Feeding behavior of crab to a pest-insect (Nilaparvata lugens) and three kinds of weeds (Spirodela polyrrhiza， Echinochloa crusgalli， Juneceus serotinlls) in rice-crab paddy-fields were studied． The results showed that crab had different food-take to the weeds at its early stage， the order was S． polyrrhiza > J． serotinlls > E． crusgalli during the crab’s period of growth. But with the development of crab，it was getting smaller and smaller， even no food-take；In designed N． lugens population density (5～40 heads)， the functional response was belong to Holling-I． Three linear regression equations of experiment were as follows：Na=0.4167N-1.75， Na=0.4486N-2.0929 and Na=0.4505N-2.1857， the correlation coefficients all reached 0.99．
SHAO Yidong， YANG Yizhong， YU Yueshu，SHAO Hong，LU Ziqiang
. Studies on control of crab to a pest-insect and three kinds of weeds in rice-crab paddy-fields.[J]. Chinese Agricultural Science Bulletin, 2004
, 20(2)
: 178
-178
.
DOI: 10.11924/j.issn.1000-6850.0402178
1Ding Y-J(丁玉娟)，Wan M-K(万明科) ．1997，Cultivate techniques of crab．Wuhan：Wuhan Press，1～2(in Chinese)
2Wang C-H(王成辉)，Li S-F(李思发)，Li C-H(李晨虹)，et al．2000． Comparison on survival rate juvenile crab of Yangtze population and Liaohe population． J Shanghai Fish Univ(上海水产大学学报)，9（2）：111～115(in Chinese)
3Chen F-X(陈飞星)，Zhang Z-J(张增杰) ． 2002． Ecological economic analysis of rice-crab model．Chin J Appl Ecol(应用生态学报)，13（3）：323～326(in Chinese)
4ShaoY-D(邵益栋)，Yang Y-Z(杨益众)，Xia H(夏慧)，et al． 2002． Present situation and development prospect ofraising crab in paddy-fields in Jiangsu． Fish Aqui(水产养殖)，（1）：35～37(in Chinese)
5Xu X-C(徐兴川) ． 1994． Theory and practice of raising crab in paddy-fields． Hubei Fish(湖北渔业)，（4）：17～20(in Chinese)
6Chai X-F(柴祥法)，He Q-F(何庆富)，Sun J-H(孙君华) ． 1996． Raising crab in paddy-fields， a experiment of stereoscopic eco-agriculture model． Shanghai Agri Tech(上海农业科技)，（6）：30～31(in Chinese)
7Chen B-L(陈炳良)，Du N-S(堵南山)，Ye H-F(叶鸿发) ．1989． Feeding habits analysis of crab． 水产科技情报， 16（1）：1～5(in Chinese)
