| Project/Area Number |
10660050
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
植物保護
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
TAKAGI Masami Faculty of Agriculture, KYUSHU UNIVERSITY, Prof., 農学研究院, 教授 (20175425)
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| Co-Investigator(Kenkyū-buntansha) |
TUDA Midori Faculty of Agriculture, KYUSHU UNIVERSITY, Assist. Prof., 農学研究院, 助手 (20294910)
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| Project Period (FY) |
1998 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2001: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 2000: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1999: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1998: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | Classical Biological control / Unaspis yanonensis / Ahytis yanonensis / Coccobius fulvus / Host-parasitoid system / Population dynamics / Introduced natural enemies / Risk of natural enermy introduction / 寄主ー寄生者系 / 地球温暖化 / 寄主-寄生者系 / 寄主体液摂取 / 寄主識別 |
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| Research Abstract |
Biological control of Unaspis yanonensis by using two introduced parasitoids, Aphytis yanonensis and Coccobius fulvus was examined as a case study for establishing basic theory of classical biological control. First, I investigated biological characteristics of the two parasitoids to evaluate their effectiveness as natural enemies. As the result, the two parasitoids were complementary as natural enemies of U. yanonensis, and it was indicated that combination of the two parasitoids resulted better results as biological control of the pest. Second, results of the study of population dynamics of U. yanonensis in orchards after the introduction of one of the parasitoids indicated that single species introduction of either species was resulted in the reduction of the population level of U. yanonensis. Howevere, density of U. yanonensis reduced again after the introduction of C. fulvus to the orchard where only A. yanonensis had been introduced This suggested the superiority of the multiple species introduction in classical biological control. The analysis of population dynamics of U. yanonensis in the orchard where the parasitoids were also introduced indicted the superiority of the multiple species introduction. On the other hand, analysis of the existing information on parasitism of the two parasitoids on indegenous scale insects suggested that there was not so serious environmental risk on the introduction of the two parasitoids. Finally, annual change in age structure of the overwintering generation of U. yanonensis fluctuated more in Amaimi than in mainland Japan because of the winter warmness and the population dynamics of U. yanonensis was not so stable as in mainland Japan. From this fact, it was suggested, the population fluctuation of U. yanonensis was intensified in citrus orchard in mainland Japan when the winter coldness was mitigated as the effect of global warmisation.
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