The authors have studied in laboratory the relation between the physical properties, especially on the surface activity of spray liquid and the perfomances of deposit on plant surfaces by the air blast spraying. It has been the main purposes to know how the strong wind of the applicator, as a mist- blower or helicopter, effects the performances of deposit on surfaces and in what degree the spray liquid activities are needed. The Diacotton Scarlet 4BS 0.25 per cent water solutions (red color) of various concentrations of non-ionic surfactant were sprayed by a glass nozzle on the planes of paper, gelatine and paraffine instead ofplant surfaces.
The results of tests are summarized as follows.
When the red color solution (without surfactant) was sprayed, only a small amount of solution was deposited on the paraffin plane but the amount of deposit increased on the paper and gelatine planes in order. As the surface activity of liquid increased, however, the amount on the paraffin plane showed linear increase. But the amount on the other two planes was unchanged because the deposition became homogenous and the excess liquid ran off.
As the surface activity of liquid was increased, the liquid spread in a thin film on the paper and gelatine planes and the amount of deposit on such planes decreased in reverse. When the density of mist was larger, the efficiency of deposit improved and the planes were covered with a small quantity of liquid and consequently the amount of spray liquid can be economized. When the distance from the nozzle to plane was long the wind force of less than 3.1m/sec velocity did not effect the deposit.
It was concluded that in diluted spray the physical properties of spray liquid were:
surface tension 34∼35dyne/cm spreading index (b) (volume V, area of bottom S of a drop on the paraffin plane S(cm)=a+bV(cc)) b=6.5∼8.0
sinking time of cotton thread over 4min.
but a middle surface activity on concentrated spray was:
surface tension 34∼35dyne/cm spreading index (b) over 8.0 sinking time of cotton thread under 2min.

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During these years the frequency of application of insecticides in apple orchards has increased in order to maintain a satisfactory control. This has been considered to be perhaps due to the appearance of resistant strain of insects to insecticides and, in certain cases, to an adverse effect of insecticides on natural enemy populations. This leads to a more intensive use of insecticides; as the result apple growers generally are applying a complex schedule of sprays. To develop additional information on the direct and indirect effects in the different number of spray applications upon the structures of arthropod communities, an experiment was conducted in an adult apple orchard. This kind of study was began by the author in 1956 and is now being continued. The present article is the first report on these experiments.
Basically, the plan of the experiments carried out in the present paper is simple. The orchard used consists of about 180 trees of 15 rows including a small number of young trees. But mostly it consists of 30 year old trees of the Jonathan and Ralls varieties. Insects and mites were kept under the schedule of 11 sprayings on half of the trees and 9 spray applications on the remaining half. In this case two check trees were selected in the center part of the west side in the orchard. Each spray plot was given a treatment of mineral oil emulsion as the ground spray, and then lime-sulphur alone, lime-sulphur plus DDT, lime-sulphur plus lead arsenate, lime-sulphur plus lead arsenate plus EPN and Bordeaux mixture during the period from early April to mid-August. Counts, both on insects and mites, were taken at intervals of 7 days from each 4 trees of the spray plots and 2 trees of the check plot. Insects collected by hand sampling and sweeping of 100 times within 1 square meter areas at the height of 1.5 meters above the ground in each survey tree, but in making counts of mites, 200 mature full sized leaves were picked at random and the number of various stages of mites was recorded.
Compositions of arthropod communities in each plot during the course of the present experiment are shown in Table 1. Of the 10, 659 individuals obtained throughout the entire season, 46.8 per cent was observed in plot of the 11 spray schedule, while remaining number was found in the two plots of 9 spray applications and the unsprayed at the rates of 28.3 and 24.9 per cent respectively. So far as the present data are concerned, it would seem that as the number of spray applications increase the greater is the population density.
As will be seen in Tables 2-4, based upon the seasonal changes of all the species composing the faunae, the seasonal succession of arthropod communities can be divided into following several groups:
Myzus malisuctus→Metatetranychus ulmi·Myzus malisuctus→Lithocolletis ringoniella·Metatetranychus ulmi on the plot treated by the 11 spray schedule; Metatetranychus ulmi·Myzus malisuctus·Eriosoma lanigera→Metatetranychus ulmi→Lithocolletis ringoniella·Metatetranychus ulmi (Lithocolletis ringoniella·Chlorita flavescence from late September) on the plot of 9 spray applications; Cacoecia xylosteana·Phenacoccus aceris→Myzus malisuctus·Metatetranychus ulmi→Metatetranychus ulmi·Lithocolletis ringoniella→Lithocolletis ringoniella·Metatetranychus ulmi (Lithocolletis ringoniella from late September) on the unsprayed plot. From the results illustrated here, it is clearly perceived that although there was no noticeable difference between the former two spray plots in the structures of community accompanying a high population through the entire season, the organization in the case of the later one, was rather complex having a poor number. Furthermore, as has been already shown in Tables

