The control effect of anthocorid predators, Orius spp., against Thrips palmi KARNY on greenhouse eggplant was evaluated by releasing various numbers of predator nymphs and then examining the population fluctuations of the prey and the predators. When two, three and five last instar nymphs of the predators were released per plant, the total density of Orius spp. adults and nymphs reached 0.1, and the T. palmi density decreased to 0.6 per leaf several weeks after the release (regardless of the number of predators released). Both populations fluctuated around that density afterwards. I concluded that Orius spp. could successfully control the population of T. palmi for a long period. In such successful control, the percentage of injured fruits is estimated to be 10%, but it appears that it would be impossible to further lower the T. palmi density by increasing predator density.

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The age-related changes in the number of Bursaphelenchus mucronatus within its vector, adult Monochamus saltuarius, and an effect of B. mucronatus on the vector life span were investigated. Forty-three vectors were reared individually in containers under outdoor conditions. Pine twigs were supplied as food, and were renewed at five-day intervals. The number of nematodes carried by a vector continued to decrease as the vector aged. When a vector had carried 1, 000 or more nematodes at emergence, a rapid decrease was observed during a period between the 15th and 40th days after the emergence. It was observed earlier for some vectors carrying less than 1, 000 nematodes. The life span of the vectors ranged from 1 to 118 days. The life span was not affected by the number of nematodes carried, although there was an insignificant, negative correlation between them. B. mucronatus, which is avirulent against pine trees, usually has a low density of susceptible pine hosts in the forest because it can reproduce itself only in declining and newly killed trees. High transmission efficiency is necessary for the pathogen to persist at low host density. Effective transmission of B. mucronatus occurs after reproductive maturation of the vector. Thus, the absence of ill effect of B. mucronatus on vector longevity plays an important role in keeping transmission efficiency high.

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Nitrogen content of rice plants was compared among chemically fertilized, poultry-manured, non-fertilized and organically farmed rice fields to clarify factors of a comparatively lower population density of planthoppers in the latter. The nitrogen content of rice plants was found to be the lowest in the organically farmed field. The content of amino acids in the phloem sap of potted rice plants was compared between the chemically and the organically fertilized cultivations. The amount of total amino acids tended to be smaller in the plants from the organic cultivation. The content of the asparagine was significantly lower in the organically cultivated plants. In pot experiments, the survival rate of the nymphs of Nilaparvda lugens and Sogatella furcifera was lower in the organic plant than in the chemically cultivated ones.

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Insecticidal activity of Steinernema kushidai against Anomala cuprea larvae, feeding activity of A. cuprea larvae, survival of S. kushidai infective juveniles (J_III) and qualitative changes of the symbiotic bacteria were examined under six different temperature conditions (10-35°C at 5°C intervals). Mortality of A. cuprea larvae was 95, 100 and 85% at 20, 25 and 30°C, respectively, but significantly lower at 10, 15 and 35°C. Feeding amount of Quercus acutissima leaves by the 3rd instar larvae was significantly greater at 20, 25 and 30°C. Survival rate of J_III in water suspension was significantly higher at 10, 15 20 and 25°C and that in soil was also higher at 10, 15, 20, 25 and 30°C, respectively. The color of colonies and antibiotic characters in relation to insecticidal activity of symbiotic bacteria were not influenced by the temperature conditions during 10 and 35°C.

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The suppressing effect of mass trapping with a synthetic pheromone on the population of the sweet potato weevil, Cylas formicarius, was studied in a small sweet potato field in Okinawa, Japan. The traps captured 65, 214 males and 18 females from July, 1989 to December, 1990. In the pheromone-treated field, the sex ratio of the population largely skewed to female and the mating rate of females was reduced. The density of weevils was notably decreased in the pheromone-treated field, probably due to male annihilation and mating disturbance. Thus, mass-trapping is promising as a controlling agent against the sweet potato weevil.

