Pine sawer, Monochamus alternatus HOPE (Coleoptera: Cerambycidae) is a serious pest which is a carrier of Bursaphelenchus xylophilus (STEINER & BUHRER) (Nematoda: Aphelenchoididae). In Japan NAC wettable powder is extensively sprayed on a forest in order to protect the pine against maturation feedings of the longicorn beetles. Recently, however, some beekeepers are afraid of a reaction of honey bee to the molasses which is one of the components of the NAC wettable powder. Therefore, authors examined the foraging behavior of honey bees on honey, molasses or honey mixed with molasses of various concentrations. The molasses were never gathered by the workers, so far as it was offered alone to them. Honey solutions including 0-10 per cent of molasses were accepted by workers, although the honey solutions mixed with the molasses of higher concentrations were less accepted. This suggests that some unknown components of molasses act as inhibitors of foraging behavior of workers.

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The larvae of the spotted cutworm collected from grass fields at the beginning and the end of winter season were reared on an artificial diet in the laboratory. The larvae which died in the course of rearing were microscopically examined. In April and May, 1983, the main causative agents of diseased larvae were identified as nuclear polyhedrosis and granulosis. Two different types of polyhedra were observed: one was tetragonal and the other was trigonal in shape. Alkaline-liberated virions were rod-shaped and measured 80-190×320-380nm in the tetragonal type and 95-165×345-385nm in the trigonal type. The occlusion bodies of GV were ellipsoidal and measured 0.2-0.3×0.4-0.6μm. Nucleocapsids of GV were slightly curved and measured 70-72×400-405nm.

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Experiments were done under the laboratory condition of 24°C and 16L-8D photoperiod. Female individuals of different body size were sampled from the culture keeping low population density condition. Males having same or smaller body size than each female were paired. Each single pair was released on a pile of 100 seeds of Vigna radiata made in the test tube (1.4cm of radius and 16cm of depth). Number of eggs deposited on the surface of the seeds were counted after all the adults had died. C. maculatus laid its eggs much deeper than C. chinensis did, and even a largest female of C. maculatus could oviposit deeper than a smallest female of C. chinensis. This might be due to that C. maculatus had much slimmer and flatter body than C. chinensis. In C. chinensis the oviposition in a pile was limited to relatively upper zones irrespective of the body size. While, in C. maculatus smaller female oviposited deeper than larger one. In C. maculatus the proportion of abdominal length to body width and the relative fecundity to body size increased with absolute decrease of body size. While, in C. chinensis the correlations were vice versa.

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The onset of female calling behavior of both Adoxophyes sp. and Homona magnanima DIAKONOFF was delayed for 20 to 40min by the presence of conspecific synthetic female-sex pheromones on a piece of filter paper in a closed glass pot (10cm×11cm) under laboratory conditions. This effect was independent of dosage between 0.01 to 100μg. A similar delay in the calling behavior of the two species was also noted under out-door conditions when the air was treated with conspecific blends of synthetic pheromones at the rate of 1mg/day/m². In a wind tunnel, calling of the downwind females of both species was suppressed by the calling of upwind conspecific females for the initial 140min. The biological meaning of delayed calling was discussed.

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The life table studies were carried out during two years from April 1982. Population density of Plutella in the area of Tokyo was high during spring and late autumn but remarkably low in summer and winter. This feature of population fluctuations could be explained with the analysis of ten life tables obtained throughout a year. Such seasonal fluctuations related with action of natural enemies. Rapid decrease of the density seen in summer was principally caused by the rise in mortality of the eggs by an egg parasitoid and predation by ants. Vast increase in spring was considered to cumulate individuals by prolongation of development during winter in every stage under the condition in the absence of natural enemies.

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Distribution and turnover of phosphorus (total phosphorus; TP), nitrogen (total nitrogen; TN) and BHC in the forest burnt by fire and pine forest (not burnt) were examined in Mt. Furutaka, Edajima-cho (stands; burnt and not burnt forests) and Yasuura-cho (stand; burnt forest), Hiroshima Pref. in 1984. There was no remarkable difference in the bioconcentration and distribution of TP, TN and BHC between the forest stands. The same tendency was found in the bioconcentration of TP and TN between the forest stands, but the content of TN was about one hundred times as high as that of TP. There was large difference in bioconcentration between two kinds of salt (TP, TN) and BHC. The content of TP and TN increased as ecological niche of food chain became higher, whereas BHC residues was highly concentrated in litter.

