Diseases
Scolecotrichum graminis Fuckel - Brown Stripe (Brown Leaf Blight) of Oats
Systematic position.
Subdivision Deuteromycotina, class Hyphomycetes, order Hyphomycetales, family Dematiaceae, genus Scolecotrichum (Ainsworth, 1971). Now this species is situated at Mitosporic fungi (Hawksworth et al., 1995).Biological group.
Hemibiotroph.Morphology and biology.
Scolecotrichum graminis infects gramineous grasses of 140 species and some cereals, e.g., wheat, rye, and oats. Lesions on leaf blades are first small, round to oval or elongated. Later they becoming gray, sharply limited, mostly brown, with red-brown border. Parallel rows of prominent olive gray to black dots, visible to the eye, develop on the lower leaf surface along the lighter veins. The arrangement of the dots readily distinguishes Scolecotrichum from the attacks of other leaf-blighting fungi. Each dot is a dense cluster of spore-bearing structures (conidiophores). Spores are ovoid or oblong, olive, with 1-3 septae, 22-48 - 8-14mkm. The Scolecotrichum fungus overwinters as masses of mycelium (stromata) in living grass leaves and crop debris from the past growing season. During spring rains the stromata swell and rupture the epidermal cells on the upper surface of affected leaves. Clusters of conidiophores emerge through the ruptured epidermis (or through stomata) and produce spores (conidia) that are disseminated primarily by splashing and wind-blown rain.Distribution.
Europe, Asia, America, Australia. All parts of Russia and neighboring states.Ecology.
Cooler (15-18.C) wet weather in spring and autumn provides optimum conditions for the disease development. During warm dry weather in summer the sporulation ceases, causing the incidence and severity of brown stripe to decrease.Economic significance.
Data on brown stripe of oats harm in Russia are absent.Related references:
Ainsworth G.C. ed. 1971. Ainsworth and Bisby's Dictionary of the fungi. CAB Int.: 663 p.Babadoost M. 1984. Brown Stripe or Leaf Streak of Forage Grasses. http: // www.ipm.uiuc.edu/diseases/series300/rpd310
Hawksworth D.L., Kirk P.M., ed. 1995. Ainsworth and Bisby's Dictionary of the fungi. CAB Intern.: 616 p.
Khokhryakov M.K., Dobrozrakova T.L., Stepanov K. M., Letova M.F. 2003. Keys to plant diseases. Saint-Petersburg, Moscow, & Krasnodar: Lan', 590 p. (in Russian)
Kostitsyn V.V. 2005. Diseases of forage grasses. Crop's diseases. Saint-Petersburg: VIZR. p. 43-48 (in Russian)
Shitikova-Rusakova A.A. 1939. Rye affection by Scolecotrichum graminis leaf blight in Otrada kubanskaia. Plant Protection. N 18. p. 71-76 (in Russian)