Dacne picta is one of the most important pests of cultivated shiitake mushrooms (Lentinula edodes) in Japan. To clarify the preferential oviposition of adults among different growing stages of mushrooms, survival and development of offspring, a census was taken in a cultivated field of the mushroom. Fruiting bodies of mushrooms were classified into three stages : growing, mature and decaying stages. A large number of adults and eggs were observed in and on the growing and mature stages of mushrooms, but few were observed on the decaying stage. Adult beetles, thus, disappeared from the mushrooms when they started to decay. An inoculation experiment of adult beetles on mushrooms revealed that the mortality of first stadium larvae was much higher in the decaying stage of the mushrooms. Rearing experiments on powdered mushrooms suggested that chemical inhibitors and/or nutritional deficiency was an important cause for the higher mortalities of the 1st stadium larvae. However, the hardening of decaying mushrooms may have prevented hatched larvae from actually consuming them. Thus, the mushroom stage chosen by ovipositing adults is closely related to the mortality of hatched larvae.

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A proteinous factor inhibiting the growth of the adzuki bean weevil (Callosobruchus chinensis L.) was separated from the seeds of Vigna mungo L. Hepper (urd bean), by sequential fractionations with ammonium sulfate, chromatographies on DEAE-cellulose, hydroxyapatite and Q-Sepharose columns. The proteinous factor was further purified to homogeneity by chromatography with a Mono-P column. The purified factor was a 40-kDa single polypeptide, as determined by SDS-PAGE, and heat-1abile but stable over a pH range from 4 to 6. It is noteworthy that this factor showed neither α-amylase and protease inhibitor activities nor lectin activity, in contrast to other growth inhibitors with those activities against bean weevils. The growth inhibitory activity was lost by respective digestions with α-chymotrypsin and subtilisin, indicating that the 40-kDa protein was a novel growth inhibitor in urd beans against the adzuki bean weevil.

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A monitoring experiment and a small scale mating disruption trial were carried out to investigate the potential value of the synthetic sex pheromone of the oriental tobacco budworm, Helicoverpa assulta (Guenee) (Lepidoptera : Noctuidae). The pheromone trap was more effective in detecting the field population than the black-light trap. The treatment with controlled-release PVC resin dispensers loaded with synthetic sex pheromone, applied at a rate of 30 g/ha in a hot pepper field, resulted in significant reduction of trap catches, indicating effective disruption of pheromonal cpmmunication of H. assulta in the field. The disruptive effect of the PVC formulation lasted for one month in the field.

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We investigated levels, genetic traits and stability of resistance to Bacillus thuringiensis in the Bang Bua Thong (BS) colony of the diamondback moth, Plutella xylostella, collected in Thailand. The BS colony exhibited 668 and 66.5-fold resistance to formulations derived from B. thuringiensis subsp. kurstaki (ToarowCT^[○!R] and B. thuringiensis subsp. aizawai (XenTari^[○!R], respectively. In order to determine the genetic traits of resistance, two reciprocal crosses and their offspring were checked for sensitivity to B. thuringiensis using the laboratory susceptible (H) and the resistant BS colonies. Analysis of the dose-mortality relationship of their progeny suggested that resistance to B. thuringiensis in the BS colony might be polyfactorial. Susceptibility to B. thuringiensis (ToarowCT^[○!R] and XenTari^[○!R] in the BS colony was not quickly restored in the absence of B. thuringiensis selection.

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Factors determining the density of aphid galls on individual host trees were examined in two closely related aphid species, Tetraneura yezoensis and T. radicicola, sharing the same primary host, Ulmus davidiana var. japonica. Gall density on a host tree is mainly determined at two stages of the life cycle: 1) host selection by autumnal migrants that fly from the secondary host, and 2) gall formation by nymphs the next spring. The density of autumnal migrants landing on each host tree and the galling success on the trees were determined, and relative gall density was predicted by multiplying the two factors. In both species, the regression of observed gall density on predicted density was highly significant. However, the main factor affecting gall density varied between the two species. In T. radicicola, host preference of migrants was mainly responsible for inter-tree variation in gall density. Migrants of this species avoided some trees on which the galling generation could have successfully induced galls. In T. yezoensis, gall density was mainly determined by inter-tree differences in galling success. The difference between the two species in host adaptation probably results from their historical relationships with U. davidiana.

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The cuticular chemicals of the cockroach, Nauphoeta cinerea, that depress wing-raising activity in adult males were characterized from the cuticular wax of post-teneral-stage last-instar nymphs. Using spectral methods, the chemical structures of the depressants were determined to be a mixture of cis-25, 26-epoxy-29-methylpentacontadiene and five cis-25, 26-epoxyhenpentacontadienes. The mixture was considered to function as a nymph recognition pheromone by conspecific mature adult males through antennal contact.