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In this paper an account is given based on a series of experiments carried out, since 1953.
Plant parasitism and morphological studies of the root-knot nematode have been put on record by many authors.
Recently, the writer has identified some species of the root-knot nematodes, Meloidogyne incognita acrita CHITWOOD, M. hapla CHITWOOD, allied species of M. javanica and allied species of M. arenaria. In the present paper, the writer wishes to describe the egg size of three root-knot nematodes species and some observations of the embryonic development in the case of M. hapla species.
The materials used in this experiment were the eggs (egg sack) prepared as much alike as possible. The results of the egg-size measurements obtained are as follows:
The Number of the egg production of the root-knot nematode which parasited on suitable host plants has been counted to be about 700∼800 eggs in the case of M. incognita acrita and 550∼650 eggs in the case of M. hapla.
On the egg size of the root-knot nematode, M. hapla is smaller than other two species, M. incognita acrita and M. javanica (?). This difference in the dimension of the egg size seems to be the remarkable feature to identify the root-knot nematode.
Any remarkable differences of the egg size between M. incognita acrita and M. javanica (?) was not recognized. M. hapla shows smaller quantities of the L-W ratio (egg length/egg width), than other two species.

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Methods of protecting citrus from laying eggs of white-spotted longicorn, Anoplophora malasiaca THOMSON, were studied using poly vinyl alcohol and poly vinyl acetate which form an insoluble membrane after evaporation of water.
1. The membrane set with technical products of DDT and BHC and the same quantity of poly vinyl alcohol (1500) remained for six months, but, the efficacy of preventing laying eggs was imperfect on the 12th day after application, accordingly it was difficult to completely prevent the laying eggs in this way.
2. The white wash in which slaked lime was set with poly vinyl acetate containing 2.5 per cent of slaked lime by weight, caused high rate of falling off of membrane, so, its efficacy proved unavailing on the 21st day after application.
3. The white wash in which slaked lime was set with poly vinyl alcohol (2000) containing 5 per cent of slaked lime by weight, was lower than the former at the rate of falling off, but its efficacy was incomplete on the 31st day after application.
4. The new white wash in which slaked lime was set with poly vinyl alcohol (2000) containing 5 per cent of slaked lime by weight and poly vinyl acetate containing 2.5 per cent of slaked lime by weight, was very low at the rate of falling off and its efficacy in controling laying eggs was almost perfect for the whole duration.
5. It was useless to add insecticides to this white wash.
6. The rate of falling off, six months after the application, was less than 7.8 per cent and the hardness measured by a rubber hardness meter was more than 732.1g in the new white wash to control laying eggs completely. This expected value was obtained by slaked lime of good quality mixed with poly vinyl alcohol (2000) and poly vinyl acetate containing 5 per cent each by the weight of slaked lime.
7. From the beginning to the middle of June, just before laying eggs, is suitable time to apply this new white wash, but eggs which have already been laid should be shaved off.
8. Though eggs are laid more frequently on aged trees than on younger trees, it is not practical to neglect, protecting the younger trees from laying eggs, and so the protection methods concerning younger trees were also studied.
9. It is desirable to extend the range of application even to twigs which are not seriously damaged by insects even if eggs are laid on them, but application should be recommended in accordance with the size and the form of trees as follows: treat to 1m above the ground surface at low-trimmed trees and 20cm above a fork of bough or main trunk at high-trimmed trees, or it should be limited to the height where eggs can be easily found, and inspection must be made at frequent intevals to determine whether or not eggs are laid on the border of a treated bough or trunk.

