A Study on Chilo suppressalis's Developing Rules in Rice-duck Compounded Ecosystem

From April to October of 2003,the author made a systemic study on the rule of Chilo suppressalis(walker)'shappening in Rice-Duck commensalism field of Taojiang county,Hunan province.The results showed:in every hectare of rice paddy feeding 300 to,450 ducks,each duck weights from 200 to 400 g,can put off 9 to 14 days for the peak of walker grub's happening.Middle rice duck-fed area compared with blank area,the second generation of chilo suppressalis (walker) grub's happening was reduced by 53.2% to 76.8%;the ratio of damaged individual plant by chilo suppressalis (walker) was lowered by 13.4% to 47.1%.Late rice duck-fed area compared with blank area,the third generation of Chilo suppressalis(walker)grub's happening was reduced by 61.8%,the ratio of damaged individual plant by Chilo suppressalis (walker) was lowered by 62.2%.