Much has been written about the possible role of climatic factors in relation to aphid feeding or reproduction. However, a little is known about the nutritional requirements of aphids. According to the opinion postulated by AUCLAIR (1963) the subject of aphid feeding and nutrition is considered in its broader sense, and is being treated with special reference to the physiological and biochemical aspects, with occasional reference to the morphologic, behavioural, and ecological aspects. With these points in mind, in the present article, an account is given of the results obtained on the reproduction of the apple leaf-curling aphids, Myzus malisuctus, and its relation to nutritional change of plants, moisture condition of environment, and ecological and behavioural natures of aphids.
In addition to above aspect, it has generally been recognized that the Myzus aphids prefer the actively growing shoots of apple tree, and that infestation and reinfestation, as a rule, take place on the immature leaves rather than on mature ones in a branch of tree. This would lead to the assumption that one reason of this may lie in the nutritional difference between the immature leaves and mature foliages. As might firstly be expected, the number of Myzus aphids settled on a leaf and reproduction rate on young leaves of apple seedling increased when greater amount of nitrogen was supplied, because increasing nitrogen supply to apple seedling may increase nitrogen uptake, and raises the level of soluble nitrogen in the plants (GOODALL and GREGORY, 1947).
Up to the present time, it has been said that the aphids more produce under the moderately moistened condition in a given circumstance than in highly moistened area or very wet weather condition. From the tests carried out in this chapter, we may say then that the reproduction of Myzus aphids was accelerated with decreasing moisture in the rearing cage used, although there was not always a very sharp limit between treatments. This may help to explain the remarkable persistence of aphid reproduction during dry season.
In connection with such a nature of this aphid, we do not yet know enough about the limiting factor of reproduction. Therefore the aphids were thirdly reared on leaves of apple seedlings kept on normal and inverse positions. Without question, aphids tended to move vigorously to the terminal leaves of tree regardless of position of leaves set in test. This would only hold true that the situation of this species that prefer the immature leaves will depend on the exact nature of physiological requirement rather than on the negative-geotropism of aphids.
Fourthly, Myzus aphid tended to produce larvae on the lower surface of apple foliages than on upper surface of leaves, and infestation accordingly taken place mostly on the former area. Further-more, there was not a reasonable close relation between the fecundity of aphids and light condition within a experimentally given circumstance. That is to say, the aphid movement to the lower surface of young leaves and reproduction on these leaves were observed regardless of light or dark conditions applied. Taking in conjunction with these descriptions together, at least it may be suggested that a plentiful hair insertion on lower surface of apple leaves would be led the leaf preference of aphids compared with less number of hair on upper surface (HUKUSTMA and ANDÔ, 1967).

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Powdery scab like disease of potato tuber has been known recently in the field of potato during the harvest season.
Instead of the fungus Spongospora, the sporangia and sporangiophores of late blight fungus, Phytophthora infestans f. sp. infestans WATERHOUSE were sometimes observed on the affected part of potato tuber.
Our investigations come to the following conclusion. The zoospores of the fungus drop to the ground from the diseased leaves in the rain and after passing through the soil they arrive soon at the surface of tuber. As the climate changed to fine and soil temperature in the field became higher than 34°C after the zoospores penetration into tuber epidermis the organisms in the tuber might probably die and consequently the callus formation would be induced in the infected tissues. The epidermis on the tissues of callus will then be burst. As the result of this curing phenomenon appearances of the lesion bear a close resemblance to the powdery scab of potato tuber.
The fungus of late blight of potato dies within 36 hrs of incubation at 32°C or at once at 34°C. No rotting of the infected tuber has so far been observed by the incubation at 28°C. The zoospores can pass through the soil, regardless of whether water in the field is kept running down or stationary. Cuticular penetration of the tuber by the zoospore takes about 8 hours at 20°C. All these observations seems to substantiate the above conclusion.
To further testify the above conclusion, the following experiments were carried out: potato tubers directly inoculated with zoospore suspension at 20°C for 8, 12, 24 hrs were incubated respectively at 34°, 36°, 40°C. Another batch of potato tubers was buried in soil, inoculated with zoospore suspension, kept at 20°C for 2 and 4 days; and then incubated at 34°. All the tubers thus incubated showed the powdery scab like symptom bearing lessions as had been found in potato field.
Histochemical analysis of the symptom development suggested that lignification and suberisation of the infected tissue of potato were initiated by about 7 days after inoculation and reached to the maximum by 14 days inoculation. Callus formation seems to become remarkable by 7 days after inoculation.

