Main Diseases and Occurrence Regularity of Next Generation Dryland Rice in Yunnan Province

Purpose This study aimed to identify field disease types and severity in next generation dryland rice (NGDR) and characterize rice blast occurrence under dryland cultivation, and to provide theoretical support for disease control.

Methods Taking the main cultivated NGDR variety Dianheyou 615 as the subject of investigation, multiple fixed survey sites were established in the main demonstration areas of Yunnan Province. Field systematic survey methods were employed to conduct field investigations on diseases throughout the growth period.

Results Rice blast was the most severe disease on NGDR, followed by rice brown spot, which occurred primarily in localized areas toward the end of the growth period; sheath blight, bacterial blight, and bacterial leaf streak occurred in localized patches; rice false smut appeared sporadically; no rice seedling blight or root-knot nematode disease was observed; and southern rice black-streaked dwarf virus was the dominant pathogen. Tillering stage was a high-incidence and sensitive period for leaf blast, and environmental conditions with a temperature of 24-26 ℃ and a relative humidity of >70% were more conducive to its spread and prevalence.

Conclusion Rice blast remains the primary target for disease control in NGDR cultivation, while rice brown spot has emerged as one of the major diseases. The occurrence of sheath blight, bacterial blight, bacterial leaf streak, and false smut has declined significantly.