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Relation between banding patterns of malic enzyme and a morphological character (ratio of length of ovipositor sheath to length of thorax) was investigated in Torymus species. In Torymus individuals that emerged from withered galls of Dryocosmus kuriphilus collected from five different localities in Japan, F or S type of banding patterns were detected. The morphological character indicated that there were two distinct groups in Torymus species : T. sinensis (large ratio group) and T. beneficus (small ratio group). The malic enzyme of T. sinensis was fixed on the S band while in T. beneficus only the F band was detected. Therefore, this enzyme is a useful hereditary index for investigating the interspecific competition and hybridization between these two closely related species.

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Seasonal population fluctuations of the imported cabbage worm Artogeia rapae (L.) and the diamondback moth Plutella xylostella (L.) were studied in southern Quebec (Canada) from 1984-1988, in nontreated check, permethrin and granulosis virus treated cabbage-plots. Timing of permethrin treatment based on an action threshold, equal to 57% of plants infested with larvae of either two species of the caterpillars, produced quality heads corresponding to the standards fro storage or fresh market. This threshold approximate one larva of A. rapae or P. xylostella per plant. A threshold of 87% of infestation (or about 3 larvae of A. rapae and 3.5 larvae of P. xylostella per plant) yielded cabbages marketable for processing. From one to three insecticide treatments a year were required with the 57% threshold, and one to two with the higher threshold. The granulosis virus of A. rapae (ArGV) was very effective to control this pest. The proportion of cabbages marketable for processing was not statistically different between ArGV and weekly permethrin-treated plots. As this virus is ineffective against P. xylostella, for fresh market in which cosmetic standards are more important, a mixture of ArGV and a half dose of permethrin yielded a high marketability crop.

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The immature development of Tabanus nipponicus was studied by laboratory-rearing. Total duration of oviposition-to-emergence was 337 ± 15 days (mean ± SD) in males and 364 ± 20 days in females. The number of larval instars ranged from five to seven, on average six in both sexes. The incubation period of eggs was three to five days. Eggs hatched simultaneously from the same egg-mass. Larvae attained the last instar in autumn. The developmental time of last instar including hibernation averaged 281 ± 13 days in males and 310 ±26 days in females over three quarters of the whole immature period. Pupal duration averaged 14 ± 3 days in both sexes. Male adults emerged from mid June to late July and females from early July to early September. This species was univoltine.

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Effects of rearing temperatures and development stages of Aedes albopictus SKUSE on susceptibility to Smittium morbosum SWEENEY were investigated in laboratory conditions. Mosquito larvae were perorally inoculated with S. morbosum trichospore suspension at 15°C, 20°C and 25°C. Rearing temperature was critical for this fungal infection of mosquito larvae : less than 10% of the 1st-instar larvae died at 25°C, whereas almost all larvae died at 15°C and 20°C when shorter than that for larvae reared at 15°C. The 1st-instar larvae were highly susceptible, whereas the 2nd-, 3rd- and 4th-instar larvae demonstrated little susceptibility.

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A continuously growing cell line was obtained from the culture of the pupal ovaries of the common cutworm, Spodoptera litura. The primary culture was initiated in MGM-450 medium fortified with 5% fetal bovine serum (FBS) and 3% Antheraea pernyi hemolymph heated at 60°C for 30 min. However, the cell line could grow in the MGM-450 medium with 10% FBS or in the MM medium with 3% FBS. The population doubling time was about 43 h in either medium at 25°C. The cells could be stored in the culture medium containing 10% glycerol at -100°C. The karyotype was typical to lepidopteran cell lines. The cell line was susceptible to S. litura nuclear polyhedrosis virus. The cell line could be distinguished from other cell lines derived from other insect species by comparison of the isozyme patterns of isocitrate dehydrogenase, malic enzyme, phosphoglucose isomerase and phosphoglucomutase. The cell line was designated as TUAT-SpLi-221.

