sign in sign up
<<
Home , Epilachna, Epilachninae, Mexican bean beetle, Phaseolus, Vigna

Jpn. J. Environ. Entomol. Zool. 24（３）：107− 115（2013） 環動昆 第 24 巻 第３号：107 − 115（2013） Review

Invasion by an exotic pest, varivestis Mulsant （Coleoptera；）into Japan and the USA

Hiroshi Nakamura １）, Yasuyuki Tikazawa １）, Shin’ya Shiratori １）, Keiko Koda ２）, Filadelfo Guevara Chavez ３）

１）Education and Research Center of Alpine Field Science, Faculty of Agriculture, Shinshu University, Minamiminowa, Nagano, 399-4598 Japan ２）Institute of Mountain Science, Shinshu University, Minamiminowa, Nagano, 399-4598 Japan ３）Laboratory of Entomology, Faculty of Agriculture, San Carlos University, Guatemala

（Received：February 26, 2013；Accepted：September 14, 2013）

Abstract The Mexican Epilachna varivestis Mulsant（Coleoptera; Coccinellidae）is an exotic insect pest which was initially confirmed in 1997 in Japan. After that, its distribution area scarcely expanded and leguminous vegetables were not injured severely. On the other hand, in the USA, E. varivestis was identified in 1883, soon became a serious pest and achieved wide expansion. We have surveyed the distribution area of this exotic insect from 1999 in Nagano Prefecture. In this review, we introduce life cycle, climate conditions, host and mortality factors of E. varivestis in Japan, the USA and Guatemala, and then discuss why this exotic insect cannot spread widely in Japan. Our conclusion is that in Japan the effective host-parasite system of Epilachna hosts（Epilachna vigintioctomaculata and Epilachna vigintioctopunctata）and their parasites（Nothoserphus afissae and Pediobius foveolatus）was already present as Guatemala when E. varivestis invaded, so E. varivestis could not expand its range as quickly as in the USA.

Key words：Epilachna varivestis, exotic insect pest, invasion in Japan, USA, Guatemala, parasite

fields in the highland areas of Nagano and Yamanashi Introduction Prefectures in central Japan（Sasaji, 1997；Fujiyama et al., 1998）. Fujiyama et al.（1998）concluded that the The Epilachna varivestis Mulsant distribution area of E. varivestis was limited to areas is one of the leaf-eating members of the between Lake Suwa, Nagano Prefecture and the central Coccinellidae which includes some highly beneficial part of Yamanashi Prefecture in 1997. It is unknown predators as well as serious pests. The adult E. when and how this beetle invaded Japan, but it was varivestis has eight black spots on each elytron and is frequently found in leguminous vegetable fields of 6 to 8 mm long and 4 to 6 mm wide. The adults are these areas several years before the first official report yellow in color on emergence, but mature adults either of its discovery was issued（Fujiyama and Shirai, may remain yellow（Fig. 1A）or may darken with age 1998）. The distribution range of this beetle extends until they become orange-brown with a bronze tinge from the areas around Lake Suwa to Matsumoto City （Fig. 1B；Sanchez-Arroyo, 2009）. However, there have or Ina City in Nagano Prefecture in 2004（Fig. 2）. been no reports on bronze colored adults in Japan. E. varivestis was first identified in the state of E. varivestis is believed to be native to the plateau Colorado in the USA. in 1883, and soon became a region of southern Mexico and Guatemala. Its range serious pest in southern Colorado. In 1920, this beetle previously extended from Panama to southern Ontario, was identified in northern Alabama. This eastward Canada（Biddle et al., 1992）, and it was not distributed expansion is believed to have been the result of the in Japan. However, it was initially confirmed in 1997 accidental introduction of individual in that E. varivestis inhabited leguminous vegetable （Biddle et al., 1992）. From 1920 to the early 1970s,

Corresponding author：Hiroshi Nakamura, [email protected]

― 107 ― Hiroshi Nakamura et ai.

the range of E. varivestis extended from Alabama to means that it spread at a speed of 23 km/year. southern Ontario, Canada（Turnipseed and Kogan, Records gathered during the northward expansion of 1976）. The distance from Montgomery, Alabama（N the beetles in the USA suggest that they are capable 32ﾟ21’, W 86ﾟ16’）to Toronto, Ontario（N 43ﾟ40’, of moving up to 200 km per year（Howard, 1922）. W 79ﾟ25’）is at least 1300 km. E. varivestis achieved However, it took 10 years for E. varivestis to expand its this expansion over a period of about 56 years, which range from Fujimi Town to Ina City（about 45 km）in

