What specific fungicide works well to control garlic purple blotch?

You can use 64% Sandofan wettable powder at 500 times dilution, or 75% chlorothalonil wettable powder at 500 times dilution, or 70% mancozeb wettable powder at 500 times dilution, for 2-3 consecutive sprays.

Detecting the symptoms of garlic purple blotch in time is very important, and this is why growers need to frequently go to the field to observe; only with early detection and early treatment can losses be reduced.

Control methods:

1. Practice crop rotation: rotate for more than 2 years with non-Allium crops (potato, wheat, cruciferous crops, etc.).

2. Select fine garlic seed and treat with chemicals: choose disease-resistant varieties for seed, such as purple-skinned garlic, or treat the seed before sowing by spraying the seed with Guoguang 50% carbendazim mixed with water, then sow after drying, to reduce the occurrence of disease.

3. Use plastic-film mulched, raised-bed cultivation with rational close planting to reduce field humidity and facilitate ventilation and light penetration for the plants, which can alleviate the occurrence of disease.

4. Rational fertilization: apply sufficient base fertilizer; 10-15 days before sowing garlic, use Guoguang Song'er fertilizer and Songda bio-organic fertilizer to build soil fertility, improve the physical and chemical properties of the soil, raise nutrient use efficiency, and at the same time inhibit the breeding of soil-borne pathogens, storing up nutrients for garlic growth. During the garlic growing period, carry out topdressing rationally according to local fertilization practices and the plant's growth condition, to promote robust plant growth and enhance the plant's disease resistance.