Abstract
A description is provided for Trichometasphaeria turcica[Setosphaeria turcica]. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Zea mays, Sorghum spp., Euchlaena mexicana and other Gramineae (RAM 41: 40). DISEASE: Northern leaf blight of maize and sorghum forming larger and fewer lesions than Cochlioholus heterostrophus (CMI Descript. 301), mostly on the leaves. They begin as small, dark, water-soaked areas, becoming irregular or elliptical, sometimes linear, brown then straw coloured or greyish, with red-purple or tan borders, often 4 × 10 cm or larger, coalescing and leading to death of leaves. Tassel infection on maize is less conspicuous, ear and crown rots and seedling infection occur (16: 450; 34: 716). GEOGRAPHICAL DISTRIBUTION: Widespread (CMI Map 257, ed. 3, 1968). Additional records not yet mapped are: Australia (NT), Cameroon, Ecuador, Fiji, Haiti, Indonesia, Iraq, Lebanon, Pakistan (E.) and Saudi Arabia. TRANSMISSION: Air-dispersed, probably violently discharged conidia and showing a diurnal periodicity with a forenoon max. (45, 795; 46, 114). The fungus occurs in seed and survives in host debris (15: 289; 19: 602).
Increased experimental conditions and marker densities identified more genetic loci associated with southern and northern leaf blight resistance in maize