Fig. 1 Photos of Epilachna varivestis. A：Adult（yellow）, B：Aged adult with a bronze tinge（Sanchez-Arroyo, 2009）, C： Egg mass, D：Fourth instar .（Reformation of Nakamura and Shiratori, 2010）

Fig. 2 Distribution area of Epilachna Fig. 3 Two hymenopteran parasites of Epilachna varivestis. A：Pediobius varivestis in Nagano Prefecture in foveolatus adults, B：Oviposition of female P. foveolatus to host larva, C： 2004.（Reformation of Nakamura Nothoserphus afissae adult, D：Oviposition of female N. afissae to host and Shiratori, 2010） larva.（Reformation of Nakamura and Shiratori, 2010）

― 108 ― Invasion by an exotic insect pest, Epilachna varivestis Mulsant（Coleoptera；Coccinellidae）into Japan and the USA

Japan. Why hasn’t it been possible for E. varivestis in due to adults was 54.9% at a density of 50 per Japan to expand its range as quickly as in the USA? 5 plants（Kabissa and Fronk, 1986）, and a yield loss- treatment cost analysis determined that the threshold E. varivestis in Guatemala level ranged from 1 to 1.5 larvae/（Michels and Burkhardt, 1981）. E. varivestis is not a serious pest over much of Central The difference in injury levels between the original America, though it is important in certain regions of and invaded regions of E. varivestis may be due to El Salvador and Guatemala. Nakamura and Guevara the presence or absence of natural enemies. The （2007）carried out an investigation into the E. varivestis rate of parasitized larvae（mummies）was 46.7％ defoliation of vegetables at Chimaltenango in in Chimaltenango（Nakamura and Guevara, 2007）. a Guatemala highland area. There was a low degree Schaefer（1983）listed 22 , including 13 tachinid of defoliation of the green bean strain of P. vulgaris flies and 8 parasitic wasps as parasites of E. varivestis, （11 plants per 1200 plants）, and no damage occurred 65 species as predators and 12 diseases. In Guatemala, on the black bean strain in ICTA fields（Institute Pedobius epilachnae（Hymenoptera：Eulophidae）, of Science and Technology Agriculture）. E. varivestis Aplomyiopsis epilachnae（Diptera：Tachinidae）, defoliation was 3 〜 10.4 ％ in Phaseolus farm fields in Strongygaster triangulifera（Diptera：Tachinidae）and Chimaltenango（Table 1）. Sarcophaga rheinhardi（Diptera：Sarcophagidae）are In Japan, the injury levels calculated by the degree listed as larval parasitoids, and Coleomegilla maculata of defoliation of P. vulgaris leaves were 87.9％ in Suwa （Coleoptera：Coccinellidae）and Hippodamia convergens City, 56.3％ in Okaya City and 50％ in Chino City in （Coleoptera：Coccinellidae）are listed as predators of 2000（G. Toyoshima, personal communication）. In the egg and young larvae（Schaefer, 1983）. USA, E. varivestis gained pest status soon after invading Colorado in 1883. The insect is a severe pest in the Climate conditions eastern United States（Turnipseed and Kogan, 1976）, and in Nebraska, as in other western states, the insect The native habitat of E. varivestis in the Guatemalan has been a serious problem with recent outbreaks highlands is“tierra templada”（the temperate area）, occurring in 1994 and 1995（Barrigossi et al., 2001）. A which has a very wet climate during the summer great deal of research on the influence of defoliation months（precipitation；172-252mm/month）（Chinchilla, on soybean yields and the economic threshold for E. 1993）. The average temperature is 18.7 ℃（maximum, varivestis has been conducted. The percentage yield loss 25.9℃；minimum, 16.4℃）in Guatemala City（Mizuno,

Table 1 Results of the investigation into Epilachna varivestis defoliation at Phaseolus fields in Chimaltenango, Guatemala（Reformation of Nakamura and Guevara, 2007）

* ICTA（Institute of Science and Technology Agriculture, Guatemala）

― 109 ― Hiroshi Nakamura et ai.

