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Prevention and cure of major pests and diseases of potato
First, potato late blight. For fungal diseases, typical symptoms are yellowish-brown or black lesions on affected foliage, and white molds on the back of leaves after the rain or when the dew is just dry. The temperature that favors the epidemic of late blight is 20-24°C, and the average relative humidity is above 80%. The disease is spread by air flow, spreading rapidly and spreading. It takes only a few days after infection to cause a large-scale death of potato seedlings, and can cause large amounts of rotten potatoes in the field and during storage. The prevention and treatment method is to spray 25% metalaxyl 500-800 times solution immediately after the emergence of the central disease strain, and it can also be used for irrigation. Heavy soil moisture and rainy days can also be applied to the root with metalaxyl of 1:40 and fine dry earth or coal ash. Second, bacterial wilt. For bacterial diseases, the typical symptoms are acute wilting of the plant, yellowing or yellowish brown vascular bundles at the base of the stem, light brownish or brownish color of tuber buds, heavy blebs, and tuber rot. The disease is currently no effective drug control, the main measure is to eliminate the source of infection. The first is the selection of healthy seed potatoes and sowing of whole potatoes. If it must be cut, every time you cut it, the knife must be disinfected with alcohol. The second is to implement rotations. The third is to bring in the soil and plant the diseased plant to bring it out of the field. Three, twenty-eight star ladybug. It is the main pest in low altitude areas. The larvae bite the leaves on the back of the leaf, leaving only the veins in the affected area, forming a transparent reticular pattern, and the plants gradually withered. Prevention and control can be taken manually to catch adults, remove the egg masses, and spray the dichlorvos 800-1000 times when the adults just emerged. The control effect is obvious. Fourth, the tiger. Serious problems occur along rivers, lakes, and low-lying depressions. The main damage to the seedlings is to bite off the stem base near the ground and cause the plant to die. During the prevention and control, one is to turn over the autumn and fall and destroy the wintering ground, which can kill a large number of larvae and eggs and reduce the overwintering base number; the second is to remove the insects in the cultivator, eradicate the weeds and the field weeds; the third is to set the molasses trap or Black light traps adult worms. The fourth is to use 50% dichlorvos per acre 500 grams, add 2.5 kilograms of water sprayed on 100 kilograms of dry sand, while spraying and mixing, made of toxic sand, in the evening near the seedlings, or 2.5% dipterex powder, each Mu 1.5-2 kilograms, mixed with 10 kilograms of fine soil in the eye.