A virus was isolated from trumpet narcissus showing symptom of mosaic and brown spots, collected in Shizuoka Prefecture in 1967. The virus was readily transmitted by juice inoculation, but not by Myzus persicae. Among the tested plants of 49 species in 14 families, 37 species in 14 families, namely, Chenopodiaceae, Amaranthaceae, Aizoaceae, Caryophyllaceae, Cruciferae, Leguminosae, Malvaceae, Umbelliferae, Solanaceae, Scrophulariaceae, Cucurbitaceae, Compositae, Liliaceae and Amaryllidaceae, were found susceptible to the virus by juice inoculation. Of these plants, Chenopodium amaranticolor, NewZealand spinach and bean were considered to be useful as differential host plants for the virus. The virus was proved to be transmitted through seed of chickweed and soybean. But the virus was not transmitted by Longidorus martini (nematode).
The virus in vitro withstood heating at 60C for 10 minutes, but not 65C, and 14 days of storage at 20C, but not 21 days. The virus particles were found to be spherical about 25nm in diameter.
Antiserm prepared by injection to rabbit showed homologous precipitin tube titre of 1/512. By agar gel diffusion tests, the virus showed negative reaction to antisera against arabis mosaic virus supplied by Dr. B.D. Harrison and against tobacco ringspot virus and tomato ringspot virus supplied by Dr. R. Stace-Smith. The antiserum against the tomato black ring virus supplied by Dr. B.D. Harrison only gave positive result. The virus and the antiserum were furthermore sent to Dr. B.D. Harrison, and the above results were confirmed, along with an additional negative results with antisera against cherry leaf roll virus, raspberry ringspot virus and strawberry latent ringspot virus. Furthemore, the virus is more closely related to beet ringspot strain than to potato bouquet strain of tomato black ring virus.
From these results, the virus was identified as beet ringspot strain of tomato black ring virus, which has not been reported before in Japan.

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Natural infection of plum line pattern virus was found on plum varieties Methley, Burbank, Red June, White plum, Beauty, Santa Rosa and Ooishi-wase, prune variety Hungarian and flowering cherry varieties Someiyoshino, Ranzan, Ruiran and Kwanzan.
Plum line pattern virus was transmitted by budding from the diseased trees of plum and flowering cherry to seedlings of peach, plum, apricot, Japanese apricot, cherry and flowering cherry.
The leaves of naturally infected trees of plum and flowering cherry showed typical yellow line pattern, yellow vein net and chlorotic ring or spot. In the case of artificial inoculation the seedlings of peach, apricot, cherry and flowering cherry showed line pattern mainly, but Japanese apricot seedlings showed line pattern, vein net as well as severe stunting.
One mechanically transmissible virus was isolated from the peach seedlings inoculated with plum line pattern. This virus induced chlorotic local lesion on the inoculated leaves of cucumber, but it did not cause any symptoms on Catjang, petunia, Nicotiana glutinosa, N. megalosiphon, Chenopodium amaranticolor and C. quinoa which have been reported as hosts of plum line pattern virus by Fulton and Kirkpatrick et al.
Methley isolate of plum line pattern virus and one isolate of apple mosaic virus caused same line pattern symptoms on Chaenomeles japonica. The former affected the seedlings of peach but not apple, and the later affected the seedlings of apple but not peach.

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A sap transmissible virus was isolated from peach seedlings grafted with plum and flowering cherry. The host range, thermal inactivation point (60-65C), dilution end point (10^-4) and longevity (13-14 days) of this virus were about the same as those of cucumber mosaic virus (CMV). This virus was transmitted by Aphis gossypii and Myzus persicae from cucumber to cucumber. The particle was spherical with an approximate diameter of 30nm. The positive reaction was observed in agar-gel serological test with this virus and the antiserum of CMV-Y. From these results the virus was identified as CMV.
CMV was isolated by Aphis gossypii and Myzus persicae from 5 among 12 trees of flowering cherry variety Someiyoshino, but it was not isolated from trees of peach, plum, apricot and Japanese apricot. CMV was isolated not only from the trees showing line pattern symptoms but also from trees with healthy appearance. This suggested that CMV was not closely related to appearance of line pattern symptoms.
Among the several isolates of CMV isolated from Prunus plants, plum isolate-1 from variety Burbank belonged to ordinary strain of CMV, plum isolate-2 from variety Methley was a member of ordinary strain group having a wide host range on Cucurbitaceae and flowering cherry isolate from variety Someiyoshino belonged to Brassica strain.
The retransmission test of CMV from herbaceous plants to Prunus mahaleb seedlings by aphids was not a success.

