Sorghum black onion mold root rot

Symptoms can occur in both seedling stage and adult stage. In the seedling stage, the disease appeared like water-deficient wilting, the cortex and vascular bundles of the diseased seedlings showed brown water stains, and the fine roots softened and rotted. The infected leaves of adult plants drooped slightly, the old leaves yellowed, and began to dry up from the tip and edge of the leaves. The diseased root and the root crown become brown and rotten. The pathogen Periconia circinata (Mangin) Sacc. It is called sorghum black onion flower mold, which belongs to the subphylum of semiknowns. Conidiophores erect, 2 Mel 3 fascicles or solitary, brown to dark brown, wall thick, 1 50 × 6 Mel 8 (um), near apical rotation, apical cells dilated, above 3 sporogenic cells, apical cells can divide, each division, forming a sporogenic cell, on which conidia are in series. The conidia are dense into capitate, black, globose, smooth or spiny surface, 12-27um in diameter. The pathways of transmission and disease conditions this bacteria is saprophytic bacteria, can induce the plant aboveground or root disease. Prevention and control methods (1) crop rotation has been carried out for more than 3 years. (2) strengthen management, appropriate density, use high ridge or high border cultivation, do not plant sorghum in low-lying land. (3) the compost made by fully mature organic fertilizer or Japanese enzyme bacteria should be drained in time after rain, and flood irrigation is strictly prohibited.