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Volume 50 (2006)
- Issue 4 Pages 283-
- Issue 3 Pages 201-
- Issue 2 Pages 87-
- Issue 1 Pages 1-
Volume 50, Issue 2
Displaying 1-10 of 10 articles from this issue
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Mini Reviews
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Nobuo Mizutani2006 Volume 50 Issue 2 Pages 87-99
Published: 2006
Released on J-STAGE: June 06, 2006
JOURNAL FREE ACCESSIt has been reported that male adults attract conspecific individuals in some species of true bugs (Heteroptera). Chemical stimuli play an important role in these attractions. Male adults attract adults of both sexes and nymphs, so the chemical stimuli are considered as “aggregation pheromones.” Some aggregation pheromones in these bugs have been identified and synthesized, but their functions have not been fully determined. It is necessary to clarify the functional significance of aggregation pheromones in order to utilize them for the control of pest bugs. The aggregation pheromones of some bug species also attract the bug's natural enemies, parasitic flies, egg parasitoids, and so on. Female parasitoids utilize the host pheromone as a kairomone to locate their hosts. Males of the bean bug Riptortus clavatus, an economically important soybean pest, emit an aggregation pheromone that attracts adults of both sexes and nymphs. The aggregation pheromone of R. clavatus consists of three components: (E)-2-hexenyl (E)-2-hexenoate, (E)-2-hexenyl (Z)-3-hexenoate (E2HZ3H), and tetradecyl isobutyrate. One of the three components alone, E2HZ3H, attracted females of the egg parasitoid Ooencyrtus nezarae, which is a predominant natural enemy of R. clavatus. E2HZ3H, however, did not attract R. clavatus. In an E2HZ3H-treated field, the parasitoids immigrated into the field earlier than the invasion of R. clavatus, and remained at higher densities than in an untreated field. E2HZ3H did not increase the density of the pest host bug. According to the data obtained from the eggs of the bugs artificially set on soybean plants, the E2HZ3H field application resulted in higher parasitism by the parasitoids as compared with the untreated field when the parasitoid density was high in autumn.View full abstractDownload PDF (434K) -
Shoji Asano2006 Volume 50 Issue 2 Pages 101-114
Published: 2006
Released on J-STAGE: June 06, 2006
JOURNAL FREE ACCESSFor more than 50 years, a variety of Bacillus thuringiensis (Bt) products have been utilized worldwide as microbial insecticides. Early quality control of Bt products was based on spore counts in each formulation. However it was demonstrated later that spore counts do not always correlate with the insecticidal activity of Bt products and hence the bioassay using insects became a prerequisite for the quality control. The standardization of the bioassay method was discussed at the international meeting in 1966, where the standard product, E-61, was assigned as 1,000 International Unit (IU)/mg and the potency of each Bt product was to be expressed in IU/mg based on comparison of LC50 between the product and the standard. Thereafter the standard bioassay method has been employed among different countries. However some problems on the standardization still remain: Stock and supply of standard materials, storage stability of the standards, insect species and methods for bioassays, calculation of potency when sample and standard differed in insecticidal spectrum, criterion of acceptance for each product based on bioassay results, and development of easier and faster bioassay method than the present one. The author reviews the history of the standardization of bioassay methods and discusses existing problems in the quality control of Bt products.View full abstractDownload PDF (352K)
Regular Papers
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Satoshi Taba, Zen-ichi Moromizato, Kazuko Takaesu, Atsushi Ooshiro, Ka ...2006 Volume 50 Issue 2 Pages 115-122
Published: 2006
Released on J-STAGE: June 06, 2006
