Australian subterranean termites (Coptotermes acinaciformis) in New Zealand

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1 Australian subterranean termites (Coptotermes acinaciformis) in New Zealand H.G. Pearson and S.J. Bennett Investigation and Diagnostic Centre, Biosecurity New Zealand, Ministry of Agriculture and Forestry, PO Box 2095, Auckland 1140, New Zealand Corresponding author: Abstract Coptotermes acinaciformis (Australian subterranean termite) is a serious pest of trees and seasoned wood. The detection of this pest at two New Zealand locations, during January 2006 in Nelson and January 2007 in rural Auckland, resulted in response actions. The source of the termite infestations at both sites was imported Australian railway sleepers used as landscaping materials ca Surveillance was conducted to determine the extent of the termite infestations at the two sites and to detect termite presence in surrounding areas and other risk sites based on tracing investigations. Movement controls were implemented on risk items to reduce the chance of further spread and delimiting surveys were conducted out to 100 metre radius in suburban Nelson and out to 500 metres in rural Auckland. Environmental data were used to model the possible distribution of winged reproductive termites (alates) from the rural Auckland site following an observed alate flight. The Sentricon termite control system has been used at both locations to deliver toxic bait to the termites. Following toxic baiting, termite activity has ceased at both locations. Sentricon in-ground monitoring stations containing Eucalyptus regnans wood-baits were installed at both locations and will remain in situ for the duration of a 5 year monitoring programme. This paper reports on the response objectives and gives results and the current status of the eradication programmes. Introduction Internationally, subterranean termites (Rhinotermitidae) are regarded as one of the most destructive urban pests. In Australia, it is estimated that 650,000 homes have been infested by termites over the past 5 years. The cost of treatment and repair of the resultant damage has been estimated at AUD$3.9 billion (Creffield 2005). Damage in the United States in 2002 was noted at around $US2 billion per annum (Wagner 2001). A successful mature colony with a ready food source typically includes several thousand individual termites, but it can be as large as several million. Termites constantly forage for food, up to 50 metres from the nest, with total foraging territory up to 200 m 2 s (Gerozisis & Hadlington 2005). Subterranean termite tunnels may be up to 200 mm underground and termite activity is seldom detected until timber in a building is damaged. The Australian subterranean termite Coptotermes acinaciformis (Isoptera: Rhinotermitidae) is a serious pest that hitchhiked into New Zealand unnoticed

2 Surveillance for biosecurity: pre-border to pest management several decades ago within utility poles, railway sleepers and wooden packaging from Australia (Ross 2005). Coptotermes acinaciformis was the focus of widespread eradication efforts, which culminated in the species being declared eradicated from the last known sites of activity in Otorohonga, Morrinsville and Matamata in Since then Coptotermes acinaciformis has been detected at two New Zealand locations, in January 2006 in Richmond, Nelson, and January 2007 in South Rodney, Auckland. The presence of the termite in both instances was brought to the attention of the property owners by distortion of the wall linings in the residences due to the construction of mud galleries within the wall cavity and the moisture associated with the termite activity. Further signs of termite activity across the two sites included galleries in wood in contact with the ground, pencil-width shelter tubes (earthen leads) and mudding between internal joinery, and landscaping timbers. The source of the infestations at both sites was imported Australian railway sleepers put in as landscaping materials c Richmond is the first record of Australian subterranean termites in the South Island. This case study summarises the surveillance programme and organism management practices implemented for eradication of C. acinaciformis in two locations in New Zealand. Surveillance Richmond In January 2006 a home owner noticed a blemish on the interior wall of a ground floor bedroom. A decision was made by the home owner to remove a section of the internal wall lining. An active termite population was found in the earthen mass, which extended from the base plate through to the first storey. The untreated Douglas fir (Pseudotsuga menziesii) internal wall framing was extensively damaged. Railway sleepers used as steps and retaining walls at various locations within the garden had substantial termite galleries indicating long term residency. The property owner had replaced two railway sleepers in the summer of 2005 as they appeared to be decayed. A delimiting survey of 13 residential properties in the immediate vicinity of the infested property was conducted in March This survey involved full interior and exterior inspection of the residences and grounds. Live C. acinaciformis activity was found in three locations within the garden of one neighbouring property. The two infested properties were separated by a four metre wide tar sealed driveway. Railway sleepers installed on five additional properties in the Nelson region, developed by the same landscaper in the same time period, were also inspected with no sign of Australian subterranean termite activity. In December 2006 another survey was conducted. This time 38 properties were surveyed within 100 metres of the two infested properties. The number of properties surveyed within this zone increased to 41 for the April 2008 delimiting

