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In 1967, the adult immigration period of the first generation, estimated by the yellow pan water traps, began from about May 20 and continued until about June 20, showing several minor peaks, in seedling beds and early transplanted paddy fields (Fig.1). In the ordinary transplanted fields immigrants were found from the end of June to mid july, which seemed to be the emergence period of the second generation.
Infection by the rice stripe virus was severe in the fields transplanted within May (Table 1).
Percentage of infective planthopper tested by the anti-body sensitized hemagglutination method of the first generation collected from 13 wheat fields in Chikugo was 7.45% (313/4199) in average, the lowest being 3.75% and the highest 10.24%. Those of adults collected in 9 rice seedling beds was 7.24% (224/3096), the lowest 5.88% and the highest 8.26%, very much similar to those obtained from wheat fields (Table 2 and 3).
In a paddy field transplanted on 19 May, symptoms of RSV appeared from the beginning of July and reached to maximum in August, over 60% of plants being infected. Percentage of infective plant hopper increased along with the increase of infected rice plant with about a half month's lag, reaching nearly 50 %, though the density of planthopper was extremely low.
Percentage of infective planthopper of overwintering generation was traced from the beginning of December to April. No consistent seasonal fluctuation of the percentage was found; being 5.77% in average (117/2026).

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Diazinon granule was applied to the rice plant in the paddy field in August for the control of the brown planthopper, Nilaparvata lugens STAL.
Application of a 3 % granular formulation of diazinon at the rate of 3 kg/10a gave excellent control of the hopper nymphs. The initial kill took place 2 days after application, and the effect lasted for about 7 days.
Two kinds of granules, other than diazinon granule and containing BHC (4 %), were residual compared simultaneously, but they were not so effective as diazinon granule.
To compare the effectiveness of insecticides, population counting of the hopper nymph in the paddy fields were conducted by sticky-board method, which was consisted of holding a 18×25cm celluloid board coated with water repellent adhesive horizontally at the lower part of rice hill, lightly patting the rice stem with hand so as to stick the nymphs on the board, and then counting the number of the nymphs collected on the board.

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The tobacco cutworm, Prodenia litura (FABRICIUS) is a serious pest of many dicotyledonous crops and vegetables in the soutwest of Japan, and the worms infected with nuclear polyhedrosis virus were found in October, 1967 in soybean fields in Chikugo, Fukuoka prefecture.
The size of the nuclear polyhedrosis virus is approximately 310×50 mμ. The inclusion bodies or polyhedra, detected as triangular, square and irregular forms with about 1.5 μ in diameter, seemed to include several virus strains.
Diseased worms became whitish yellow, rose or pinkish beige before death usually occurred 4-7 days after feeding on the clover leaves contaminated with polyhedra at 25°C. Per-oral virulency did not seem to be low.

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Effects of heavy infestation of the citrus red mite in the autumn in 1965 on the growth and the yield of the Kawano-Natsudaidai variety were investigated in the citrus orchards (9 years old trees) in Kurume in following 1966 and 1967.
In the plot infested heavily with the citrus red mite of the Kawano-Natsudaidai trees, number of defoliated leaves from January to March in 1966 is more than that of the lightly infested plot. The trees infested heavily were strikingly reduced the vegetative growth, length of new leaf and new spring shoot, and number of fruits in 1966.
The reduction of the yield in number and in weight of the fruits of heavily infested tree was about 45 per cent and 43 per cent, respectively, from that the lightly infested one in 1966.
Though such heavy infestation of the citrus red mite affected the growth of the tree for two years, little yield difference between heavily and lightly infested tree has been found in this period.

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This work was carried out in 1966 and 1967 to obtain a fundamental knowledge on the mass production of Allotrope sp. in the laboratory. Allotrope sp. is an effective larval parasite of Planococcus kraunhiae KUWANA, the pest insect of persimmon and citrus trees.
This parasite is preovigenic and the average number of ovarian egg is 482. The virgin female produces only male progeny.
The number of mummies produced by a female were 82 in average, 187 in maximum, and 25 in minimum, respectively. Of the total number of mummies, 85 per cent were produced on the day of emergence.
Of 2000 adults emerged newly from the mummies, 53 per cent was female, and male emerged earlier than female. Emergence rate is about 90 per cent.