2005）. In Guatemala, E. varivestis has 4 or 5 generations E. vigintioctomaculata（Shirai, 1991）, which is a native per year and the time of development from egg to species in Japan. Pfaender et al.（1981）suggested the adult is 33 days on average. reproductive diapause of E. varivestis by measuring In the southeastern USA, there are 3 or 4 several physiological attributes, and William et generations per year and the generations overlap al.（1984）reported that at 20 and 15℃, summer considerably with the larvae and adults coexisting generation adults entered reproductive diapause throughout most of the season. In South Carolina, and then completed post diapause oviposition. This the population densities reach economic injury levels characteristic is a good adaptation which allows the only in August（Turnipseed and Kogan, 1976）. In the adults to pass through the dry and cool winters of the western and northern USA, there is one generation native highlands in Mexico and Guatemala. per year, with a partial second generation（Howard, However, in new habitat areas in the USA or Japan, 1922; Hagen 1986；Biddle et al., 1992）. Based on an the number of generations per year of E. varivestis investigation of the seasonal prevalence of occurrence may be determined by the effective accumulative throughout the year, there are two generations of E. temperature and low winter temperatures in the varivestis in Nagano Prefecture per year（Toyoshima habitat area. and Kobayashi, 1999）. About 20％ of adult beetles survive through the The effects of temperature and moisture on the winter in New Mexico（Wallis and Douglass, 1955）. distribution of E. varivestis have been studied in the In Japan, it was confirmed that adults of this species USA（Marcovitch and Stanley, 1930；Sweetman, overwinter in Nagano and Yamanashi Prefectures, 1932）. Precipitation has a direct influence on beetle where the temperature in winter is below 0℃, and that emergence, and the percentage emerging is directly their survival rate in winter is 37％（Nakahara et al., influenced by the temperature during the period of 1999；Toyoshima et al., 2002）. In the USA, adults of this rainfall（Douglass 1928）, whereas dry weather such as species overwinter in woodlands or within well drained that during the 1930 drought delays emergence from areas of field margins（Douglass, 1933）. In Japan, they hibernation sites（Howard 1931）. Climatic conditions survive winter under fallen leaves at the base of trees such as intense rainfall or extended drought with high along the sunny edge of woodlands and are found with temperature have been shown to significantly reduce the overwintering E. vigintioctomaculata and Harmonia larval and adult populations（Biddle et al., 1992）, and axyridis. the high egg mortality was likely related to drought Differing climate conditions may not explain the stress of the host plants, because stressed plants turn difference in the expansion speed between Japan and their leaves over and expose the eggs to sunlight the USA. （Barrigossi et al., 2001）. From laboratory experiments, the effects of Host plants temperature and relative humidity on survival, longevity and fecundity were clarified. At 32℃, no Abiotic factors, such as drought, have long been eggs were laid regardless of humidity（Kitayama et al., recognized as important factors affecting the population 1979）and larval survival was low（Wilson et al., 1982）. dynamics and pest status of E. varivestis（Marcovitch No egg development occurred at 12.8℃ and 32.2℃ and Stanley 1930, Miller 1930, Howard 1931）and play （Hammond, 1984）. The accumulative temperature from an important role in geographic distribution（Sweetman the egg to adult stage was estimated to be about 377 1932）. Recent studies have established the sensitivity degree-days and the minimum threshold values in the of the eggs and larvae of E. varivestis to humidity and degree-days model for the egg, larval and pupal stages temperature（Kitayama et al. 1979）. However, the were 8.6, 7.9 and 9.3℃ , respectively（Fan et al., 1992）. precise causes of outbreaks may also be related to In Japan, Shirai and Yara（2001）reported that larval other abiotic and biotic factors that potentially affect development was markedly inhibited at 30℃ , and the the survival of E. varivestis. survival rate declined to nearly 0％ when exposed to In Guatemala, Phaseolus , the soybean Glycine 32.5℃ for more than five days. max（L.）, the unguiculata（L.）and other There have been no reports that newly emerged leguminous plants are known to be host plants of E. E. varivestis adults have summer diapause in varivestis. In Japan, this beetle was found on the adzuki midsummer by short photoperiod conditions, unlike bean Vigna angularis（L.）, the kidney bean Phaseolus

