Hibernation sites of adult olive weevils, Dyscerus perforatus (ROELOFS) were surveyed from January to March in four olive orchards where pest controls had not been used for more than 5 years. The olive tree trunks and branches, and the ground within 1m from each trunk base were surveyed. The ground at three of the four orchards was completely covered with weeds and fallen leaves and many emergence holes were found on all the olive trees surveyed in these orchards. The number of hibernating adults found in the survey area of living trees ranged from 16 to 117 per tree, whereas only two hibernating adults were found on and around a dead tree. Most hibernating adults were found on the ground surface within 50cm of the trunk base. The ground at the other orchard was sparsely covered with weeds and fallen leaves. In this orchard, only a small number of emergence holes were found on each olive tree and two hibernating adults were found at most in the survey area.

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The seasonal and annual prevalence of adult spotted cutworms in the Tokachi district of Hokkaido was investigated with a light trap from 1973 to 1986. The average date for 50% capture was June 28 for the overwintering generation and September 3 for the first generation. The average number of adults captured the 757 for the overwintering generation and 5, 900 for the first generation with two distinct seasonal peaks for the separate generations. The hypothetical zero point and effective heat accumulation were obtained by minimizing the coefficient of annual variation in the heat accumulation until the date of 50% moth capture by the light trap. This afforded better prediction of the dates for both the overwintering and first generations than for experimentally-reared ones. There was high correlation between the number of captured overwintering-generation adults and the total precipitation in October and December of the previous year. The relationship is expressed by the multiple regression equation, Y=2.475-0.804X₇+1.175X₉ (R²=0.838), where Y, X₇, and X₉ represent the trapped adult number and precipitation in October and December as logarithmic values, respectively. This equation estimates the real adult number with good accuracy. However, in the first generation, the correlation between the adult number and meteorological factors was not so high.

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The relationship between feeding and gustatory responses to plants was investigated in the silkworm larvae, Bombyx mori L. The leaves of nine plant species, Morus alba, Cudrania triloba, Ulmus pumila, Lactuca laciniata, Ricinus communis, Ailanthus altissima, Prunus donarium, Quercus acutissima and Liquidambar formosana, were used in the experiments. The feeding responses to aqueous leaf-extracts in an agar diet were examined. The response to M. alba was strongest; C. triloba came second. Next in order were U. pumila and L. laciniata. No response was found to R. communis, A. altissima, P. donarium, Q. acutissima and L. formosana.
In electrophysiological studies, the frequencies of the L_S-impulse (basic feeding stimulation signal), L_I-impulse (synergistic signal for feeding stimulation), and R-impulse (feeding deterrence signal) were used as indices of the gustatory response to the aqueous leaf-extracts. The results could be classified into four types: L_S-L_I, L_S-L_I-R, L_S-R, and R. The feeding responses of the silkworm larvae were influenced by the reciprocal interactions between the L_S-impulse, L_I-impulse and R-impulse. A “bitter substance” both activated the R-receptor as a feeding deterrent and inhibited the sensitivity of the L_S-receptor.

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The aerial concentration of a synthetic sex pheromone component (Z-11-tetradecenyl acetate) and the mating ratio of tethered females of the smaller tea tortrix were measured under field conditions. The aerial concentration of the pheromone component and mating ratio show a logarithmic linear relationship. The aerial concentration of the synthetic pheromone component should be more than 20ng/m³ to suppress the mating to less than 30%.

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Argopistes coccinelliformis is usually a univoltine species and the newly-emerged adults enter diapause under the field conditions in southern Kanto, central Japan. Adults deposit eggs on new sprouts or leaves of host plants but not on mature leaves. Some newly-emerged adults, however, could oviposit when supplied with new leaves soon after eclosion. Adults prefer new leaves to mature ones regardless of the season. This evidence suggested that some of the beetles may be multivoltine. Oviposition was interrupted when mature leaves were supplied but was resumed when new leaves were supplied again. No eggs were found in the ovaries of adults during the periods of interrupted oviposition. The beetles seem to use the food condition as a cue to the suitability of the environment for oviposition.

