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Volume 47 (2003)
- Issue 4 Pages 129-
- Issue 3 Pages 85-
- Issue 2 Pages 53-
- Issue 1 Pages 1-
Volume 47, Issue 3
Displaying 1-3 of 3 articles from this issue
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Regular Papers
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Takenori Miyashita, Kenji KawanishiArticle type: Regular Paper
Subject area: [not specified]
2003 Volume 47 Issue 3 Pages 85-90
Published: 2003
Released on J-STAGE: November 25, 2003
JOURNAL FREE ACCESSThe larvae of the rice leaf roller, Cnaphalocrocis medinalis (Guenèe), fed rice leaves from the vegetative growth period until panicle formation developed to the 5th instar and pupated regardless of the variety and position of leaves given to them. In larvae fed leaves after the booting period, 6th or sometimes 7th instar larvae appeared. The frequency of these extra-molting-type larvae increased as the rice growth stage advanced. In addition, the growth speed of the larvae was reduced even within the same instar. Larvae fed leaves at the ripening stage showed a decrease in pupal weight. These influences on larval development also varied according to the position of the leaves given. Marked negative effects were observed in larvae fed flag leaves as compared to those fed lower leaves. Particularly, many 1st instar larvae fed flag leaves during the ripening period died. Thus, the position of leaves consumed appears to affect larval survivorship. These changes in larval development and survival rate seem to be caused synergistically by differences in the nutritional value and hardness of leaves of the food plant.View full abstractDownload PDF (50K) -
Takashi MizutaArticle type: Regular Paper
Subject area: [not specified]
2003 Volume 47 Issue 3 Pages 91-95
Published: 2003
Released on J-STAGE: November 25, 2003
JOURNAL FREE ACCESSDifferences in development and reproductive ability of the mulberry scale, Pseudaulacaspis pentagona Targioni, were investigated using resistant and susceptible tea varieties. The developmental period of the second larval instar, the pupal stage, and the period from egg hatching to emergence in males was longer on the resistant varieties than on the susceptible ones. The second instar preoviposition period and period from egg hatching to the beginning of egg-laying in females were also retarded on the resistant varieties. Only 18.5% and 23.8% of neonate female larvae reached the adult stage on the resistant varieties, Hatsumomiji and Sayamakaori, respectively. In contrast, 42.4% and 59.5% of larvae developed to adults on the susceptible varieties, Yutakamidori and Takachiho, respectively. The number of laid eggs and ovarian eggs in females reared on the resistant varieties, Sayamakaori and Hatsumomiji, were reduced to 5.4% and 11.3%, respectively, of the susceptible variety, Takachiho.View full abstractDownload PDF (55K)
Notes
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Hiroshi Sato, Yasuhisa Shirai, Sadanori Tanaka, Taro Imamura, Akihiro ...Article type: Note
Subject area: [not specified]
2003 Volume 47 Issue 3 Pages 97-100
Published: 2003
Released on J-STAGE: November 25, 2003
JOURNAL FREE ACCESSThe purpose of this study was to determine the mechanisms by which Plodia interpunctella (Hübner) infest chocolate cartons and to test the effect of sealing tightness of wrapping film on infestation. The carton samples were wrapped with 25 μm thick OPP film by an industrial wrapping machine. Each chocolate carton was placed in a closed plastic box (215×147×130 mm) together with 5 mg of eggs, two weeks old larvae, three weeks old larvae or five pairs of mating adults of P. interpunctella. The plastic boxes were kept at 25°C and 70% R.H. The number of larvae infesting chocolate was recorded after 10 days. Only newly hatched larvae were able to invade the chocolate cartons in these experiments. However, no entry holes made by the larvae were found on the outer coveringfilm, indicating the larvae invaded through tiny unsealed portions of the outer coveringfilm. To test the effect of tightness of the film on larval invasion, outer coveringfilm of chocolate cartons with different air leak values (>100, 100–200, 200–300, 300–500 cc/min) were exposed to newly hatched larvae. A carton without wrapping was used as a control. In cartons with less than 100 cc/min air leak, no larvae were found three weeks after the beginning of the experiment. Furthermore, the number of larvae which invaded cartons increased as the air leakage value increased. It is recommended that the air leakage value of the outer coveringfilm should be less than 100 cc/min to protect chocolate cartons from the infestation of P. interpunctella.View full abstractDownload PDF (118K)
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