Transmissibility of potato leaf roll virus by green peach aphids collected from Hokkaido, Gunma and Nagano Prefectures were examined. The results indicated that 9 strains from these localities were varied 53-100% in the transmissibility and these differences were considered to be due mostly to differences in survival on the inoculated plants (Physalis floridana BUAD.).
It seemed that there was little difference in the transmissibity between alate and apterous forms of green peach aphids.

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Ten years ago, about 40 species of spiders were recorded from the apple or chard by the senior author, while engaged in a study of the effects of spray programs on pest population and beneficial organisms (HUKUSIMA, 1961). Of these collections Misumenops tricuspidatuswas considered first as an important predator of orchard pests, because of its universal occurrence and frequent abundance. But almost nothing is known of the bionomics of this species up to date. From an economic side, at present, the first thing to do in analysing the property of the hunting spider as regulating agents in orchards is to know some aspects of life histories and habits.
Based on the field survey, M. tricuspidatus hibernates in various instars of nymphal period and adult stage from November among the ground cover of fallen leaves and dead herbaceous plants, but adults or larger immature stages are the most case which is frequently observed during winter in orchards. As the season advanced, overwintered adults and immatures leave their hibernation qua ters on warm days in following early March, and rest on the trunks and branches of fruit tree. Meanwhile, the peaks of seasonal occurrences were formed over 3 times, on mid-April, early July early August and mid-October.
According to the observations in a insectary, the mating takes place mostly in the daytime without food intake except particular case. At the time of oviposition, the female builds a crude nest by tying two or more overlapping leaves together and constructs the lenticular egg-sac within it. Thus the 1st egg-sacs were produced on late May early July, and next during the period from late August to early October. In this case, the number of eggs per egg-sac varied with different seasons, and an average of 163.1 and 87.7 eggs per egg-sac was counted corresponding with above seasons respectively.
M. tricuspidatus mostly feed on living organisms like other spider species, but under the fasting condition they sometimes utilize the dead arthropods. Such a habit would servefor the recovery from exhaustion by hunger. In contrast to male behavior, the feeding activity of females does not become weak after they reached adulthood, but 7 times of male meal per day were consumed when prey was supplied in suitable number. The daily food consumption of immature stages, as a rule, increases keenly about 2 days after moulting, and also adult females tend to increase their foods just after the final moulting and mating.
With regard to the number of moults, all individuals reared did not moult in the same number, but they moulted 5 to 9 times after leaving the egg-sac. In this context, it is well known fact that the number of moults necessary for maturity in many species of spiders is somewhat variable, and may be increased under unfavorable conditions. This assumption would seem easily to admit in the present case. Namely the phenomenon that the number of moults in M. tricuspidatus increases under the lower rearing temperature and with the decrease of food supply, was clearly evidenced. Further this tendency strongly appeared in the females than in the males.
Already as a few case was mentioned, a considerable variation of life histories and habits under different temperature conditions is thought to be worthy of notice. As might be expected, within 25-30°C the duration of each instar shortened with increasing temperature, and at the same time much more foods were consumed at higher temperature condition, though the feeding intensity was not necessarily indicated in the same pattern between males and females. On the other hand, the number of egg-sacs per female was somewhat more under 25°C, and the rate of hatching was also higher than that under 30°C.

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Since 1966 at a grassland in Kitakami mountain range, Iwate prefecture, the orchardgrass have been severely damaged by the spotted spittlebug, Aphrophora stictica MATSUMURA.In 1969 field experiments were undertaken to evaluate the effect of several organic phosphorus insecticides in controlling the spittlebug. Insecticidal application was made in the course of hatching of the overwintering eggs in early to mid May, and the number of survivors was counted at 27th May and at 24th June. The results showed that a substantial control was given by diazinon granules at 9kg, diazinon dust at 6kg, and Bycid dust at 6kg per 10 a applied on the peak of hatching, and 0.1% solution of Bycid emulsion at 200 liter per 10 a sprayed just after the completion of hatching.

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The residual toxicity of eleven insecticides, ten acaricides and eight fungicides were examined against the adult of Holcothorax testaceipes RATZEBURG, one of the most important parasite of Lithocolletis ringoniella MATSUMURA, in the laboratory. These pesticides could be divided into 4 major groups: Group A (materials that showed high toxicity at the day of treatment on apple leaf and were harmful as 15-day old residues): NAC, PMP, PAP, DDT, vamidothion and binapacryl, Group B (materials that showed high toxicity at the day of treatment and were harmful as 2-to 10-day old residues): MEP, diazinon, phosalon, MNFA, Padan, nicotine sulfate, DPC, DDVP, lindane and Salithion, Group C (materials that showed low toxicity at the day of treatment): lead arsenate, chlorobenzilate, dicofol, Galecron, Monox (ziram 50%+bis (dimethylthiocarbomoyl)-ethylen-bis (hydrosulfamine) 30%) and bordeaux mixture, and Group D (materials that showed little toxicity): chloropropylate, PPPS, captafol, dodine, Sanquinon (dichlone 20%+TMTD 20%), polyoxin and wettable sulfur.

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[in Japanese]

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[in Japanese]

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[in Japanese]

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It is well known that the rice plants affected with node blast lodge easily, but, on the other hand, leveled rice plants resulted from a storm and so forth, are frequently attackedwith the node blast disease.
In this paper the authors intended to ascertain the reasons of the latter case. In order to lodge the plants artificially, they were laid down to the ground as they were grown in the pots, or were bent down by a rope in the field. The ears of those plants suffered from such treatment recovered an erect posture in a few days later by the apogeotropic action of the node tissue, when they were in a short time after heading. The curvature of stem node of those plants was maximum in the lowest nodes. On both natural and artificial inoculation tests, the more the curvature was, the more infection of node blast occurred. Water content and S-N/T-N (%), an index of disease proneness, were also higher in heavily lodged plants than in lightly lodged ones, though the relation of the ratio was seen only in the lower node. Besides, relative humidity and conidia density in the plant layer were surveyed, suggesting the circumstances conditioned by lodged plants to be apt for infection of the nodes.
It may be concluded that nodes of lodged plants incline to be attacked with the fungus because of not only environmental factors but also of their disease proneness.

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