How to prevent and control rice purple sheath disease? Practical methods and key technical points

Symptoms After rice heading, dense pinhead-sized purple dots appear on the leaf sheath of the flag leaf, then gradually spread to most of the leaf sheath or the entire leaf sheath turns purplish-brown, especially obvious on the outer wall of the leaf sheath, sometimes infecting the inner wall or reaching deep into the stem. In severe cases, the flag leaf dies 7-10 days early. Sometimes it spreads to the second to third leaf sheaths, but the leaves do not die. When humidity is high, white powdery substances appear on the diseased parts, namely the conidiophores and conidia of the pathogen. Infected grains develop brown lesions or brown spots, and the 1000-grain weight decreases. Some consider this symptom to be the purple sheath type that occurs after heading in rice sheath rot disease.

Pathogen Sarocladium sinense Chen, Zhang et Fu. It is called Chinese broom-branch stalk spore, belonging to the Deuteromycotina fungi. Its morphological characteristics are basically similar to S. oryzae. Some consider this disease and sheath rot disease (S. oryzae) to be the same pathogen.

Transmission routes, disease conditions, and control methods see rice sheath rot disease. When controlling purple sheath disease, 50% benomyl wettable powder 1500 times liquid should be sprayed when 6% of the rice has headed. In addition, per 667 sq m, 50% carbendazim 60 g plus 5% jinggangmycin 80 ml can be selected, mixed with 65-70 L of water and sprayed, with a control effect of more than 80%.