Journal of the American Control Association, 19(2):121-124,2003 Copyright @ 2003 by the American Mosquito Control Association, Inc.

GEOGRAPHIC DISTRIBUTION OF OCHLEROTATUS JAPONICUS IN NEW YORK STATE

JOANNE OLIVER,' ROBERT G. MEANS, AND JOHN J. HOWARD3

ABSTRACT Tires and other water-holding containers throughout New York State were sampled during 20O0 for the presence of immature or adult Ochlerotatus japonicus to determine the geographic distribution of this species. Waste tire stockpiles were one of the primary sites surveyed. Immature or adult Oc, japonicus were confirmed in 18 counties in New York State, including the northernmost recorded occutrence of this species in the United States.

KEY WORDS Ochlerotatus japozicus, mosquito, tires, New York State

INTRODUCTION ficial containers for the presence of Oc. japonicus in New York State. In Asia, Ochlerotatus japonicus japonicus (Theobald) (Reinert 2001) is a container-breeding species found in a vadety of natural and artificial MATERIALS AND METHODS collections of water. Larval surveys conducted in A list of the regulated tire facilities, including Japan by the U.S. Army found that 95Vo of larval county and town locations and specific Oc. japonicur were collected from either movable addresses, was obtained from central and regional offices of (e.g., barrels and buckets) or stationary (e.g., cis- the NYSDEC. Sampling during 2000 emphasized terns and latrines) artificial containers (LaCasse and sites in relative proximity to the 4 major interstate Yamaguti 1948). Larval surveillance data from the transpoftation routes (Fig. 1). eastern USA have largely confirmed these obser- We collected mosquitoes at each vations (Andreadis et al. 2001, Scott et al. 2001). site by various collection methods, including Fonseca et al. (2001) assumed that the introduction larval dipping, mouth-aspirated adult landing collections, and spread of Oc. japonicus in the USA was as- and car- bon dioxide-baited New Standard Miniature sociated with trade in scrap tires. Tires were not Light Traps (John W. Hock Company, listed as a larval source among the 18 categories Gainesville, FL). We sampled readily accessible tires that were listed in the Army surveys of 1946 and 1947 on the ground or in low piles. Stockpiles were sampled (LaCasse and Yamaguti 1948), probably because at for approximately 60 min or upon obtaining that time tires were a controlled commodity in oc- a sam- ple of more than 100 larvae. We recorded cupied Japan. In 1993, Laird et al. (1994) reported water temperatures of each tire sampled for japonicus finding Oc. japonicus and 3 other species in scrap Oc. with a Reotemp@ digital (Model tires imported to New Zealand from Japan. thermometer TM99A, Reotemp Instrument Waste tire stockpiles containing more than 1,000 Corporation, San Di- ego, CA). tires are regulated as solid waste disposal sites by Specimens were transported the New York State Department of Environmental alive in coolers to the New York State Department Conservation (NYSDEC). Stockpile regulations in- of Health labora- tories at Griffin Laboratory volve both environmental and health issues includ- in Albany or the State University of New York, ing fire potential, proximity to bodies of water, road College of Environmental Science and Forestry, Syracuse. accessibility, and presence of potential vector in- Aspirated adults were killed by placing them in -60'C sects and rodents. Currently, more than 100 regu- a freezer for approximately 5 min. After preserving lated sites exist, which contain approxrnately 24 a represen- tative sample of larvae from million tires. Six of these sites contain more than I each collection site, the remaining immatures were million tires each and I site has an estimated 8-9 transferred to mos- quito emergence chambers (BioQuip Products, million discarded tires and is reported to be the 3rd Inc., Gardena, CA) and held in a programmable Iargest waste tire stockpile in the USA. Here we incu- bator at 22"C until all specimens had report on our investigations of tires and other arti- emerged or died. Adult and immature specimens were identi- fied to species by using keys of Stojanovich (1961) '-Borne york Disease Program, New State and Means (19"79, 1987). We checked larval mor- Department of Health, Diagnostic Laboratory, College of phologic characteristics suggested Veterinary by B. Harrison Medicine, Cornell University, Ithaca, Ny (personal 14853. communication) for the separation of lar- 'Arthropod-Borne val Oc. japonicus from Ochlerotatus Disease Program, New york State atropalpus (Coquillett). Department of Health, Griffin Laboratory, 5668 State Adult specimens of suspecred Oc. ja- Farm Road, Slingerlands, NY 12159. ponicus were compared to the description of Oc. 3 Arthropod-Borne Disease Program, New york State japonicus published by Peyton et al. (1999). Col- Department of Health, Office of public Health, 217 Sourh lections of Oc. japonicus made by local health de- Salina Street, Syracuse, NY 13202. partments(LHDs) during (WN) JounNa.l op rHr AveRrceN Moseurro CoNTnol AssocrarroN VoL. 19.No.2

Ehenmal FGA iffi

'{ ffi Ochlerotatuqia@nicus presenr 1.1,.'iulOn" or moresites checked; no Ochlerotatusiaoonicus found

lE Interstatetransportation route

! Notchecked N&YTdid

Fig. 1. Location of sites surveyed by county for the presence of Ochlerotatus japonicus in New York State, 2000.

