Phytophthora rot of cucumber is commonly seen in Nara Prefecture in Japan and the damage is especially severe when the plants are attacked at the seedling stage, which results in the damping-off symptom. This study was conducted to survey the species of Phytophthora attacking cucumbers in Nara Prefecture, to examine their pathogenicity to cucumber and other crops, and to test some fungicides for their controlling effect against the disease.
1) The incidence of Phytophthora rot of cucumber varies from year to year depending upon the amount and duration of the rainfall. The seasonal change of the incidence also depends on the condition of cucumber cultivation. The disease becomes prevalent once a year in vinylhouse culture (from March through April), while two peaks of prevalence are seen in open-field culture (May to July and late in August through September), and in gravel culture and water solution culture (April to June and September to October).
2) Sixteen isolates of Phytophthora were obtained from diseased cucumber plants including a squash stock, which exhibited the damping-off symptom. Of these isolates, thirteen were identified as Phytophthora melonis KATSURA, and two were identified as P. capsici LEONIAN, on the basis of the morphological characteristics of their zoosporangia and their pathogenicity to the fruit of cucumber and eggplant. The one other isolate was found to be a mixture of these two species of Phytophthora.
3) The isolates were tested for their pathogenicity to seedlings of cucumber and squash. Phytophthora melonis showed intense pathogenicity to cucumber and induced the damping-off symptom, but did not invade squash. On the other hand, P. capsici showed intense pathogenicity to squash and induced damping-off, but was weakly pathogenic to cucumber, making some lesions on the leaves and stems without the damping-off symptom.
4) The fungicides were tested for their controlling effect against Phytophthora rot of cucumber in a field artificially infested with P. melonis. Of these, Pansoil E (40 % WP) at concentrations of 133 and 200 ppm was highly effective for control of the disease under the condition of severe outbreak.
5) Judging from these results, the species of Phytophthora responsible for the damping-off symptom of cucumber are considered mostly to be P. melonis. Phytophthora capsici may possibly attack cucumber only under continuous unfavorable conditions and also can attack the squash stock used for the grafting. It can be said that the damage by the former species is acute while that by the latter is chronic in most cases.

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1. Two species of Phytophthora causing basal stem rot of cucumber, P. melonis KATSURA and P. capsici LEONIAN, were tested for their pathogenicity to various kinds of cucurbitaceous crops under soil and water culture conditions. Cucumber, muskmelon, watermelon, oriental melon, and oriental pickling melon were attacked by both fungi, while squash was attacked only slightly P. melonis. Cucumber appeared to be more susceptible to P.melonis than to P. capsici, except when squash was used for the resistant stock, which was easily attacked by P. capsici. Loofah was found to be resistant to both species of Phytophthora.
2. A large number of varieties of squash, pumpkin, and loofah were screened for their resistance to P. capsici. All the tested varieties of squash and pumpkin were susceptable, but most of the loofah varieties proved to be highly resistant to P. capsici. A suggestion was proposed as to the possibility of utilizing loofah instead of squash as the resistant stock against the disease.
3. Several fungicides were tested for control effectiveness in a field artificially infested by P. melonis. Among them, Difolatan wettable powder (×800) and Pan soil emulsion (×2,000)were effective for control of the disease as well as was chloropicrin, when they were applied to thesoil at a rate of three liters per square meter.

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Recently, the squash-grafting culture of cucumber is be coming common in Kyoto Prefecture in Japan for the control of Phytophthora rot of cucumber due to the resistance of the squash stock. It is, however, not always clear whether the squash stock is satisfactorily resistant to both species of Phytophthora known to be pathogenic to cucumber, P. melonis KATSURA. and P. capsici LEONIAN. This study was undertaken to assess the value of squash as the resistant stock against both fungi.
1. Samples of Phytophthora-affected cucumber, squash, watermelon, tomato, and pepper were collected from various localities in the Tokai-Kinki Region including Kyoto Prefecture. Isolation and identification were made using the cucumber-fruit trap method proposed by KATSURA and MIYATA et al. All the isolates from cucumber were identified as P. melonis, while the isolates from the other crops were found to be P. capsici.
2. Cucumber and squash were planted on soil artificially infested with P. melonis or P. capsici. Cucumber was attacked very severely by P. melonis and moderately by P. capsici, while squash was attacked severely by P. capsici but was not attacked by P. melonis. When they were grown on soil infested with both fungi, an isolation experiment showed that all the isolates from cucumber were P. melonis while all the isolates from squash were P. capsici.
3. Seven varieties of squash for the stock were tested for their resistance to P. capsici, but all of them were found to be susceptible.
4. These results suggest that the squash-grafting method is highly effective for the control of Phytophthora rot of cucumber caused by P. melonis, but not necessarily effective when the disease is due to P. capsici, which is apparently pathogenic to the squash stock.

