Choose tangerine or sour pomelo as rootstock to cultivate strong seedlings; plant reasonably densely, 60 to 80 plants per acre is appropriate; use deep grooves and large holes to raise the planting; apply base fertilizer heavily and top-dress in time; mainly use farmyard manure , supplemented by chemical fertilizers; pay attention to crown cultivation, rational shaping and pruning, sparse and pruning lightly, remove strong branches (strong branches and leggy branches) and leave weak ones; strictly prevent damage by diseases and insect pests.
This variety can be used as the main variety for the construction of the pomelo industrialization base in Enshi Prefecture.
1. Bordeaux mixture. Bordeaux mixture is a sky-blue liquid prepared from copper sulfate and lime milk. It is a protective agent that can prevent pathogens from invading plants. This product is a low-toxic pesticide and basically non-toxic to humans and animals. It can be used to prevent and treat diseases such as anthracnose, scab, and resin disease in white grapefruit. Its concentration is 0.3%, 0.5%, 1%, etc., which can be adjusted by the amount of copper sulfate. According to the ratio of copper sulfate to quicklime, it can be divided into half-lime type, lime equal-amount type, and lime-excess type (the amount of lime exceeds copper sulfate by more than twice).
When preparing Bordeaux mixture, for example, use 0.5% lime doubling formula, that is, use 0.5 parts of copper sulfate, 1 part of quicklime, and 100 parts of water (0.5:1:100). Use a small amount of water to digest lime and a small amount of hot water to dissolve copper sulfate, and then add half of the total water to make copper sulfate liquid and lime milk. Store them in buckets or cylinders respectively until the temperatures of the two liquids are equal and not too high. At room temperature, slowly pour the two liquids into three containers at the same time, stirring while pouring. The medicinal liquid prepared by this method is sky blue, viscous, of good quality and has good disease prevention effect.
Precautions during preparation and use: ① White lumpy quicklime and bright blue crystallized copper sulfate should be selected. Weathered slaked lime and copper sulfate containing many impurities should not be used. ② When mixing copper sulfate and lime emulsion, the temperature should not exceed room temperature, otherwise it will easily cause precipitation and affect the quality. ③No metal containers should be used during preparation, and spray equipment should be washed promptly after application to avoid corrosion. ④ Application should be avoided in humid weather or before the dew has dried; after spraying, lime sulfur mixture must be used 20 days apart; if Bordeaux mixture is used again, the interval must be 7-10 days, otherwise it will cause phytotoxicity. ⑤ Bordeaux mixture cannot be mixed with soap, rosin mixture, lime sulfur mixture, oil emulsion, trichlorfon and other pesticides. ⑥ After using Bordeaux mixture, it is easy to induce mites, so the inspection and prevention of mites should be strengthened.
2. Lime sulfur mixture. Lime sulfur mixture is a bactericidal and acaricide. It is a reddish-brown transparent liquid boiled with quicklime and sulfur powder and water. It smells like rotten eggs and is highly alkaline. This agent has low toxicity to humans and animals, and white pomelo is not prone to phytotoxicity. It is often used to prevent and treat white grapefruit anthracnose, scab, sooty disease and various mites and scales. The concentration used to prevent disease is 0.3-0.5 Baume degree, and to control mites is 0.5 (spring and summer)-1.5 (winter) Baume degree.
When preparing, use 1 part quicklime, 2 parts sulfur powder, and 10 parts water. First put the water in a pot and boil it to about 50℃, put the quicklime into the hot water and stir it. After liquefying, take out some lime water and mix the sulfur powder into a paste. When the lime water is about to boil, pour in the sulfur paste and stir while pouring. After pouring all the water, mark the height of the water surface, then heat it to boil, stir continuously, and use hot water to make up for the evaporated water at any time. Boil for 40-60 minutes until the liquid becomes reddish brown. After the fire ceases, filter to obtain the original solution. After cooling, use a Baume hydrometer to measure its concentration, which is generally between 22-28 Baume degrees. The original solution can be placed in a bottle or cylinder for later use, and the degree should be marked. When using, it can be diluted with water according to the required concentration. The formula is: kilograms of water added per kilogram of original solution = [Beauty degree of original solution / Baume degree of used liquid] - 1.
Precautions when preparing and using: ① To prepare high-quality lime sulfur mixture, the key is to choose white-colored and light-weight raw stone. Lime containing many impurities or weathered lime should not be used; sulfur powder The fineness requires a passing aperture of 0.44 mm (No. 40 mesh); the firepower must be large. ②The original solution must be sealed and protected from sunlight when stored. At the same time, a layer of mineral oil (such as kerosene) can be added to the liquid surface to isolate it from the air. The diluent should be ready for use. ③ Lime sulfur mixture is highly corrosive to metals. Do not use copper or aluminum utensils for cooking or serving. Clean the spray equipment in time after use. ④ This agent is strongly alkaline and cannot be mixed with rosin mixture, soap, copper, tribute preparations or Bordeaux mixture and most types of pesticides that are avoid alkaline. White grapefruit needs Bordeaux mixture for 20 days before lime sulfur mixture can be sprayed; while using lime sulfur mixture can only spray Bordeaux mixture for 7-10 days. It takes 15 days after the engine oil emulsion has been sprayed and 20 days after the rosin mixture has been sprayed before the lime sulfur mixture can be sprayed. ⑤ When the temperature is higher than 32℃ or lower than 4℃, do not spray lime sulfur mixture on white pomelo. Applying fruits at high temperatures can easily cause sunburn, and applying them at low temperatures can aggravate the occurrence of freezing damage.
3. Rosin mixture. Rosin mixture, also known as rosin mixture, is a dark brown rosin soap made from rosin and alkali (sodium carbonate). This product has a specific irritating odor, is highly alkaline, has a strong contact killing effect on pests, has strong adhesion and permeability, especially has a strong corrosive and destructive effect on the wax of scale insects, and is also effective on mites. It also has a certain preventive effect. Dilute it with water 10-12 times in winter and 20-30 times in summer.
When preparing, use 3 parts of rosin, 2 parts of alkali (sodium carbonate), and 10 parts of water. First put the water in a pot and boil it, then add the soda ash. After it is completely dissolved, slowly add the rosin powder into the pot. Stir while adding, the heat should be strong, and use hot water at any time to make up for the water lost by evaporation.
Cook for about half an hour and when the liquid turns dark reddish brown, stop the fire and filter out the impurities to obtain the original liquid. When using, just add water in the required multiples.
Precautions when preparing and using: ① Use brown old rosin, or yellow hard and brittle rosin; the water must be river or lake water. ② The volume of the boiling pot should be at least 1/4 larger than the volume of the medicine to avoid overflowing; or when overflowing, add a small amount of cold water. ③ It cannot be used during the budding and flowering stages of white pomelo, when the tree is weak or in drought. It should not be applied when the temperature is above 30℃ in summer or when the air is humid after rain to avoid phytotoxicity. ④Do not mix with organophosphorus pesticides, Bordeaux mixture, lime sulfur mixture, etc. After spraying the rosin mixture, it will take more than 20 days before spraying Bordeaux mixture or lime sulfur mixture.