Kyushu Plant Protection Research

1.In Nagasaki prefecture, wheat stripe rust was observed widely along the Ariake and ShimabaraBay and partly in northern, western districts of the prefecture and the Goto Islands, at the beginningand in the middle of May, 1960.
2.Density of uredia was 2000n an average. Flag-leaves were infected most and less in lowerleaves.
Wheat "Norin No. 61" which had been annually resistant to P. glumarum was attacked' more severely than the susceptible variety of "Sotome".
Barley and naked barley were free from P. glumarum.
3. In Tamana city, Kumamoto prefecture, "Norin No. 61" was severely infected by P. glumarum. Damage on April 25 was as follows;
Density of uredia on flag-leaves Area
80%—40 a
50%—60 a
10%—80 a
It was supposed that uredospores of P. glumarum were flown to the north-eastern districts of Nagasaki prefecture over the sea, but the causes of outbreak in Tamana city were not evident.
4. Yellow dust, observed in Hitoyoshi city, Kumamoto prefecture on April 16, was recorded under 0.5km in visual range.
And the relation between yellow dust and stripe rust will be solved by further experiments including physiologic races of P. glumarum.

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Close relationship has been found between the number of causal bacterium in or on rice seedlings and the prevalence of bacterial leaf blight in paddy field. Seedling. treatment with chemicals, therefore, seemed to be effective to retard or depress the prevalence of the disease.
Two methods of treatment, spraying with or soaking in streptomycin (Hitomaishin) and other chemicals, were applied to rice seedlings.
From the results in 1956, four to five spray applications with 200u/cc of streptomycin to rice seedlings were as effective as the spray after flag leaf emergence. Even one to three applications of spray were still effective compared with untreated control.
Good results were also obtained by three spray applications with 500u/cc of streptomycin, in the field tests carried out during 1957-1960.
Soak treatment of rice seedlings in streptomycin and mercury compounds showed promising results, especially for depressing the early development of the disease.

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This work was undertaken to establish the method of the survival test that have been estimated the vitality of rice planthoppers. Therefore, time-survieal curves of groups of unfed females which were tested separately and together with males in several experimental apparatus as figured in Fig.1, were obtained and were analysed comparatively. Thus obtained results were concluded as follows:—
1. Method I and IV represented in Fig. 1 are suitable apparatus for survival test of rice planthoppers. However, method I is more suitable than IV, the time taken to finish the test being longer than that of method IV.
2. To obtain greater uniformity of result, virgin females of about 7 days after emergence are used separately as test subjects. Nevertheless, virgin females survived significantly longer when with males than when alone, and their longevities varied depending on the ages of co-caged males.
3. Time-survival curves of rice planthoppers are also varied due to the difference of sampling methods. Therefore, it is necessary to unify the method of insect sampling.

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The present study was undertaken to clarify that the paper chromatography on free amino acids can be successfully applied to the discrimination of individuality in the developmental stages of the brown planthoppers, Nilaparvata lugens STAL.
Paper chromatographic method was applied to whole specimens of insect, and one-or twodimensional chromatograms were obtained and qualitative and quantitative differences of individualities were revealed by their respective. patterns of ninhidrin-positive substances. Thus obtained results were concluded as follows.
1. Though the one-dimensional chromatograms of the 1 st to 3 rd instar nymphs were easily obtained, two-dimensional ones of them were very difficult because of their small quantities of free amino acids.
2. From the qualitative and quantitative comparisons of two-dimensional chromatographic patterns, three groups of amino acids in 5th instar nymphs, two groups in macropterous females, three groups in brachypterous males and two groups in macropterous males were clearly recognized, respectively.
3. Sensitivities of ninhidrin-reaction of specimens which were reared by mature leaves of rice plant were superior to those of specimens reared by young rice plants. And reactions in autumn generation were far more sensitive than those in summer generation.
Thus, it may be considered that the paper chromatography can be employed as a comparative tool to whole insect specimens.

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