Professor, Zhejiang University
Hangzhou, PR China
Yunnan province is situated in the Southern Western part of China. The main agricultural activity there is tobacco but rice is an important food crop grown in about 1 million ha. Their average rice yield is 6 tons/ha and most farmers have adopted hybrid rice varieties.
Early planthopper immigrants were observed in March 2009 which was about 10 days earlier than usual in Yunnan and 99% of them were WBPH. The highest daily records under light traps in Jinping and Jiangcheng counties were 92,400 on May 6 and 65,368 on April 16, respectively. The total catches under light traps from March to Mid-May in the two counties were 0.1-0.2 millions and were the highest ever recorded.
The infested areas included 56 counties in the southern part of Yunnan (close to Vietnam, Laos and Thailand). Total areas infested with high WBPH densities of about 10 to 30 per hill were about 6 millions Mu (~ 400,000 ha) and the insecticide control areas were more than 10 millons Mu. The highest density observed was 525 hoppers per hill.