Japanese Journal of Applied Entomology and Zoology
Online ISSN : 1347-6068
Print ISSN : 0021-4914
ISSN-L : 0021-4914
Volume 42, Issue 4
Displaying 1-6 of 6 articles from this issue
  • Masatoshi Takeuchi, Hiroshi Fujita
    1998 Volume 42 Issue 4 Pages 197-200
    Published: November 25, 1998
    Released on J-STAGE: February 12, 2009
    JOURNAL FREE ACCESS
    The habitat status of the grasshopper, Eusphingonotus japonicus, an endangered species in Kanagawa Prefecture, was investigated at one large remaining site in the riverbed of the Nakatsu River in Aikawa-cho, Kanagawa Prefecture in the autumn of 1996. There were remarkable differences between the species composition of plants and orthopterans at three observation areas in the riverbed, and E. japonicus was found only in the area where the plant cover was low; other grasshoppers, Locusta migratoria and Oedaleus infernalis, predominated. It is suggested that the change in vegetation caused by plant colonization of the riverbed area may affect the occurrence of E. japonicus as well as other orthopteran species. The destruction and fragmentation of habitats due to human activity such as riverbank protection work may damage many populations of E. japonicus in Kanagawa Prefecture.
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  • Hideo Uematsu, Atsushi Nomiyama, Masahiko Hashizume
    1998 Volume 42 Issue 4 Pages 201-208
    Published: November 25, 1998
    Released on J-STAGE: February 12, 2009
    JOURNAL FREE ACCESS
    Diamondback moth, Plutella xylostella, pupae were collected from fields in March, August, and December 1988, and in May and July 1990 in Miyazaki, southern Japan. The number of eggs laid per day per female (NEDF) which emerged from the collected pupae was measured in chambers (20°C, 14L 10D) and meteorological screen boxes. Age-specific fecundity curves were analyzed based on mating age. The highest NEDF was observed on the mating day or next day. (Means were from 93.4 to 125 for the March population.) The fecundities of females mating successfully within 48h after emergence were 480.6 (March), 374.4 (May), 277.3 (July), 263.2 (August), and 478.8 (December), when the females were supplied with 2% sugar solution. The fecundities decreased by 60% to 70% when females were supplied only with water. Fluctuating ambient temperature in the warmer seasons of May and July had no effect on fecundity. In winter (December), oviposition lasted for about 1 month, although it was frequently suppressed by low temperature. The fecundity of females in the meteorological screenbox in winter was smaller than at a constant temperature of 20°C, suggesting that fluctuating winter ambient temperature lowers fecundity in the diamondback moth.
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  • Masahiko Morishita
    1998 Volume 42 Issue 4 Pages 209-213
    Published: November 25, 1998
    Released on J-STAGE: February 12, 2009
    JOURNAL FREE ACCESS
    The susceptibility to insecticides of the diamondback moth, Plutella xylostella L. collected during 1985-1997 from commercial fields of cabbage and broccoli in Gobo, Wakayama Prefecture was determined at the 3rd-instar larvae by the leaf-dipping method. The resistance to Bacillus thuringiensis toxin (Toarow CT®) varied with the frequency of application. Higher LC50 values were observed during 1986-1987 when BT products were applied often and lower LC50 values were observed during 1988-1990 when alternative pesticides were used due to the lower effectiveness of BT formulations. Chlorfluazuron was remarkably effective when it was introduced. However, extended treatment promoted development of high resistance to chitin synthesis inhibitors in early 1991. With organophosphates, LC50 values of prothiofos and phenthoate fell because applications were less frequent. The moth population maintained high resistance to the pyrethroid group from 1986 when they first developed resistance to fenvalerate.
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  • Shinzaburo Sone, Takamasa Maki, Koji Iwaya, Yuichi Otsu
    1998 Volume 42 Issue 4 Pages 215-220
    Published: November 25, 1998
    Released on J-STAGE: February 12, 2009
    JOURNAL FREE ACCESS
    A new bioassay method for Thrips palmi, called the CST (Cucumber Seedling Treatment) method, was established. The CST method is characterized by easy chemical application, easy observation, long observation period, high survival rate and high reproducibility. The 1st-instar larvae attached to a cucumber seedling grow healthily, and the rate of pupation and emergence is very high (90%-100%). These merits enable evaluation of slow-acting compounds, such as chitin synthesis inhibitors and hormone analogues. In the CST method, the feeding damage appears as dead spots on the leaves, and visual evaluation of control efficacy is easy. The CST method can be used to determine susceptibility of Thrips palmi to insecticides with different modes of action.
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  • Hideshi Naka, Natsuko Kobayashi, Koji Tsuchida, Hironori Sakurai
    1998 Volume 42 Issue 4 Pages 221-226
    Published: November 25, 1998
    Released on J-STAGE: February 12, 2009
    JOURNAL FREE ACCESS
    The Persimmon Fruit Moth, Stathmopoda masinissa Meyrick is an important pest of Japanese persimmon fruit, but it is difficult to rear under artificial conditions. We report an artificial rearing method using cultured tip tissue of the Japanese persimmon, Diospyros kaki. Significant differences were not found for different sterilizing conditions using corrosive sublimate at egg hatching, but were found at different solution concentrations at pupation and emergence. The decline in hatchability is thought to be due to excess humidity and the lethal effect of the solution on eggs when used for more than the optimum sterilizing period. These results suggest that the best sterilizing condition is a 0.4% solution for 3min. The pupation and emergence rates are highest at 25°C. The theoretical developmental zero point is 12.4°C and the total effective temperature is 523.78 day degrees. The optimum rearing density is two eggs per bottle. Laboratory-reared adults were smaller than wild adults.
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  • Shin-ichi Yoshimatsu, Kazuhiro Arimura, Tadayuki Shimanuki
    1998 Volume 42 Issue 4 Pages 227-229
    Published: November 25, 1998
    Released on J-STAGE: February 12, 2009
    JOURNAL FREE ACCESS
    The population growth rates of Tribolium confusum reared on seeds of three cultivars of ground tall fescue (Festuca arundinacea Shreb.) infected and not infected with endophytes were compared. The numbers of adults reared on seeds of the three cultivars infected with endophytes were significantly lower than the numbers of adults reared on seeds without endophyte infection, after 10 weeks (p<0.0001; structured ANOVA). The results suggest that endophyte-infected seeds adversely affected the population growth of Tribolium confusum. A similar experiment was carried out using seeds of two cultivars of endophyte-infected ground perennial ryegrass (Lolium perenne L.) and seeds of three cultivars of non-infected ground perennial ryegrass. In this case, the inhibitory effect of endophyte-infected seeds was not detected.
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