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Gall parasitism by moth larvae of unisexual galls produced by Trichagalma serratae (ASHMEAD) in Nose, Osaka, Japan was surveyed by dissection of galls. Larvae or pupae of Andrioplecta pulverula (MEYRICK) and Characoma ruficirra (HAMPSON) were found in the galls. The two moth species did not significantly affect the survival of T. serratae on seven of the eight trees examined. Overall, attack by Megastigmus habui KAMIJO was the most important mortaliy factor for the gall wasp after gall initiation. Larval feeding habits of the two moth species were examined under laboratory conditions. A. pulverula larvae were able to feed on Q. acutissima leaves, but preferred unisexual galls of T. serratae. Some of the A. pulverula larvae boring into the galls fed on the larval cells and their inhabitants. The moth is therefore usually a cecidophage, but often becomes a predator of the gall wasp. Like A. pulverula, C. ruficirra larvae were able to feed on Q. acutissima leaves, but preferred T. serratae galls. However, the C. ruficirra larvae boring into the galls did not attack the larval cells, though they could feed on T. serratae larvae that had been artificially exposed. Thus, the larval cell wall of T. serratae functions as a barrier against C. ruficirra larvae. This moth is regarded as a commensal of T. serratae.

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Almost all the green rice leafhopper Nephotettix cincticeps UHLER placed on seedlings of Norin-PL6, a newly established leafhopper-resistant rice variety, died within 6 days. About 90% of nymphs placed on a related variety, Toyonishiki, survived and molted to further nymphal instars. Daily mortalities on Norin-PL6 seedlings were completely cancelled if the survived nymphs were transferred to Toyonishiki seedlings. A large amount of amino acids and sugars (mainly sucrose, glucose and fructose) were found in honeydew of adult males fed on Toyonishiki, but non-detectable or only faint levels were in those from Norin-PL6.

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The best method for collection and hatching of eggs of Aphis spiraecola was studied in the laboratory. Almost 80% eggs were deposited during the first seven days. Most eggs were obtained when the cotton cloth was used as the oviposition surface and aphids were maintained at 20°C. However, eggs on the cotton cloth did not pigment as fast as those on the filter paper, and the final percentage of pigmentation was lower on the cotton cloth than on the filter paper. In addition, eggs on the cotton cloth easily detached from surface when eggs were dipped in water. It is concluded that the filter paper is better surface for egg collection. The highest percentage of pigmented eggs (90%) gained when eggs on the filter paper were maintained at 14°C. Females with an artificial diet did not produce more eggs than those without it. Sterilization by 1% formaldehyde solution treated immediately after oviposition had the ill effect for the egg pigmentation. Prolonged pre-cooling incubation period at 14°C did not affect post-diapause development of eggs.

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The control threshold of Chilo suppressalis in terms of the pheromone trap catches was estimated in Okayama Prefecture. In both cases of infestation caused by the first and the second generation larvae, a significant linear relationship between the total number of moth catches by the pheromone traps and the proportion of subsequent injured stems of rice plants was obtained. In addition, significant correlations between the total number of moth catches by the pheromone traps and the egg-mass density, and between the egg-mass density and the proportion of injured stems were detected in both generations. Thus, it was possible that the rice plant damage could be estimated by the pheromone trap catches. The relationship between the pheromone trap catches up to the peak day and the proportion of injured stems was examined for each generation, resulting in also a significant linear relationship in each of the generations. From this relationship, the pheromone trap catches up to the peak day (i.e. a tentative control threshold) corresponding to a 5% yield loss of rice plants were estimated to be 56 and 144 for the overwintered and the first generation moths, respectively.

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The dynamics of sperms in the male reproductive organs during copulation was investigated with a nymphalid butterfly, Polygonia c-aureum. It was demonstrated that the males did not transfer all the sperms stored in the duplex to females by one mating. As soon as mating occurred, sperms in the duplex began to flow back to the middle vas deferens, but it seemed to stop on the way of mating. Sperms still remained in the duplex were then ejaculated to the female. This means that part of sperms existed in the duplex before mating were used for the insemination. Since sperms moved from the vas deferens into the duplex again shortly after mating, they probably could be used at the next mating. The significance of this sperm movement specific at mating is discussed.