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The effects of entomopoxvirus infection in Pseudaletia separata on the development of a pupal parasitoid, Brachymeria lasus, were investigated under laboratory conditions. Surviving fifth-stadium P. separata larvae infected with the P. separata entomopoxvirus (PsEPV) exhibited extended developmental time in the prepupal phase after molting to the last stage. Although about half of the PsEPV-infected larvae pupated, greater than half of those pupae were incompletely pigmented in the first abdominal segment and failed to develop into adults. Infection of P. separata pupae with PsEPV was detrimental and adversely affected the development of B. Iasus. Parasitoid emergence was inversely related to prepupal duration. Significantly fewer parasitoids emerged from PsEPV-infected pupae, and these parasitoids spent an additional day or two in pupae with a longer prepupal phase. This lower rate of survival was due to a large number of parasitoid imagos having died in the PsEPV-infected pupae, which was a function of prepupal duration. There was little or no growth in parasitoids developing in PsEPV-infected pupae with a longer prepupal phase.

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Genetic bases of several traits of the soldier-producing aphid Pseudoregma bambucicola (larval period, reproductive age, adult body size, colony fitness, and proportions of adults, alates and soldiers) were examined by quantitative genetic analyses with particular reference to colony-1evel stabilizing selection on soldier proportion. Five aphid clones were grown on Bambusa multiplex shoots that were clonal but of different ages. The age of the shoot was regarded as an environmental factor affecting aphid fitness. Mixed model ANOVA detected no significant effects of genotype and genotype-environment interaction on colony fitness, whereas the fitness was higher on younger hosts. This suggests that no single clone exceeds other clones in fitness in all environments. While a significantly larger amount of genotypic variance was detected in body size and adult proportion, the soldier proportion exhibited less genotypic variance. This result suggests that the soldier proportion is intimately associated with fitness and is under strict stabilizing selection. A negative genetic correlation was detected between soldier proportion and colony growth. This also suggests that stabilizing selection has operated on soldier proportion so as to maintain eusociality in P. bambucicola that lacks kin recognition.

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Two techniques were used to discriminate between second instar Orius minutus (L) and Orius sauteri (Poppius) which occur sympatrically in eggplant fields of Japan. Isoelectric focusing (IEF) was used to discriminate between the two species utilizing the enzyme isocitrate dehydrogenase (IDH). Moreover, IEF was also shown to detect the presence of the prey Thrips palmi Karny in O. sauteri nymphs immediately after feeding by using phosphogluco-isomerase (PGI). PCR generated internal transcribed spacer I (ITS-1) regions for nymphs of both species were also diagnostic as the O. minutus PCR product was much larger than the O. sauteri PCR product (900 vs. 600 bp). Moreover, by comparing ITS-1 PCR product sizes and using the restriction enzyme HinfI on ITS-1 products of similar size to pr.oduce restriction fragment length polymorphisms (RFLPs), consistent differences among five Japanese Orius species were also demonstrated.

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The host plants of Epilachna vigintioctopunctata in the Southeast Asia region are still not fully known. Larval survival and development of E. vigintioctopunctata on solanaceous, cucurbitaceous and leguminous plants were examined for seven local populations from Japan, Thailand, Malaysia and Indonesia. All populations showed the highest emergence rate and largest adult body size when reared on plants of the genus Solanum (Solanaceae). On Cuccinia indica (Cucurbitaceae), the Malaysian population had an emergence rate of 32% and the Thailand and two Indonesian populations each had an emergence rate of ca. 10%. However, newly emerged adults of these four populations were not able to produce the next generation when reared on C. indica because of very low fecundity and hatchability. On Centrosema pubescens (Leguminosae), the Malaysian and two Indonesian populations each had an emergence rate of ca. 30%. Newly emerged adults of these three populations showed 62 to 72% hatchability when reared on Ce. pubescens. It is concluded that the major host plants of E. vigintioctopunctata in Southeast Asia are solanaceous plants and this species is unable to complete its life cycle solely on cucurbitaceous plants.