― 110 ― Invasion by an exotic insect pest, Epilachna varivestis Mulsant（Coleoptera；Coccinellidae）into Japan and the USA

vulgaris L., the scarlet runner bean P. coccineus L. and Waddill and Shepard（1975）determined the the soybean Glycine max（L.）（Fujiyama and Shirai, potential of two pentatomids, Podisus maculiventris（Say） 1998; Funakubo et al., 1998）. In addition to these four and Stiretrus anchorago（Fabricius）, against eggs and leguminous crops, two leguminous weeds, the kudzu larvae, and Wadill et al（1976）developed a computer Pueraria lobata（Willd.）Ohwi and silk tree Albizia simulation model for populations of E. varivestis on julibrissin（Willd.）Durazz., were recorded as host soybeans in South Carolina. Thereafter, the requisites plants of E. varivestis in Nagano Prefecture（Toyoshima of generalist predators in crop fields were shown by and Funakubo, 1998）. Abe et al.（2000）reported that studies of the searching strategy of P. maculiventris P. lobata may be used as a temporary resource by E. （Wiedenmann and O’Neil, 1992）. O’Neil et al（1996） varivestis before this beetle colonizes more suitable described the impact of this predator on the population plants and that V. angularis was not as suitable as P. dynamics of E. varivestis using a simulation model. vulgaris for larval development and reproduction. There were few effective parasitoids in the USA. E. varivestis is a serious pest of soybeans in only the when E. varivestis invaded. Barrigossi et al.（2001） coastal plain areas in the USA. Host plant selection reported in their life table study even in 1995 and 1996 has been investigated by various researchers. Larvae that no parasitized or diseased larvae were observed fed with soybeans had a longer developmental period in their study fields or in those used for parasitism than larvae reared on Phaseolus beans（Bernhardt tests in New England. To suppress this beetle in the and Shepard, 1979）and mortality was much greater USA two hymenopteran parasites, Tetrastichus ovulorum on soybeans than on green beans（Hammond, 1984）. Ferriere, a solitary egg parasitoid, and Pediobius The population growth of E. varivestis reared on foveolatus（Crawford）（Hymenoptera：Eulophidae）, a different bean species was compared（Wilson et al., gregarious larval parasitoid, were introduced from India 1982；Kauffman et al., 1985）and the highest rate of （Angalet et al., 1968）. Moreover, one monoparasitic population growth occurred on the‘Henderson Bush’ species, Nothoserphus afissae Watanabe（Hymenoptera： Phaseolus lunutus L.（Flanders, 1984）. Serphidae）, was imported from Japan in 1980（Schaefer, In addition, evidence was found that some soybean 1983）. Only P. foveolatus was able to reduce the E. varieties adversely affected the behavioral and varivestis population in Maryland（Stevens et al., 1975a） physiological functions of E. varivestis（Campbell and Washington, D.C.（Barrows and Hooker, 1981）. and Brett, 1966；Van Duyn et al., 1971, 1972）. These However, it apparently could not overwinter in the differences among soybean varieties were investigated USA. and yearly releases of P. foveolatus were necessary as host-plant resistance（Kogan, 1972）. Todd et to use a means of biological control（Stevens et al., al.（1972）reported that greater numbers of E. 1975a）. In contrast to the lack of native parasitoids varivestis on soybeans were associated with increased to E. varivestis in the USA., several tachinid flies and leaf protein, which suggests that the beetle probably parasitic wasps as parasites of E. varivestis were listed responds to the nutritional quality of the plants. in native habitats（Schaefer, 1983）, and currently a In the USA, E. varivestis is a serious pest of soybeans, new species of Pediobius from Epilachna was reported although the soybean is not attacked as severely as it in Costa Rica（Hansson and Nishida, 2002）. is in Japan, but there may be no clear relation between In Japan, two species of parasitic wasps, P. foveolatus soybean damage by E. varivestis and the expansion and N. afissae（Fig. 3）, were identified from the pupae speed in the USA. of E. varivestis（Fujiyama et al., 1998）. These wasps were known as parasites of Epilachna beetles in Japan Mortality factors （Tachikawa, 1976）. Fujiyama et al.（1998）said that natural enemies, including these two wasps, may be In the USA, the natural control organisms of E. useful for reducing the beetle population in Japan, varivestis include at least 17 species of predators and and Saitoh and Matsumoto（2000）determined the 10 species of parasitoids in soybean fields during the developmental zero and the accumulative effective vegetative stages（Sanchez-Arroyo, 2009）. Various temperature of this wasp by laboratory rearing. potential predators have also been recognized in Toyoshima et al.（2001）reported that P. foveolatus and soybean fields（Shepard et al., 1974）. In the early N. afissae were observed from the 3rd and 4th instar part of the season, predators may suppress egg and larvae and pupal stages in the scarlet runner fields in larval populations（Turnipseed and Korgan, 1976）. Fujimi Town and Chino City, Nagano Prefecture, and