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Seasonal population prevalence of aphids was investigated in a potato field at Hitsujigaoka, Sapporo, Japan (43°0'N, 141°25'E) from late May to late September in 1991 - 1993. The aphid species surveyed on potato were Myzus persicae (SULZER), Aulacorthum solani (KALTENBACH), Macrosiphum euphorbiae (THOMAS) and Aphis gossypii GLOVER. Immigration of A. solani and M. persicae started in late May or early June, and that of m. euphorbiae and A. gossypii in mid-June, and mid- to late June, respectively. A single peak of apterae in A. solani and M. persicae appeared in mid-June or early July. While some peaks of them in M. euphorbiae and A. gossypii appeared between late June and late August. Seasonal prevalence of alatae and alatoid nymphs showed that M. euphorbiae tended to produce more alatae than the other three species, and that only A. gossypii frequently immigrated into the potato field. Since few alatae were usually produced in the four aphid species in the field, emigration from the field must have been rare.

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Population fluctuations of aphids and their natural enemies were investigated in a potato field at Hitsujigaoka, Sapporo, Japan (43°0'N, 141°25'E) during the periods from late May to late September in 1991-1993. The aphid species mainly observed on potato were Myzus persicae (SULZER), Aulacorthum solani (KALTENBACH), Macrosiphum euphorbiae (THOMAS) and Aphis gossypii GLOVER. Main predators were Orius sauteri (POPPIUS) (Anthocoridae), Coccinella septempunctata bruckii MULSANT (Coccinellidae) and Harmonia axyridis (PALLAS) (Coccinellidae). The numbers of Chrsophidae, Cecidomyiidae, Syrphidae and other predatory arthropods were relatively small, except for spiders. The most abundant parasitoid was Aphidius gifuensis ASHMEAD (Aphidiidae), which attacked mainly A. solani and M. persicae. Aphids had the first population peak from mid-June to early July, declined rapidly from mid- to late July, and then had a second peak in the first half of August. The first peak was mainly constructed with A. solani and M. persicae and the second one with A. gossypii. The population fluctuation of coccinellieds (C. septempunctata bruckii and H. axyridis) closely related to the first peak and that of O. sauteri to the second peak. The first peak of aphids in 1993 was relatively higher than those in other years. This was considered to be caused by the late colonization of natural enemies due to low temperatures and much precipitation in June and early July in 1993. Aphid population dynamics seemed to be influenced by their natural enemies and weather conditions.

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Traps baited with male Leptoglossus australis (FABRICIUS) captured its egg parasitoid, Gryon pennsylvanicum (ASHMEAD), along with host adults. G. pennsylvanicum showed high parasitization of host eggs artificially set in a cucurbit plot where L. australis occurred but lower parasitization in eggs placed away from the plot. However, parasitization increased when caged L. australis males were placed next to the eggs. This indicates that G. pennsylvanicum uses chemicals originating from the host male as a kairomone in its host-searching process. A sign of the presence of the host male may help the parasitoid find host eggs- L. australis males attract conspecific females, which lay their eggs o host plants in the neighboring area, with a pheromone. The chemicals functioning as a kairomone for the parasitoid may be the pheromone of L. australis males, although experiments using a synthetic pheromone should be done for confirmation.

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Egg and nymphal periods and body size (body length and pronotal width) of emerged Orius sauteri (POPPIUS) adults were examined under 16 L : 8 D combined with four different temperatures : 15, 22, 25 and 30°C. First and second instar nymphs of Myzus persicae SULZER on potato leaflets were used as prey. The mean developmental time at 15, 22, 25, and 30°C was 15.2, 5.2, 4.3 and 3.1 days for the egg, 48.2, 14.7, 11.6 and 8.8 days for the nymph, and 63.4, 19.9, 15.9 and 11.9 days for the period from egg to adult emergence, respectively. The developmental threshold and effective accumulative temperature were calculated to be 11.0°C and 58.8 day-degrees for the egg, 11.3°C and 163.9 day-degrees for the nymph, and 11.4°C and 220.9 day-degrees for the period from egg to adult emergence, respectively. The body size of the female was always larger than the male at each temperature. The higher the temperature, the smaller the body size in both sexes.

