1. Um die Infektionsperiode von Reisviren im Nagasaki Bezirk festzustcllen, wurde diescr Feld-versuch im Jahre 1964 durchgeführt. Ein Batist, mit dem die Reispflanzen bedeckt waren, wurde während jeder fünf Tagen in der verschiedencn Zeit weggenommen, um die Viren durch Zikaden zu impfen.
2. Streifenkrankheit: Im frühzeitigen Bau war ihr erstens Auftreten am 25. Mai zu bcobachtcn. Die vom 21. -25. Mai geimpften Reispflanzen zeigten das höchsten Infektionsprozent und die Durchschnittstemperatur in diesem Termin war 22.3°C. Die Bevölkerungsdichtigkeit von Del-phacodes striatella FALLEN war am größten vom 26-31. Mai.
Im gewöhnlichzeitigen Ban kam sic schon in der Zeit der Pflanzschule vor. Die Infektion verursachte ein hohes Prozent auf den vom 11. -15. und vom2l. -31. Juli geimpften Pflanzen. Die Durchschnittstemperatur war besonders hoch(27.9°C) in jenern.
3. Zwergkrankheit: Im frühzeitigen Bau tritt sic am 15. Mai crst auf. Ihr Infektionsprozent war hoch auf den Pflanzen, die bis 15. Mai(von der Zeit der pflanzschule bis zum Anfang der Fel-dperiode), sowie vom 25. -31. Mai geimpft wurden. Der Infektionsprozent war beinahe parallel mit der Bevölkerungs-dichtigkeit von Nephotettix bipunctatus cincticeps UHLER. Im gewöhn-lichzeitigen Bau war ihr Auftreten schon in der Pflanzschule zu beobachten. Ihre Infektion zcigte ein hohes Prozent in der Periode bis 5., vom 11. -15. und vom 21. -30. Juli. Dies schcint auch in einem Parallel -verhältnis mit der Bevölkerungsdichtigkeit der Zikade und mit der Höhe der Durchschnittstemperatur zu stehen.
4. Gelbzwergkrankheit: Im früh-und gewöhnlichzeitigen Bau kam sic am 5. Juli vor. Das Infe-ktionsprozent im frühzeitigen Bau scheint hoch beim Impfen bis 20. Nlai und vom 6. -10. Juni zu scin. Im gewöhnlichzeitigen Bau war es aber undcutlich.
5. Mit diesen Resultaten scheinen eine grosse Bevölkerungs-dichtigkeit der Zikade und einc hope Temperatur bci der Infektionsperide den Infektionsprozentsatz von Rcisviren zu enccben.

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1. Rice plants were grown on field plots, in which 0.5-3.0kg of nitrogen per are was applied except in check plots, in 1962 and 1963. The plants were infected under natural conditions with dwarf disease. The more were the amounts of nitrogen, the severer the disease occurrence.
2. Rice plant were grown on 1/5000 α Wagner's pots in which 0.2, 0.5 and 1.0 gm of nitrogen per pot was spplicd. The plants were infested at 14-or 16-leaf stage with viruliferous green rice leafhoppers (Nephotittix cincticeps Uhler) that had reared on dwarf-affected rice plants. High nitrogen plants proved to be more susceptible to the disease than low nitrogen plants, at the late leaf age. When the plants were at 14-leaf stage, symptoms developed on plants to which 0.5 and 1.0 gm of nitrogen was applied. Degree of symptom development was much severer on the latter. No symptom developed on plants to which 0. 2 gm of nitrogen was applied. When the plants were at 16-leaf stage, symtoms developed only on plants to which 1.0 gm of nitrogen was applied.
3. Leaves were detached from rice seedlings grown in diffent amounts of nitrogen, and then were covered by single cage. Rice green leafhoppers were allowed to feed on caged leaves for 24 hours. Leafhoppers were attracted toward the leaves of high nitrogen level. At certain plant-age, the number of infesting viruliferous leafhoppers per plant influences the percentage of infection.

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This paper gives a knowledge on the relationship between the humus contents of soil and the occurence of white root rot (caused by Rosellinia necatrix Prill) in 26 loquat orchards at Mogi, Nagasaki Prefecture.
In this study, the authers found a positive correlation between the amount of humus in orchard soil and the percentage of infested trees by white root rot (see Fig. 2 and Fig. 3).
It seems that the contents of humic acid in soil humus have a positive correlation with the percentage of infested trees in the orchard (see Fig.4).

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Present work was carried out to clarify the effect of insecticides for citrus leaf miner control on the numerical population of the citrus red mite, preparing 30 young citrus trees planted in one orchard. Of 30 citrus trees, 10 were sprayed with nicotine sulfate (×600), 10 were sprayed with the mixture of nicotine sulfate (×800) and endrin (×1, 000), and 10 were set for the check, respectively. Insecticides were sprayed from spring to autumn once a week. And the number of the citrus red mite of these three sets of citrus trees were examined about 15 days interval from the autumn in 1963 to the summer in 1964.
In the case of the set sprayed with nicotine sulfate, the population level of the red mite did not so increase throughout the experiment. In the case of check, the red mite increased in August and September and then decreased. However, the population of mite in the set sprayed with mixture of nicotine sulfate and endrin increased remarkably even in the winter season from November to January in next year.