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The hazelnut beetle (Balaninus nucum L., Coleoptera : Curculionidae) is the single greatest source of damage to hazelnut fruits throughout the world. It causes approximately 30-40% of the total economic damage to hazelnut products per year in Turkey. In this study, we investigated the bacterial fiora of the hazelnut beetle collected from the vicinity of Trabzon (Turkey) during 1995-1997 and tested them for insecticidal activities. The number of total bacteria in larvae (1.8×10⁹ cell/1arva) and adults (1.41×10¹1 cell/adult) was identified. Based on colony colour and morphology, five isolates were identified. According to morphological, physiological, biochemical and molecular characters of the isolates, they were identified as Bacillus thuringiensis. Pseudomonas fluorescens. Micrococcus luteus. Serratia marcescens and Escherichia coli. The insecticidal activities of these bacterial isolates on third-stadium larvae of B. nucum were investigated. The highest insecticidal effect determined on B. nucum within three days was 100% with S. marcescens. The effects of the rest of the isolates are 45% for B. thuringiensis, 20% for P, fluorescens, 30% for M. luteus and 25% for E. coli.

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We investigated the infiuence of physical factors, i.e., texture, color, shape and size, on host selection of the tachinid fiy, Exorista japonica, using various host models in choice tests. Female flies approached and examined equally semi-cylindrical black rubber tubes, paper tubes and silicone tubes of the same size, 4.0 ×1.0×0.5cm, but oviposited only on the black rubber tubes. They examined black tubes more frequently than white tubes. They did not examine black rubber sheets but they did examine black rubber cubes. Also, female fiies preferred models of small diameter (0.8>1.0>1.2cm) and those that were longer (2.0<4.0<6.0cm). These results indicated that female fiies recognized a target's color before examination, and the texture and curvature of targets by tarsal examination. E, japonica females appear to have a host size preference.

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Methyl anthranilate and 15 related compounds were evaluated for their attractiveness to, and electroantennogram (EAG) activity in the adult soybean beetle, Anomala rufocuprea. When combined with the female sex pheromone, six methyl benzoate derivatives, i.e. methyl anthranilate, methyl m-aminobenzoate, methyl benzoate, methyl salicylate, methyl o-toluate and methyl o-anisate, exhibited significantly higher attractiveness than a single application of the sex pheromone alone, with methyl anthranilate exhibiting the highest activity. EAG responses of the male antennae varied between the compounds in the amplitude range of 0.07-0.28 mV, all of which were much lower than the response to the female sex pheromone. The relationship between EAG amplitude and chemical structure was not clear, but a positive correlation between the EAG responses and volatility was shown (r=0.903). Methyl anthranilate, the most attractive compound tested, gave an average amplitude level in the EAG : 0.14 mV. For the tested compounds, EAG responses did not correlate with attractiveness for the adult A. rufocuprea.

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Heleanna fukugi Nasu, n. sp., the larvae of which cause damage to Garcinia subelliptica Merr., is described from Japan (Ryukyu). The adult, genitalia and immature stages are illustrated. The biology is briefly summarized.

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Labiate plants, such as spearmint, thyme and rosemary, inhibit the settling of Myzus persicae (Sulzer) on them. The effects of their essential oils on the aphids' behaviors are little known thus far. In this study, the antifeeding, settling inhibitory and insecticidal activities of 10 labiate oils were investigated. On EMIF (electronic measurement of insect feeding behavior), 8 of the ten oils (rosemary and sage oils were exceptions) significantly reduced the total penetration time, average penetration time, and maximum penetration time, and increased the frequency of penetration. In the no-choice test, aphids rarely settled on the sealing film which covered the diet containing spearmint or thyme oil and most died. In the toxicity test, pennyroyal and thyme oils indicated relatively high toxicities while toxicities of the other oils were low. In the choice test, all 10 oils exhibited settling inhibitory activities. Spearmint, thyme, pennyroyal, mint and peppermint oils had especially high activities. Although the mechanisms of the settling inhibition differed among the oils tested, all the oils inhibited the aphids from settling under the choice condition. Labiate essential oils may play a role in deterring aphids from settling on these plants by effecting the aphids' gustatory and/or olfactory sense.

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Ice nucleus production of larvae of the rice stem borer, Chilo suppressalis Walker has been observed to be related to diapause and cold temperature exposure. To determine the effects of insect hormones that regulate larval diapause on ice nucleus production, non-diapausing mature and overwintering (diapausing) larvae were treated with juvenile hormone (JH) and ecdysone. When JH-I was applied, the crystallization temperature of the muscle and epidermis rose in non-diapausing mature larvae, but not in overwintering larvae, which might contain highly endogenous JH. However, injection of 20-hydroxyecdysone lowered the crystallization temperature in overwintering larvae. These results show that ice nuclei in the muscle and epidermis are activated by JH and inactivated by ecdysone.