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A root and crown rot of tomato caused by Fusarium oxysporum SCHLECHT.(SNYD. & HANS.), different from the ordinary wilt in its symptoms, has been found in several districts of Japan in recent years. This disease occurs in vinyl green houses in winter, but not in warmer seasons.
Diseased plants are stunted and chlorotic, then wilt and die. The whole root system exhibits a dry brown rot of the cortex and xylem. Necrosis of the cortex in the stem may develop at or under the soil line. Browning of vascular bundles in the stem rarely develops more than ten cm above the soil level. These symptoms are observed both in the field and in inoculated plants.
Isolates of F. oxysporum from these diseased plants were examined for their pathogenicity to twenty-two species of vegetable crops belonging to the Solanaceae, Cucurbitaceae, Cruciferae, Leguminosae, and certain other families. They were not pathogenic at all to crops other than the Solanaceae. Among solaneceous crops, the tomato was severely affected and exhibited the above-mentioned symtoms. Eggplant and pepper were slightly affected by a few isolates. As they are mainly pathogenic to the tomato, they are considered to belong to f. sp. lycopersici.
These isolates were also examined for their pathogenicity to tomato varieties. They were pathogenic to all of the tested varieties, that is, Ponderosa and two other varieties susceptible to f. sp. lycopersici races J1 and J2, Okitsu 3 and three other varieties resistant to race J1 and susceptible to race J2, and Walter, resistant to both race 1 and 2 (American differential system).
These reactions were different from those either race J1 or J2, the races so far known in Japan. The optimum temperature for the growth of these isolates was estimated at 27-28°C, being similar to the races J1 and J2. On the other hand, the optimum temperature for the disease development was 10-20°C, being apparently lower than that for the wilt caused by race J1 or J2.
On the basis of the above-mentioned results, it was proposed to add Walter to the Japanese differential system as a new diffrential variety, and to set up a new race of f. sp. lycopersici, race J3, which is pathogenic to all the three differential varieties. The isolates from the newly found root and crown rot of tomato fell into the new race.

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In southwest Japan the mulberry tiger moth, Spilarctia imparilis Butler, has attacked the satsuma orange during the last several years. This moth is an insect of extreme polyphagy and its ability for dispersal is considerable. So far it has been reported that as many as 124 species belonging to 32 families have served as the host plants of this larva. However, the adult distinguishes plants for oviposition from plants for feeding, and lays eggs on the following three species : Mallotus japonicus, Faraga ailanthoides, and Robinia pseudo-acasia. In autumn the larvae remained on and fed on the plants on which the egg-masses were deposited. After hibernation they attacked and accepted various kinds of plants. In May it was not infrequent to observe a sudden mass invasion of the final instar larvae into the orchards of satsuma orange and other fruit trees causing severe damage to growing leaves and flowers.

