3. Major diseases of wheat: symptoms, biological features of pathogens, distribution, and harmfulness
According to scientists from the CIMMYT international center, wheat is affected by 25 fungal diseases, 3 bacterial diseases, 1 viral disease, 3 nematode diseases, 4 physiological-genetic diseases, and 8 diseases caused by mineral nutrient deficiencies and other abiotic factors. The species composition of pathogens affecting winter and spring wheat does not differ significantly, except for certain cases. It is affected by four types of smut, three types of rusts, powdery mildew, septoria leaf spot, and helminthosporium leaf spots, as well as root rots (Table 1). This crop also experiences bacterial, yellow, or slime diseases, basal diseases, and viral diseases [1–3].
Table 1 - Disease spectrum of spring wheat and their pathogens, affected plant organs
|
Disease |
Pathogen(s) |
Affected plant organs |
|
Loose smut |
Ustilago tritici |
entire ear |
|
Common bunt (Stinking smut) |
Tilletia caries, T. levis |
spikelets |
|
Ergot |
Сlaviceps purpurea |
grains |
|
Stem rust |
Puccinia graminis f. sp. tritici |
stems, glumes, leaves |
|
Leaf rust (Brown rust) |
Puccinia recondita f. sp. tritici |
leaves |
|
Powdery mildew |
Erysiphe graminis |
leaves, stems, glumes |
|
Septoria leaf blotch |
Stagonospora nodorum Septoria tritici |
leaves, stems, glumes |
|
Tan spot (Yellow leaf spot) |
Drechslera tritici repentis |
leaves, stems |
|
Root rot - Helminthosporium type |
Bipolaris sorokiniana (syn. Helminthosporium sativum) |
primary and secondary roots, stem internodes |
|
Root rot - Fusarium type |
Fusarium spp. |
primary and secondary roots, stem internodes |
|
Black point |
Alternaria alternata, B. sorokiniana |
grain, seeds |
|
Wheat streak mosaic |
Triticum virus |
leaves |
|
Mucilaginous or yellow bacterial blight |
Rathayibacter tritici |
leaves |
|
Basal bacterial disease |
Pseudomonas syringae pv. atrofaciens |
leaves |