Control of Leaf Curl Disease of Pepper Seedling

When pepper seedlings are raised in winter and spring, leaf curling, growth stagnation and even death often occur after seedling division.

I. causes and symptoms

⑴ physiological disease: long-term low temperature and high humidity in seedling bed, resulting in poor plant development, stem and leaf yellowing, top leaf curling, growth retardation, serious retting root withered, root rust color, and then rot. ⑵ virus disease: pepper virus disease in greenhouse, which occurs in all seasons. The top leaves of the diseased plants are wrinkled and curved in the shape of fern leaves. ⑶ tea yellow mite harm: the leaf margin of young leaves curls down, the back is brown and oily, and the terminal bud dries up when it is serious. The harm of ⑷ aphids: the leaves curled and deformed at the initial stage, and then blackened when the leaves were covered with oil stains due to insect dung pollution.

II. Prevention and control measures

1. Eliminate low temperature and high humidity: let the sun shine fully, connect the overcast and low temperature weather, and increase the heating facilities. The temperature of the seedling bed was kept at 25-30 ℃ during the day and 18-20 ℃ at night. If the temperature is too high at noon, you can cover the grass to cover the shade and evenly heat the seedbed; if the temperature is too low at night, you can cover more grass to keep warm. After slowing down the seedlings, the temperature was cooled for 3-5 ℃ day and night, and the dry plant ash or fine dry soil was sprinkled to absorb moisture and increase the temperature. Spraying 500 times photosynthetic micro-fertilizer or the mixture of potassium dihydrogen phosphate and urea to promote its growth. The young and old seedlings can be sprayed with gibberellin solution with a concentration of 15 mg / kg to promote their budding.

2. Prevention and treatment of virus disease: spray 20% virus A, spray Shibao mixture (50 kg water plus 100 grams of virus A, 5 ml) or 5% Shiduqing 300 times or 1.5% Zhanshiling EC 800 times, once every 7 days, 3-4 times in succession.

3. Kill tea yellow mites: spray 15% diclofenac EC 300x, or 20% diclofenac EC 800x, or 20% methamphetamine 2000 times on the back of the leaves.

4. Aphid control: spray 2.5% Uranus or 50% aldicarb 2000 times.