3 Australian subterranean termites (Coptotermes acinaciformis) in New Zealand survey. On both occasions no additional Australian subterranean termite activity was found. South Rodney Signs of termite activity were noticed by the tenants in a twostorey dwelling on the South Rodney property at least one year prior to the Ministry of Agriculture and Forestry - Biosecurity New Zealand (MAFBNZ) being notified. Mud deposits were found around interior wall trims, and interior wall linings on both the ground and first floor showed distortion. Further termite activity within the walls was confirmed using a moisture meter and a sound detection device. Raised planter boxes built adjacent to the dwelling in 1995 using Australian railway sleepers were found to have mud galleries between each sleeper. Thousands of winged reproductive termites (alates) were observed emerging from one of the six raised planter boxes 4 days after the initial notification in mid-january The planter boxes were covered in fine meshed fabric to prevent further alate flights escaping. Because of the known alate termite flight, the potential distribution of the alates was modelled to help determine the size of a delimiting survey. Based on the time period the termites had been at the site (since 1995) and estimates of C. acinaciformis colony growth until alates are produced, the colony was thought to have had the potential for alate production for perhaps as long as 5 years. Data from 10 weather stations in the northern Auckland region were analysed for days showing favourable weather conditions for alate flight for the period The weather conditions considered favourable for alate flight were based on available literature and expert experience, and required the following parameters in combination: ambient air temperature greater than 19ºC; light winds with low level wind speeds less than about 9 km/h (2.5 m/s); one to two days after rain; relative humidity exceeding 65%; and time of day between 1900 and 2100 hours. Another model assumption was that alate flights occurred at altitudes within 30 metres of the ground. For the period , 74 evenings were identified that had favourable weather conditions for alate flights. Of the 74 evenings, most occurred in the warmer months of January (28%), February (39%) and March (23%), with the remainder occurring in November (3%) and December (7%). Modelling of alate distribution for the 74 evenings was undertaken by NIWA using a CALMET/CALPUFF dispersion model analysis to account for terrain effects on winds and dispersion. Results suggested alates would have dispersed aerially towards either the south west or the north east and were unlikely to have dispersed beyond 500 metres of the property s boundary (Figure 1). A delimiting survey out to 500 metres from the termite infestation was conducted in March This included full inspection of residences (interior and exterior) and possible host material of 18 lifestyle blocks, part of Riverhead Forest and riparian vegetation bordering water courses within the survey zone. No sign of

4 Surveillance for biosecurity: pre-border to pest management C. acinaciformis activity was discovered as a result of this survey. A repeat of this survey in April 2008 also found no signs of activity. Figure 1. Contour map of relative probability of final destination of alate flight originating at South Rodney modelled using CALMET/CALPUFF (NIWA). Organism management MAFBNZ previously used the Sentricon termite monitoring and baiting system (Dow AgroSciences) to successfully eradicate C. acinaciformis from Otorohonga ( ). Based on this past experience, the Sentricon system is being used for the responses at Richmond and South Rodney. The Sentricon System utilises a cellulose bait matrix containing the active ingredient hexaflumuron (at 5 g/kg). Hexaflumuron is a chitin synthesis inhibitor that inhibits the production of chitin, preventing the termites from successfully moulting. Worker termites feed on the bait matrix then pass the active ingredient to other members of the colony through behaviour called trophallaxis resulting in elimination of the termite colony. Trophallaxis is the transfer of food among members of a termite community through proctodeal (anus-to-mouth) feeding. Hexaflumuron was not registered for use in New Zealand at the time the Richmond and South Rodney incursions were initiated. In each instance an application to the Environmental Risk Management Authority (ERMA) was submitted for approval for

