Master the application method: place fumigants at 3-5 points per mu, ignite sequentially from inside out, ventilate after 5-6 hours. Determine frequency based on pest pressure: initial problems may need only one application. Middle-late stage infestations may require 2-3 applications at 7-10 day intervals. Master correct dosage based on greenhouse space volume. Know your target pest and select appropriate fumigant. Safety first: avoid direct contact with skin and eyes, wash with soapy water after handling.