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Conidial germination of Helminthosporium oryzae (Cochliobolus miyabeanus), No.13, was discussed in relation to some environmental factors.
Conidial germination of this strain was initiated soon after the incubation and reached 7% at 10 minutes after incubation.
Alternate shift of temperature, 2-3°C and 28 or 45°, favored the germination. Exposure to 45° especially increased the germination rate.
Effect of sporulation media on conidial germination was also tested with Czapek and Czapek yeast extract agars. Additional presense of yeast extract in the sporulation media was found to favor the conidial germination. However, washing the conidia with distilled water negated the effect.
Several nitrogenous compounds were also tested for their effects on conidial germination. Ammonium sulfate enhanced the initial germination of conidia at the concentration of 10^-3M, while calcium nitrate and potassium nitrate inhibited the initial germination at the same concentration. This inhibition was apparent by 100 minutes of incubation. Tincture of iodine inhibited conidial germination at the concentrations higher than 100 dilution. Germination capacity of the treated conidia was recovered by washing with distilled water.
Ethyl alcohol did not give any major effect on germination at concentrations less than 1%.

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In order to find out an effective control method of the cherry tree borer, Synanthedon hector BUTLER, one of the most destructive insect pests of peach in Japan, branch and trunk spray tests of endosulfan against this insect were carried out from 1962 to 1965 at Bodaiji, Kosei-Cho, Koga-Gun, Shiga-Ken.
Results show two applications of endosulfan, the first at the small peak of the early adult moth emergence in mid-June and the second at the main peak of the emergence in mid-September, gave excellent control of the borer throughout a year. The proper concentrations of endosulfan for this spray schedule were 0.2 or 0.1% of the active ingredient. Even one application in mid-September could considerably reduce the borer population on the sprayed peach trees in such relatively high concentrations. This spray schedule is very practical for the peach growers since it does not coincide with busy times such as fruit thinning, fruit bagging, and harvest; furthermore, it has little possibility for the fruits contaminating with the chemical.
Besides, it was confirmed that spray of endosulfan also killed the newly established young larvae of the borer which became abundant in late fall. After sprayed, the larvae were dead with the anal end protruded out of the burrow in many cases (Fig. 3). No significant difference was observed between the stage of the dead larvae and that of the survivals. Endrin and lindane were also effective to the young larvae, but spray of DDT gave poor control against them.

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(1) The experimental researches of the species of chestnut borer par a tree and of attacking places in the trees which were classified by the age were undertaken.
(2) More species of beetles were observed in elder trees. They belonged to the 3 Genera (10 species) so-called “ambrosia beetles”; such as: the Genera of Xylosandrus (1 species), Xyleborus (8 species) and Scolytoplatypus (1 species) at the eleven years old trees.
(3) The species of beetles and the number of attacking holes were more observed in elder trees, but the 3 species of Xylosandrus germanus (BLANDFORD), Xyleborus saxeseni (RATZEBURG) and Xyleborus canus NIIJTMA highly attacked in the young trees and they were seemed to be more injurious than the others.
(4) Almost species of beetles entered by the parts of lenticels, but Xylosandrus germanus (BLANDFORD) and Scolytoplatypus mikado BLANDFORD more attacked into the other parts.
(5) The results of observation of the attacked parts on classified by the age of branches, by high and thickness of trees were as follows:
as the attacking beetles almost parts of the tree…… Xylosandrus germanus (BLANDFORD), Xyleborus saxeseni (RATZEBURG), Xyleborus canus NIIJTMA and Xyleborus laetus NIIJTMA.
as the attacking beetles only the parts of trees being closed to ground…… Xyleborus defensus BLANDFORD, Xyleborus seiryorensis MURAYAMA, Xyleborus validus EICHHOFF and Xyleborus adumbratus (BLANDFORD).
as the attacking beetles only the young branches…… Scolytoplatypus mikado BLANDFORD.