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This study examined the distributions of the pre-calling period (PCP) and the time at which calling starts in three Japanese Helicoverpa armigera populations collected from Ushimado and Souja (both in Okayama Prefecture) and Ishigaki Island (Okinawa Prefecture) in September 1996. Around 50% of the females called at night 2 (the night of eclosion of a female moth was designated at night 0), although the range of the calling occurred from night 1 to night 6. However, the distribution of the PCP was significantly different among populations. The Souja moths called significantly earlier than the Okinawa and Ushimado moths. About 75% of the Ushimado and Souja moths started calling in the last 2 h of the night while the start of calling by the Okinawa moths was almost uniformly distributed in the 2nd half of the night. The start of calling by the Okinawa population (average=5.9 h after lights-off) was significantly earlier than the Souja and Ushimado populations. These results suggested that there are genetic variations in the PCP and the starting time of calling among local populations of H. armigera in Japan.

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Three temperature-sensitive (ts) mutants of Bombyx mori nucleopolyhedrovirus (BmNPV), designated as ts-S2, ts-S3, and ts-S4, were isolated, based on a lack of or reduced polyhedra production at a non-permissive temperature of 33°C. Each mutant was characterized at a permissive temperature of 25°C and at 33°C, and at a dose of 7.2 TCID₅₀/cell. Viral DNA synthesis in BmN4 cells infected with ts-S2 was defective at 33°C, but partially defective at this temperature in BmN4 cells infected with ts-S3 and ts-S4. Production of budded virus and polyhedrin synthesis in cells infected with ts-S2 were severely diminished at 33°C, but only slightly reduced in cells infected with ts-S3. For ts-S4, production of budded virus was partially defective and polyhedrin synthesis was completely defective at 33°C. These distinct phenotypes among the 3 ts mutants were complementary to each other in recovering the wild-type characteristics in culture when BmN4 cells were coinfected with a pair of ts mutants, demonstrating that these were distinct ts mutations. Marker rescue tests to identify ts mutations of the mutants showed that ts-S2 possessed a ts mutation within an ORF for a putative DNA helicase gene, and both ts-S3 and ts-S4 possessed multiple ts mutations in separate regions of the genomes.

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Larvae of Trichoplusia ni, Helicoverpa zea and Heliothis virescens were assayed for their relative suscepti-bility to in vitro produced, nonoccluded virus (P^-NOV) from a deleted polyhedrin-gene strain of the nucleopolyhedroviruses of Autographa californica (P^-AcMNPV) and Helicoverpa zea (P^-HzSNPV). There was a 90-fold difference in P^- NOV activity (LC₅₀ values based upon TCID₅₀/mm²) between P^-AcMNPV (vs. T. ni) and P^-HzSNPV (vs. H. zea) when each virus was assayed against its respective permissive host. These differences in P^-NOV activity were within the same range one would expect based upon their reported LC₅₀ values and the estimated numbers of virions embedded in occlusion bodies (OB) of the wild-type (Wt) isolate of these viruses. Differences in LC₅₀ values (TCID₅₀/mm²) between P^-NOV of P^-AcMNPV and P^-NOV of P^-HzSNPV using H. virescens larvae (a permissive host susceptible to both viruses) however, were much greater ( > 300-fold) than expected if based upon the number of virions/WtOB. Closer agreements in LC₅₀ values between P^-NOV and occluded viruses of WtOB were obtained for H. zea or H. virescens larvae exposed to P^-HzSNPV (ca. 1.3-fold difference) or H, zea and H. virescens larvae exposed to P^-AcMNPV (ca. a 15-fold difference). Results using a non-susceptible host (P^-NOV of P^-HzSNPV vs. T. ni) or a semi-permissive host (P^-NOV of P^-AcMNPV vs. H, zea) generally agreed with previous citations using occluded virions of WtOB.

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Male hairpencil scent of Conogethes punctiferalis was analyzed and its function was studied. A component detected by GC-EAD, was identified as (E)-2-methyl-2-butenoic acid (tiglic acid) by GC, GC-MS. Males had no tiglic acid right after emergence but tiglic acid concentrations increased to an average of 1-2 μg/male by 2 weeks. Males with hairpencils from which tiglic acid was washed away by hexane and with removed hairpencils showed significantly lower mating success than control males. Less mating success occurred in females antennectomized bilaterally and normal males than with normal pairs. Tiglic acid was concluded to be a sex pheromone which functions in conspecific male recognition and also may be important as an aphrodisiac pheromone. Small numbers of males were attracted to hairpencil extracts or tiglic acid in a wind tunnel, but females showed no orientation or attraction to tiglic acid.