JOURNAL FREE ACCESSThe toxicity of a nematicide (fosthiazate) to the nematode-trapping fungus Monacrosporium ellipsosporum, and the control effect of granule formulations containing fungal propagules and the nematicide on the southern root-knot nematode, Meloidogyne incognita were examined. The nematicide had no effect on spore germination or hyphal growth at 3,000 or 300 ppm in CMA medium, but drying of the granules sometimes decreased the survival rate of the fungus. The fungus from the formulations formed trapping organs and actively trapped nematodes by infection hyphae. The trapping rate by fungal knobs was inversely correlated to the concentration of the nematicide. The control test of M. incognita on tomatoes using the fungus-nematicide formulations showed a very high effect when mixed with the total soil in pod experiments. The fungus was detected in all of the soil samples upon completion of the tests.View full abstractDownload PDF (740K) -
Ken Tabuchi, Seiichi Moriya, Nobuo Mizutani, Kenji Ito2006 Volume 50 Issue 2 Pages 123-129
Published: 2006
Released on J-STAGE: June 06, 2006
JOURNAL FREE ACCESSTo save labor for monitoring the occurrence of the bean bug Riptortus clavatus (Thunberg), we used automatic counting traps baited with synthetic attractants from July to December, 2004. This automatic counting trap utilizes a solar battery to work continuously and sends data automatically via a built-in mobile phone. The occurrence of the bugs was also monitored by three water-pan traps. The number of bugs counted automatically and the actual number of catches in the automatic counting trap were not always consistent. One of the reasons for this inconsistency might be due to that the current automatic counting trap could not eject clogged insects in a roller electrode. However, the number of seasonal catches by automatic counting and water-pan traps showed similar trends, and the catch numbers of these traps reached a peak around the same time, in October. Although the automatic counting trap needs improvement, it should be useful for investigating the occurrence of the bean bug population utilizing less labor.View full abstractDownload PDF (676K) -
Mika Murata, Taro Imamura, Akihiro Miyanoshita2006 Volume 50 Issue 2 Pages 131-136
Published: 2006
Released on J-STAGE: June 06, 2006
JOURNAL FREE ACCESSThis study examined the mechanisms by which the Indian meal moth, Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae), invaded instant noodles packaged in a heat-shrunk sealed foam polystyrene cup, and the development of the larvae feeding on the instant noodles. The last-instar larvae tended to invade the space between the shrunk film and the cup. We observed numerous enlarged holes bitten by larvae on the air vent holes and holes on the back lining (the seal between films) of the PP (polypropylene) film covering the side and the bottom of the cup. On the lid flange, it was confirmed that larvae bored through the foam polystyrene as well as the PP film of the lid flange to enter the inside of the cup, where they fed on the instant noodles. When the larvae were reared on the instant noodles from first instar, the average larval developmental period at 30°C was 33.1 days (males) and 34.3 days (females), being significantly longer than when fed on the rice bran. The percentage of adult emergence was 30.0. From the viewpoint of prevention of insect contamination, we concluded there was room for improvement of the heat-shrunk packaging and the cup surface of the instant noodle product.View full abstractDownload PDF (557K) -
Hiroaki Takeuchi2006 Volume 50 Issue 2 Pages 137-143
Published: 2006
Released on J-STAGE: June 06, 2006
JOURNAL FREE ACCESSTo estimate the occurrence of pecky grain damage caused by Leptocorisa chinensis in rice fields, I censused the rice bug utilizing the sweeping method, and checked the occurrence of pecky grains among total hulled grains from 2000 to 2004. Using the data obtained from the field census, I constructed 30 logistic regression models. The explanatory variables of each model were different combinations of rice variety, date of initial heading stage, number of adults at early ripening stage, and numbers of adults, nymphs and their total at the mid-ripening stage. The dependent variable of all models was whether or not the occurrence of pecky grains among total hulled grains was over 0.1%. Akaike's information criteria indicated that a model whose explanatory variable was number of nymphs at the mid-ripening stage was statistically better than the other models. These results suggest that a census of nymphs at the mid-ripening stage, which is 200–300 day-degrees from the initial heading stage, is an appropriate way to estimate the occurrence of pecky grains.View full abstractDownload PDF (309K) -
Hideo Uematsu2006 Volume 50 Issue 2 Pages 145-150