― 111 ― Hiroshi Nakamura et ai.

the percentage parasitism of P. foveolatus was 80-90 % beetles and two parasites, P. foveolatus and N. afissae at the second generation in 1999 and 2000（Table 2）. in Nagano Prefecture. It is evident that E. varivestis is The parasitization of E. varivestis by P. foveolatus was a desirable host species for the parasites. P. foveolatus monitored in Phaseolus fields in Nagano Prefecture in particular can complete one more generation in the from 1999 to 2006 and the high percentage of autumn season on E. varivestis because it has enough parasitism shows the ability of P. foveolatus, the native accumulative effective temperature（Saitoh and natural enemy, to suppress the density of E. varivestis, Matsumoto, 2000）. In the USA., despite some positive the invading pest. Nakamura et al.（2007）reported the results using P. foveolatus（Angalet et al：1968）, the developmental duration and the adult survival duration parasite could not survive the winter in the field and of P. foveolatus which parasitized E. varivestis. maintenance in the laboratory was required during the winter（Stevens et al., 1975b）. Sanchez-Arroyo（2009） Effects on native species in Japan reported that P. foveolatus parasitized E. varivestis larvae during the growing season but failed to overwinter There are several leaf-eating Epilachna species for lack of diapause capability and/or available host which injure agricultural solanaceous plants in Japan. material. Epilachna vigintioctomaculata Motschulsky and Epilachna Epilachna hosts and their parasites were already vigintioctopunctata（Fabricius）feed on eggplants and present, when E. varivestis invaded Japan. Thus, E. potatoes, and also Epilachna yasutomii（Katakura） varivestis could not expand its range as quickly as in （pest type）feed on mainly potatoes. In addition to the USA, where there was no effective host-parasite these crop pests, several Epilachna species are known system. This is an interesting case of the native to feed on wild plants in Japan. There is no relative parasites suppressing an exotic species, E. varivestis. In phytophagous species which compete with E. varivestis, the future, a survey of the seasonal prevalence of the an exotic insect pest, for leguminous plants. occurrence of these parasitic wasps and E. varivestis Fig. 4 shows the seasonal occurrence of Epilachna needs to be performed.

Table 2 Percentage parasitism of Phaseolus foveolatus to Epilachna varivestis larvae in the scarlet runner bean fields in Fujimi Town, Nagano Prefecture.

Fig. 4 The seasonal occurrence of the larvae of three Epilachna beetles and their parasites, Pediobius foveolatus and Nothoserphus afissae in Nagano Prefecture.

― 112 ― Invasion by an exotic insect pest, Epilachna varivestis Mulsant（Coleoptera；Coccinellidae）into Japan and the USA

