Disease
Onion has downy mildew, purple spot, atrophy, soft rot and so on.
1. Onion rust: spray with 20% Triadimefon emulsifiable oil 1000 times, once in 7-10 days, for 2-3 times continuously.
2. Onion downy mildew: use 75% chlorothalonil wettable powder for 600 times; Spray with 500 times of 64% disinfectant alum wettable powder, once every 7-10 days, and 2-3 times continuously.
3. Onion white rot: use 50% carbendazim wettable powder 500 times liquid spray to prevent and control once in 7 days, and continuously prevent and control 2-3 times.
4. Onion blight: spray with 68% jinleidomil 1000 times solution, once every 7-10 days, for 2-3 times continuously.
5. Gray mold of onion: spray with 1500 times liquid of 50% chlorhydrin wettable powder once every 10 days and 2-3 times continuously.
6. Onion black spot: use 600 times liquid spray of 75% chlorothalonil wettable powder to prevent and control onion black spot once every 10 days and for 2-3 times continuously.
7. Onion soft rot disease: control with 4000-5000 times of neophytomycin, once every 7 days and 1-2 times continuously.
Pest
Onion pests mainly include root maggot, leaf miner and onion thrips.
1. Root maggot: spray 1000-1500 times of 48% Lisbon emulsion once every 7-10 days in the initial stage of disease, and spray for 2-3 times;
2. Spot Miner: spray 2.5% deltamethrin or 20% fenvalerate or other pyrethroid pesticides 1500-2000 times continuously from its spawning peak to the early stage of larval hatching;
3. Prevention and control of onion thrips: spray 3000 times of 5% Regent suspension or 2500 times of 10% imidacloprid wettable powder at the peak of nymph occurrence, once every 7-10 days, and spray for 2-3 times.
