Eight Methods for Preventing Cotton Boll Rot Explained

1. Digging trenches to drain waterlogged fields Cotton is most afraid of autumn waterlogging; the higher the humidity in the cotton field, the more severe the boll rot. Continuous rainy weather is even more likely to cause boll rot. Therefore, after heavy rain, the accumulated water in the cotton field should be drained promptly, the soil should be allowed to dry to lower humidity, the field microclimate should be improved, boll opening should be accelerated, the reproduction and spread of pathogens should be inhibited, and boll rot should be reduced.

2. Reasonable pruning For cotton fields with high density and vigorous growth, after the full flowering stage, empty fruiting branches should be cut off promptly, vigorous buds should be removed, and the side tips of the middle and lower parts and the old leaves on the main stem should be removed in stages and batches, to enhance ventilation and light penetration, lower temperature, and reduce boll rot.

3. Hilling soil around the roots and earthing up Strong winds and heavy rain often cause cotton plants to lodge, leading to severe boll rot. Timely earthing up before wind and rain can significantly enhance the anchoring and support capacity of the aboveground part, helping resist wind and prevent lodging. Earthing up can raise soil temperature, promote root growth, and also facilitate drainage after rain, lower field humidity, and promote root growth.

4. Pushing plants apart and merging rows For cotton fields that stay green and ripen late and become shaded, on a sunny day, push the cotton plants apart by hand in alternate rows to form ventilation channels between rows, and after one week, push apart the two rows of cotton plants that were merged. By alternately pushing apart and merging in this way, ventilation and light penetration conditions can be improved, early ripening can be promoted, and boll rot can be prevented.

5. Preventing diseases and controlling pests The flowering and boll-setting stage of cotton is the peak period of damage from various pests. Cotton boll rot is mostly caused by pathogens entering through insect wounds; therefore, pests should be controlled promptly to reduce the damage from boring pests and ensure the normal development of cotton bolls.

6. Spraying for protection In August to September, under high-temperature and high-humidity climatic conditions, when 0.1% of plants in the cotton field show boll rot, begin spraying for protection. Generally, Bordeaux mixture prepared at 1:1:200, 50% carbendazim wettable powder at 800 times dilution, or 40% fosetyl-aluminum wettable powder at 500 times dilution can be used, and spraying 1 to 2 times is sufficient. The spray solution should preferably be applied to the cotton bolls in the middle and lower parts of the cotton plants, and it should be sprayed finely, evenly, and thoroughly.

7. Foliar fertilization Generally, it should be carried out from late August to early and mid-September. For plants with excessive growth and signs of boll rot, a 2% superphosphate extract plus a 1% to 2% potassium chloride aqueous solution, or a 0.3% potassium dihydrogen phosphate solution, can be sprayed. For plants showing signs of fertilizer deficiency, 0.75 to 1 kg of urea can be added to 50 kg of phosphorus and potassium fertilizer solution for spraying. Generally, spray 2 times, and this can be combined with pesticide spraying for disease and pest control.

8. Harvesting rotten bolls promptly Boll rot generally starts from the boll shell, then gradually spreads to the cottonseed, forming dead boll cotton, and finally causes the cotton boll to rot. Therefore, old bolls, diseased bolls, insect-bored bolls, and yellow-shelled bolls in the middle and lower parts of the cotton plants should be picked promptly and taken out of the cotton field to be shelled and dried, so as to reduce losses. At the same time, the cotton shells should be destroyed to reduce the spread of disease.