Occurrence and control of diseases and insect pests in winter potato

In recent years, the planting area of potato in our city has been expanding, and all kinds of potato diseases and insect pests have occurred alternately, seriously affecting the yield and quality of potato. At present, it is the potato growing season. According to a recent survey in Tieyong, Nim Mountain and other places in this station and Huidong Station, the main diseases and pests of potatoes grown in winter in our city are: potato bacterial wilt, black shank, late blight, virus diseases, underground pests, aphids and so on. All localities should strengthen the investigation, especially to do a good job in the prevention and control of potato soil-borne diseases.

I. occurrence of diseases and insect pests

1. Ralstonia solanacearum: the typical symptoms in the field are acute wilting of leaves, branches or plants, that is, turquoise death, yellow or yellowish brown vascular bundles at the base of stems, cross-sectional tubers, annular rot, and vascular bundles automatically overflow turbid white bacterial pus. The rate of diseased plants in some early fields is generally 2.6%, and the highest rate in some serious fields is as high as 13.3%.

2. Black shank disease: mainly infects stems or potato tubers, which can occur from seedling stage to late growth stage. Seedlings infected generally short plants, internodes shortened, or leaves curled, chlorotic yellowing, or abdomen blackened, wilted to death, cross-cut stems can be seen three main vascular bundles turned brown. The rate of diseased plants in some early varieties is generally 1.7%, and the highest rate in some serious fields is as high as 6.1%.

3. Late blight: it is a devastating epidemic disease. Most common leaf diseases start from the tip or edge of the leaf, with water-stained green spots at the beginning, then gradually enlarged, nearly round and dark brown, and there is a white mildew layer on the edge of the disease. at the same time, the disease spot can develop to the petiole and stem along the leaf vein, forming brown stripes. In severe cases, the leaves droop and blacken, which can cause the whole plant to die. The rate of diseased plants in some early-planted fields is generally 1.23% 3.78%, with a maximum of 6.37%.

4. Virus disease: according to the different pathogens, there are great differences in field symptoms, such as mosaic, macula, curly leaves, wrinkle, arbuscular branches, yellow dwarf, purple top wilting, etc., mainly transmitted by juice friction and insects such as aphids. The rate of diseased plants in the field is generally 0.5% 1.7%, and the highest rate is 3.6% in some cases.

5. Underground pests: there are mainly ground tiger, mole cricket, etc., which can bite off the underground stem of the seedling, wither the seedling, bite the tuber, cause disease infection and affect the quality of potato. The injury rate of seedlings in the field is generally 0.64% 2.25%, with a maximum of 5.79%.

In addition, potato ring rot, aphids and 28 lady beetles also occurred to varying degrees.

II. Opinions on prevention and control

During the growth period of potato, the plant protection policy of "giving priority to prevention and combining prevention and control" should be grasped, fertilizer and water management should be strengthened, field humidity should be controlled, and diseased plants should be removed in time to reduce the spread and spread of pathogens. Create an environment conducive to plant growth and not conducive to the occurrence of diseases and insect pests.

1. Ralstonia solanacearum, black shank and ring rot: diseased plants should be pulled out in time, lime should be applied in the hole, and stagnant water in the field should be excluded to avoid flood irrigation and series irrigation, so as to reduce the spread and spread of bacteria. Other plants can choose 20% Ye Kuning (Ye Qingshuang, Chuanhua 018) 100 grams with water 60 murals 80 kg or 25.9% phytobaoling water agent 100 ml, 50% carbendazim soluble powder 1000 Mel 1500 times liquid irrigation or spray 2 Mel 3 times for protection. If the disease is serious, the amount of water can be increased to control the spread and spread of the disease.

2. Late blight: we should pay attention to the prevention and control in the middle and later stage, and apply medicine immediately after the central diseased plant is found. The medicament can be treated with 58% Redomir-Manganese Zinc wettable powder 75% Remicol 120 grams plus 40 Mel 60 kg, 25% Metalaxyl 150-200 g 60 kg, 72% Kelu wettable powder 500 times, germicidal alum 500 times and 75% chlorothalonil 600 ml 800 times, etc., one at a time is selected for rotational use.

3. Virus diseases and aphids: if wrinkled mosaic, curled leaves, leaf wilting and ring rot plants appear 20 days after emergence, they should be removed in time. At the initial stage of the disease, the virus A500Mel 700 times solution was foliar sprayed 2Mel for 3 times, and aphid control was done after seedling completion and before and after flowering, with 2.5% aphid wettable powder 20g or 10% aphid net 15g per mu, adding water 50kg spray 2Mel 3 times.

4. underground pests: mainly control ground tigers, mole crickets, etc., first, they are mixed with Lesben granules, quick-killing granules and base fertilizer in the fertilization ditch (or combined with soil cultivation) to poison the underground pests at the seedling stage. Second, when fertilizing for the first time and the last time, spray 90% crystal trichlorfon 800 / 1000 times or 50% phoxim or deltamethrin 1000 times or 50% fenitrothion 1000 / 2000 times to protect seedlings.