPlace ofOriginAustralia NewZealandNorfolkIslandGuava, Myrtaceae Sth America + + +Psidium sp.Feijoa, Acca Myrtaceae Sth America - + Not presentsellowianaLilly pilly – Myrtaceae Australia + - Not presentSyzygiumpaniculatum,S. australeAcmena Mytaceae Australia + - Not presentsmithiiMacadamia Proteaceae Australia - + ?spp.Citrus spp. Rutaceae SE Asia + + ?Loquat, Rosaceae China - + ?EriobotryajaponicaPeach, Pyrus Rosaceae China - + +sp.Plum (Old Rosaceae Europe - + ?World),Prunus spp.Pear, PyruspyrifoliaRosaceae Europe - + ?

It is not known whether the differences in host fruit choice by guava moth in New Zealand, Australia,Norfolk Island and New Caledonia guava moths is due to the:• presence of different biotypes of guava moth with different feeding preferences, or• presence of different insects co-habiting or competing for fruit, or• differing host fruit range available.Further data are required from guava moths across a broader geographical range (including NewCaledonia and Norfolk Island) to determine the origin of the New Zealand guava moth haplotypes.In the meantime, the differences recorded thus far are not great enough that any NZ specimens canbe recognised as representing separate species. At present, C. improbana, as a single species, is stillconsidered as the target for a biocontrol programme.FUTURE PLANSThe small amount of variation seen in the COI gene is typical of within-species differences.Therefore, guava moths identified by morphological characteristics in New Zealand and Australia canstill be considered a single species. The present data suggest that the geographic source of the NZguava moth is mixed and includes areas other than where guava moth was collected in Sydney.More samples from different regions in Australia and NZ would be needed to confirm this.Collections of guava moth in New Caledonia and Norfolk Island are planned.Confirmation that the Ichneumonidea parasitoid wasps reared during this project are indeedparasitizing guava moth is the next step in a biocontrol programme for guava moth. The waspspecies identified as potential biocontrol agents for guava moth would be exposed to guava mothinfestedfruit of lilly pilly, in the absence of other insect species, to determine the level of parasitism.REFERENCESBlanche, R., Bauer, R., Cunningham, S. and Floyd, R. (2002). Services and dis-services of rainforestinsects to crops in north Queensland. Cooperative Research Centre for Tropical Rainforest Ecologyand Management. Cairns. (20 pages)Common, I. F. B. (1990). Moths of Australia. Melbourne University Press, Carlton, AustraliaFay, H. A. C., De Faveri, S. G., Storey, R. I. and Watson, J. (2001) Sigastus weevil – an emergingpest of macadamias in north Queensland. Proceedings of the 6th Workshop in Tropical AgriculturalEntomology, Darwin, NT, 11–15 May 1998. NT-DPIF Technical Bulletin No. 288.Gibb, A. R., Suckling, D. M., Morris, B. D., Dawson, T. E., Bunn, B., Comeskey, D. and Dymock, J. J.(2006). (Z)-7-Tricosene and Monounsaturated Ketones as Sex Pheromone Components of theAustralian Guava Moth Coscinoptycha improbana: Identification, Field Trapping, and Phenology .Journal of Chemical Ecology 32(1): 221–237.Jamieson, L. E., Dymock, J. J., Dawson, T., Froud, K. J., Seldon, D. S., Suckling, D. M., and Gibb, A. R.(2004). Guava moth in New Zealand – Distribution, hosts, lifecycle observations and discussion ofpest management options. New Zealand Plant Protection 57: 13–19.