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Volume 41 (1997)
- Issue 4 Pages 187-
- Issue 3 Pages 115-
- Issue 2 Pages 75-
- Issue 1 Pages 1-
Volume 41, Issue 2
Displaying 1-7 of 7 articles from this issue
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Masaya MATSUMURA1997 Volume 41 Issue 2 Pages 75-82
Published: May 25, 1997
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSThe seasonal ovarian development in macropterous females of the Whitebacked Planthopper, Sogatella furcifera was observed in paddy fields in 1990, 1992, and 1993. Very few first-generation macropters developed ovaries and emigrated from the field in 1990. By contrast, a fraction (5% to 30%) of first-generation macropters did not emigrate but had complete eggs in most ovarioles in 1992 and 1993. Second-generation nymphal density was high in these two years. Analysis of synoptic weather conditions associated with peak catches in light traps showed that non-migratory first-generation macropters contributed to the second-generation occurrence in 1992. A laboratory experiment showed that ovarian development in macropters is delayed when rearing densities are high, suggesting that crowding is an important factor in determining ovarian development of macropters. However, in paddy fields, there was no noticeable relationship between adult density and ovarian development in first-generation macropters. The effects of other factors on ovarian development such as the growth stage of rice plants should be clarified in the future.View full abstractDownload PDF (1053K) -
Keiji YASUDA1997 Volume 41 Issue 2 Pages 83-88
Published: May 25, 1997
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSThe occurrence of the West Indian Sweet Potato Weevil (WSPW) and the damage it causes in sweetpotato fields treated and not treated with insecticide from planting to harvesting were surveyed. WSPW females invading the fields oviposited first in the stems, and the mean number of insects including larvae, pupae and adults in stems increased to 1.22-3.90 per plant in untreated plots. The first appearance in tubers was later than that in stems and the mean number of the weevils in the tubers increased to 5.04-7.97 per plant at harvesting. Stems damage by the WSPW larvae was found 30-60 days earlier than tuber damage in untreated plots. When the insecticide was applied topically on the ground near stems, the level of damage and number of WSPW did not increase as much in both stems and tubers. Damage to stems did not affect the growth of the sweet potato, and seemed acceptable. It is possible that the ratio of damaged stems can predict tuber damage and whether to apply insecticide or not.View full abstractDownload PDF (734K) -
Satoko YOKOTA, Chisa YASUNAGA, Takeshi KAWARABATA, Syoji HAYASAKA, Kat ...1997 Volume 41 Issue 2 Pages 89-94
Published: May 25, 1997
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSSpores of Nosema mesnili NM-HC-A8801 primed with 0.1-N KOH solution were inoculated in Antheraea eucalypti cell cultures at a ratio of 30 spores per cell. The inoculated insect cells were cultured at 27°C in GRACE'S medium supplemented with 10% fetal bovine serum. At 1h post-inoculation, the percentage of hatched spores was approximately 20%, and about 5% of A. eucalypti cells were infected initially with sporoplasms. At 96h post-inoculation, many-coiled mature spores were produced and an infected A. eucalypti cell contained about 40 protozoans. A rapid increase in cell infection rates was observed and the percentage of infected cells reached 90% 120h post-inoculation. In the life cycle, N. mesnili NM-HC-A8801 was diplokaryotic and showed disporous development which are typical of the genus Nosema. However, the spread of infection and spore production were markedly different from N. bombycis and Nosema sp. NIS M 11.View full abstractDownload PDF (2161K) -
Katsuo TSUDA, Tetsuya YOSHIOKA, Takafumi TSUTSUMI, Masahiro YAMANAKA, ...1997 Volume 41 Issue 2 Pages 95-98
Published: May 25, 1997
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSThe pathogenicities of 9 isolates of Beauveria bassiana obtained from Plautia stali and Scotinophara lurida were compared by bioassay using 4th instar nymphs of P. stali. A new rearing case was developed for individual rearing of infected nymphs. There were significant differences between the virulences of the isolates. The results suggest that the most virulent isolates have potential as biological control agents for P. stali.View full abstractDownload PDF (1360K) -
Katsuo TSUDA, Takafumi TSUTSUMI, Masahiro YAMANAKA1997 Volume 41 Issue 2 Pages 99-101
Published: May 25, 1997
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSTransmission by mating behavior of an entomogenous fungus, Beauveria bassiana (E-9102), was examined by allowing inoculated Plautia stali adults to mate with non-inoculated ones. There were significant differences in transmission. Inoculated adults could transmit the fungus to non-inoculated partners by mating behavior. The antennae play an important function in transmission of the fungus.View full abstractDownload PDF (392K) -
Tomoaki HONGO, Nobuo OBAYASHI1997 Volume 41 Issue 2 Pages 101-105
Published: May 25, 1997
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSDownload PDF (667K) -
Kenji FUKUYAMA1997 Volume 41 Issue 2 Pages 105-107
Published: May 25, 1997
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSTo test the JANZEN hypothesis, I investigated the proportion of injuries caused by Prociphilus oriens MORDVILKO on Fraxinus lanuginosa KOIDZ. saplings planted with mature host trees in Sapporo, Japan, in 1993. There is a significant negative relationship between the proportion of injuries caused by P. oriens and the distance from mature trees, supporting part of the JANZEN hypothesis.View full abstractDownload PDF (408K)
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