For the purpose of sampling oribatid mites, floors of six natural forests in Hokkaido were stratified. These natural forests included Gm (Picea glehni-moss), Gr (P. glehni-Ph. communis), Gs (P.glehni-Sasa amphitricha), Fs (Fagus crenata-S.paniculata), Fm (F. crenata-S. nipponica) and Th (Thujopsis dolabrata-S.paniculata). In each forest, samples were collected from five kinds of materials, namely, M1 (bark), M2 (moss), M3 (fallen plant materials such as twigs and cones), S1 (0-5 cm soil layer), and S2 (5-10 cm soil layer), from each plot Species of orbatid mites were extracted with a modified Tullgren apparatus and respectively numbered 47, 61, 57, 49, 52 and 45 in the Gr, Gm, Gs, Th, Fs and Fm forest samples. It was found that each of the strata contained peculiar fauna, and the large number of individuals as well as species of orbatid mites in moss stratum was comparable to that observed in soil strate. From the values of Cλ, the five strata of each forest were grouped into the folowing : one group in Fs, three groups (M1, M2-S1, M3-S2) in Fm, three groups (M1, M2, M3-S1-S2) in Th, and four groups (M1, M2, M3, S1-S2) in Gm, Gr and Gs.
Anterior 1-type lobes of salivary glands of Colladonus montanus leafhopper vectors infected with Western X mycoplasmalike (WXM) organisms were cultured in a variety of media using an organ culture method. The suitability of various media was judged by the preservation of the ultrastructure of the spherical electron transparent bodies of WXM. The best medium found was that used for maintaining leafhopper cells lines supplemented with 0.2 M sucrose. Infected lobes cultured 1 week in this medium exhibited some infectivity.Direct culturing of WXM was tried in 3 variations of the standard leafhopper tissue culture medium. The variations were made by the addition of 0.2 M or 0.9 M sucrose, or by forming a 'conditioned' medium by adding medium and cells from the actively growing monolayers of the C. montanus cell line. The primary cultures were started using crushed WXM-infected anterior 1-type lobes of the salivary glands of C. montanus.One week after beginning the cultures, little infectivity was detected. After 2 weeks, the assay results (expressed as the percentage of inoculated test insects that transmitted the WXM agent) were 22.5, 62.5, and 32.5 for the media containing 0.2 M, 0.9 M sucrose, and 'conditioned' medium, respectively. Spherical dense bodies were the main morphological form in the 'plasmolysing' (0.9 M sucrose) medium 1 week after the start. After 2 weeks the large polymorphic, as well as the small spherical, electron transparent bodies appeared. It was presumed that some multiplication of WXM had occurred.
Several cereal products were exposed to gaseous hydrogen phosphide in sealed glass flasks under different conditions of exposure period, temperature, concentration of fumigant and particle size of the cereal product. The amount of hydrogen phosphide adsorbed to these samples were measured colorimetrically.The concentration of hydrogen phosphide adsorbed to the surface of seeds of millet, wheat, azuki bean and soy bean was 27 ng/cm2, while that on hulled rice was 17 ng/cm2 following a 6 day exposure at an air concentration of 0.37% and temperature of 25°C.With a rise in temperature or increase in the concentration of fumigant, the amount of hydrogen phosphide adsorbed to samples showed an increase.A reduction in particle size favored the adsorption. Furthermore, it was demonstrated that the adsorption of hydrogen phosphide to cereal seeds is mainly dependent on the surface area.
A microsporidian was isolated from the progeny of field-collected cabbageworm larva. Its spore size was from 3.1 to 5.3 μm in length and from 1.7 to 2.3 μm in width. When spores were stimulated to extrude their polar filament by hydrogen peroxide, their length ranged from 47 to 108 μm. Schizonts underwent binary fission and multiple fussion, and most of sporonts were monosporoblastic, though few were disporoblastic.Of lepidopterous insects used, eight species including silkworm, rice stem borer and cotton leafworm were susceptible, but the site of infection and pathogenicity varied from species to species. In the case of cabbageworm, infection occurred in the midgut most severely and their death time came earliest. In cotton leafworm, infection localized in nervous tissue particularly, and in silkworm and rice stem borer though the development of discase was slow, the disease well developed in muscle, silk glands and Malpighian tubes, and advancing to other tissues gradually.This microsporidian was identified as Nosema mesnili PAILLOT (1918) from its morphology, life cycle, host range and infected tissues.