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The effect of plant hormones on the local and systemic infections by tobacco mosaic virus (TMV) was investigated. Kinetin inhibited local lesion formation on bean caused by TMV (Fig. 1), while giberrelin stimulated (Fig. 2). Indolacetic acid (IAA) and its precursors, indolacetonitrile (IAN)and tryptophan (TRP) inhibited the lesion formation at high concentrations (Fig. 3). MH had a different type of inhibitory activity (Fig. 4). From the effect on TMV multiplication in tobacco leaves, plant hormones under investigation may be divided into the following three kinds ; 1) stimulate at low concentrations, but no effect or rather inhibit at high concentrations (IAA, 2, 4-D, giberrelin), 2) stimulate in proportion to the increase in concentrations (kinetin), 3) no effect (MH).
The synergic action of plant hormones and antiviral agents on TMV multiplication in tobacco leaves was tested. The mixed solution of IAA, kinetin, and succinic acid had no effect or rather reversed the inhibitory activities of thiouracil and blasticidin S on TMV multiplication. This was also confirmed by the spraying experiments on tomato seedlings infected with TMV or TMV+ potato virus X (PVX).
From these results, it is concluded that plant hormones used had no distinctly inhibitory activity upon TMV multiplication and had no synergic action with antiviral substances.

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This paper deals with the results of investigations on the development of warty lesions of physalospora canker which were occured on the twigs of Japanese pear variety “chojuro”, the influence of temperature and ray to the formation of pycnospore, and the relation between dispersal of the pycnospore and the existing place of the pathogene in field.
1. Optimum temperature for the formation and development of the lesions at the surrounding parts of warty projections on the twigs was approximately 30°C, and followed by 25°C. Unsuitable temperature for the development of lesions was nearly 20°-15°C.
2. Pycnospores on the lesion were produced abundantly al temperature of 25°-30°C. At a temperature of 30°C, the sporulation on the lesions occured from the earliest season and occured continually for a long period of time.
3. When the diseased twig was withered artificially, the pycnospore occured rapidly.
4. When the diseased twig was kept under dark state intercepting the light, the lesion hardly produced the pycnospore, but under the light abundantly. Quantity of sporulation had relation to strength of light. It seems that the pycnospore have been able to occur sufficiently under the natural light in field.
5. The pycnospores were able to gather in field from the first decade of April to the second decade of September, and abundantly from the last decade of May to the first decade of August.
Quantity of collected pycnospores were influence by place of the source of infection in field and amount of pathogene. When the pathogene were put on the stockade, pycnospores were gathered abundantly.

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Three insecticidal effects, such as contact toxicity, systemic toxicity and residual effect against the brown plant hopper, Nilaparvata lugens STÅL, are described.
In the dipping method of the rice seedling, BHC, CPMC (2-chlorophenyl-N-methylcarbamate), PHC (2-isopropoxyphenyyl-N-methylcarbamate), Malathion, Mecarbam, Smithion were high contact toxicity. DDT and NAC were also considerably toxic, while the toxicity of EPN has proved to be least of all used compounds in the test.
Susceptibility of the brown plant hopper to these compounds generally ranked as follows: adult of male> adult of female> nymph of 4th-5th instar.
On the other hand, Dimethoate, Thiometon and Vamidothion were outstanding in systemic toxicity, their effectiveness against the insect being superior to that of NAC, BHC, Malathion and Mecarbam. The effect of NAC, however, was higher than that of BHC, Malathion and Mecarbam.
A 1.5% NAC dust or a 0.03% NAC emulsion was found to give residual effect for nearly 20 days in the pot test, but the same effects of 1.5% Malathion dust, 0.05% Malathion emulsion and 3% BHC dust have been given in a few days.

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Because the density of the citrus ground mealy bug, Rhizoecus kondonis KUWANA, has a great influence with water content of its living place, it is necessary to examine the relation between them. For this purpose, a special apparatus was deviced for planting citrus tree, on which mealy bug was reared. Water content of the subtarranean environment where the insect was reared was controlled by a special method shown in Fig. 1. The value of water content of sawdust shown by meter (Y) was in the relation of following formula with that measured directly by dessication (X). Y=32.3+0.66X The value of water content was shown by the amount of water supplied to 50g of completely dried sawdust. The planting apparatus was kept for 84 days under the illumination of 5,000 lux and constant temperature 26°C. The growth of citrus tree was the greater, water content was the more, but insect survival was optimum at the intermediate water content. The damages of citrus roots caused by this insect were observed in the cases of higher water content, and especially the damage of old root was observed remarkable.

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[in Japanese]

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[in Japanese]

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