Japanese）. References Fujiyama, N., H. Katakura and Y. Shirai（1998）Report of Epilachna varivestis Mulsant（Coleoptera： Abe, Y., T. Nakamura and H. Inoue（2000） Coccinellidae）in Japan. Appl. Entomol. Zool. 33：327 Exploitation of plants by Epilachna − 331. varivestis（Coleoptera：Coccinellidae）in Japan. Funakubo, T., M. Yoda, K. Shinya and Y, Murakami Appl. Entomol. Zool. 35：81 − 85. （1998）Occurrence and search of insecticide for Angalet, G. W., L. W. Coles and J. A. Stewart（1968） control of Mexican bean beetle, Epilachna varivestis Two potential parasites of the Mexican bean beetle （Mulsant）in Yamanashi Prefecture. Proc. from India. J. Econ. Entomol. 61：1073 − 1075. Kanto-Tosan Plant Protec. Soc. 45：171 − 174（in Biddle, A. J., S. H. Hutchins and J. A. Wightman（1992） Japanese）. Pests of leguminous crops. In Vegetable Crop Pests Hagen, A.（1986）Dry bean insects in Nebraska. （P. G. McKinlay ed.）. MacMillan Press, London, pp University of Nebraska Coop. Extn. Pub., G86 − 786. 162 − 212. Hammond, R. B.（1984）Development and survival Barrigossi, J. A. F, G. L. Hein and L. G. Higley（2001） of the Mexcan bean beetle, Epilachna varivestis Life tables and larval dispersal of Mexican bean Mulsant, on two host plants. J. of Kansas Entomol. beetle（Coleoptera：Coccinellidae）on dry bean in Soc. 57：695 − 699. the high plains. Environ. Entomol. 30：235 − 243. Howard, N. F.（1922）The Mexican bean beetle in the Barrows, E. M. and M. E. Hooker（1981）Parasitization south eastern U. S. J. Econ. Entomol. 15：265 − 275. of the Mexican bean beetle by Pediobius foveolatus Howard, N. F.（1931）The effect of 1930 drought upon in urban vegetable gardens. Environ. Entomol. 10： insect populations：The effect on the Mexican 782 − 786. bean beetle. J. Econ. Entomol. 24：660 − 662. Bernhardt, J. L. and M. Shepard（1979）Comparative Kabissa, J. and W. D. Fronk（1986）Bean foliage development, reproduction, and leaf area consumption by Mexican bean beetle（Coleoptera： consumption by the Mexican bean beetle on Coccinelliidae）and its effect on yield. J. of Kansas Phaseolus spp. and soybeans. J. Georgia Entomol. Soc. Entomol. Soc. 59：275 − 279. 14：191 − 198. Kauffman, W. C., R. V. Flanders and C. R. Edwards Campbell, W. V., and C. H. Brett（1966）Varietal （1985）Population growth potentials of the resistance of beans to the Mexican bean beetle. J. Mexican bean beetle, Epilachna varivestis Econ. Entomol. 59：899 − 902. （Coleoptera：Coccinellidae）, on soybean and lima Chinchilla, M. A.（1993）Geografia Visualizada. Libros bean cultivars. Environ. Entomol. 14：674 − 677. Sin Fronteras Inventory, El Salvador. Kitayama, K., R. E.. Stinner and R. L. Rabb（1979） Douglass, J. R.（1928）Precipitation as a factor in the Effects of temperature, humidity, and soybean emergence of Epilachna corrupta Mulsant from maturity on longevity and fecundity of the adult hibernation. J. Econ. Entomol. 21：203 − l3. Mexican bean beetle, Epilachna varivestis. Environ. Douglass, J. R.（1933）Habits, life history, and control Entomol. 8：458 − 464. of the Mexican bean beetle in New Mexico. US Kogan, M.（1972）Feeding and nutrition of insects Dep. Agric. Tech. Bull. 376. 45pp. associated with soybean. 2. Soybean resistance Fan, Y., E. Groden and F. A. Drummond（1992） and host preferences of the Mexican bean beetle Temperature-dependent development of Mexican Epilachna varivestis. Ann. Entomol. Soc. Am. 65：675 − bean beetle（Coleoptera：Coccinellidae）under 683. constant and variable temperatures. J. Econ. Marcovitch, S. and W. L. W. Stanley（1930）The Entomol. 85：1762 − 1770. climatic limitations of the Mexican bean beetle. Flanders, R. V.（1984）Comparisons of bean varieties Ann. Entomol. Soc. Am. 23：666 − 686. currently being used to culture the Mexican Michels, J. G. Jr., and C. C. Burkhardt（1981）Economic bean beetle（Coleoptera：Coccinellidae）. Environ. threshold levels of the Mexican bean beetle on Entomol. 13：995 − 999. pinto beans in Wyoming. J. Econ. Entomol. 74：5− 6. Fujiyama, N., H. and Y. Shirai（1998）An exotic Miller, D. F.（1930）The effect of temperature, relative ladybird unexpectedly found illustrated in an humidity and exposure to sunlight upon the insect atlas for children. Insectarium 35：40− 45（in Mexican bean beetle. J. Econ. Entomol. 23：945 −

― 113 ― Hiroshi Nakamura et ai.