The smaller tea tortrix (Adoxophyes fasciata WALSINGHAM) and the summer fruit tortrix (A. orana FISCHER VON ROSLERSTAMM) are closely related species. Of the two, only A. orana has been recorded from Hokkaido and the cooler northern and central montane areas of Honshu, however both species occur sympatrically in the warmer parts of Honshu, Shikoku and Kyushu. Thus, there is no geographic isolation between the two species. In the sympatric area, there is no evidence of hybridization, even though habitant isolation due to different preferences for food plants is not complete. It is therefore probable that other isolating factors exist which are responsible for this situation.
A synthetic female sex attractant pheromone of Spodoptera litura (F.), a mixture of cis-9, trans-11-tetradecadienyl acetate (component A) and cis-9, trans-12-tetradecadienyl acetate (component B), for which the name "litlure" was proposed, was evaluated in the field. Attractiveness of "litlure" for male moths changed with the ratio of the components. The optimum ratio of components A and B ranged from 8 : 2 to 39 : 1. A trap baited with 1 mg "litlure" (A : B=10 : 1) was nearly equivalent to a trap baited with 10 virgin females of 2-day-old for two months. Neither cis- nor trans-isomers of 9- and 11-tetradecenyl acetates had synergistic effect on "litlure" or its components.
Existence of alarm pheromone in stink bugs was demonstrated. The secnt discharged from the stink bugs for the purpose of defense against their enemies, made the other individuals of the same species alert and disperse. trans-2-Hexenal, one of the majnor components of the scent, had the same alarm effect. The activity was not species-specific among at least three species of Pentatomid bugs, Eurydema rugosa, E. pulchra and Nezara viridula.
The median lethal dosages of metepa administered orally to the fifth instar larvae of Papilio xuthus L. and P. protenor demetrius CRAMER were 5657.2 (4859.6∼6475.1) and 4959.5 (1833.1∼2355.0) μg/larva, respectively, and those of hempa were 5411.7 (4728.4∼6269.5) and 4895.5 (1362.9∼9035.6) μg/larva. Hence the former species was a little more tolerant to the lethal activities of metepa and hempa than the latter. A characteristic deformity was induced concentratively in the wing parts of pupae of both species by the oral administration of metepa at the fifth larval instar. The deformity was induced in both species at almost the same rate for a given dosage. No similar effect on pupa, however, was recognized by hempa in the range of the dosages tested. The deforming dosages increased with the lapse of time of administration of metepa in the fifth larval instar. Both larval and pupal stages were considerably retarded by the administration of metepa.
The interaction between a cytoplasmic-polyhedrosis virus (CPV) and an infectious flacherie virus (IFV) of the silkworm, Bombyx mori, was investigated. Following the simultaneous infection of the larva with both CPV and IFV, the two viruses multiplied independently in the midgut. CPV multiplied in the columnar cells and IFV in the goblet cells, suggesting that there was no apparent interference between the two virus at the host tissue level, but that a condition of independent coexistence had been attained. However, the period of lethal infection was shorter in larvae subjected to double virus infection than in those infected with each virus separately.
The leaf blades of rice plants (Oryza sativa L. cv. Taichung Native 1) infested with adults of the brown planthopper, Nilaparvata lugens, declined in chlorophyll, moisture, soluble protein, and protease activity, but increased in level of free amino-N, and amino acid incorporation compared with leaf blades of uninfested plants. The leaf sheaths of the infested plants showed simillar effects. They also had lower dry weight and level of sugars, than leaf sheaths of uninfested plants. Heavy infestation resulted in over 30-fold increased in the levels of arginine, asparagine, lysine, proline, and tryptophan with a 6-fold increase in free amino acids of leaf blades. Increasingly severe planthopper damage to the plant was accompanied by decline in the rate of leucine-U-14C uptake by the plant. Restriction of feeding site to either leaf blades or leaf sheaths resulted in localized damage.
Field observations of an epizootic in gypsy moth (Lymantria dispar japonica MOTSCHULSKY) population by two pathogenic fungi during the summer of 1972 in a larch forest in Tohoku District of Japan indicated that fungus-killed larvae occurred in about 99% of the population. Mixed infection of Paecilomyces canadensis (VUILL.) BROWN et SMITH and Entomophthora aulicae (REICH.) SOROK. occurred in about 20% of the dead larvae, which showed typical muscardine. Only E. aulicae was found in the remaining fungus-killed larvae. Most of the dead larvae were found near the base of the tree trunks.