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Resistance of five or ten rice varieties to lesion formation and to sporulation of three blast fungus strains on host plants was tested in a greenhouse. Varietal difference of resistance to sporulation was found in a few experiments, but varietal difference of resistance to lesion formation was difficult to find, because of a large variation of pathogenicity index (aggressiveness) by which varietal resistance was estimated. However, correlation of field resistance was higher with resistance to lesion formation than with resistance to sporulation. Correlation between resistance to lesion formation and that to sporulation was not found.

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An unfamiliar disease of tobacco plants, the symptom of which is brownish or blackish angular spot on the leaves, occurred in Yamaguchi prefecture in 1970. The author obtained five bacterial isolates from the diseased leaves, and tested their characteristics in comparison with Pseudomonas tabaci.
Not any differences were observed between the pathogenic isolates and P. tabaci in bacteriological and serological characteristics.
Angular leaf spot symptoms produced by these pathogenic isolates were found to be apparently distinguishable from those produced by P. tabaci.
From these results, the pathogenic isolates were tentatively identified as P. angulata causing angular leaf spot disease of tobacco.

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Antibody production in tumorous (Ehrlich's) ascites of mice injected with various antigens, tobacco mosaic virus (TMV), several strains of cucumber mosaic virus (CMV), and healthy tobacco protein, was investigated. Highest antibody titre of the mouse ascitic fluid was 1024-fold when injected with 3mg of TMV antigen mixed with equal volume of Freund's complete adjuvant. Ascitic fluids having antibody titre, 128 and 512-fold were also obtained from mice injected with 0.3mg and 1.75mg of CMV-O antigen, respectively. Maximum volume of ascitic fluid containing antibody obtained from single mouse was 38ml. From the results of the present experiments, It was concluded that three weekly injections of 0.1-1mg of antigen mixed with Freund's adjvant, followed by injection of tumor cells was convenient for obtaining a high content of antibody.
This technique will be useful for antibody production to some plant viruses which have poor yield and are difficult to purify.

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A virus, designated as beet necrotic yellow vein virus (BNYVV), was isolated from sugar beet plants affected with rizomania disease. The virus was transmitted through the soil and by sap inoculation, but not by the aphids, Myzus persicae and Aulacorthum solani. Of 84 species of plants belonging to 16 families inoculated by sap, 15 of 17 species belonging to Chenopodiaceae, Tetragonia expansa and Gomphrena glohosa plants became infected with the virus. The virus tended to be restricted to the inoculated leaves of all host plants, but sugar beet, spinach, and Beta macrocarpa plants occasionally became infected systemically. The thermal inactivation point of the virus was between 65 and 70C, the dilution end point was 10^-4, and the infectivity was retained for 5 days at 20C or for 8 days at 4C. BNYVV particles (isolate YS) had a diameter of about 20nm and three peaks of length distribution at 95-110nm, 255-270nm, and 370-390nm. The virus was partially purified by organic-solvent clarification and polyethylene glycol precipitation. An antiserum to BNYVV had a titer of 1/1, 024 in ring precipitin tests. In agar gel-diffusion tests, a band of precipitation was produced between the virus and its antiserum. BNYVV did not serologically relate to soil-borne wheat mosaic virus, tobacco rattle virus, and tobacco mosaic virus. The present cryptogram of BNYVV is ^*/^*:^*/^*:E/E:S/(Fu).

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Changes in the number of the propagules of Macrophomina phaseoli (Maubl.) Ashby in naturally-infested soils were assayed by the soil plate method in elapse of time after storage at 20C.
In Nagano soil, an average of 9 propagules of this fungus per gram of soil were initially detected, but after 2.5 or 4.17 years' storage, the number was reduced to 4 or 2per g of soil, respectively. The half-life in the soil was calculated at 1.88 years on an average.
In 2 different sugar cane field soils of Okinawa after 3.5 years' storage, 3 or 8 propagules of this fungus were detected, but after 5.75-6 years, this fungus was never detected.
Longevity of M. phaseoli in artificial preparations was also compared by testing viability of 50-100 sclerotia of each isolate of the respective preparations.
Three years after storage, cultured sclerotia of 3 isolates tested were 16-40% viable, and in 4 years, they were 5-8% viable.
In tissue-formed sclerotia, 3 isolates tested were 1-27% viable, after 3 years but another isolate was not viable, although it was 2% viable in 2.25 years.
The soil-formed sclerotia originated from a poor substrate of water agar were 4% viable, but those from PDA were 56% viable after 3 years.
The half-life of cultured, tissue-formed, or soil-formed sclerotia was 1.05, 0.84, or 0.65-3.59 years, respectively.
Sclerotia of M. phaseoli in artificial preparations were different in longevity according to differences of isolates, preparation methods, or nutritional sources.