surveillance programs also were included as county at 8 negative stockpiles ranged from 18.3 to27.2"C records for this species if the authors confirmed during June through September. At sites with Oc. identification of 1 or more specimens of Oc. japon- japonicus, the most frequently observed immatures icus. of other species were Ochlerotatus triseriaras Say followed by Oc. atropalpus, Culex restuans Theo- bald, and Culex territans Walker. The same species RESULTS were found at stockpiles where no Oc. japonicus We surveyed 9 regulated waste tire stockpiles be- were present. The most abundant species collected tween May and September 2000 and collected im- in landing collections at all sites was Oc. triseria- mature or adult Oc. japonicus from 4 stockpiles in trr.r, with an occasional Oc. atropalpus. Collections 4 counties. Three of the sites were along the Route of adult mosquitoes from New Standard Miniature 81 corridor in Cortland, Oswego, and Jefferson Light Traps included small numbers of Oc. japon- counties (Fig. l) and the 4th was along the Route icus. Two male and 2 female Oc. japonicu,r were 90 corridor in Seneca County. The Jefferson Coun- collected from light traps set June 7 on the perim- ty site was approximately 5 km west of Watertown. eter of a large tire pile bordering a NYSDEC-reg- Ochlerotatus japonicus was not found in the re- ulated wetland in Oswego County. Other species maining regulated waste tire stockpiles in Jefferson found in this collection included cinereus (l), Wayne (l), Cattaraugus (1), and Erie (2) coun- (Meigen), punctipennis (Say), Anopheles ties. quadrimaculatus Say, Coquillettidia perturbans No apparent ecological or entomological differ- (Walker), Culiseta melanura (Coquillett), Ochlero- ences were found among stockpiles with or without tatus canadensis (Theobald), Ochlerotatus stimu- Oc. japonicus. We collected immature Oc. japoni- lans grotp (i.e., (Walker), cas from tires exposed to full sunlight, and partial Ochlerotarus fitchii (Felt and Young), and Ochler- to full shade. Negative sites had similar settings. otatus excrucians (Walker)), and Ochlerotatus tri- Water temperatures in tires containing larvae churus (Dyar). ranged from 11.1 to 23.9"C during June through Mosquito surveillance activities by LHDs result- September. Water temperatures of 32 tires sampled ed in the documentation of Oc. japonicus in I I oth- JUNE 2003 OCHLERoT'ATUS JAq)NICUS rN NEw YoRK STATE 123

er counties. Latvae were collected from a water (Armstrong, personal communication) and near trough in Rockland County and discarded tires in Watertown, Jefferson County, NY, as reported here- Orange, Dutchess, Ulster, Columbia, Albany, Sche- in, expanded the range of Oc. japonicr,r to the east nectady, Greene, and Onondaga counties (Fig. 1). and north, respectively. This species now appears Adults were collected in carbon dioxide-baited established in a 850,000-km' (635 x 1,330-km) light traps in Madison and Erie counties. area of the Northeast and upper Midwest. The range of Oc. japonicus has not expanded as rapidly in the USA as has the range of the Asian tiger mos- DISCUSSION qllito, Aedes albopictus (Skuse). The lst report of We confirmed the presence of Oc. japonicus in Ae. albopictus in the USA was from Houston, TX, l8 New York State counties during 2000. Although in 1985 (Knudsen 1986). In 1987, it was found at now documented in only 19 of62 counties, the spe- the waste tire site in Oak Hill, OH, approximately cies probably is"present in other counties. Mosquito 1,960 km to the northeast. It did take an additional collection data from new or expanded county mos- 8 years for Ae. albopictus to expand into New Jer- quito surveillance programs throughout New York sey (Crans, personal communication). Although the State may reveal additional geographic locations concerns over the involvement of Ae. albopictus as for Oc. japonicus during 2001. Although no Oc. a presumed vector of arboviruses in the USA have japonicus were observed at a single unregulated tire largely not been realized (Knudsen 1986, Shroyer pile sampled in Broome County, the senior author 1986), the role of Oc. japonicus as a vector of WN collected this species from a single tire behind a is open to speculation. Laboratory studies indicate rural residence in Harvey's Lake, PA (Lake Town- that Oc. japonicus is a highly efficient vector of ship, Luzerne County), approximately 1 15 km WN (Turell et al. 20Ol). In New York, isolations south of the Broome County site. of WN were reported from pools of Oc. japonicus Establishing the presence of Oc. japonicus at submitted from Columbia (1), Orange (2), Rock- even the largest waste tire stockpiles was remark- Iand (l), and Westchester (1) counties (White et al. ably easy. On 2 occasions, adults were found sitting 2001). However. inoculation of Vero cells with sus- on the surface of the water dipped from tires. Rest- pensions of these same pools failed to yield infec- ing males and females were aspirated from the in- tious virus particles and the high mosquito infection side walls of tires at other sites and females could rate, O.7 of 1,000, may be attributed to the fact that be observed as they alighted on the investigators the number of specimens per pool ranged from 3 during tire sampling. Stockpiles and tires were the to 12 (Kramer, personal communication). The as- primary sources used to establish the presence of sociation between Oc. japonicus and WN would be this species in New York State but larvae also were strengthened if the 2 expand concurrently in the found in other artificial containers, including tarps, forthcoming years. A better understanding of the buckets, and pool covers. life history of this species is needed to explain its The earliest collection of Oc. japonicus, in late rapid range expansion in the USA. Studies of its March, was of 4th-stage larvae collected from a adult behavior have been limited by the difficulty rain barrel in Dutchess County (Luke, personal of collecting large numbers of specimens with ex- communication). Although this observation sug- isting mosquito trapping methodologies. gests that this species may overwinter in the larval stage, we were unable to collect larvae from iced- ACKNOWLEDGMENTS over tires in October at a stockpile where Oc. ja- ponicus was abundant. The latest specimens col- We thank county health department staff in east- lected in the season were adults in early October ern New York for providing mosquito specimens, from the Oswego County stockpile. and staff of the NYSDEC for providing assistance The lst report of Oc. japonicus in the USA was in locating waste tire stockpiles. based on the identification of adults collected in 1998 from sites in Suffolk County, Long Island, REFERENCES CITED NY and Ocean County, NJ (Peyton et at. 1999). 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