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The author made some observations on the alighting and distribution of Myzus persicae in a rape field in Fukuoka City.
The green peach aphid, Myzus persicae (SULZER) invaded to the rape field planted in late November, and alighted from December to following January.
Adult aphids observed were all alate viviparous females. As none of the 3rd and 4th instar nymphs had wing-pads, it was supposed that all of the alate aphids were immigrants from other cruciferous fields. The number of aphids per plant was concerned, the following facts were recognized:
1) Alate aphids alighted on the rape field at random, and the frequency distribution of aphid counts fitted to the Poisson distribution.
2) Offsprings of the invaded alatac distributed on the plants contagiously and the frequency distribution of aphid counts fitted to the negative binominal distribution. By such a manner of invasion and distribution as mentioned above, the overwintering popu-lations of Myzns persicae are built up in rape fields by the viviparous females.

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Fluorescent characteristics of rice planthoppers and leafhoppers were studied by means of the paperchromatography concerning with the utility of application for detection of the ecological differences of the insects.
Test insects were collected from early seasonally cultured rice nursery, early seasonally cultured paddy, weeds in levee and chinese milk vetch in early spring, respectively. Light trap catch at 15m level was also made to compare at the same time. The brown planthoppers. Nilaparvata iugens(HORAVATH), reared successfully as long as 2 generations on 2 nutritiously different rice varieties, Binan-Mochi and Norin-18, were tested to make clear the effect of the diet to the chromatogram, as well.
Paperchromatographic method was applied to whole specimens of insects, and one- and twodimensional chromatograms were obtained with n-butanol-acetic acid and phenol solutions as for the solvent. Fluorescent materials were developed on the paper by their fluorescence in ultraviolet light with 3660 A in wave-length. Thus, obtained results were as follows: 1. In the case of the one-dimensional chromatogram, chromatographic patterns were recognized into 12 types for the butanol-developed figures and 2 types for the phenol-developed ones, respectively. Species specificity seems to be shown in the phenol-developed chromatograms, however, ecological differences in the same species were not detectable. The ecological differences and or sexuality should be characterized clearly in the butanol-developed chromatograms.
2. In the case of the two-dimensional chromatogram, the fluorescence of the female hoppers was more obvious than that of the male ones, in general. Any chromatographic figures of the small brown planthoppers, Delphacodes striatella FALLEN, and the brown planthoppers obtained from ecologically different sources made no difference with each others, respectively. The figures of the green rice leafhopper, Nephotettix cincticeps UHLER, in the different sources had their own chromatographic figures. Nutritive difference of rice variety was concerned as for the diet, thus two varieties, Binan-Mochi and Norin-18, were chosen to rear the appropriate two brown planthopper populations(Suenaga, 1963) in the laboratory. Then, it was clarified that chromatographic fluorescence was advantage for the population reared on Binan-Mochi, and such advantage can be detected in the 4th-5th instar stage.
3. Thus, it may be considered that the chromatogram characterized by fluorescent materials can be employed in detection of some ecological differences of the rice planthoppers and leafhoppers, especially in the invasive populations in the spring having no common fluorescent figures among different species, and of the nutritiously different populations of the insects, as well.

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1. The experimennt was carried out every 10 days to clarify the distribution and population density of the green rice leafhopper in the four paddy fields trnsplanted on respective dates,
2. In the fields transplanted on May 8 and May 26, nymphs immigrated into the fields from the surrounding grass in levee, thus density of adult population of the first generation concentrated extremly to the marginal parts of the fields.
3. In the case of new generation after immigration, both nymph and adult distridutions were heterogeneous having one or several dense patch. And then numerical population of the insect increased gradually covering all parts of the fields.
4. The adults of the second generation in the fields transplanted on May 8, appeared as much as 20-30 days earlier than that in light trap catch.

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The susceptibilities to insecticides of the green rice leafhopper, Nephotettix cincticeps UHLER, collected in the different parts of Kyushu, south-western Japan, were determined by means of microtopical application method and compared with each other.
The local differences of susceptibilities of the insects to metyl parathion and to malathion were recognized as shown in Figures 1, 2 and 3.
From these figures, it seems to be fact that even the insect which had relatively low susceptibility to malathin in Kyushu was more susceptible than the insect which had been recognized as a registant one to malathion in Kochi or Tochigi prefectur.
As shown in Figure 5, it is considered that there might be some correlation between the susceptibility of the insect to malathion and that to Sevin.

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Plant-parasitic nematodes in soil were surveyed covering 97 sugar-cane fields and other 36 cropones in the Satsunan Islands, including Tanegashima, Yakushima, Kikaigashima, Tokunoshima, Okino'erabujima and Yoronto, where annual mean temperature was 20°C or so.
The genera found and their distribution were shown in table 1, and the species discussed were listed in the text with short morphological notes, if necessary.
Of the 17 genera investigated, the following S genera of Helicotylenchus, Pratylenchus, Tylenchorhynchus, Meloidogyne and Rotylenchulus appeared frequently. Some main species of these genera were tabulated in table 4 with their distribution in this region. The genus Tylenchorhynchus is striking for its wide distribution and Tylenchorhynchus sp. 2 is considered as a species in warmer regions.

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