954. 36：43 − 46. Mizuno, J. ed.（2005）Globe-trotter travel guidebook. Sanchez-Arroyo, H.（2009）Mexican bean beetle, Diamond Big Co., Ltd. Tokyo 416pp Epilachna varivestis Mulsant（Insecta：Coleoptera： Nakahara, S., T. Tsuchida, T. Nezu, T. Funakubo, M. Coccinellidae）. UF/IFAS Featured Creatures. Yoda and K. Shinya（1999）Biology and control http://creatures.ifas.ufl.edu. of Mexican bean beetle, Epilachna varivestis Sasaji, H.（1997）Note on Epilachna variveslis in Nirasaki MULSANT（Coleoptera：Coccinellidae）. 2 City, Yamanashi Prefecture, Japan. Nejirebane No. Overwintering sites of Epilachna varivestis in 77：5（in Japanese）. Yamanashi Prefecture, Japan. Res-Bull. Pl. Prat. Schaefer, P. W.（1983）Natural enemies and host Japan 35：73 − 76. plants of species in the （Coleoptera： Nakamura, H and F. C. Guevara（2007）Report of the Coccinellidae）A world list. Bull. Agric. Experi. Stn. investigation on Epilachna varivestis defoliation in Uni. of Delaware 445：1 − 42. Guatemala high land. Bulletin Shinshu University Shepard, M., G. R. Carnner and S. G. Turnipseed（1974） Alpine Field Center 5：77 − 82.（in Japanese with Seasonal abundance of predaceous in English summary） soybeans. Environ. Entomol. 3：985 − 988. Nakamura, H., M. Totsuka, Y. Tikazawa and S. Shirai, Y.（1991）Seasonal changes of adult populations Shiratori（2007）Morphology, survival duration of three Epilachna species（Coleoptera: of adults, number of emergence adults per host Coccinellidae）in Ina area, Nagano Prefecture. New and developmental duration of Pediobius foveolatus Entomol. 40：17 − 23（in Japanese with English （Crawford）（Hymenoptera：Eulophidae）, the summary）. native parasitoids to the exotic insect pest, Shirai, Y. and K. Yara（2001）Potential distribution Epilacnna varivestis（Mulsant）（Coleoptera： area of the Mexican bean beetle, Epilachna varivestis Coccinellidae）. The Annals of Environmental Science （Coleoptera：Coccinellidae）in Japan, estimated Shinshu University 29：59 − 64.（in Japanese with from its high-temperature tolerance. Appl. Entomol. English summary） Zool. 36：409 − 417. Nakamura, H. and S. Shiratori（2010）The progress Stevens, L. M, A. L. Steinhauer and J. R. Coulson（1975a） of invasion of insect pest, the Mexican been Suppression of Mexican bean beetle on soybeans beetle, Epilachna varivestis in Nagano Prefecture. with annual inoculative releases of Pediobius Proceedings of The International Symposium foveolatus. Environ. Entomol. 4：947 − 952. 2009 of Institute of Mountain Sciences Shinshu Stevens, L. M, A. L. Steinhauer and T. C. Elden（1975b） University,“Management and Analysis of Laboratory rearing of the Mexican bean beetle and Organism using Remote Sensing and Geographical the parasite, Pediobius foveolalus, with emphasis on Information”, Journal of the Faculty of Agriculture parasite longevity and host, parasite ratios. Environ. Shinshu University 46：105 − 111. Entomol. 4：953 − 957. O’Neil, R. J., K. Nagarajan, R. N. Wiedenmann and J. Sweetman, H. L.（1932）The effects of temperature C. Legaspi（1996）A simulation model of Podisus and moisture on the distribution of the Mexican maculiventris（Say）（Heteroptera：） bean beetle, Epilachna corrupta Muls. Ann. Entomol. and Mexican Bean Beetle, Epilachna varivestis Soc. Am. 25：224 − 40. （Mulsant）（Coleoptera：Coccinellidae）, population Tachikawa, T.（1976）Occurrence of Pediobius foveolatus dynamics in soybean, Glycine max（L.）. Biological （Crawford）（Hymenoptera：Eulophidae）parasitic Control 6：330 − 339. on （Coleoptera：Coccinellidae）in Pfaender, S. L., R. L. Rabb and R. K. Sprenkel（1981） Japan. Trans. Shikoku Ent. Soc. 13：61 − 63. Physiological attributes of reproductively active Todd, J. W., M. B. Parker, and T. P. Gaines（1972） and dormant Mexican bean beetles. Environ. Populations of Mexican bean beetles in relation Entolnol. 10：222 − 225. to leaf protein of nodulating and non-nodulating Saitoh, M. and N. Matsumoto（2000）Studies on soybeans. J. Econ. Entomol. 65：729 − 31. Pediobius foveolatus（Hymenoptera：Eulophidae）, Toyoshima, G. and T. Funakubo（1998）Biology aparasitoid of the Mexcican bean beetle and occurrence areas of a newly recorded pest （Coleoptera：Coccinellidae）. 1. Parasitoization and Mexican bean beetle Epilachna varivestis（Mulsant）. developmental temperature. Res. Bull. Pl. Prot. Japan Shokubutsu-boeki 52：309 − 3l3（in Japanese）.

