What are the control methods for Verticillium wilt in sunflowers?
How do you control Verticillium wilt when growing sunflowers? Please explain the methods. The damage Verticillium wilt causes to sunflowers: symptoms mostly begin on the lower leaves of the plant. At first, the local tissue at the leaf tip or leaf edge loses turgor pressure and wilts green; it can also occur on tissue in the middle of the leaf, with an irregular shape, but the edge appears water-soaked, yellowing, and the chlorotic leaf tissue...
How do you control Verticillium wilt when growing sunflowers? Please explain the methodsThe damage Verticillium wilt causes to sunflowers:Symptoms mostly begin on the lower leaves of the plant. At first, the local tissue at the leaf tip or leaf edge loses turgor pressure and wilts green; it can also occur on tissue in the middle of the leaf, with an irregular shape, but the edge appears water-soaked, yellowing, and the chlorotic leaf tissue rapidly expands, spreading into the interveinal tissue within the leaf, where the affected tissue then necroses, turns brown and dries up, and progressively spreads further into the leaf, until finally, apart from the main vein and the leaf tissue on either side of it, which barely remains greenish-yellow, all the rest of the leaf tissue turns brown, scorched, necrotic and brittle, and the diseased leaf shrivels and becomes deformed.
In the later stage, all the leaves of the diseased plant show marked symptoms, drying up and scorching, and the plant is slightly stunted. When the diseased stem is cut open, the vascular bundles are seen to have turned brown. When humidity is high, white mold can appear on both surfaces of the leaves or on the stem. The pathogen of this disease overwinters in the soil, in diseased plant residues and in seeds. The seed coat carries the pathogen, while the embryo and endosperm do not. The pathogen can survive in the soil for a long time.
Control methods for Verticillium wilt in sunflowers:
1. Foliar spraying: in the early stage of the disease, choose 65% zineb wettable powder at 500-600 times dilution, or 50% tuijunte wettable powder at 500 times dilution, or 50% carbendazim wettable powder at 500 times dilution, or 70% thiophanate-methyl wettable powder at 800-1000 times dilution; or 64% sandofan wettable powder at 1000 times dilution, or 77% kashade 101 wettable powder at 400 times dilution; 20% longkejun wettable powder at 400 times dilution, or 14% copper-ammonia complex wettable powder at 250 times dilution, or 75% chlorothalonil wettable powder at 800 times dilution, etc., for foliar spraying.
2. Root drenching: for fields with more severe disease, drench the roots with 12.5% zhiweiling emulsifiable concentrate at 200 times dilution, applying 100ml of the solution to each diseased plant.
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