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Volume 17 (1973)
- Issue 4 Pages 171-
- Issue 3 Pages 121-
- Issue 2 Pages 49-
- Issue 1 Pages 1-
Volume 17, Issue 4
Displaying 1-11 of 11 articles from this issue
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Fusao NAKASUJI, Hisaaki YAMANAKA, Keizi KIRITANI1973 Volume 17 Issue 4 Pages 171-180
Published: December 25, 1973
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSIn an atempt to develop an integrated control programme of Spodoptera litura, investigations were carried out in a taro field in 1972 in Ino, Kochi. Three kinds of plots were prepared as follows: (1) weeds in a plot were cut by a sickle at a height of 5cm above the ground, straw mats were spread all over the ground, and the plot was treated fortnightly with 30ppm of chlorophenamidine emulsion 3 times during summer (improved control), (2) weeds were removed by hands, and 450ppm emulsion of methomil was used instead of chlorophenamidine (conventional control), (3) weeds were removed by hands, straw mats were spread and no pesticide was used (untreated). Incidences of caterpillars and their natural enemies were recorded every other day. Yield was examined at harvest. Densities of the 1st and 4th instar larvae of S. litura were lower in the improved control plot than the other two plots. But the density of 6th instar larvae in the conventional control plot was as low as that in the improved control plot. Presumably, larvae in the former plot emigrated out of the plot due to lack of the straw-mat shelter. Thirty ppm emulsion of chlorophenamidine was satisfactory in preventing hatchlings of S. litura from establishment on the leaf up to 7 days after the treatment, and no appreciable effect was observed on larvae of advanced stages as well as on polyphagous predators. Methomil killed not only larvae of all stages but also predators. Consequently, the order of abundance of predators was improved, untreated and conventional plots in a decreasing order. Survivorship curves of the larval populations which originated from those egg masses having deposited between the insecticidal treatments were compared among the three plots. The lowest survival rate was found in the improved control plot. The negative correlation between survival rate of S. litura and density of predators was observed among four combinations of predator group and larvae of vulnerable stage of S. litura. The yield was highest in the improved control plot, followed by conventional and untreated ones in a decreasing order. It was concluded that S. litura could be controlled by an integrated use of polyphagous predators and ultra-low concentration of chlorophenamidine.View full abstractDownload PDF (1310K) -
Hiroshi HAMA, Toshikazu IWATA1973 Volume 17 Issue 4 Pages 181-186
Published: December 25, 1973
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSThe mortality caused by combined topical application of carbamate and organophosphorus insecticides was not more than expected from additive effect against a susceptible leafhopper strain and two strains which were resistant to organophosphorus but susceptible to carbamate insecticides. However, against the Nakagawara strain (N), which was resistant to both organophosphorus and carbamate insecticides, remarkable synergism was detected between a carbamate insecticide, propoxur, and organophosphorus insecticides such as malathion, diazinon, demethoate and phenthoate. When any one of seven carbamate insecticides were combined with malathion and applied against the N strain, the LD50 were almost the same, ranging from 25.0 to 42.5μg/g of body weight of the insect. The LD50 values of these insecticides, when applied singly, ranged from 18.8 to 263μg/g. Synergism was also detected at the similar degree between malathion and propoxur against the other leafhopper populations which were resistant to both organophosphorus and carbamate insecticides.View full abstractDownload PDF (779K) -
Kazuo NAKAMURA1973 Volume 17 Issue 4 Pages 187-192
Published: December 25, 1973
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSIn order to determine the effects of different conditions of temperatures and sex-ratios on the number of eggs laid and rate of egg hatching in Spodoptera litura, experiments were carried out in the laboratory and in a field plot which was covered with net. The number of eggs laid by a female per day was the largest on the first and second days after emergence and decreased gradually thereafter under the range of temperatures from 18 to 30°C. The temperature did not affect the total number of eggs laid during adult period and the rate of hatching of the eggs. It was shown from lxmx-curve that females laid almost all eggs by the seventh day after emergence under the range of temperatures studied. The number of egg masses laid by the unmated females was larger than that by the mated females, but the number of eggs laid by the former was much smaller than that laid by the latter. Laboratory experiments showed that both females and males mated only once or less during the first night. Males could mate at the same rate on the second night, but appeared to avoid the mating with the females which had mated already. As a result, the experiment in the laboratory showed that the rate of egg masses hatched, rate of egg hatching and the number of eggs laid reduced apparently with the decrease in the sex-ratio on the first day after emergence, but the tendency of reduction in these values decreased gradually on the second and the third days. In the experiment made in the field plot covered with nets, these values also reduced with the decrease in sex-ratio both on the first and second day and on the third day.View full abstractDownload PDF (783K) -
Shiro KOBAYASHI, Hiroaki SHIBATA1973 Volume 17 Issue 4 Pages 193-202
Published: December 25, 1973
