两种稻虱缨小蜂对稻飞虱的控制作用

稻虱缨小蜂和拟稻虱缨小蜂是稻飞虱卵期重要的寄生性天敌。南京江浦稻田8月上旬前以稻虱缨小蜂为主,主要寄生于灰飞虱和白背飞虱卵,8月中旬以后则以拟稻虱缨小蜂占优势,主要寄生于褐飞虱卵。水稻苗期灰飞虱卵寄生率平均为27.3％,白背飞虱和褐飞虱卵寄生率,杂交稻田为10.87％和21.5％,晚粳稻田为20.67％和19.6％。白背飞虱寄生卵量与总卵量间里直线相关,而褐飞虱寄生卵量与总卵量间呈幂回归关系,回归方程分别为Y=-18.2128+0.2075x和Y=0.006807x~(1·4887)

STUDIES ON THE POTENTIAL OF TWO MYMARID PARASITES IN CONTROLLING RICE PLANTHOPPERS

Two mymarid wasps, Anagrus nilaoarvatae Pang & Wang and A. parani1aparvatae Pang & Wang Hym.:Myroaridae], were found to be important egg parasites of rice planthoppers in Nanjing area. A. nilaoarvatae was predominant before early August and attacked mainly the eggs of Laodelphax striatellus and Sogatella. furcifera. After the middle of August, A. paranilaparvatae became the dominant species and mainly parasitized the eggs of Nilaparvata lungens. The mean egg parasitization of L. striatellus was 27.3% during the seedling stage, .while that of S. furcifera and N. lungens were 10.8% and 21.5%, respectively in the hybrid-rice paddies, and 20.7% and 19.6%, respectively in the late rice fields. A linear correlation was found between the egg parasitization and the total number of S. furcifera and N. lugens eggs. Their regression equations are presented in the paper.