Watermelon diseases and pests include damping-off, anthracnose, bacterial blight, viral infections, aphids, leafhoppers, fruit flies, and melon thrips. Effective management requires a combination of cultural, biological, and chemical control methods to ensure healthy growth and high-quality yields.
**I. Agricultural Control**
1. **Field Cleanliness**: Removing weeds around the watermelon fields is crucial, as they serve as hosts for pests and pathogens. This reduces the risk of virus transmission, especially for the watermelon mosaic virus, which can spread through weeds before affecting the crops. Diseased plants should be removed, buried deeply, or burned to prevent the spread of disease.
2. **Foliar Fertilization**: While farmers often focus on base fertilizers, foliar applications play a key role in enhancing plant health. A 0.2% solution of potassium dihydrogen phosphate mixed with pesticides can improve plant growth and disease resistance. After fruit set, applying 0.3% potassium dihydrogen phosphate during pesticide sprays helps boost plant vigor and increase sugar content. For weak plants, adding 0.2-0.3% urea can further support growth. Foliar feeding also slows down disease progression in infected plants.
**II. Biological Control**
1. **Use of Bio-Pesticides**: Apply 2% nantianmycin at a dilution of 200–250 times when viral diseases first appear. This natural compound helps control the spread of viruses effectively.
2. **Aphid Management**: Use 0.9% insecticide diluted at 3000 times to manage aphid populations. This method is both effective and environmentally friendly.
**III. Chemical Control**
1. **Damping-Off and Vine Blight**: Spray 66.5% propiconazole at 1000–1500 times or 64% antivirus glutinous rice 8 wettable powder at 400–500 times. Mixing 200 times dry fine soil with the solution and applying it to the base of seedlings can reduce disease incidence.
2. **Fusarium Wilt**: Apply 50% carbendazim wettable powder (2 kg per 100 kg of fine soil) directly into planting holes. Alternatively, use 50% carbendazim WP at 500 times or 70% thiophanate-methyl at 1000 times for root irrigation. Digging a circular pit around affected plants and applying the same solutions can help treat the disease effectively.
3. **Bacterial Blight**: Spraying 70% thiophanate-methyl at 800 times or 64% antivirus glutinous rice 8 WP at 500 times can control this disease.
4. **Viral Disease Prevention**: Control vectors like aphids by spraying 20% imidacloprid at 1500 times before their peak season. Fumigation using 1.5% ziram smoke agent (300 g per 667 m²) or 80% dichlorvos (150–200 g per 667 m²) can protect crops. If infected plants are found, spray 20% virus A at 600 times every 7 days for 2–3 applications.
5. **Anthracnose Control**: At the early stage, apply 80% mancozeb at 800 times or 70% thiophanate-methyl at 500 times. Using 45% chlorothalonil smoke agent (200–250 g per 667 m²) every 8–10 days can also help manage the disease.
6. **Leaf Fly Management**: Spray 40% green vegetable poison at 800 times, 25% lindane at 1000 times, or 40% dimethoate at 1000 times to control larvae. Timely control of adult insects is essential to prevent damage.
7. **Integrated Pest Management**: Combine fungicides, insecticides, and foliar fertilizers like potassium dihydrogen phosphate. Avoid mixing with anti-virus cricket agents. Most pesticides last about 7 days under sunny conditions, so spraying once every 7 days ensures continuous protection while promoting strong plant growth.
Botanical extract refers to substances extracted or processed from plants (whole plant or part) as raw materials using appropriate solvents or methods, which can be used to improve health or other purposes. Depending on the components of the extracted plants, they can form glycoside, acid, polyphenol, polysaccharide, terpene, flavonoid, alkaloid, etc. According to different characteristics, they can be divided into vegetable oil, concrete, powder, crystal, etc.