Population dynamics and temporal niches of Bemisia tabaci and its dominant natural enemies on cucumber and tomato cultivated under greenhouse planting

Abstract

[Objective] To study population dynamics of Bemisia tabaci and its dominant natural enemies on cucumber and tomato cultivated under greenhouse planting, and to provide scientific basis for comprehensive management of B. tabaci on cucumber and tomato cultivated under greenhouse planting.

[Method] Through the systematic investigation, recording the species and quantity of B. tabaci and its natural enemies on cucumber and tomato cultivated under greenhouse planting by five sampling points; the quartile methodwas used to divide its main activity period, and the temporal niche relationships between B. tabaci and its dominant natural enemies were analyzed by using niche index.

[Result] The result showed that the dominant natural economies of B. tabaci on cucumber and tomato cultivated under greenhouse planting were Nesidiocoris tenuis, Erigonidium graminicola and Encarsia formosa. The population dynamics of B. tabaci and its dominant natural enemies were slightly different on two protected crop fields. The activity period of B. tabaci on cucumber field was earlier than that on tomato field, and the population growth was quickly. During the main activity period of B. tabaci, the population quantity on tomato field was 1.03 ind/cm ², which was significantly higher than that oncucumber field ( P<0.05, the same below). The main activity period of B. tabaci on cucumber field was from seedling period to flowering and fruit setting period, and on tomato field was from tomato early blooming period to young fruit period. There was no significant difference in the population quantity of the N. tenuis and E. graminicola in the two crops fields ( P>0.05). However, the time niche width values of the two natural enemies differred greatly in different planting environments. The niche breadth of E. formosa was smaller and the activity period was more concentrated than N. tenuis and E. graminicola. At the main and late activity periods, the population quantity of E. formosa on tomato field were 0.34 and 0.24 ind/cm ², both were significantly higher than that on cucumber field. The largest niche breadth parameter with B. tabaci was N. tenuis on two crops fields, being 0.9664 and 0.9637 respectively.

[Conclusion] The main activity period of B. tabaci on tomato field is from tomato early blooming period to young fruit period, and on cucumber field is from seedling period to flowering and fruit setting period. During the main occurrence period of B. Tabaci, chemical control and other control methods should be supplemented to coordinate controlling the population of B. tabaci.

Abstract

摘要：【目的】明确设施黄瓜和番茄田间烟粉虱及其优势天敌发生动态, 为设施黄瓜和番茄田间烟粉虱的综合治 理提供科学依据。 【方法】通过系统调査, 利用五点取样记录昆明市宜良县设施黄瓜和番茄田间烟粉虱成虫及其天敌 种类、数量, 采用四分位法划分其发生时期; 利用生态位相关指数分析烟粉虱及其优势天敌在时间生态位上的关系。 【结果】设施黄瓜和番茄田间烟粉虱优势天敌均为烟盲蝽( Nesidiocoris tenuis)、草间小黑蛛( Erigonidium graminicola)和丽蚜小蜂( Encarsia formosa)。不同设施作物田间烟粉虱及其优势天敌的消长规律略有差异, 设施黄瓜田间烟 粉虱较设施番茄田发生时间早、种群数量增长迅速; 在烟粉虱主要发生时期, 设施番茄田间的种群数量为1.03头/cm ², 显著高于设施黄瓜田( P<0.05, 下同)。烟粉虱在设施黄瓜田间主要发生时期为黄瓜苗期-开花坐果期, 设施番茄田间 主要发生时期为番茄初花期~幼果期。草间小黑蛛和烟盲蝽在2种作物田间的同一发生时期, 种群数量间无显著差 异( P>0.05), 但2种天敌的时间生态位宽度值在不同种植环境下差异较大。丽蚜小蜂生态位宽度值较小, 发生较集 中, 在主要发生时期和发生晚期, 设施番茄田间种群数量分别为0.34和0.24头/cm ², 均显著高于设施黄瓜田。设施黄 瓜和番茄田间与烟粉虱生态位重叠指数最大的天敌均为烟盲蝽, 分别为0.9664和0.9637。 【结论】设施番茄田间烟粉虱 主要发生时期在番茄初花期~幼果期, 设施黄瓜田间烟粉虱主要发生时期在黄瓜苗期~开花坐果期。在烟粉虱主要 发生时期应辅以化学防治等其他防治措施, 以压低烟粉虱种群数量。