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The developmental characteristics of larvae of the box-tree pyralid, Glyphodes perspectalis (WALKER), were studied under various laboratory conditions with special reference to the number of instars and developmental period. When reared on the box-tree, Buxus microphylla, under continuous light conditions at 25°C, larvae developed continuously and had 6 instars, each lasting about 3 days except for the final instar (ca. 8 days). At 20°C, some larvae went through only 5 instars before pupation. However, when larvae were fed on other host plants, B. semipervirens and B. microphylla var. insularis, a few 7th instars appeared. At a photoperiod of 12L-12D, most larvae entered diapause at the 4th instar and a few did so at the 5th. More diapausing 5th instars were observed at 15°C or 25°C. The proportion of larvae entering diapause at the 5th instar increased with photoperiod at 20°C. Such individuals underwent a stationary molt in the cocoon and the shed head capsules were smaller than those of non-diapause larvae at the same instar. Overwintered larvae pupated after 3 or 4 ecdyses in the laboratory, suggesting that they had a total of 7 larval instars.

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A toxicity test was conducted in search of a combination of insecticides that is effective against an organophosphorus-resistant strain of housefly. Remarkable potentiation was exhibited when diazinon was paired with carbofuran. The potentiation was greatest when the two compounds were mixed at the ratio of their LD₅₀. However, diazoxon coupled with carbofuran showed little potentiation. Since carbofuran does not inhibit degradation of diazoxon, it seems that diazoxon degradation is not involved in the potentiation between diazinon and carbofuran. When a mixture of diazinon and carbofuran was injected into houseflies, diazinon at a concentration below the LD₅₀ inhibited carbofuran degradation, decreasing the first order rate constant 3.4 times for the carbofuran disappearance. A comparison of the rate of deacylation of acylated acetylcholinesterase produced in vivo by application of a mixture of diazinon and carbofuran and that produced in vitro by diazoxon or carbofuran, showed that the in vivo inhibition of acetylcholinestcrase is mainly caused by carbofuran. From these results, it is reasonable to conclude that the potentiation is attributable to an increase in the internal concentration of carbofuran, which inhibits more acetylcholinesterase, resulting from inhibition of carbofuran degradation by diazinon at sublethal concentrations.

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The mortality of Homona magnanima pupae was investigated at the tea gardens in Mizuho and Fuchu, Tokyo from 1989 to 1990. Two species of chalcids, Brachymeria lasus and B. excarinata, 6 species of ichneumonids, Itoplectis alternans spectabilis, Coccygomimus disparis, C. luctuosus, C. nipponicus, Agrothereutes lanceolatus, and Scambus vulgaris, 2 species of tachinids, Zenillia dolosa and Bessa parallela, and an entomopathogenic fungus, Erynia radicans were reared from the pupae collected from both sites. The ichneumonid, Phaeogenes sp., a cytoplasmic polyhedrosis virus, and an entomopox virus were recorded only at Mizuho. The mortalities due to these factors changed with time and locality. The highest mortalities caused by parasitic wasps, tachinids. E. radicans, and viruses were 68.8%, 17.9%, 15.8%, and 4.0%, respectively. The species structure of the parasitoid complex differed among host generations: I. alternans spectabilis and C. disparis were the major species in the overwintering generation, while B. lasus and B. excarinata were dominant from the 1st to 3rd generations.

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The susceptibility of diamondback moths Plutella xylostella collected from three sites in Osaka prefecture to BT formulation (Toarro CT^®) was determined by the leaf-dipping method using 3rd instar larvae. Larvae from a greenhouse growing watercress in the Kohno area have shown a high level of resistance (LC₅₀>280ppm) to the insecticide from October 1988. The development of high BT resistance in the Kohno population has probably occurred because watercress is grown throughout the year with frequent spraying of the BT formulation (15-20 times a year) and also because there is very little immigration of the moth into the greenhouse.

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The diurnal searching activity of adult Ascogaster reticulatus WATANABE (Hymenoptera: Braconidae) was observed in a tea field by walking along the rows of tea plants and capturing all adult parasitoids found on the plants. The peak number of insects was collected at 07:00 or 08:00 and the number decreased in the late morning to afternoon. The sex ratio of these adults was male-biased (86% male). Adults spent most of the time in searching by walking on leaves rather than by flying from leaf to leaf. The average flight distance between leaves was about 15cm. The tendency to spend a lot of time in searching on a leaf is well correlated with the oviposition and mating behavior of this species.

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