5 Australian subterranean termites (Coptotermes acinaciformis) in New Zealand the importation and use of hexaflumuron. In addition, Dow AgroSciences controls the use of the Sentricon System through a certified operator programme. This restriction required MAF to contract specialist services from Pestforce Pty Ltd, New South Wales, Australia, for the duration of the toxic baiting programme. Methods While awaiting ERMA approval for the use of hexaflumuron termite bait, monitoring equipment was installed on the two infested properties and four neighbouring properties in Richmond, and around the infested property at South Rodney. This included the following methods for surveillance and response: In-ground Sentricon stations containing Eucalyptus regnans wood at intervals of 3-5 metres around the perimeter of the buildings on the infested properties and neighbouring properties (221 stations at the six properties in Richmond; 78 stations at the infested property in South Rodney). Trenches were dug between the in-ground Sentricon stations and filled with untreated Pinus radiata wood chips. The trench was lined with plastic coreflute sheets in an attempt to attract termites in the soil to begin feeding on the wood chips and ultimately be steered to the Eucalyptus regnans in the Sentricon stations. Timber baits consisting of Pinus radiata in-ground stakes capped with Eucalyptus sp. hardwood blocks (19 blocks at the two infested properties in Richmond; 63 blocks between the infested property and Riverhead Forest in South Rodney). Both these two timber species are susceptible to Coptotermes spp. attack. Insect sticky traps on utility poles during the predicted alate flight season. Restrictions on the movement of host material out of the response areas (under Section 130 of the Biosecurity Act 1993). Postal distribution of termite fact sheets to persons likely to be affected. Insect sticky traps were also installed at the Eves Valley Landfill during the predicted alate flight season in following information that two decayed railway sleepers removed from the Richmond property were disposed of in the landfill by the Tasman District Council Refuse Transfer Station. ERMA approval for the importation and use of hexaflumuron was received in May 2006 (Richmond) and January 2007 (South Rodney).This allowed targeted use of the toxic bait matrix in areas of known termite activity. Feeding on the bait was often determined by the positioning of the bait relative to where termites were active. Placing baits near foraging termites too early (low worker numbers) often causes them to abandon and seal off with mud the area where they have been exposed, reducing the likelihood of drawing the termites out of the foraging site to feed on the bait. Above-ground bait stations were installed at sites of termite activity on interior wall linings, over mud leads and galleries, holes on railway sleepers and attached to in-ground Sentricon stations where termites were foraging on the wood baits

