How to control top rot in sorghum cultivation?
How to control sorghum top rot? Please provide an introduction to the control methods. Sorghum top rot mainly occurs from the seedling stage to the adult plant stage. The symptoms of top rot are mainly as follows: infected top leaves at the seedling and adult plant stages show chlorosis, deformity, wrinkling or twisting, with many horizontal knife-cut-like notches appearing along the edges; in some cases, the leaf tissue along one side or both sides of the midrib takes on a whittled appearance. Brown spots form on diseased leaves, and in severe cases the leaf tips of the top 4-5 leaves or the entire leaves rot and wither. Later, the leaves become short and small or only part of the tissue at the base remains, appearing torn. In some varieties, the top leaves twist or wrap around each other, taking on a long whiplike, bent and drooping form. When leaf sheaths and stems are infected, the leaf sheaths dry up and the stems become soft or lodge. When the inflorescence is infected, the panicle head is short and small; in mild cases some florets abort, and in severe cases the entire panicle sets no seed. When the main panicle is infected early, side branches develop, forming multiple panicle heads, and tiller panicles develop poorly. When humidity is high, a layer of pink mold grows on the diseased parts.
How to control sorghum top rot? Please provide an introduction to the control methods.Sorghum top rot mainly occurs from the seedling stage to the adult plant stage. The symptoms of top rot are mainly as follows:
Infected top leaves at the seedling and adult plant stages show chlorosis, deformity, wrinkling or twisting, with many horizontal knife-cut-like notches appearing along the edges; in some cases, the leaf tissue along one side or both sides of the midrib takes on a whittled appearance. Brown spots form on diseased leaves, and in severe cases the leaf tips of the top 4-5 leaves or the entire leaves rot and wither. Later, the leaves become short and small or only part of the tissue at the base remains, appearing torn. In some varieties, the top leaves twist or wrap around each other, taking on a long whiplike, bent and drooping form. When leaf sheaths and stems are infected, the leaf sheaths dry up and the stems become soft or lodge. When the inflorescence is infected, the panicle head is short and small; in mild cases some florets abort, and in severe cases the entire panicle sets no seed. When the main panicle is infected early, side branches develop, forming multiple panicle heads, and tiller panicles develop poorly. When humidity is high, a layer of pink mold grows on the diseased parts.
Main transmission routes and conditions for disease development of sorghum top rot: the pathogen overwinters as mycelium and conidia on diseased plants, seeds, diseased residues and in the soil. The following year it can infect plants at both the seedling stage and the adult plant stage. The optimum temperature for disease development is 22-28 degrees C. During the disease period, abundant rainfall and high relative humidity tend to worsen the condition.
Control methods for sorghum top rot:
1. Implement crop rotation of 3-4 years or more.
2. Promote the application of microbial fertilizers such as compost fermented with effective microorganisms. For example, 5406 bacterial fertilizer can reduce disease occurrence.
3. In areas with severe disease, spray or drench at the early stage of disease with 50% benomyl wettable powder at 1500 times dilution, or 60% Fangmeibao ultra-fine wettable powder at 600-700 times dilution, or 60% Jiameiling wettable powder at 1000 times dilution.
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