Occurrence Regularity and Chemicals Control of Tobacco PVY Diseases in West Henan

Occurrence regularity and control effect of PVY with 4 chemicals were studied in four successive years. The results showed that early occurrence stage of the diseases at tobacco growing areas in west Henan was in the first ten-day period of June, and full occurrence stage was from the last ten-day period of June to the first ten-day period of July;the occurrence of the disease was closely related to climate, transplanting time, fertilization, and Myzus persicae (Sulzer)etc.;and the control effect of Jinyebao in one 200th dilution among the 4 chemicals was the best and reached 71.47%.