6 Surveillance for biosecurity: pre-border to pest management Results In-ground and above-ground Sentricon stations were serviced by Pestforce Pty Ltd on average every 4 weeks over the warmer months (October to May). Servicing was reduced to every 6-8 weeks over the colder June-September period. In Richmond, toxic baiting began on the two infested sites in May 2006 with termite recruitment to the bait (i.e. members of the termite colony attracted to the bait and using it as a food source) observed at the first inspection after 28 days. Feeding on the toxic bait was recorded at the two infested properties for 43 weeks during which five of the seven bait stations (six above-ground and one in-ground station) were recruited to. The ratio of soldier termites to worker termites altered as the bait was depleted, with soldiers out-numbering workers until live activity ceased in March A total of 425 g of toxic bait was consumed between the two properties at Richmond. C. acinaciformis elimination was declared in June 2007 after a period of three consecutive months with no signs of activity. A delimiting survey conducted in April 2008 did not detect any new subterranean termite activity. At South Rodney toxic baiting began in January 2007 with termite recruitment to the bait observed after 4 days. Feeding on the toxic bait occurred for 13 weeks. Live termite activity ceased at this site at the beginning of May One entire bait matrix (85 g) on a raised planter box was consumed within 27 days and minor recruitment occurred at seven of the twelve above-ground stations. Deconstruction of the all of the raised planter boxes in December 2007 revealed a central nest adjacent to where the alate flight emerged in January Factors specific to this site (i.e. interference with bait stations and chemical spray applications) dictated that colony elimination could not be declared after a three month period of no activity (based on industry standard). Toxic baiting continued through the hottest months of the summer to assess whether there were any isolated nests or observations of alate flights. C. acinaciformis elimination at South Rodney was declared in April 2008 after a period of 11 months with no sign of activity. A delimiting survey conducted in March 2008 did not detect any new subterranean termite activity. Discussion The continued absence of termite activity at the Richmond and South Rodney sites confirms that the surveillance and organism management programmes implemented in January 2006 and January 2007 appeared to be successful in eradicating populations of C. acinaciformis. A long-term monitoring programme, beginning from when termite activity ceased will continue at the two locations for a period of 5 years. MAF Biosecurity New Zealand requires the completion of this programme with no further termite activity before it will formally announce the eradication of subterranean termites at the two locations. When termite activity is located, it is imperative that the species of termite is determined. Finding the colony hinges on species identification because nesting habits vary significantly between termite species. Responses to incursions of C. acinaciformis in New Zealand focus on locating the colony, taking into account the

7 Australian subterranean termites (Coptotermes acinaciformis) in New Zealand possibility of second or third colonies in the immediate vicinity, and eradicating them. In New Zealand, colonies of C. acinaciformis have often been large enough to produce winged reproductives, with flights being observed from late November to mid January (Ross 1999). Currently there is no evidence to suggest that C. acinaciformis colonies have established in New Zealand from an alate flight. All previous subterranean termite activity at other sites has been linked to imported host material. As a consequence, outbreaks have been discovered only in localised areas providing the opportunity for effective control. The Sentricon termite monitoring and baiting system is one of the most effective mechanisms in eradicating and monitoring treatment efficacy of C. acinaciformis (Ross 2005). This is evident at Richmond and South Rodney where results indicate a high probability of the eradication being successful. In the event that MAFBNZ respond to another incursion of Australian subterranean termites, advancements in equipment to detect colonies in building structures will be assessed. Infra-red cameras, thermal imaging technology and the use of a termite detector dog are areas of interest for preparedness in the future. Acknowledgements We thank Shane Clarke and Phillip Dwyer (Pestforce Pty Ltd) for their expertise and knowledgeable advice throughout the eradication programme, the staff of AsureQuality New Zealand and SPS Biosecurity Ltd for their assistance during the delimiting surveys and Dave Voice and Sheree Christian (MAFBNZ) for their support. Specialist weather data was expertly provided by Tony Bromley (NIWA). We would also like to acknowledge the cooperation and support of local residents from Richmond and South Rodney. References Creffield J Termites a major threat to Victoria. (accessed 27 June 2008). Dow AgroSciences Australia Ltd Technical Manual 2004: Sentricon II Advanced Termite Control. Dow AgroSciences Australia Ltd., 20 Rodborough Road, Frenches Forest, New South Wales 2086, Australia. 19 pp. Gerozisis J, Hadlington PW 2005.Urban pest management in Australia. University of New South Wales Press Ltd, Sydney, Australia. 314 pp. Ross MG Subterranean Termite Infestation Otorohanga: Technical Discussion Document. Ministry of Agriculture and Forestry Biosecurity New Zealand, PO Box 2526, Wellington, New Zealand. 10 pp. Ross MG Responding to incursions of Australian subterranean termites in New Zealand. Proceedings of the Fifth International Conference on Urban Pests. Singapore, July Pp

8 Surveillance for biosecurity: pre-border to pest management Wagner T Wood Products Insect Research SRS-4502 The Termite Unit. (accessed 27 June 2008)