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A simple method for collecting eggs of the oriental chinch bug, Cavelerius saccharivorus Okajima, was developed using an artificial ovipositional substrate which consists of a small glass test tube and a piece of laboratory film. To examine the efficiency of egg collection using this method, the average total number of eggs collected per female, the average survival period of adults of her introduction to the egg collection device, and the average egg-1aying period from the first to the last oviposition were compared between the artificial substrate and the cut spindle (the upper soft part of the sugar cane stalk excluding the leaf blades) which is the natural oviposition substrate of the chinch bug. There was no significant difference between the two substrates in average survival period or average egg-laying period. However, the average total number of eggs collected per female on the artificial substrate was about twice that collected on the cut spindle. The findings demonstrate a high efficiency of this new method using an artificial ovipositional substrate.

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The p143 gene of the Spodoptera exigua multinucleocapsid nucleopolyhedrovirus (SeMNPV) Il isolate was cloned and sequenced. This process revealed a 3, 666-nucleotide open reading frame (ORF), which encodes a deduced 1, 222-amino acid polypeptide with a molecular weight of 143, 285 (P143). The SeMNPV 11 P143 possessed seven consensus motifs conserved in members of the superfamily of DNA or RNA helicases. Seven amino acid substitutions were identified, when compared with the P143 of the SeMNPV US isolate. Of the seven substitutions, six were localized within the amino acid residues from 484 to 547. The deduced amino acid sequences in this region were compared among five geographically distinct isolates after amplification by PCR. The results showed that these were identical with that of the I1 isolate. SeMNPV I1 P143 had approximately 40% identities and more than 66% similarities to other NPV DNA helicases. However, the carboxyl-terminus region including the consensus motifs was identical within the SeMNPV isolates and relatively conserved among four NPVs.

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In the brown planthopper, Nilaparvata lugens, triacylglycerol (TG) content and its fatty acid composition were analysed by GLC and compared during three days after the final moult. This analysis compared long and short-winged morphs, which were derived from predominantly macropterous and brachypterous strains, and allowed to feed but not mate. For both sexes, the levels of TG on a dry weight basis in the long-wing form were 1.6 times higher shortly after adult eclosion for both sexes than those in the short-wing form. The ratios of TG content between the two wing-morphs increased to 2.8 times for females and 3.7 times for males two days after eclosion, the stage estimated to be the most adapted to migration. Thus the macropters apparently store considerably more fuels for fiight than the brachypters. In female macropters, TG per dry weight decreased slightly during the pre-feeding period but returned to the initial level two to three days later due to feeding, possibly providing energy for migration. In contrast, TG Ievel per dry weight in brachypters continuously declined, maintaining TG content per individual with gradual weight gain during this period, suggesting the storage of materials other than TG by feeding for ovarian development. In males, TG Ievel declined more in brachypters than in macropters, possibly refiecting greater adaption for copulation in the former and migration in the latter. Fatty acid compositions of TG were essentially the same for both morphs and also both sexes at the time of adult emergence, but the composition in brachypterous males changed greatly after one to two days of adult life.

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The cuticular hydrocarbons of Reticulitermes from Japan and neighboring countries were identified and quantitated. Three distinct phenotypes were revealed by gas chromatography of hydrocarbons among five subspecies of R.speratus : (1) three subspecies from the Japanese mainland, (2) R.s.okinawanus, and (3) R.s. yaeyamanus. Hydrocarbon components of R. flaviceps flaviceps differed from those of R. f. amamianus. R. miyatakei. R. sp. 1, R. sp. 2, and R. sp. 3 have components specific to each species. The overall results revealed that there are nine cuticular hydrocarbon phenotypes in the genus Reticulitermes occurring in Japan and neighboring countries. It also appears that some morphological characters usually used in taxonomy are of little taxonomic value.

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The occurrence of Epilachna pusillanima was confirmed on Ishigaki Island, the Ryukyus, southernmost Japan, in June, 1997. This is the first record of the species from Japan. E. pusillanima infested two cucurbitaceous weeds, Trichosanthes bracteata and Trichosanthes sp. I, but was not observed on cucurbitaceous crops, though it is known as a notorious pest of cucurbits in Southeast Asia. E. pusillanima is externally similar to another cucurbit feeder, E. boisduvali, which also occurs on Ishigaki Island, in that both have 12 spots on the elytra and similar body size. However, the two species are easily distinguished by 1) the structure of the genitalia of both sexes, 2) the color and maculation of prepupae and pupae, and 3) diet. Results of a mate choice experiment suggest that E. pusillanima and E. boisduvali are reproductively isolated by ethological isolation and/or gametic isolation.

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