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As described in the previous paper, it was clear that N-lauroyl-L-valine had protective effect on rice blast. Experiments were conducted to examine the fungicidal activity of this compound on each stage of the fungal life cycle, i.e. spore germination, appressorial formation, hyphal penetration, hyphal growth, and sporulation, and to compare the activities between optical isomers. The results indicated sodium N-lauroyl-L-valinate inhibits almost completely the appressorial formation at 100μg/ml, and the mycelial growth at 200μg/ml. The isomer inhibited the appressorial formation and the mycelial growth above 90 per cent at 300μg/ml, but no other serious inhibition was observed. The DL-mixture inhibited the appressorial formation at 100μg/ml, and showed less inhibitory effect than the L-isomer in other stages.
Thus, appressorial formation was suggested to be one of the main inhibitory sites by N-lauroylvaline isomers in protection against rice blast.

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A new disease of chinese cabbage has been observed since 1966, and the occurrence area has been gradually increasing every year.
The leaves of the diseased plants turn blight yellow in color, and the plants are a little stunted. These plants do not form compact central heads even near a harvest time. Their roots and stems become dark brown or blackened in the vascular tissues.
Hyphae were always observed in the vascular tissues of the diseased plants. Fusarium oxysporum, the suspected causal fungus, was never isolated from the freshly dissected stem or root tissues of the diseased plants. Cephalosporium sp. was one of the most frequently isolated fungi, but its pathogenicity onto chinese cabbages was not positive. Verticillium albo-atrum is another frequently isolated fungus. It showed pathogenicity onto 3 varieties of chinese cabbages tested under a greenhouse condition at 20C. The symptoms of the plants grown in artificially infested soils were more or less identical with those in naturally infested soils. In addition, V. albo-atrum was recovered from the diseased plants. Vascular discoloration of the roots or the stems were generally observed in some 40 days after seeding in the artificially infested soil at 20C.
As Verticillium disease of chinese cabbage in nature appears not to have been previously reported, this plant may be included as a new host of this fungus. “Yellows” (Japanese name, Ohkabyo) may be coined to this new disease.

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Around 1955, a bacterial disease of potato plant, distinguished from soft rot caused by E. carotovora, was found at Nakashibetu Cho in Nemuro Area of Hokkaido. Since then, it has gradually spread through Kushiro and Abashiri Areas. In 1970, the outbreak of this disease was observed in several parts of Tokachi and Kamikawa Areas in Hokkaido.
The symptom of this disease was simillar to blackleg disease as reported in other countrles.
The causal organism quickly decayed vegetables, showing typical soft rot appearance. They produced the same symptom as those of naturally infected potato plants, when inoculated in the potato stems at the soil line. Intensity of the symptom at 18C was higher than that at 24.5C.
When healthy seed tubers were inoculated with the causal organism by corkborer, many of the plants that grew from those seed tubers showed blackleg symptom. Also, E. chrysanthemi produced the blackleg symptom when inoculated by the same method.
The bacterial and serological characteristics of the causal organism agreeded with the descriptions of E. atroseptica, reported by Graham et al. It had been recoginized that Logan's medium was useful for differentiation of the causal organism from E. carotovora or E. chrysanthemi.
Agar gel diffusion patterns showed that the causal organism possessed species-specific antigen, which did not react with E. carotovora and exsisted in almost all isolates, as well as common antigen with E. carotovora (including aroideae strain). But E. chrysanthemi did not possess any common antigen with the causal organism or E. carotovora.
From these results, we identified the causal organism with Erwinia atroseptica (van Hall) Jennison according to Bergey's system.
According to Dye, the scientific name E. carotovora var. atroseptica (van Hall) Dye is suggested for this bacterium. However we are inclined to retain, for the time being, E. atroseptica as the species name.

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Stemphylium sp. was isolated from the lesions of asparagus plants in Hokkaido. The early symptoms on stems and cladophylla are spots which are light brown to gray in the center with red brown margin, 2-5×3-12mm. in diameter and the cladophylla defoliate later. The fungus is identified to be S. botryosum Wallr. and the author proposes the name of asparagus Hanten-byô (Stemphylium leaf spot).

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