Diseases

Pseudomonas syringae pv. phaseolicola (Burkholder)Young et al. - Holo Blight of Bean.

Systematic position.

Kingdom Procaryotae, section Gram-negative aerobic rods and cocci, family Pseudomonadaceae, genus Pseudomonas.

Synonyms.

Phytomonas medicaginis var. phaseolicola Burkholder, Ph. puerariae (Hedges) Bergey et al., Bacterium medicaginis var. phaseolicola (Burkholder) Link and Null, V. pueratiae Hedges, Pseudomonas medicaginis var. phaseolicola (Burkholder) Stapp and Kotte, P. phaseolicola (Burkholder) Dowson, Xanthomonas medicaginis var. phaseolicola Burkholder.

Biological group.

Hemibiotroph.

Morphology and biology.

Holo Blight of Bean attacks all elevated parts of the plant. In early phases of growth, the disease is found on the cotyledons. Indistinct oily spots and brown fine spots in the form of warts appear. In the first phase, fine, angular, oily dark-green spots appear on the leaves, settling between leaf ribs. Later the spots become dark brown. Then they turn a red-brown color. The centers of the diseased tissue may merge; however, distinct angles of these spots remain visible. Dirty white exudate emerges in places of lesion during damp weather. It dries up, appearing on the lower side of a leaf as a thin gray film. An important diagnostic attribute of the Holo Blight of Bean is the presence of big chlorotic zones around the lesions. Sometimes leaf apices slightly wither and lengthened gray-green (later brown) spots appear on the stems of the diseased plants. On beans, oily aqueous spots have a round form, which later merge. The infection passes to seeds from ripening fruits. At that point, it is possible to find yellowish and yellow-brown spots on the beans, resembling punctures made by insects. Seeds wrinkle and remain underdeveloped and small. Cells of P. syringae pv. phaseolicola are straight bacilli, usually 0.7-1.5 x 1.5-3 mkm, moving by means of flagella. They are Ggram-negative. On nutrient mediums, colonies are round, gray-white, and raised in the center, with transparent blue borders. Forming levan and fluorescing pigment. Diluting gelatin slowly. Not reducing nitrates. Forming NH₃. Not curdling milk. Not excreting indol and H₂S. Hydrolyzing starch. Oxidase reaction is negative. Forming acids from dextrose, galactose, levulose, mannose, arabinose, xylose, saccharose, and glycerin. Not forming acid from ramnose, maltose, lactose, raffinose, mannitol, or salicine. Optimum temperature for growth is 20-23°C, minimum 2.5°C, maximum 33°C. The bacterial infection is kept in the diseased vegetation residues and seeds.

Distribution.

Holo Blight of Bean occurs in meets in the USA, Brazil, Australia, and the European countries. It is distributed in all territories of the former Soviet Union where this culture is growing; i.e., in the Russian Federation, and also in Uzbekistan, Moldova, Lithuania, Latvia, Estonia, Kazakhstan, Ukraine.

Ecology.

Development of the bacteriosis is promoted by rainy weather and low temperatures.

Economic significance.

The disease severity consists in destruction of seedlings, in destruction of and adult plants, owing to a break of the stem in places where the lesions occur, resulting in a reduction of yield because of due to the diseased leaves of plants. In Moldova, the amount of diseased plants during epiphytotics reaches 50-80% in some years, and yield losses reach 30-60%. Control measures include optimal agriculture, maintenance of crop rotation, cultivation of relatively resistant varieties, careful removal of plant residues, pesticide treatment of seeds before sowing, and treatment of plants by pesticides during vegetation period.

Reference citations:

Bilai V.I., Gvozdyak R.I., Skripal I.G., Kraev V.G., Ellanskaya I.A., Zirka T.I. & Muras V.A. 1988. In: Bilai V.I., ed. Microorganisms - pathogens of diseases of plants. Kiev: Naukova Dumka, p. 254-255 (in Russian).
Chumaevskaya M.A. 1982. Results of studying bacterial diseases of plants in the USSR. Biologicheskie nauki 8: 5-19 (in Russian).
Gerasimov B. & Osnitskaya E. 1961. Pests and diseases of vegetable cultures. In: Savzdarg V.E., ed. Moscow: Gosudarstvennoe izdatelstvo selskokhozyaistvennoi literatury, zhurnalov i plakatov, p. 358-361 (in Russian).
Gorlenko M.V. 1947. A survey of geographical distribution of bacterial plant diseases in the USSR. Byulleten obshchestva ispytatelei prirody, otdelenie biologii 32 (2): 61-70 (in Russian).
Gorlenko M.V. 1949. Results of studying bacterial diseases in the USSR for 30 years (1917-1947). Mikrobiologiya 18 (1): 71-81 (in Russian).
Gorlenko M.V. 1966. Bacterial diseases of plants. Moscow: Vysshaya shkola. 291 p. (in Russian).
Izrail.skii V.P. 1960. Bacterioses of leguminous plants. In: Izrail.skii V.P., ed. Bacterioses of plants. Moscow: Gosudarstvennoe izdatelstvo selskokhozyaistvennoi literatury, p.221-227 (in Russian).
Kazenas L.D. 1965. Diseases of agricultural plants of Kazakhstan. In: Jundin I.A., ed. Alma-Ata: Kainar, p. 227-228 (in Russian).
Kiryukhina R.I., ed. 1979. Diagnostics of bacterial diseases of leguminous cultures and measures of their control. Methodical recommendations. Moscow: Kolos. 28 p. (in Russian).
Korsakov N.I., ed. 1982. Investigation and diagnostics of pathogens of bacterioses, studying resistance of annual leguminous cultures to them. Methodical instructions. Leningrad: VIR. 90 p. (in Russian).
Kunichenko N.A. 1985. Bacterioses of vegetable cultures in Moldova. In: Gvozdyak R.I., ed. Bacterial diseases of plants (Abstracts of reports). Part 2. Kiev: Naukova dumka, p. 67-68 (in Russian).
Pavlyushin V.A., ed. 2006. Bacterioses of leguminous cultures and measure of their control (Methodical recommendations). St. Petersburg: VIZR. 41 p. (in Russian).
Shpaar D., Kleinkhempel G., Myuller G. & Naumann K. 1980. Bacterioses of cultural plants. Handbook. Moscow: Kolos. 143 p. (in Russian).
Vzorov V.I. 1938. Species and spreading of bacterioses of agricultural plants in the Soviet Union. In: Borover S.Ya., ed. Byulleten Rostovskoi stantsii zashchity rastenii 9: 87-91 (in Russian).

© Lazarev A.M.

Photo is taken from Archive of documentary photographs of Federal Management on research of selection of cultural plants (Aschersleben, Germany) and is published with kind permission of Prof. Dr. K. Naumann (Germany).