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Plant-parasitic nematodes were surveyed covering Okinawa-hontô, Kumejima, Minami'daitojima, Miyakojima and Ishigakijima where annual mean temperatures are 22-23°C. Table 1 shows the genera of plant-parasitic nematodes found in Okinawa region. The genera obtained from soils around roots of the sugar-cane, the sweet-potato, the pineapple and the banana plants are listed in Table 2, 3, 4 and 5, respectively.
Of 69 sugar-cane fields surveyed, 86 percent or more appeared to be infested with stunt nematodes. Tylenchorhynchus martini and a species of Tylenchorhynchus (T.sp.(Ryukyu-A)), which bears clavate tail tip and no transverse striation on lip region, are widely dtsributed in Okinawa region. T. nudus was found in Ishigakijima and another stunt nematode (T. sp. (Ryukyu-B)) was obtained in Idjima near Okinawa-honto. Helicotylenchus, Pratylenchus, Meloidogyne and Hoplolaimus were found in 81, 58, 55 and 22 percent of the sugar-cane fields surveyed, respectively. Pratylenchus coffeae, P. zeae and Helicotylenchus dihystera are common in this region and P. brachyurus was found in Minami'daitojima.
Helicotylenchus and Tylenchorhynchus were the most frequently encountered genera in the sweet-potato fields in Okinawa. Meloidogyne, Pratylenchus and Rotylenchulus were found, too. Some nematodes isolated from sweet-potato soils were identified as Pratylenchus coffeae and Tylenchorhynchus sp. (Ryukyu-A).
Meloidogyne, Tylenchorhynchus, Pratylenchus and Helicotylenchus found were major nematodes in the soy-bean fields. Meloidogyne, Tylenchorhynchus, Helicotylenchus and Pratylenchus were extracted from tobacco soils. Besides root-knot namatodes, Helicotylenchus, Pratylenchus, Tylenchorhynchus, Rotylenchulus and Paratylenchus occurred in some vegetable fields. Helicotylenchus is the most common genus in the pineapple fields. Pratylenchus zeae was isolated from soils around roots of the pineapple plant and from uncultivated one nearby. From almost all banana soils surveyed, Helicotylenchus and Tylenchorhynchus, including T. nudus and T. sp. (Ryukyu-A), were found. Pratylenchus coffeae was isolated from banana soils in several times. Meloidogyne appeared to infect this plant, too. Tylenchulus, Helicotylenchus, Paratylenchus, Tylenchorhynchus and Criconemoides were obtained from soils around citrus roots; Meloidogyne, Helicotylenchus and Aphelenchus, were from those around papaya roots; Meloidogyne, Paratylenchus, Hernicriconemoides, and Helicotylenchus, were from those around tea roots. In Ishigakijima, Pratylenchus coffeae was found from bamboo soil. The white-tips of rice-plants caused by Aphelenchoides were seen in Okinawa-hontô and specimens of the genus Hirschmanniella were ascertained from roots of the paddy-rice.

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The rice plants, variety "Hôyoku", infected with rice leaf spot were collected from twentyone places in Fukuoka Prefecture and the yields and qualities of them were analysed.The contamination degrees were grouped into five classes on account of the number of the spots on the flag leaves and the unhilled grains were classified into seven types by their degree and state of the causal discoloration. As the results, it was evident that the number of leaf spots on flag leaves increases, the weight of unhulled and hulled rice per 1000 grains reduces with increase of numbers of the rusty kernells, blue and immatured spikelets. Conclusively, the weight of hulled rice per 1000 grains is influenced by the infection of the spikelets and the degree of causal discoloration. Especially the latter performes great reduction of the quality of rice.

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In 1965, draped parts of the first internode of some rice plants were evidently infected with Piricularia oryzae. This is a peculiar case since no report and observation have beeen made. The authers report the result of investigation on this epidemic disease appeared in Amagi District of Fukuoka Prefecture in the present paper. The investigations were made in 2 paddy fields planted with varieties, "Hoyoku" and "Norin No. 12", respectively. Approximately 1 to 2 percent of the draped part was infected with the rice blast, and usually one diseased spot per ear was found. The length of the spot is about 3 cm, and the distance from the ear neck to the center of the spot is 8 to 13 cm. This unique disease on the draped part commonly appears on the rice infected with leaf tongue blast disease, as well. The cause is not clear enough unless the inoculation test is conducted, however, the rice plant delaying the head sprouting finish due to the low temperature and much rainfall during the heading period may accept the disease.

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It was reported that only insufficient infection with TMV of Xanthi-nc tobacco would be resulted unless TMV was inoculated immediately after abrasion (Fig. 1), and that the wounds of trichomes of Nicotiana glutinosa leaf stalk, made with electric shaver wetted with the virus suspension were much inferior in TMV infection to the wounds made by rubbing method with abrasive (Table 1).

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