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Toxicity of the supernatant from liquid culture of Bacillus thuringiensis serovar kurstaki strain KB500 was investigated with and without pellet against larvae of three lepidopteran species, the common cutworm, Sphodoptera litura, the diamondback moth, Plutella xylostella, and the smaller tea tortrix, Adoxophyes sp. using a diet incorporation method. Supernatant shoed a lower larvicidal activity than that of pellet or whole culture against all three insects tested. Interestingly, however, a strong synergistic effect was shown in the supernatant when mixed with pellet. This effect was detected on S. litura larvae only. The toxicity of the mixture of supernatant and pellet against S. litura was enhanced up to 32 times higher than that of pellet alone. The lower larvicidal activity and synergism in the supernatant might be derived from different substances. The former larvicidal activity could be explained by soluble δ-endotoxin in the supernatant but the latter synergism might be due to unknown substance(s).

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Using a newly devised simple apparatus, comparative study was made on the movement speed of three Bursaphelenchus isolates : S1, a pathogenic isolate of Bursaphelenchus xylophilus ; S0, a nonpathogenic isolate of B. xylophilus ; M, a nonpathogenic isolate of B. mucronatus. Among these isolates, the M isolate moved fastest through the interspace between glass beads in the apparatus at all nematode densities examined. The S1 isolate moved slightly slower than S0 isolate at low densities, however, the former moved more quickly at high densities. Generally, the time required for the half number of nematodes to pass through the apparatus doubled when the interspace between beads was reduced by half. The threshold low temperature for movement was lowest in the M isolate, followed by the S1 and S0 isolate. Regarding the S1 and M isolates, the threshold low temperature for movement was lower than those for development.

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Hydatothrips (Neohydotothrips) samayunkur n. sp. is described on the basis of both sexes and second instar larvae collected in Fukuroi, Shizuoka, central Japan. The species was first reported as Neohydatothrips variabilis from Hawaii, and now is also found in Florida and Okinawa. The differences between H. (N.) samayunkur and its close relative H.(N.) variabilis n. comb. are given. It only feeds on marigold (Tagetes spp., Compositae).

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Z, Z-6, 9-Heptadecadiene was identified as the alarm pheromone of a Tortonia sp. [Astigmata : Suidasiidae] (Kenaga-tsutsuhana-chibikonadani, in Japanese) found in the nest of Osmia cornifrons (RADOSZKOWSKI). The synthetic compound was active at 100 ppm. From the mite extract, two new hydrocarbons, heptadecatriene and heptadecadiene, were obtained. Their chemical structures were elucidated as 4, 8, 11-heptadecartiene and 4, 8-heptadecadiene either by partial hydrogenation and subsequent GC/MS analysis of their dimethyldisulfide (DMDS) derivatives or by GC/MS analysis of their DMDS derivatives. Configurations of their double bonds were determined as Z by synthesis, which was also supported by GC-FT/IR measurement. Z, Z, z-4, 8, 11-heptadecatriene and Z, Z-4, 8-heptadecadiene are revealed to be new compounds of natural products from astigmatid mites.

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Aphicidal activity of an insecticidal soap, M-Pede, on the green peach aphid, Myzus persicae, was observed under three different humidity conditions (30, 60 and 90% RH) in order to determine its practical value. The results revealed that humidity greatly affects activity : as humidity fell so did aphicidity. Reductions in activity under lower humidities were minimized by a high-dose application (0.6% AI) or by adding compounds which retard the solution evaporation, such as potassium acetate, glycerin, chondroitin sulfate sodium salt, sodium pyroglutamate, sodium polyacrylate, sodium carboxymethyl cellulose, xanthan gum, and sodium alginate.

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Octopamine elevated cAMP level in head membranes of common cutworm (Spodoptera litura) larvae in a concentration-dependent manner, indicating the activation of receptor-linked adenylate cyclase. Several octopamine analogues, in which the hydroxyl groups of octopamine are replaced by other groups such as a chlorine atom, also showed agonist activities comparable to that of octopamine. However, no activation was seen with norepinephrine and dopamine. The rank order of potency of known agonists was : naphazoline >__- octopamine >__- 2-(2, 6-diethylanilino)-2-imidazoline >__- de-N-methylchlordimeform > clonidine > tolazoline. Mianserin appeared to be the most potent antagonist, although clear differences in potency between tested antagonists were not observed. The head of larval S. litura appears to contain heterogeneous octopamine receptors, with properties somewhat different from those of other insects.

