Latest Control Methods for Common Sunflower Pests and Diseases

The sunflower is an important economic crop in China and is grown across a very wide range. However, as its planting area continues to expand, the harm caused by its pests and diseases is becoming increasingly severe, seriously affecting the yield and quality of sunflowers and causing economic losses for growers. So which pests and diseases harm sunflower yield and quality? Let's take a look with Qinnong Web.

1. Sclerotinia rot

Sunflower sclerotinia rot is caused by the pathogen Sclerotinia sclerotiorum, and mostly occurs during periods of low temperature and frequent rain in spring. When the disease strikes, brown lesions appear on the stems or leaves of the sunflower. As the disease progresses, the brown lesions gradually spread to other parts, and finally concentric rings form at the lesion sites. In humid environments, white mycelium and brown sclerotia appear at the lesion sites. In severe cases, the plant becomes wilted and withered, and the diseased tissue decays and breaks easily, with black sclerotia inside.

Control methods: The main cause of sclerotinia rot is that the pathogen overwinters dormant in the soil, diseased residues, and seeds. When temperatures rise the following year, it begins to multiply in large numbers, spreads by wind, and finally invades the sunflower. Therefore, these measures should be taken at planting time: deep plow and disinfect the soil, burn diseased residues in a centralized manner, disinfect and sterilize the seeds to reduce the pathogen, apply more phosphorus and potassium fertilizer at planting to increase the plant's disease resistance, and when the disease occurs, spray treatments such as thiophanate-methyl and procymidone wettable powder.

2. Verticillium wilt

Verticillium wilt mainly harms adult sunflower plants, and mostly occurs in low-lying land and when planting density is high. When the disease strikes, the leaf tips begin to lose their green color, then the entire leaf loses its green color, and the areas between the leaf veins turn yellow and then brown. As the disease progresses, the leaves of severely affected plants gradually dry up and die. In environments with air humidity, white mold-like growth appears on the leaf surface.

Control methods: Similar to sclerotinia rot, the pathogen also overwinters in the soil, diseased residues, and seeds, and after sowing it invades through wounds or young roots. The preventive measures are the same as for sclerotinia rot. When diseased plants are found, they should be promptly removed from the field and burned, and the diseased planting holes should be disinfected. When necessary, drench the roots with a 400-fold dilution of 20% carboxin emulsifiable concentrate, which gives good results.

3. Rust

Rust is a fungal disease to which sunflowers are susceptible. During an epidemic of this disease, it can cause severe yield reductions in sunflowers. The leaves, petioles, stems, and flower heads can all be infected. When the disease strikes, a small number of spore masses appear at the affected sites. As the disease progresses, after the spores rupture, brown powder appears, which later turns into black powder, ultimately causing the plant to wither and die.

Control methods: The pathogen likewise overwinters or oversummers in the soil, diseased residues, and seeds, so the preventive measures are similar to the previous two. Choose varieties with strong disease resistance for planting, strengthen management at planting, and apply more phosphorus and potassium fertilizer to increase disease resistance. When the disease occurs, remove diseased plants from the field and burn them, and spray a 1000-1500-fold dilution of 15% triadimefon wettable powder or an 800-fold dilution of 50% carboxin emulsifiable concentrate for control.

4. Downy mildew

Downy mildew can occur in both seedlings and adult plants, and is prone to occur under low temperature and high humidity, when soil moisture is high, or in continuous cropping land. When the disease strikes, the leaves begin to lose their green color, and a white downy mold layer appears on the underside of the leaves, causing slow growth and stunting in the plants. As the disease progresses, the area of chlorosis expands, the white downy mold layer spreads, and in the late stage of the disease the leaves turn brown and die, and the plant loses its heliotropic ability, often resulting in abnormal seed set or empty stalks.

Control methods: Downy mildew is mainly caused by the pathogen lying dormant in the seeds. After sowing, when temperatures rise, the pathogen begins to multiply and invade. At planting, crop rotation must be practiced, varieties with strong disease resistance should be chosen, and rational close planting should be used. If individual diseased plants are found, promptly pull them out and take them out of the field to burn. If a large area is affected, spray a 1000-fold dilution of 58% metalaxyl-mancozeb wettable powder or an 800-fold dilution of 64% oxadixyl M8 wettable powder for control.

The above are the control methods for common sunflower pests and diseases brought to you by Qinnong Web. That is all for the content on sunflower pests and diseases. To learn more, please stay tuned to Qinnong Web.