How to prevent and control Fusarium wilt? Introduction to practical prevention and control methods
Fusarium wilt, also known as blight, is a plant disease caused by fungi or bacteria. It strikes suddenly, and symptoms include severe spotting, wilting, or the death of leaves, flowers, fruits, stems, or the entire plant. Fast-growing young tissues are often attacked. Most major economic crops are infected by one or more types of blight. Let's take a look below at the prevention and control methods for Fusarium wilt!
Symptoms of Fusarium wilt
After young plants are infected, they grow poorly. The leaves of diseased seedlings turn pale, with no obvious symptoms. In severe cases, the petiole bends downward near the leaf sheath, withers and dies, and then the stem wilts and dies. Finally, the diseased roots turn brown and rot, the stem base splits lengthwise, and cutting the stem open reveals browning of the vascular bundles. In mature plants, old leaves turn yellow, accompanied by loss of green in the vascular bundles of the outer leaf sheaths. The yellowing starts from the leaf margins and then gradually spreads toward the midrib; in some leaves the entire blade turns yellow. A pink mold layer forms on the surface of diseased parts, namely the pathogen's conidiophores and conidia. Finally, the diseased roots turn brown and rot, the stem base splits lengthwise, and cutting the stem open reveals browning of the vascular bundles.
Patterns of Fusarium wilt occurrence
The pathogen mainly overwinters as mycelium, chlamydospores, or sclerotia in uncomposted organic fertilizer or soil, and can survive in soil for 6 to 10 years. The pathogen can spread through seeds, fertilizer, soil, and watering, with compost and waterlogged manure being the main route of spread. The occurrence of this disease is closely related to temperature and humidity. The pathogen's growth temperature is 5 to 35°C, and a soil temperature of 24 to 30°C is suitable for the pathogen's germination and growth. This disease is a soil-borne disease, and the degree of occurrence depends on the amount of infective inoculum in the soil. Generally, continuous cropping, many underground pests, extensive management, or heavy, moist soil lead to severe occurrence of the disease.
Preventive measures for Fusarium wilt
1. Irrigation prevention: Dilute 41% polyoxin · pyrimethanil to a 600 to 800 times solution, and irrigate the seedbed before sowing or after sowing and before planting, before 10 a.m. or after 5 p.m.
2. Root drenching prevention: At planting time or after planting and before the expected period when the disease commonly occurs, dilute 41% polyoxin · pyrimethanil to an 800 times solution for root drenching, applying once every 7 days, with the number of applications depending on the condition of the disease.
Treatment methods for Fusarium wilt
1. Foliar spraying: Dilute 41% polyoxin · pyrimethanil to a 600 to 800 times solution and spray evenly; when the disease is severe, the dosage may be appropriately increased.
2. Root drenching treatment: For diseased plants, dilute to 600 to 800 times and use for root drenching. If the pathogen also harms the aboveground parts, while drenching the roots, spray the aboveground parts at the same time, applying about once every 7 days.