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Analysis of the dichloromethane extract of Parafontaria laminata armigera VERHOEFF (Xystodesmidae) revealed five components as possible defensive substances. The chemicals were identified as benzaldehyde, mandelonitrile, benzoyl cyanide, mandelonitrile benzoate and benzoic acid, among which mandelonitrile was the major constituent (ca. 83% of the total, on second major compound (ca. 16% of the total, on average). Quantities of each component differed between sexes. Males contained twice as much of these defensive compounds as females did, in spite of being smaller.

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A new species of the anthocorid bug, Wollastoniella parvicuneis, is described and illustrated. This species preys on Thrips palmi KARNY together with W. rotunda YASUNAGA et MIYAMOTO in eggplant gardens of the northern Thailand.

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Beauveria bassiana cultured on nonwoven fabric strips was applied in the field to control Monochamus alternatus larvae under the bark. In the summer, the strips with the fungus were placed using various methods on the bark of pine logs infested with M. alternatus larvae. Approximately 80% on average and a maximum of 100% of the larvae were infected and killed with the fungus using this method. Differences in mortalities between application methods of strips were not clear. This method was also effective for branches infested with M. alternatus larve. As an application method for B. bassiana to control M. alternatus larvae, the utilization of nonwoven fabric strips impregnated with the fungus was found to be more effective than ordinal spraying and more practical than the implantation of wheat-bran pellets containing the fungus which was developed previously by the authors.

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The Torymus (Syntomaspis) sinensis population established in an experimental chestnut orchard in Kumamoto, southwestern Japan, where the parasitoid was released in 1982, had not increased in six years following its release. However, it has increased since 1989 ; more than seven adults of the parasitoid emerged per 100 galls of the host cynipid, Dryocosmus kuriphilus, and the parasitism rate reached a level of ca. 17% in 1993. Although total parasitism by all parasitoids including native species tended to increase to ca. 41% in 1993, the tendency might not be caused by Torymus spp. but by native parasitoids other than Torymus (Syntomaspis) beneficus. The density of the host cynipid has not yet decreased but fluctuates at a high level. Two factors might play an important role in the delay in the increment of the introduced parasitoid ; the low female sex ratio during several years after establishment, and high mortality associated with the activity of native facultative hyperparasitoids.

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Fluorescence in situ hybridization (FISH) has been used as the technique for gene localization on chromosomes of Bombyx mori. This is particularly useful due to the difficulty in constructing chromosome maps in Bombyx mori. We could detect r DNA as one large cluster on pachytene and metaphase chromosomes at the first meiosis and the interphase nucleus of the spermatocyte using fluorescein isothiocyanate (FITC). A single copy gene, egg specific protein (ESP) gene, was detected using 7-amino-4-methylcoumarin-3-acetic acid (AMCA).

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Effects of a trehalase inhibitor, validoxylamine A (VAA), on the activity and haemolymph components were studied in three species of flies, Musca domestica, Boettcherisca peregrina and Calliphora nigribarbis. Haemolymph components were analyzed by NMR spectrometry. Overall activity of the housefly was suppressed by VAA injection (2.5 μg/fly) and 30% of them died in 2 days. The activity of the fleshfly also decreased but without death (2μg/fly). VAA injection (5 μg/fly) acted, however, stimulatively rather than suppressively on the blowfly flight. Trehalose concentration in the haemolymph rose by VAA injection in a day to 2.6, 3.3 and 3.7 times in M. domestica, B. peregrina and C. nigribarbis, respectively. The trehalose accumulation seemed to be caused by inhibition of trehalose metabolism and by active synthesis of the trehalose from glucose by inhibition of trehalose metabolism and by active synthesis of the trehalose from glucose which was not affected by VAA injection. The result that inhibition of trehalose metabolism did not evoke the reduction of the flight activity in the blowfly, suggests the use of alternative energy source in its body.

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