Diseases

Alternaria alternata (Fr.) Keissl. - Alternaria Spot of Rice, Glume Mold of Rice

Systematic position.

Division Eumycota, subdivision Deuteromycotina, class Hyphomycetes, order Hyphomycetales, family Dematiaceae, genus Alternaria.

Synonyms.

Torula alternata Fr., Alternaria tenuis Nees.

Biological group.

Hemibiotrophic parasites.

Morphology and biology.

Disease appears during the phase of grain ripening. Olive or black-brown conidiophores appear on leaves and stems, especially those that are dying-off. All elements of panicle turn brown. Ovaries die off and turn to a black mass consisting of mycelium and spores. Disease causes damage at first to plants injured by wind, birds, insects, and other diseases. The fungus produces toxins, which damages the quality of seeds and reduce germination vigor. Seeds and vegetation residues are a source of the infection. The seed infection may cause destruction or weakening of shoots. The fungus is registered on various vegetative substrata. Colonies are usually olivaceous black. Conidiophores solitary or aggregated in small groups, simple or branched, sometimes geniculate, olivaceous or golden brown, smooth, to 50 microns long, 3-6 microns thick, with one or several conidial scars. Conidia are formed in long, often branched chains; obclavate, obpyriform, ovoid, or ellipsoidal; pale to moderately golden brown; smooth or warty, with several longitudinal or oblique septa; 20-63 (37) x 9-18 (13) microns. Beak is pale, short, conic or cylindrical, sometimes to 1/3 the length of conidia, 2-5 microns, thick.

Ecology.

Optimum temperature for growth and sporulation is 25-30.C. Development of the disease is promoted by increased humidity, wind, and highly fertile soil.

Distribution.

Found everywhere in zones of rice cultivation. In the Krasnodar Territory the disease incidence is 0-30%. It is found in Kazakhstan, Uzbekistan, and Tajikistan.

Economic significance.

Harmful activity of the disease is insignificant in droughty areas. In damp years yield losses may reach 40%. In the Primorskii Territory the disease develops on seeds annually. Protective actions include crop rotation, eradication of residues and treatment of seeds by fungicides before sowing.

Reference citations:

Ainsworth G.C. 1971. Ainsworth & Bisby's Dictionary of the fungi. Sixth edition. Kew, Surrey: Commonwealth Mycological Institute. 663 p.
Baimataeva B.K., Kuzhantaeva Zh.Zh. 1978. Fungal diseases of rice. Bulletin of agricultural science of Kazakhstan (Alma-Ata), 3: 86-88. (In Russian)
Berdysh Yu.I. 2004. Distribution of main pests and diseases of crops in Krasnodar Territory in 2003 and prognosis of its incidence in 2004. Krasnodar: STAZR. 28 p. (In Russian)
Dorofeeva L.L., Kodyakov A.A., Kratenko V.P., Lebedev M.B., Motovilin A.A., Tikhonova N.A. 1992. Fungal diseases of rice. Tashkent: FAN. 94 p. (In Russian)
Dorofeeva L.L., Sizova T.P., Shapovalova R.A. 1993. Phytopathologic state of rice crops in Central Asia. Mikologiya i fitopatologiya, 27 (3): 62-66. (In Russian)
Egorova L.N., Oksenyuk G.I. 1989. Mycoflora of rice in Primorskii Territory. In: Reifman V.G., D'yakonov K.P., eds. Protection of plants in the Far East. Vladivostok: Dalnevostochnoe branch of Academy of Science of SU. 66-71 p. (In Russian)
Ellis M.B. 1971. Dematiaceous Hyphomycetes. Kew: CMI. 608 p.
Kazantseva T.P., Sorokin N.S., Vasil'eva I.A., Dolgova T.M., Martynov A. Ya., Gavrilova E.A., Bakalova G.A., Logvinenko T.S., Bespalova A.P., Chichikhina T.V., Dolaberidze S.D., Artokhin K.S., Makhota V.M. 1997. Prognosis of incident and distribution of pests, diseases of crops, weeds and quarantine objects on the territory of Rostov region in 1997 year and measures of control. Rostov-na-Donu: Yug. 128 p. (In Russian)
Sherstyanykh O.I., Luk'yanchikov V.P. 1978. Distribution of fungal diseases of rice in Krasnodar Territory. Bulletin of scientific and technical information of the All-Union research institute of rice (Krasnodar), 25: 56-58. (In Russian)

© Gasich E.L.