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Pyrethrum and its cultivation techniques
The chrysanthemum plant, which is distributed across the Jiangnan region of China, is the ideal raw material for the manufacture of green plant pesticides. Pyrethrum asteraceae perennial herb, mainly containing pyrethrin and whithrin, flowers, stems, leaves can be made pyrethrum pesticides, is the synthesis of enemy killing, rapid extermination killing and mosquito coils, mosquito oil, kill The important raw material of lotus root powder, therefore, artificial cultivation of pyrethrum has broad prospects. Research institutes such as the Kunming Institute of Botany, the Chinese Academy of Sciences and the Hubei Kono Plant Pesticide Research Institute have succeeded in using pyrethrum to develop green plant pesticides and have screened out their improved varieties. Pyrethrum - the secondary planting can be harvested for more than 7 years, generally produces more than 100 kilograms of flowers per 667 square meters of flower peak year, 300-500 kilograms of dried stems and leaves, and more than 2,000 yuan per 667 square meters of income. Now we introduce the biological characteristics and main cultivation techniques of pyrethrum as follows: Biological characteristics. Pyrethrum is perennial or biennial grass, plant height 30-80cm, whole plant grayish green, covered with green hair. The main root is conical, with many lateral roots, slender, whisker-like, pale brown. Stems much branched. Leaves oblong or ovoid, apex acute: base leaves long-handled, upper leaves nearly sessile. Flowering in summer, solitary branches of capitulum, ca. 3 cm in diam.; ray flowers white, apex 3-lobed, middle tubular flower yellow, 5-lobed: achene narrowly conic-conical, ca. 4 cm, with 4-5 ribs, smooth or With glandular spots. 2. Site preparation. Should choose cool, dry, ventilated, loose soil, household or slightly alkaline soil planting (usually low mountains, hills, plains can be planted), sticky or low-lying land should not be planted. After the autumn crops are harvested, they should be ploughed in time, with a cultivating depth of about 0.33m, and a width of 1-1.33m. Every 667m2 of compound fertilizer 50-70kg as base fertilizer, evenly sowing. 3. Nursery. The spring sowing chrysanthemum can not flower, the winter sowing can not bloom until the third year of spring, autumn can be the second year to bloom, so it is better to use autumn sowing. Specific sowing time: spring broadcast 2-4 months, autumn broadcast 8-11 months. One week before sowing, the seeds were immersed in water for 5-6 hours until they were swollen after water absorption. They were mixed with 50 times wet coke sludge, and the soil was sowed in the room for 5-6 days. About 20% of the seeds were germinated and added in small amounts. Soil sowing. After sowing, sprinkle a layer of mud ash and lightly press it with wooden board. Cover it with straw and sprinkle water to keep the floor moist. Dry season nursery needs scaffolding, covered during the day and uncovered at night. The use of seedlings for seedlings is 500g/667m2, which generally occurs after 15 days. For every 667m2 seedlings transplantable 1.33hm2 (ha). 4. Transplanting. When the seedling height is 6.6-10cm, it can be transplanted. Transplanting should be intensively cultivated, and sufficient base fertilizer should be applied. Before the transplanting, the seedbed is dripping with water, and the seedlings have more mud to facilitate survival. When transplanting, open the hole according to the spacing 0.33-0.5m, apply superphosphate and coke ash (grasswood ash can also), 1 per hole, cover soil should not be too thick. The output of Pyrethrum was slightly lower in the first year after planting, and was the peak of production in the 2nd to 4th year. The output decreased after the 5th year and needs to be updated. In addition to the sowing method, the ramet method can also be used. The method is: In the rainy days from September to October, the mother plants are divided into 4-5 strains and planted by one plant per hole. You can also use the cutting method, that is, in March-April, select the mother plant that grows for 2-3 years, cut the stem and cut it into the soil, cover the straw, and then water it often to sprout it. 5. Fertilization. About 10 days after transplanting, manure was applied once and every other month and then once again. Each time, 667m2 was applied with 1000kg. After the fertilization three times each year, 667m2 of small snow before the application of calcium phosphate 20kg, calcium magnesium phosphate fertilizer 15kg, mud (grasswood ash, soil miscellaneous fertilizer) 1000kg. After the beginning of spring, apply a pumping moss fertilizer, and apply 1500kg of livestock manure water per 667m2, and use potassium dihydrogen phosphate lOOg, urea 500g, and water 50kg. Do not apply directly into the roots at the 6.6cm from the root. After the flower is harvested, it is necessary to apply another fertilizer. 6. Tear soil and intercropping. After loosening and transplanting, the soil should be loosened once. Afterwards, every year in the months of March, April, and July and every winter, loose soil and sorghum should be removed. Before the soil is loosened in July, the old stalk should be cut 3.3 cm away from the ground. In the first and second years of planting pyrethrum plots, crops such as corn can be intercropped. 7. Pest Control. Pyrethrum is not pest-free and has fewer diseases. High temperature, high humidity, or excessive fertilization may cause rust and nuclear diseases. Once the disease occurs, the diseased plant can be removed and the diseased area can be disinfected with 50% thiophanate powder or lime powder. 8. Flower processing. From May to June, when the corolla was not fully expanded and the corolla was gradually expanded, the content of active ingredients in flowers was the highest, which was the optimum time for harvesting flowers. Pyrethrum flowers can generally be opened within 10 days. Therefore, sunny harvest should be selected. The flowering period is small to full. Picking is based on the degree of openness of the flowers in batches, picking them in time and picking them out. Dried in time after harvest, if it is rainy, it can be dried or air-dried at a temperature of 55-60°C to reduce the water content to 6%-12%. The whole plant was harvested in summer and autumn and dried for use. Pyrethrum flowers contain insecticidal components that are prone to hydrolysis failure, so they must be fully dried and protected from moisture and light. Generally impatient for long storage, if stored for one year, the effectiveness of insecticide is reduced by half. 9. Keep seed. Due to the strong season of pyrethrum planting, when the first and second batches of flowers are opened, they must be planted in a planned manner. When the green part of the preserved flower blooms black down to 6.6 cm from the flower, it is a manifestation of seed maturity. Cut off with a knife and stalk, hang in a cool and ventilated place, and then put it under weak light for a few days to dry. Avoid exposure, and store the seeds in a dry and ventilated place with a paper bag or cloth bag.