Published: 2006
Released on J-STAGE: June 06, 2006
JOURNAL FREE ACCESSThe pentatomid bug, Andrallus spinidens (F.), is a polyphagous predator on lepidopteran larvae in crop fields in southern Japan. The basic life history biology of the bug was studied using a laboratory incubator with temperature set at 25°C. The nymphs were reared in Petri dishes in groups of 10 and were fed on the 3rd–5th instar Spodoptera litura larvae. The mean development period from egg to adult was 32 d. The pre-oviposition period lasted 7 to 8 d, after which eggs were laid in batches every 2–3 d. The mean number of eggs per mass was 75.4 and the mean total number of eggs laid by each female was 499. The net reproductive-rate (R0), mean generation time (T) and intrinsic rate of natural increase (r) were 153.8, 49.8 d and 0.101/d/female, respectively. Groups of 10 nymphs attacked 4–8 of the 3rd–5th instar S. litura larvae per day. Pairs of adult pentatomids killed 3–5 of the 5th instar S. litura larvae weighing 450–550 mg each day. This study provides important life history information for using the predator A. spinidens as a possible biological control agent.View full abstractDownload PDF (498K) -
Shoji Asano2006 Volume 50 Issue 2 Pages 151-156
Published: 2006
Released on J-STAGE: June 06, 2006
JOURNAL FREE ACCESSA silkworm assay using the 3rd instar stage of silkworm, Bombyx mori and a diet incorporation method has been utilized for the quality control of Bacillus thuringiensis (Bt) products in Japan since 1973. The potency of test sample relative to a standard was calculated based on lethal activity (LC50). The LC50 values were usually estimated by probit analysis on the mortality at the levels of 5–6 doses. In the present study the author tried simpler silkworm assays based on the lethal activity of Bt products against the 2nd instar of silkworms using 1–2 doses. It was shown that the potency of the sample relative to the standard based on assays with 1–2 concentrations is similar to that based on assays with six concentrations.View full abstractDownload PDF (210K) -
Takuhiro Yamaguchi, Kanae Tokimura, Youichi Hara, Naoki Atari2006 Volume 50 Issue 2 Pages 157-165
Published: 2006
Released on J-STAGE: June 06, 2006
JOURNAL FREE ACCESSWe compared three sweet potato cultivars used mainly for starch and alcohol production, (‘Shirosatsuma’, ‘Shiroyutaka’ and ‘Koganesengan’) with another used for cooking (‘Tosabeni’) to study the feasibility of those three cultivars as an inexpensive diet material for the mass-production of adult sweet potato weevils to be sterilized for insect release. About 1,500 adult weevils (sex ratio≒1:1) were reared on sweet potato storage roots for 2 wk to allow oviposition. Four roots (ca. 800 g) were set out at a time and were replaced with new ones at intervals of 3–4 d. The emergence time of new adults from the roots of Shiroyutaka tended to be a little earlier, and those of Koganesengan a little later than those of Tosabeni. The number of adult weevils available for sterile insect release was no more than 2.7% less when weevils were reared on Koganesengan than when reared on Tosabeni. There was no significant difference in the number of adult weevils produced per gram of sweet potato root between the three cultivars and Tosabeni. Importantly, the percentage of males among emerged adults (sex ratio) was significantly higher in the three cultivars than in Tosabeni. The weevils in a root of Shiroyutaka tended to reach the stage suitable for irradiation 1–2 d earlier than those in Tosabeni. Based on these results, it was concluded that the three cultivars 'Shirosatsuma, Shiroyutaka and Koganesengan' were suitable as diet materials for the mass-production of weevils.View full abstractDownload PDF (516K)
Note
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Hiroya Higuchi2006 Volume 50 Issue 2 Pages 167-169
Published: 2006
Released on J-STAGE: June 06, 2006
JOURNAL FREE ACCESSEgg parasitoids of the rice leaf bug, Trigonotylus caelestialium, and seasonal trends in parasitism by them were studied during 2000–2002 in Italian rye-grass fields, Joetsu, Niigata Prefecture, Japan. Oligosita sp. and Telenomus sp. were identified as the parasitiods of the bug eggs. Parasitism by each of these two egg parasitoids fluctuated widely between May and September.View full abstractDownload PDF (206K)
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