Broccoli Pest and Disease Control Methods and Technical Key Points

1. Downy mildew occurs all over the country and mainly damages leaves. It is prone to occur under conditions of sudden cold and heat and rainy, high-humidity weather. It is most likely to develop at 7°C-13°C, and the disease tends to stop at 25°C. Control measures: clean the field before plowing, rational close planting, and semi-high ridge cultivation as the main methods. In the early stage of the disease, spray 75% chlorothalonil wettable powder 500-800 times solution, or 65% zineb wettable powder 500-700 spray, or 1:2:300 Bordeaux mixture. Once every 7-10 days, with good control effect.

2. Sclerotinia rot occurs relatively rarely in North China, but once it occurs, spray control can be carried out early. You can choose 50% thiophanate 500 times solution, or 25% carbendazim 500 times solution. Or spray 0.2%-0.3% Bordeaux mixture, once every 7 days, spraying 2-3 times in succession. When spraying, focus on the stem base and the ground surface.

3. Black spot occurs at all stages and mainly damages leaves. It spreads through wind and rain. High temperature of 25°C-30°C, rainy conditions, dew, or heavy fog favor the disease, and continuous cropping in low-lying fields leads to severe incidence. Control measures: avoid continuous cropping with cruciferous crops, transfer seeds from disease-free areas, and disinfect seeds. Chemical control: at the initial stage of the disease, spray 50% amobam 1000 times solution, once every 7-10 days, spraying 2-3 times in succession, and note that the drug must be stopped 15 days before harvest.

4. Black spot mainly damages leaves and leaf stalks, and is prone to occur under low temperature and high humidity. A relative humidity above 85% and an air temperature of 17°C to 20°C are the most suitable conditions for disease development. Control measures: clean the field, disinfect seeds, increase the application of phosphorus and potassium fertilizers, rational close planting, high ridge cultivation, and chemical control. In the early stage of the disease, use 75% chlorothalonil 500-600 times solution, or 50% thiophanate 500 times solution, or 50% carbendazim 1000 times solution spray, once every 7-10 days, spraying 2-3 times in succession to control the development of the disease.

5. Cabbage caterpillar: use 1200-1500 times solution of Bacillus thuringiensis for control (add 0.1% laundry detergent as an adhesive). Spray immediately after finding white butterflies in the field; when the field insect population density is high, use 20% fenvalerate 2000 times solution, or 90% trichlorfon crystal 800 times solution spray.

6. Diamondback moth: spray 1.8% abamectin emulsifiable concentrate 3000 times solution, or Weinong No. 1 70 ml, Shamieling 70 ml plus 50 L water spray, which can also control Noctuidae and various other pests.