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To investigate the effects of deep water culture of rice plants on the injury of the rice stem borer, Chilo suppressalis in its second generation, the rice plants were cultured in the water controlled 0, 5, 10, and 20cm-depth for 40 days from the beginning of September to the middle of October after the eggs and the first instar larvae were inoculated on the rice plants. The injury, number of larvae and yields were surveyed at the time of harvesting. Percentages of the stems injured in rice plants cultured in the water of 0, 5, 10, and 20cm-depth were 56.4, 66.0, 37.3, and 22.4%, respectively. That is, the injury of the second generation larvae decreased with depth of water except for 0cm-depth. The yields were inversely correlated to the percentages of stems injured. Similar results were obtained in the field experiments in which the water depth was controlled 1-5cm or 15-20cm. However, effectiveness of deep water culture on the yields was not observed, although the percentages of stems injured were significantly different between shallow and deep water culture. This result seemed to be due to low level injury of the rice stem borer in experimental plots.

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The efficiency of the traps baited with the synthetic sex pheromone which consists of three components ((Z)-11-hexadecenal, (Z)-13-octadecenal, (Z)-9-hexadecenal) was mainly compared with that of the light-traps in the rice stem borer moth, Chilo suppressalis WALKER. The attractivity of the pheromone-traps was very high in the both first and second flight seasons of moths. The number of moths caught in the pheromone-traps was about 3-5 times greater than that of the light-traps. The fluctuation pattern of moth catches in the pheromone-traps was similar to that of the light-traps. These results suggest that the sex pheromone would be of value for population monitoring in Chilo suppressalis.

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The effects of temperature on population growth of Thrips palmi KARNY were examined by rearing experiment at constant temperatures. The threshold temperature of development and the thermal constant for pre-adult stage were estimated to be 11.6°C and 189.1 day-degrees, respectively. The fecundity of female adult and the rate of oviposition per day became maximum at 25°C, and the values were 59.6 eggs and 3.8 eggs per day, respectively. The adult longevity and the generation time (T) became shorter as the rearing temperature became lower. The net reproductive rate (R₀) was maximum at 25°C. The intrinsic rate of natural increase (r) became higher as the rearing temperature became higher. The value was 0.144 at 30°C and the reproductive rate per month was 75.2.

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Synthetic sex pheromones used were those of the oriental fruit moth Grapholita molesta, the Asiatic leafroller Archippus breviplicanus, and the peach fruit moth Carposina niponensis. Actually no G. molesta were caught when their sex pheromones were placed side by side with those of A. breviplicanus in the same traps. A. breviplicanus was not caught in any of the traps set up. In either of G. molesta and Pammene nemorosa which were frequently caught in the G. molesta traps, curves depicting the trend in the cumulative percentage of daily catches in the summer and autumn did not show significant differences between Japanese pear and chestnut. This fact indicates that the dispersal activities of the males of both species can be traced over wide areas in different environments including chestnut trees, which are not the habitual host plants of G. molesta. It is suggested that in the summer and autumn, G. molesta males invaded extensively the Japanese pear plots studied, which consisted of young trees with a canopy thin. C. niponensis males were caught both in the Japanese pear plots and in a chestnut plot, although the total number of catches was small in all the plots.

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The susceptibilities of dicofol resistant and susceptible two-spotted spider mites, Tetranychus urticae KOCH to various pesticides were determined by a spray method. The resistant strain showed a high degree of resistance to many pesticides tested. Prothiophos, binapacryl, cyhexatin and a mixture of polynactins and BPMC were most effective against the dicofol resistant spider mites both in the laboratory test and in the field test. The cross resistance to dicofol was observed not only in di-allyl carbinol acaricides resemble to dicofol in its structure but also in organophosphorous insecticides.

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Distribution and turnover of total phosphorus (TP), total nitrogen (TN) and BHC in temperate zone forest ecosystems were analyzed in Taiwan (Chung Hsing Univ.; Huy Shun Experimental Forest, and Mt. Yushan Hsin Alishan and Chin Chung) and in Japan (Mt. Sobo; Takeda City, Oita Pref.) from May to November 1984. The results were as follows. There was no difference between the distribution of TP and TN at Huy Shun Experimental Forest and at Mt. Sobo, but the contents of TP and TN at Mt. Yushan were slightly higher than those at Mt. Sobo. The content of BHC at Mt. Sobo decreased with the elevation of the position of the ecological niche of the food chain, while, the distribution of BHC residues was different from that in Taiwan.

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[in Japanese]

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[in Japanese]

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