Detailed Explanation of Key Technical Points for Dusting Application in Greenhouses

1. Adjustment of the duster. Use a hand-cranked duster, available in Fengshou-5 and Fengshou-10 models. The cranking speed of the Fengshou-5 handle must reach no less than 36 revolutions per minute, and the Fengshou-10 must reach 50 revolutions per minute. This enables the dusting outlet to generate sufficiently strong air to discharge the powder evenly. Adjust the powder discharge rate to 200 grams per minute, with 1 kg of dust formulation used per mu per application. Load the dust formulation into the powder tank of the duster, and note that there must be no water or moisture inside the tank.

2. Preparation of the greenhouse before dusting. Before dusting, close the ventilation openings of the greenhouse and the door at the other end, and cover the plastic sheeting of the greenhouse tightly, achieving a sealed state as much as possible; if the greenhouse sheeting has small damaged spots, it has no effect on the dust.

3. In the greenhouse, use the retreating horizontal dusting method. Starting from the inner end of the greenhouse, the operator stands on the walkway in front of the north wall, with their back to the north wall and facing south, using the retreating method of dusting into the air. According to crop height, the dusting tube can be swung up and down appropriately; while dusting, retreat toward the other end until exiting the doorway, then close the door. Check the powder tank; if there is leftover powder, extend the dusting tube through the ventilation window into the greenhouse to dust until the remaining powder is fully discharged.

4. In the large tunnel, use the left-right swinging dusting method into the air. Starting from the north end, the operator stands on the walkway and swings the dusting tube to dust toward the left and right sides; according to crop height, the dusting tube can be swung up and down appropriately; while dusting, retreat backward along the central walkway until exiting the doorway at the south end, then close the door. Check the powder tank; if there is leftover powder, extend the dusting tube through the ventilation openings on both sides from outside the tunnel into the tunnel to dust until the remaining powder is fully discharged.

5. For small and medium arched tunnels, use the outside-tunnel dusting method. Because arched tunnels are low and small, the operator cannot enter, so dusting can be done from one side or both sides outside the tunnel, that is, lift part of the tunnel sheeting from the outside, extend the dusting tube into the tunnel to dust, swinging the tube left and right. According to the size of the tunnel and the amount of formulation used, the sheeting can be lifted at different parts of the arched tunnel for dusting until finished.

6. Suitable time for dusting. Choose to do it in the evening or in the morning, as this gives a higher deposition rate of the powder on the crops; on cloudy and rainy days, dusting can be done at any time. About 2 hours after dusting, the ventilation openings can be opened. If dusting in the evening, you can wait until the next morning to open the ventilation openings. The first dusting is at the early stage of disease onset, and according to disease severity, dust once every 7 days to 10 days.