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It has been reported by Bergman and Schoenbeck that several antibiotic substances, such as tuliparin, are present in the tulip plant, especially in the stigma of the pistil. In this paper, using the crude extracts obtained by tissue decoction and their antibiotic spectra, the difference in antibiotic contents among several tulip varieties and the occurrence of the active substances over the period ofa year were studied.
As shown by inoculation tests, Phytophthora porri invades the tulip bulb through the young bud but not through the scaly leaf. The root is infected but the hyphae hardly develop as far as the bulb through the root plane. On medium made from the bulb decoction, Botrytis cinerea grew well, but P. porri, P. citrophthora, P. capsici, and P. melonis were inhibited their growth. These inhibitory actions of the decoction for Phytophthora are also shown by the bulb decoction media of garlic and lily, but not those,of onion and hyacinth within the Liliaceae. There are few differences in the contents of the inhibitory substances among three tulip varieties, Maureen, Flying Dutchman, and The Bishop.
Inhibitory action of the decoction decreased while the bulbs were stored at comparatively high temperatures (35°C, 45°C). When the bulbs were planted in early winter, the contents of active substances in the bulb are not so great. Nor does the content of active substance increase with the emergence of buds from the bulb through the soil. When the new leaves are elongated and their assimilation ability becomes active, the active substance increased gradually in the leaves. At the time when the new bulbs increase in size, the substances synthesized in the leaves moved to the new bulb in early spring and then disappeared in the leaves with their senescence.
Therefore, it can be concluded that the infection of P. porri in tulip plants is accomplished while the sprouts are emerging through soil, before the active substance appear to inhibit the fungus invasion.

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As there are almost no microorganisms found on the leaves of Eucalyptus gunnii, experiments were carried out to separate several fractions from the leaves by organic solvents and to bioassay them in the expectation of finding antimicrobial substances in the leaves.
Microorganisms used in the assaying tests were Cochliobolus miyabeanus (S. Ito et Kuribayashi) Drechsler for antifungal substances, Bacillus subtilis (Ehrenberg) Cohn for antibacterial substances, and TMV-N strain for TMV-inhibiting substances.
Antifungal activities were observed in the benzene, n-butanol, water, and ethyl acetate (acidic, basic and neutral) fractions and in the residue of the ethyl acetate fractions. Ethyl acetate, n-butanol, and water fractions had antibacterial activity. Inhibition of TMV multiplication was observed in the basic ethyl acetate and water fractions.
In the ethyl acetate fraction, three crystalline substances were isolated as antimicrobial substances. One of them was identified as gallic acid by NMR, IR, UV, MS, and other techniques, but the identity of the others has not yet been determined.

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In order to develop a method for controlling the Anomala schöenfeldti Ohaus increase in turfgrass, the authors sprayed turfgrass with certain agricultural chemicals at their emergence period on the ground, examined the change of imagoes in number, the efficacy in killing them, and the distance oftheir flight.
(1) Sumithion emulsion had the greatest efficacy for controlling this insect, and their density could be decreased below 5% by spraying 10 a with 250l of 1/1000 diluted emulsion.
(2) In the Tokai district two peaks of emergence of the imagoes were found, from the middle of June until the middle of July and from the middle of August until the end of that month. So, to control this insect, the spraying of this emulsion is needed three times: in the middle of June, at the beginning of July, and in the middle of August.
(3) This imago emerges on the ground copiously even on a rainy day; the peak of this emergence is from the middle of June until the middle of July, which is the rainy season.
To control this insect, the spraying of chemicals must be carried out on a clear day.

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Hymexazol (3-hydroxy-5-methylisoxazole), which has been developed as a soil-fungicide, was found to be effective against rice sheath blight caused by Pellicularia sasakii. In these experiments, its effectiveness with respect to the time at which application was made and its antifungal activities in vitro, in the greenhouse and in the field were investigated. The results were as follows: 1) Hymexazol was more effective as an eradicant than as a protectant: it showed no apparent inhibitory effect on the mycelial growth on leaves which had been treated previously by the chemical. In field trials, a significant controlling effect of hymexazol was noticed when the chemical was used shortly after inoculation. 2) The inhibitory effect of hymexazol when checked by the agar dilution method against P. sasakii was not so remarkable; however, the mycelium of P. sasakii which was grown of PSA medium containing hymexazol was thin and its sclerotium formation was inhibited at the low concentration of 10-100 μg/ml for over 10 days after treatment. The pathogenicity of this fungus was weakened by the treatment with hymexazol. On the other hand, the growth of P. sasakii was completely inhibited at a very low concentration of hymexazol (2.5 μg/ml) in a liquid culture. 3) The enlargement of lesions of rice sheath blight was retarded by direct contact of hymexazol with the pathogen. When hymexazol was applied to a mycelial colony of P. sasakii, the intensity of the pathogenicity of the peripheral mycelium which was not in direct contact with hymexazol was apparently weakened.

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