| 摘要: |
| 1978到1981年,作者在陕西武功查清了棉田食蚜天敌主要有12类,分属8目、16科、39种。采用将食蚜天敌个体捕食或寄生寄主的功能反应与大田中食蚜天敌的数量反应相结合的方法, 以统一的天敌单位数表示各类天敌作用的大小。四年平均每年每亩食蚜天敌约100万头次,折合天敌单位数为42071。各类食蚜天敌按其作用大小依次为:瓢虫、蜘蛛、蚜霉菌、食蚜蝇、草蛉、食蚜绒螨、花蝽、姬猎蝽、蚜茧蜂、食蚜盲蝽等。不同季节天敌种类不同,瓢虫和蜘蛛是季节稳定种,食蚜绒螨和蚜霉菌是季节发生种,以上均为棉蚜关键性天敌。棉蚜的种群数量水平,明显的受食蚜天敌的自然控制。在棉花苗期,由于天敌的作用,无蚜期可维持15至20天。八月份如多雨潮湿,蚜霉菌可完全控制伏蚜为害。 |
| 关键词: |
| DOI： |
| 分类号: |
| 基金项目: |
|
| An Investigation on the Effectiveness of Aphidophagous Natural Enemies in Cotton Field |
|
|
| Abstract: |
| In order to bring the suppressive role of the natural enemies into full play, the authors studied their species composition variation of quantities and natural effects in wugong,Shaanxi in 1978-1981.It was found through our investigation that there are 12 groups of natural enemies belonging to 8 orders, 16 families and 39 species. In order to illustrate the effective differences of the natural enemies we used their unit number as a unified standard.In 4 years,the average unit number of natural enemies was 42071/mu,with a total of limilion/mu.In the order of population size,the natural enemies in the whole year are Coccinellidae,Araneida,Entomophthoraceae,Syrphidae,Chrysopidae,Trombidiidae,Anthocoridae,Nabidae,Aphidiidae,Miridae,etc. At the different stages of cotton growth in a year,the species of natural enemies are different.It was shown through investigation that Coccinellidae,Araneida are seasonal steady species,and Trombidiidae,Entomophthoraceae are seasonal varying species. The results clearly indicated that the level of quantities of aphid population dynamics was controlled by the natural enemies.The appearance of two peaks of aphids was followed by two peaks of the natural enemies,when the number of aphids fell immediately.Owing to the controlling effects of natural enemies,the period without aphid harm may last for 15-20 days or so. The controlling ability of the natural enemies is related to their seasonal variation,and under the particular favorable conditions trombidiidae and entomophthoraceae may greatly surpass all the other natural enemies.Therefore,they can control aphid damage at the seedling stage and during the hot summer days. |
| Key words: |
