Xantomonas campestris pv. carotae (Kendrick) Dye - Bacterial Blight of Carrot.

Systematic position.

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


Pseudomonas carotae Kendrick, Phytomonas carotae Kendrick.

Biological group.


Morphology and biology.

Bacteriosis starts to develop at apices of lobules of lower leaves as wet yellow spots. These spots quickly darken, becoming brown in color. The tissue surrounding these spots has a yellow color. Leaves roll and dry up at strong development of the disease. Leafstalks may be also attacked, appearing as brown spots on these leaves. Leaves, stems, and umbels are attacked in seed plants. Small oblong, dark, aqueous spots and stripes appear on their stems. The infected young umbels grow dark in the budding stage. They become covered with sticky liquid and dry up. Sometimes only a part of umbels is affected; other inflorescences develop normally and give ripe seeds. Curved umbels are observed in diseased plants at affection of fruit stems. Strongly affected seed plants lag in development. The disease shows itself on root-crops as poorly pressed-in, fine brown spots. Cells of X. campestris pv. carotae are straight rods, usually 0.42-0.85 x 1.38-2.75 mkm in size, moving by means of 1-2 polar flagella. Gram-negative. Aerob. Having no dormant stage. Non-sporing. On potato agar, colonies are round, smooth, shining, with even borders, yellow. Not reducing nitrates. Forming H2S from peptone. Not hydrolyzing starch. Forming acid from glucose, xylose, saccharose, lactose, raffinose, trehalose, glycerin; but not forming acid from maltose, ramnose. Diluting gelatin. Optimum temperature of growth is 25-30°C. The infection is kept in seeds and infected vegetation residues.


Bacteriosis is present in the USA, Canada, Australia, and other countries. This disease is registered in territories of the USSR in the Voronezh, Tomsk, Kemerovo, Novosibirsk Regions, in the Altai and Primorskii Territories, in Republic of Altai, also in Moldova, Kazakhstan, Georgia, and Ukraine.


Intensive development of the bacteriosis is observed in warm weather, at daily average temperature of 20-25°C. Development of the bacteriosis depends on the sum of positive temperamperatures and precipitation during the vegetation period.

Economic significance.

Severity of this bacteriosis results in reduction of quality and productivity of carrot. Epiphytotics of the Bacterial Blight of Carrot are observed sporadically, only when a combination of favorable conditions for the pathogen exist during the vegetation season (humidity and temperature of air and soil), depending on the level of resistance of a variety. The zone of high severity includes Ukraine, West Siberia (Tomsk, Kemerovo, and Novosibirsk Regions, Altai Territory, Republic of Altai), Primorskii Territory. E.g., in conditions of forest-steppes (Ukraine), the bacteriosis is particularly dangerous to carrot during the first year growth; losses reach 10-12% of plants. In some years, the bacteriosis distribution in Altai (in the first year of cultivation) is 22.4-100% on plants, 14-15.8% on root crops (in the period of harvest), 21-53% at storage, 31.5-92.5% on seed plants. It has been established for the Shantene carrot cultivar that losses of 1% to 75% of sheet surface leads to decrease of plant productivity by 12.8% to 44.7%. Essential reduction in productivity of carrot is observed at 0.1% point of affection (2% of sheet surface); thus, losses at productivity 30, 60, and 75 t/ha are 4.1, 8.1, and 10.1 t/ha, accordingly. At 1 point of affection (15.6% of the sheet surface) yield losses are 6.2, 12.3, and 15.4 t/ha; at 2 points (30.2%) 8.1, 16.2, and 20.3 t/ha; at 3 points (49.7%) 11.1, 22.2, and 27.8 t/ha; and at 4 points (68.3%) 13.1, 26.1, and 32.6 t/ha, accordingly. Control measures include optimal agriculture, maintenance of crop rotation, cultivation of relatively resistant varieties, careful removal of plant residues, separating seeds from shrunken grains, pesticide treatment of seeds before sowing, and pesticide treatments of plants during vegetation period.

Reference citations:

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Borodai V.V. 2005. Development of bacterial diseases on carrot roots during storage. In: Podgorskii V.S., ed. Phytopathogenic bacteria. Phytoncidology. Allelopathy. Collection of articles of participants of International Scientific Conference. Kiev: Gosudarstvennyi Agroekologicheskii Universitet, p. 19-22 (in Ukrainian).
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Rybalko A.A. 1988. Method of immunological estimation of carrot to bacteriosis and initial material on complex stability to diseases in Western Siberia. PhD Thesis. Moscow: VNIISSOK, 24 p. (in Russian).
Rybalko A.A. 1990. Distribution and harmfulness of bacteriosis of carrot in Western Siberia. In: Gvozdyak R.I., ed. Phytoncides. Bacterial diseases of plants. Materials of conference. Part 2. Kiev & Lvov: KGT-2, p. 80-81 (in Russian).
Rybalko A.A. & Samokhvalov A.N. 1985. Selection of carrot on stability to bacteriosis in conditions of Western Siberia. In: Gvozdyak R.I., ed. Bacterial diseases of plants (Abstracts). Part 2. Kiev: Naukova dumka, p. 130-131 (in Russian).
Rybalko A.A. & Samokhvalov A.N. 1990. Structure of population of the pathogen of bacteriosis of carrot in Western Siberia. In: Gvozdyak R.I., ed. Phytoncides. Bacterial diseases of plants. Materials of conference. Part 2. Kiev & Lvov: KGT-2, p. 80-81 (in Russian).
Tsilosani G.A. & Tukhareli A.R. 1981. Bacterial disease of carrot in Georgia and measures of its control. In: Gorlenko M.V., ed. Bacterial diseases. Moscow: Kolos, p. 194-200 (in Russian).
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