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Volume 51 (2007)
- Issue 4 Pages 265-
- Issue 3 Pages 165-
- Issue 2 Pages 81-
- Issue 1 Pages 1-
Volume 51, Issue 4
Displaying 1-4 of 4 articles from this issue
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Regular Papers
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II. Effect of Cultural Conditions on Flower-visiting ActivityMasaaki Miyamoto, Masato Ono, Masami Sasaki, Isao Kenmochi2007 Volume 51 Issue 4 Pages 265-272
Published: 2007
Released on J-STAGE: December 15, 2007
JOURNAL FREE ACCESSTo stabilize the flower-visiting activity of honeybees, Apis mellifera, in unheated, semi-forced eggplant culture, the effect of pollen amount was investigated using two experiments. In the first experiment, the start and number of days that honeybees spent in flower-visiting activity on eggplants was compared in two greenhouses with different amounts of pollen per eggplant flower. The start of flower visiting in the greenhouse with less pollen per flower was later than in the greenhouse with more pollen. In the second experiment, the effect of water-tube mulch heat insulation on night temperatures at honeybee introduction was evaluated for pollen productivity and fruiting stability. Water-tube mulching kept the mean night temperature 1 to 3°C higher than in a simple plastic tunnel. Water-tube mulching increased the amount of pollen and reduced the number of days before honeybees started visiting flowers. The rate of high-quality fruiting on honeybee pollination was improved.View full abstractDownload PDF (312K) -
Masahiro Hirae, Katsunori Tamura, Yoshimichi Fukuta2007 Volume 51 Issue 4 Pages 273-280
Published: 2007
Released on J-STAGE: December 15, 2007
JOURNAL FREE ACCESSTo evaluate the resistance to green rice leafhopper (GRH), Nephotettix cincticeps (Uhler), under field conditions, the density of GRH was investigated in relation to GRH-resistant near-isogenic lines (NILs) of rice plants in paddy fields in Joetsu, Niigata Prefecture. The population of GRH on the rice cultivar “Kinuhikari”, carrying no resistance gene, increased from late August and reached a peak during early to mid-September; however, the GRH population was suppressed in NILs carrying each of the GRH resistance genes Grh 1, Grh 2, Grh 3(t), and Grh 2 and Grh 4. The resistances of NILs to GRH collected from Joetsu, as investigated using the leaf blade test, differed among NILs. Resistance decreased rapidly during the maturation stage of rice in lines carrying the Grh 2 or Grh 3(t) gene, while it remained high in lines carrying the Grh 1 or Grh 2 and Grh 4 genes. Temporary resistance is effective in suppressing the GRH population in Joetsu paddy fields because the GRH density remained low on NILs with decreased resistance to GRH in the maturation stage. The number of adults and nymphs of GRH increased slightly on NILs carrying the Grh 1, Grh 2 or Grh 3(t) gene in the field in Chikugo.View full abstractDownload PDF (382K) -
Wataru Ashihara2007 Volume 51 Issue 4 Pages 281-287
Published: 2007
Released on J-STAGE: December 15, 2007
JOURNAL FREE ACCESSThe survival of Diaphorina citri adults during the winter in Tsukuba (Ibaraki, Japan) and under various low temperatures was investigated. When adults were released into a screened cage containing a potted Citrus unshiu tree in the field in Tsukuba, new generation adults emerged and reached a peak in late October. Rapid population decline was not observed by December 24 when daily minimum temperatures had decreased below 0°C for 4 days and an extreme low temperature reached −3.9°C. Adults died between December 25 and January 5, when daily minimum temperatures were continuously below 0°C and an extreme low temperature reached −6.4°C. When adults maintained at 15°C on Murraya paniculata and C. unshiu were transferred to the field in Tsukuba in mid-January and early February, they did not die immediately, even though the minimum temperature decreased below −4°C on the first and third days after transfer. Mortality trends did not differ between D. citri maintained on M. paniculata and C. unshiu. When adults were exposed to temperatures decreasing at 1°C/h, mortality rates were 58 and 89% at −10 and −11°C, respectively. At a constant temperature of −6°C, it took 4 hours to reach 50% mortality. At constant temperatures of 12.5 and 15°C, psyllid adults on M. paniculata survived for more than 50 days. Mean adult longevity decreased as temperatures fell below 10°C. With water alone and without water or leaves, the longest longevity (34 and 28 days, respectively) was observed at 12.5°C. Mean adult longevity on M. paniculata under alternating temperatures of 12.5°C (12 h)/5°C (12 h) was more than 50 days, longer than at a constant temperature of 10°C (38 days). These results suggest that maximum and minimum temperatures are more important than the mean temperature in determining winter survival of the psyllid, and they would be able to survive the winter in areas where mean daily minimum and maximum temperatures of the coldest month are above 5 and 12.5°C, respectively.View full abstractDownload PDF (399K)
Note
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Shinichi Masui2007 Volume 51 Issue 4 Pages 289-291
Published: 2007
Released on J-STAGE: December 15, 2007
JOURNAL FREE ACCESSThe reproduction period of overwintered adults of yellow tea thrips, Scirtothrips dorsalis Hood (Thysanoptera: Thripidae) was investigated in tea groves and adjacent bigleaf podocarps trees (Podocorpus marcrophyllus). Overwintered adult S. dorsalis females started egg development from late March to early April while inhabiting tea groves that sprout in late March. First-generation larvae were found in the tea groves from late April to early May, and adults began to emerge in mid-May. First-generation larvae were barely detected in bigleaf podocarps trees that sprouted from mid- to late April. First-generation adults moved to bigleaf podocarp trees in mid-May, and second-generation larvae occurred from late May to early June.View full abstractDownload PDF (206K)
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