How To Use Fungicides Correctly

The key to the correct use of fungicides lies in accurate disease diagnosis, strict adherence to the instructions for mixing, and timely application. Here are the key operational points:

1. Selection and Diagnosis

Select the right fungicide for the disease: First, identify the type of disease (fungus, bacteria, or virus). Protective fungicides are used for prevention before disease onset; systemic therapeutic fungicides (such as carbendazim and tebuconazole) are used for treatment in the early stages of disease.

Verify and Register: Confirm that the fungicide is registered for the current crop to avoid misuse on sensitive crops (such as cucurbits sensitive to fluazinam), which could lead to phytotoxicity.

2. Preparation and Concentration

Two-stage dilution method: First, prepare a stock solution of the fungicide with a small amount of water, then pour it into a sprayer filled with water and stir well to ensure accurate concentration.

Strictly prohibit arbitrary dosage increases: Strictly follow the dilution ratio on the label. Excessive concentration can easily cause phytotoxicity, while insufficient concentration is ineffective and may induce resistance.

Caution with Mixing: Acidic pesticides should not be mixed with alkaline pesticides (such as lime sulfur or Bordeaux mixture). Copper-based pesticides and biopesticides should generally not be mixed with other pesticides arbitrarily; small-scale trials are necessary first.

3. Application Timing and Environment

Optimal Time: Choose before 9:00 AM or after 4:00 PM, avoiding midday high temperatures and strong sunlight to prevent rapid evaporation or leaf burn.

Weather Requirements: Wind force less than level 3, and no rain within 6 hours after application; if rain occurs, re-spray immediately.

Key Stages: Application before disease onset or in the early stages of disease is most effective; reduce concentration or use milder formulations during seedling and flowering stages.

4. Spraying Techniques

Full Coverage:Focus on spraying the undersides of leaves, stem base, and fruit areas. Use fine mist to ensure even coverage and no missed areas.

Rotation of pesticides: The same type of fungicide should not be used consecutively more than twice. Alternate between fungicides with different mechanisms of action to delay the development of pathogen resistance.

5. Safety and Interval

Safety Interval: Strictly adhere to the pre-harvest safety waiting period to ensure that pesticide residues meet standards.

Personal Protective Equipment: Wear masks, gloves, and goggles when applying pesticides. Clean exposed skin and tools after application.