― 114 ― Invasion by an exotic insect pest, Epilachna varivestis Mulsant（Coleoptera；Coccinellidae）into Japan and the USA

Toyoshima, G. and S. Kobayashi（1999）Ecology Waddill, V. and M. Shepard（1975）A comparison of and control on Epilachna variveslis.（1）Seasonal predation by the pentatomids, Podisus maculiventris prevalence of occurrence and mortality factors. （Say）and Stiretrus anchorago（F.）, on the Mexican Reports of the experimental results on disease and pest bean beetle, Epilachna varivestis Mulsant. Ann. in Nagano Vegetable and Ornamental Crops Experiment Entomol. Soc. Am. 68：1023 − 1027. Station（1999）：46− 47. Waddill, V. H., B. M. Shepard, J. R. Lambert, G. R. Toyoshima, H. Fujito, G., Y. Chikazawa and H. Carner and D. N. Baker（1976）A computer Nakamura（2001）Ecology and control on simulation model for populations of Mexican bean Epilachna variveslis. 8. Native parasitic wasps as beetle on soybeans. S. C. Agric. Exp. Stn. Bull. 590： mortality factor. Summary of the 45th Annual Meeting 17pp. of the Japanese Society of Applied Entomology and Wallis, R. L. and L. Douglass（1955）Winter mortality Zoology：7（in Japanese）. of the Mexican bean beetle in New Mexico. J. Econ. Toyoshima, G., Y. Chikazawa, N. Morimoto and H. Entomol. 48：96 − 101. Nakamura（2002）The overwintering sites of the Wiedenmann, R. N. and R. J. O’Neil（1992）Searching Mexican bean beetle Epilachna varivestis Mulsant strategy of the Predator Podisus maculiventris（Say） （Coleoptera：Coccinellidae）in Nagano Prefecture. （Heteroptera：Pentatomidae）. Environ. Entornol. New Entomol. 51：5 − 10（in Japanese with English 21：1 − 9 summary）. William, K. M., A. Allegro and S. E. Propts（1984） Turnipseed, S. G. and M. Kogan（1976）Soybean Adult reproductive diapause in the Mexican bean entomology. Annu. Rev. Entomol. 21：247 − 282. beetle（Coleoptera：Coccinellidae）：Interaction Van Duyn, J. W., S. G. Turnipseed and J. D. Maxwell of temperature with photoperiod. Environ. Entomol. （1971）Resistance in soybeans to the Mexican 13：409 − 414. bean beetle：I. Sources of resistance. Crop Sci. 11： Wilson, K. G., R. E. Stinner and R. L. Rabb（1982） 572 − 573. Effects of temperature, relative humidity, and Van Duyn, J. W., S. G. Turnipseed and J. D. Maxwell host plant on larval survival of the Mexican bean （1972）Resistance in soybeans to the Mexican beetle, Epilachna varivestis Mulsant. Environ. Entomol. bean beetle： Ⅱ . Reactions of the beetle to 11：121 − 126. resistant plants. Crop Sci. 12：561 − 562.

インゲンテントウの日本とアメリカ合衆国への侵入について

中村寛志１）・近澤泰幸１）・白鳥晋矢１）・江田慧子２）・Filadelfo Guevara Chavez ３）

１）信州大学農学部附属アルプス圏フィールド科学教育研究センター ２）信州大学山岳科学総合研究所 ３）サンカルロス大学農学部，グアテマラ

インゲンテントウ Epilachna varivestis Mulsant（コウチュウ目；テントウムシ科）は，1997 年に日本に侵入したこ とが公式に確認された．しかし，その後分布域はあまり拡大せずマメ科作物にも大きな被害を及ぼしていない．一方， 1883 年にアメリカ合衆国に侵入したときは，インゲンテントウは作物に重大な被害を与え，急速に分布域を拡大した． 我々の研究室では長野県において 1999 年以降侵入したインゲンテントウの分布域を調査してきた．ここでは日本，ア メリカ合衆国及び原産国のグアテマラにおける本種の生活史，気候条件，寄主植物及び死亡要因を比較し，なぜこの侵 入害虫が日本では分布拡大ができないかについて考察した．我々の結論として，日本では原産地のグアテマラと同じ く，すでにエピラクナ属のホスト（オオニジュウヤホシテントウ Epilachna vigintioctomaculata, ニジュウヤホシテントウ Epilachna vigintioctopunctata）と２種の寄生蜂（Nothoserphus afissae，Pediobius foveolatus）の効率的な寄主―寄生者関係 が確立していたため，インゲンテントウが侵入してもアメリカ合衆国と違って急速な分布拡大ができなかったと考えた．

― 115 ―