The low-volume spray has the advantages of saving water, labor, and labor, high chemical efficiency, low cost, low pollution, and natural enemies and operators. The author's experience of low-volume spray for more than a decade is: "Three must, four keep, five do not spray." 1. Before Spraying Three must be 1 Spraying technique must be skillful. Low-volume spray is a low-capacity, high-concentration spray technique. The concentration of the liquid used is large, and it is easily affected by weather factors such as wind force, wind direction, updraft, temperature, and humidity. Operators must be familiar with the techniques of plant protection such as pesticides and machinery. Knowledge, proficiency in spraying techniques to increase the use of pesticides, ensure control effectiveness and avoid phytotoxicity. At present, low-volume spray can be applied to both Type 16 and Type 14 backpack-type manual sprayers and Type 18 backpack-type motorized mist sprayers. The 16- and 14-type sprayers only need to replace a 0.6-0.7 mm head piece for low-volume spraying. 2 must be filtered when adding the liquid. Add liquid medicine through the filter on the medicine box to prevent clogging of the nozzle outlet or adjustment switch. 3 liquid must be fully stirred. Whatever method of dispensing must be fully stirred, the original drug should be emulsified and dissolved to prevent precipitation from causing phytotoxicity. 2. Keep 4 at the time of spraying to keep the distance between the nozzle and the top of the crop moderately. The type 16 and 14 knapsack sprayers are suitable for 30 cm from the top of the crop, and the type 18 knapsack mobile mist sprayer is 50 cm. Too high liquid loss is severe, and the control effect is poor. The liquid medicine distribution is too uneven or not atomized, and even produces phytotoxicity. 2 The spraying direction is consistent with the wind direction or slightly included, and the operation starts from the lower tuyere. Otherwise, the operation is difficult, leading to the drift of mist particles and uneven dispersion, reducing the control effect, but also likely to cause injury. The top wind operation reduces the spray amplitude and the mist particles become larger, forming a heavy spray and directly threatening the personal safety of operators. 3 The swing speed of the spray head is consistent with the walking speed and the flow rate of the liquid medicine. According to the flow rate of the liquid medicine, the walking speed is determined, and the walking speed determines the swing speed of the sprayer. The organic coordination and the close coordination of the three can avoid the heavy spray and the leak spray to ensure the control effect and improve the work efficiency. The general walking speed is 1 meter/second (approximate normal adult walking speed). 4 The direction and direction of the wind shall be kept perpendicular or slightly off-angle, but the angle between the direction of wind and the direction of wind shall not be less than 45 to ensure smooth operation, uniform distribution of fog particles, and increase control effect and avoid the occurrence of phytotoxicity. 3. Do not spray 1 do not spray high-toxic pesticides (such as methamidophos, parathionite, methyl parathion, phosphorus and other complex formulations have been withdrawn from registration). The low-volume spray liquid has a high concentration and a fine mist, and is easily lost in the atmosphere, causing environmental pollution and directly threatening the personal safety of operators, causing poisoning accidents. 2 phytotoxicity can not be sprayed. Different crops and different growth stages of the same crop are sensitive to dichlorvos of different types of pesticides, and diluting 800 times or less will produce phytotoxicity. Therefore, carefully observe the control effect while spraying, and immediately stop the operation if there is any curled leaf, yellow leaf, or coke leaf, so as to avoid loss. At level 33 or higher, the liquid is not sprayed when it is easy to drift. 4 Do not spray when there is a large updraft. Spray on sunny days before 10 o'clock in the morning and at 15 o'clock in the afternoon. Spray on cloudy days. Spray 3 to 4 hours after spraying. 5 When the dew is large, the liquid is easy to drain and cannot be sprayed. In short, the low-volume spray should be used flexibly according to the type of pesticides, pesticides, pests and diseases, crop types, growth period, crop density, and hazard sites combined with weather factors.