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSSeasonal changes of the population density of spiders were investigated in a paddy field during the period from April to November, 1972. In dikes the density of spiders was only 50 individuals per m2 in April, but increased considerably by September, showing a saw-teeth-like curve with 3 peaks. On the contrary, the density of spiders in paddy fields remained at a very low level during the first two months after transplantation of rice plants. However, spiders began to increase rapidly from July to August, and the resulting high density was maintained until the rice havest. The maintenace of this high density of spiders in paddy fields was closely related to the emigration of spiders from dikes, and to the plentiful availability of their prays. From these results, it was suggested that dikes served as a preserver not only for the spiders but also for their prays and that the abundance of preys was one of the important factors which affect the density of spiders.View full abstractDownload PDF (1300K) -
Yoshiaki KONO1973 Volume 17 Issue 4 Pages 203-209
Published: December 25, 1973
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSPhotoperiodic sensitivity of diapausing pupae and of the larval brains which were implanted in the decerebrated diapause pupae was investigated in Pieris rapae crucivora. Ultrastructural changes of the neurosecretory cells (NS-II cells) of implanted brains were also observed in order to explain the influence of photoperiod on these cells. After the insensitive stage of certain days, diapause pupae were able to respond to the long photoperiod, and begin the adult development without chilling. The implanted brain from a short-day larvae in the age of the 4th day of the 5th instar exhibited the sensitivity to the photoperiodic stimulation. When exposed to the long photoperiod, the brain brought on the adult development of host pupae and the brain itself showed signs of adult development in its appearance and in the ultrastructure of NS-II cells. In this case, it took about ten days for the short-day brain to be entrained by the long photoperiod. When exposed to the short photoperiod, the host continued diapause and the NS-II cells of the implanted brain resembled those of the diapausing pupa kept at low temperature in ultrastructural view, because they appeared to be in inactive stage of secretion.View full abstractDownload PDF (5419K) -
II. Environmental Factors, especially Vegetation and Soil PropertiesYoshio NAKAMURA1973 Volume 17 Issue 4 Pages 210-214
Published: December 25, 1973
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSThe present study deals with the relation between earthworms and some environmental factors, especially vegetation and soil properties. Six species were collected from 66 sampling localities in Sapporo; Allolobophora japonica MICHAELSON (A and B forms), A. caliginosa (SAVIGNY), A. rosea (SAVIGNY), Eisenia foetida (SAVIGNY), Dendrobaena octaedra (SAVIGNY), Bimastus tenuis (EISEN). Among them, A. japonica (A form) and D. octaedra were collected from many sampling localities and often found together. The sampling localities were divided into nine habitats in reference to vegetation, and the species compositions of forest and grassland were similar each other at three seasons, spring, summer and autumn. No clear correlation was observed between three soil properties (water and organic matter contents and pH value) and the total population density or that of each lumbricid species.View full abstractDownload PDF (522K) -
Teiji OMINO, Shinji YOKOI, Hideakira TSUJI1973 Volume 17 Issue 4 Pages 215-220
Published: December 25, 1973
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSUnderground concealment and resting behaviour of noctuid larvae during the day was investigated under laboratory conditions at 25°±1°C and 16:8 (hours) light-dark regime. Preliminary experiments on the phototaxis of these species as well as that of the common cutworm, Agrotis fucosa, were also carried out. When larvae were mounted on a cut leaf of the Chinese cabbage in a glass dish, 1st and 2nd instar larvae of A. ipsilon were usually found on the leaf, but half of the 3rd instar larvae, most of the 4th and 5th instar ones, and all the 6th (final) instar ones hid in soil (vermiculite). In M. brassicae, some of the 5th instar larvae, the majority or all of the 6th (final) instar ones were found in soil, but no younger larvae hid in soil. Results in S. litura were similar to those in M. brassicae, though most of the larvae got into soil just before their pupation. When larvae were mounted on leaves of cowpea plants growing in a glass pot, most of the 1st instar larvae of A. ipsilon found were on the plants especially on buds, though about 40% of the larvae used were not found. Second and 3rd instar larvae of this species were usually found on the soil surface, and the majority of the 4th and 5th instar ones and all of the 6th (final) instar ones were in soil. Results in M. brassicae were similar to those obtained in the glass dish. In S. litura, 1st to 3rd instar larvae were found mostly on the food plants, and 5th and 6th instar ones were found on the surface of soil, entering into soil just before their pupation. Reaction of the larvae to light when an electric lamp (60W) was placed at a distance of 60cm was as follows. Larvae of S. litura and M. brassicae showed a positive phototaxis during their 1st and 2nd instar stages and a negative one in the 5th and 6th instar stages. No clear phototaxis was observed in the 3rd and 4th. On the other hand, the reaction of larvae of A. fucosa and A. ipsilon to the light was not clear during most of their larval stage, though 17 days old larvae (just before pupation) of A. ipsilon showed a negative phototaxis.View full abstractDownload PDF (1523K) -
Socho NASU, Masako NAKASUKA1973 Volume 17 Issue 4 Pages 221-223
Published: December 25, 1973
Released on J-STAGE: February 12, 2009
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Yoshiharu MATSUMOTO, Toshio SHONO1973 Volume 17 Issue 4 Pages 223-225
Published: December 25, 1973
Released on J-STAGE: February 12, 2009
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Toshio OKU, Heisuke SATOH1973 Volume 17 Issue 4 Pages 225-227
Published: December 25, 1973
Released on J-STAGE: February 12, 2009
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Hisashi NEMOTO1973 Volume 17 Issue 4 Pages 227-230
Published: December 25, 1973
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSDownload PDF (2059K)
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