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Though many chemical control measures on ticks which live in pastures or are parasitic on animals are being carried out, the effective dosage on an individual tick still remains to be studied.
The topical application method was adopted to assay the dosage to inhibit the development of the adult female tick (average body length of 6.1mm) and the lethal dosage to the detached ticks in various feeding state of Boophilus caudatus.
The dosages of γ-BHC, allethrin and pp'-DDT, causing a drop of 50% of feeding ticks in the rapid developing phase, are 2.05, 68.5 and 385μg per tick, respectively. The development ofthe tick was not influenced by treatment with 1mg of α-BHC.
From the inhibitory and lethal dosage, it is supposed that the resistance of engorged ticks to γ-BHC increases about 10⁶ times or more than that of unfed ticks. No correlation is observed between the change of the cuticle thickness and the increase of γ-BHC resistance.
Chemical control of ticks will be conducted most efficaciously when they are in an unfed or an earlier feeding state, because unfed ticks are not so resistant to insecticides.

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Under the experimentally controlled condition of 30°C and 70 per cent of relative humidity, the duration of developmental stage of the parasitoid wasp, Nemeritis canescens GRAVENHORST2 was examined, when it parasitizes on the different ages of the host, the almond moth, Ephestia cautella WALKER.
The wasp can parasitize during the whole period of the larval stage of the host. The number of its progeny is great when it parasitizes on the host larvae between the tenth day and the twenty-second day from their egg development. The duration of the preimaginal period of the wasp varies markedly with the age of the host from seventeen days (when it parasitizes on the older host) to thirty-seven days (on the younger host), but it becomes constant at about eighteen days when parasitized on the host larva more than nineteen days old.
The optimum age of the host for parasitismmay be the larval stages of about nineteen∼twenty-two days from their egg development, when it is evaluated from the following two criteria: the number of progeny and the duration of the developmental stage of the wasp.
When the wasp parasitizes on Ephestia cautella, the wasp population fluctuates depending on the host population in a routine culture, where the synchrony between host and parasitoid wasp is not perfect, because the duration of preimaginal stage of wasp may be prolonged and the efficiency of parasitism may not be operative in its maximum rate.
When the wasp parasitizes on Plodia interpunctella HÜBNER, there is no distinct fluctuation either in the host and the wasp populations. This is different from the case of Ephestia and Nemeritis combination. The reason for this difference may be the ecological characters of Plodia population.

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1. The polygonal patterns can be seen on the surface of sclerites of silkworm larvae only after the cuticle is treated with alkalis. They are irregularly hexagonal in shape, as seen in the normal pupae. However the cuticle of intersegmental membrane bears no such sculpturing.
2. The endocuticle of the arthrodial membranes is thick, while in the sclerite area it is thinner, but it appears in the histological sections that the number of the horizontal laminae are much the same in the both areas.
3. The laminal structure of the endocuticle becomes less clear after the treatment with alkalis.
4. In serial sections of the cuticle washed in distilled water after being treated with alkalis the layers of cuticulin and exocuticle are not stained with either haematoxylin or acid fuchsin, but show affinity to anilin blue. These staining reactions are in inverse relation to those in the untreated cuticle.
5. The changes of the staining reactions in the larval cuticle after being treated with alkalis take place more remarkably in the arthrodial membranes than in the sclerite areas. This may be related in part to the difference in the restriction on alkali penetration through the cuticles of both regions.

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Apple-Grain Aphid, Rhopalosiphon padi LINNÉ (=Rhopalosiphum prunifoliae FITCH) is a common pest of rice plant, wheat, barley and many other graminae crops in Japan. In the present paper, the effects of constant temperatures on its fecundity or nymphal period were described. The aphids were reared on the potted young barley, bearing one aphid in each, in the dark condition under a considerably wide range of constant temperatures (6.0∼35.0°C); as for the relative humidity, it was not constant but was usually maintained as approximately saturated.
As shown in Fig. 1, the environmental temperature has a direct effect on the fecundity of apterous viviparous female; at a temperature as low as 6.0°C. The fecundity is very small, but it increases gradually with the rise of temperature from 12.0°C to 27.5°C, and then it decreases suddenly to the minimum level at 35.0°C.
On the other hand, the effect of temperatures on the duration of each instar is as shown in Fig. 2; any development can be scarcely observed in the first instar at 6.0°C, the longevity is shortened gradually with the rise of temperature and reaches its minimum at 25.0∼27.0°C in 90 hours, but at temperature as high as 35.0°C, almost all nymphs die before reaching the fourth instar.
As the development zero is calculated to be 6.1°C, the theoretical value of the total temperature affecting the development of this aphid seems to be 27 degree-days.
The morphological variations on the body colour under the temperature from 25.0 to 32.5°C are varied from green-blue to pale-reddish brown, but other characteristics on this species are not observed.

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