中稻田三种飞虱的捕食性天敌优势种及农药对天敌的影响

对两优0923非防治的中稻田白背飞虱、灰飞虱和褐飞虱与其天敌间的关系,采用灰色关联度法、生态位分析方法,对盆拍法调查的3种飞虱与其捕食性天敌在数量、时间和空间三方面关系进行分析,对每一种天敌对应的关联度、生态位重叠指数和相似性比例等参数标准化后的密切指数相加,按照密切指数值之和大小排序,评判3种飞虱捕食性天敌优势种.并用同样方法分析常规防治田农药对飞虱捕食性天敌的影响,以期为合理施药,科学保护和利用天敌优势种提供科学依据,其结果是,非防治田白背飞虱前三位天敌是条纹蝇虎、草间小黑蛛和锥腹肖蛸；灰飞虱的是八斑球腹蛛、茶色新园蛛和锥腹肖蛸；褐飞虱的是纵条蝇狮、四点亮腹蛛和黑肩绿盲蝽.防治田白背飞虱前三位天敌是条纹蝇虎、草间小黑蛛和锥腹肖蛸；灰飞虱的是拟水狼蛛、四点亮腹蛛和草间小黑蛛；褐飞虱的是黑肩绿盲蝽、拟水狼蛛和四点亮腹蛛.盆拍法的防治田和非防治田之间3种飞虱前三位的相同天敌,白背飞虱完全相同,灰飞虱没有相同天敌,褐飞虱的是黑肩绿盲蝽和四点亮腹蛛.飞虱与天敌在时间和数量关系上,扫网法的防治田和非防治田之间3种飞虱前三位的相同天敌,白背飞虱的是锥腹肖蛸和四点亮腹蛛,灰飞虱完全相同,褐飞虱的是纵条蝇狮和条纹影虎.两种稻田的差异主要是农药杀伤了飞虱,使飞虱数量减少,并对天敌有一定杀伤力,进而影响到天敌的发生规律.非防治田的盆拍法和扫网法之间,3种飞虱前三位相同的天敌,白背飞虱的是锥腹肖蛸,灰飞虱的也是锥腹肖蛸,褐飞虱的是纵条蝇狮.防治田两调查方法结果之间,白背飞虱的是锥腹肖蛸,灰飞虱和褐飞虱前3位天敌中没有相同天敌,其差异主要是两法调查稻株的部位不同所致.

The dominant species of predatory natural enemies of three kinds of planthoppers and impact of pesticides on natural enemies in paddy field

To provide a scientific basis for proper application and conservation as well as utilization of the dominant natural enemies, in this paper, the quantity, time and space framework of Sogatella furcifera (Horvath), Laodelphax striatellus(Fallen), Nilaparvata lugens (Stål) and their predatory natural enemies were systematically studied using grey system analysis, ecological niche analysis and aggregated-intensity index analysis of spatial patterns in both control and non-control paddy fields of rice variety "Two Excellent 0923". The same methods were also used to analyze the impact of pesticides on predatory natural enemies of three species of planthoppers. The synthetic ranking results indicated that, in non-control field, the orders of main natural enemies of Sogatella furcifera (Horvath), Laodelphax striatellus(Fallen) and Nilaparvata lugens (Stål) were, respectively, Plexippus setipet (Karsch), Erigonidiun graminicolum(Sundevall) and Tetragnatha maxillosa (Thoren); Theridion octomaculatum(Boes et str.), Neoscona theisi (Walckenaer) and Tetragnatha maxillosa (Thoren); Marpissa magister (Karsch), Singa pygmaea (Sundevall) and Cyrtorhinus lividipennis (Reuter). In control field, the orders of main natural enemies of Sogatella furcifera (Horvath), Laodelphax striatellus(Fallen) and Nilaparvata lugens (Stål) were, respectively, Plexippus setipet (Karsch), Erigonidiun graminicolum(Sundevall) and Tetragnatha maxillosa (Thoren); Pirata subpiraticus (Boes et Str), Singa pygmaea (Sundevall) and Erigonidiun graminicolum(Sundevall); Cyrtorhinus lividipennis (Reuter), Pirata subpiraticus(Boes et Str) and Singa pygmaea (Sundevall). The comparing analyses showed that the top three dominant natural enemies of Sogatella furcifera (Horvath) were identical, and in those of Nilaparvata lugens (Stål) only Cyrtorhinus lividipennis (Reuter) and Singa pygmaea (Sundevall) were same, whereas those of Laodelphax striatellus(Fallen) were completely different between the control field and non-control field by beat-pan method. Compared to the beat-pan method, the top three dominant natural enemies of Laodelphax striatellus(Fallen) were identical, whereas there were two same kinds of natural enemies, i.e. Tetragnatha maxillosa (Thoren) and Singa pygmaea (Sundevall) in those of Sogatella furcifera (Horvath), and Marpissa magister (Karsch) and Plexippus setipet (Karsch) in those of Nilaparvata lugens (Stål) between the control field and non-control field. The differences of these dominant natural enemies between two kinds of paddy fields were mainly caused by using pesticides, which kill and wound the three species of planthoppers, so pesticides affected the occurrence of natural enemies. In the non-control field, there was only a same kind of natural enemy (Tetragnatha maxillosa (Thoren)) in the top three dominant natural enemies of Sogatella furcifera (Horvath) and Laodelphax striatellus(Fallen), and Marpissa magister (Karsch) in those of Nilaparvata lugens (Stål) between beat-pan method and sweep net method. However, in the control field, the same natural enemies in the top three dominant natural enemies of Sogatella furcifera (Horvath) was only Tetragnatha maxillosa (Thoren), but no same natural enemies were found in those of Laodelphax striatellus(Fallen) and Nilaparvata lugens (Stål). The difference seems to be mainly caused by the two different investigation methods.