What diseases should be prevented and controlled when growing sunflowers?
What diseases should be prevented and controlled when growing sunflowers? Please give an introduction. Sunflowers need prevention and control of the following diseases: I. Symptom identification 1. Sunflower rust is an important disease of sunflowers, reducing yields by 40-80% in pandemic years. After infection, rust-like spore piles can form on leaves, petioles, stems, flower discs and other parts. When leaves are infected...
What diseases should be prevented and controlled when growing sunflowers? Please give an introduction.
Sunflowers need prevention and control of the following diseases:
I. Symptom identification
1. Sunflower rust is an important disease of sunflowers, reducing yields by 40-80% in pandemic years. After infection, rust-like spore piles can form on leaves, petioles, stems, flower discs and other parts. When leaves are infected, brown small blisters first appear on the underside of the leaves; these are the uredinia of the pathogen. After the surface ruptures, brown powder is released, namely the urediniospores of the pathogen. Later, many dark brown small blisters develop on the diseased parts, namely the telia of the pathogen, releasing black powder, namely the teliospores. Severe cases cause the leaves to dry up early.
2. Sunflower brown spot is also called leaf blight. It can occur at the seedling stage and the adult plant stage. When cotyledons and seedlings are infected, nearly round brown spots form on the leaves, surrounded by yellow halos, and the underside of the spots is grayish white. When adult plants are infected, the spots are angular, brown, also with yellow halos, and later small black dots form on the spots, namely the pycnidia of the pathogen. In rainy and humid conditions, the spots tend to fall off or perforate, and in severe cases the spots merge and the entire leaf dies. When stems and petioles are infected, the spots are brown, narrow and elongated. It is an important disease widely distributed in the world.
II. Prevention and control recommendations
1. Sunflower rust This year, due to excessive precipitation across the city, the climatic conditions are favorable for sunflower rust epidemics. In addition, in recent years the sunflower planting area has expanded and variety resistance is poor, creating favorable ecological conditions for disease development. Recently, it is recommended that major planting areas take corresponding control measures according to different disease situations. In the early stage of the disease, spray with 80% zineb at 600-800 times dilution, using 75-100 liters of water; or spray with 25% triadimefon wettable powder at 1000-1500 times dilution, using 35-40 grams per mu.
2. Sunflower brown spot At autumn harvest, clean the field in time, remove diseased and residual leaves, and burn them in a centralized manner or compost them; it is recommended to apply compost fermented with Japanese enzyme bacteria or decomposed organic fertilizer; in the early stage of the disease, remove diseased leaves, and if necessary, spray with 50% carbendazim wettable powder at 1000 times dilution or 50% thiophanate-methyl at 1500 times dilution.
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