摘要
【目的】明确吡虫啉种衣剂对玉米田节肢动物群落及主要非靶标害虫的影响,为种衣剂的科学使用及玉米害虫防控提供理论依据。【方法】分别于2015年和2016年6—9月,在河南农业大学许昌校区试验田,设置600 g·L-1吡虫啉悬浮种衣剂推荐最高使用剂量及其2倍和4倍剂量进行种子包衣,以清水为对照,每个处理重复4次,随机区组排列。每小区采用5点取样方法,每点连续标记10株玉米,分别在玉米苗期、喇叭口期、孕穗期、灌浆初期和灌浆中期调查样点内玉米植株上全部节肢动物的种类及其数量,分析不同处理区节肢动物的群落特征。在玉米灌浆期,调查样点内玉米穗部害虫种类及数量;玉米成熟时每小区收获两行,每行连续收取50株,调查雌穗上和茎秆中的鳞翅目幼虫种类和数量,分析吡虫啉种衣剂对主要非靶标害虫的影响。【结果】种衣剂处理不影响玉米田节肢动物群落物种种类,处理区与对照区的物种丰富度随时间的变化趋势基本相似,同一时间内不同处理区物种丰富度的差异与有些物种的密度低而在调查样点内的分布不均匀有关。吡虫啉种衣剂处理不会造成玉米田节肢动物群落多样性和均匀度下降,在靶标害虫玉米蚜发生量大时还能通过抑制玉米蚜的数量而使多样性和均匀度增加。种衣剂处理对玉米田节肢动物优势种的影响不仅年份间有差异而且不同玉米生育期间也有差异,在靶标害虫玉米蚜种群数量较高的2015年,玉米生长前期种衣剂处理区的植食性昆虫和捕食性天敌优势种与空白对照区基本一致,灌浆期黏虫和草间小黑蛛分别成为种衣剂2倍和4倍剂量处理区的植食性昆虫和捕食性天敌的优势种;在玉米蚜种群数量较小的2016年,孕穗期以后亚洲玉米螟和棉铃虫为各处理区植食性昆虫优势种,龟纹瓢虫和异色瓢虫成为捕食性天敌优势种。玉米不同生育期各处理区优势种的优势度指标与其优势集中度指标变化趋势相似。种衣剂处理对穗部鳞翅目幼虫的影响程度较复杂,如玉米灌浆初期和灌浆中期种衣剂处理区亚洲玉米螟幼虫种群数量均高于或显著高于对照区;灌浆初期种衣剂处理区桃蛀螟幼虫种群数量均显著高于对照,灌浆中期则低于或显著低于对照;灌浆中期种衣剂处理区黏虫幼虫种群密度均高于对照;种衣剂处理区棉铃虫幼虫密度与对照区虽有不同,但差异不显著。综合两年的调查结果,玉米灌浆期种衣剂处理区亚洲玉米螟、桃蛀螟和黏虫幼虫种群密度有增加的现象,但其种群密度与600 g·L-1吡虫啉悬浮种衣剂处理剂量没有明显的相关性。【结论】建议吡虫啉种衣剂处理玉米田应注意防控鳞翅目穗部害虫。
【Objective】The objective of this study is to investigate the effects of imidacloprid flowable concentrate for seed coating(FSC) on the arthropod community and the non-targeted insects in maize field, in order to provide a theoretical basis for the application of seed coating agent.【Method】The study was conducted in the experimental field in Xuchang Campus of Henan Agricultural University from June to September in 2015 and 2016, respectively. Maize seeds were coated with the recommended dose of 600 g·L^-1 imidacloprid FSC and its doubled and quadrupled dose, with water as control. Each treatment was repeated for 4 times and arranged with randomized block. The density of the arthropods in maize field was estimated by using 5 sampling spots methods, each spot with 10 tagged plants at seedling, bellmouthed, booting and filling stages of the maize plants. The characteristics of the arthropod community including arthropod species and their amounts in different treatment areas were analyzed. In order to analyze the effects of imidacloprid FSC on non-targeted insects, the amount of insect pests in maize ears within the sampling spots at filling stage and the amount of lepidopteran larvae in maize ears and stalks by sampling 100 plants within two lines at mature period were surveyed. 【Result】Imidacloprid FSC treatment had no effect on the number of species of arthropod in maize field, and the species richness in the treatment areas showed similar change trend to that in the control area. The difference of the richness in different treated plots at the same time was related to the low density and uneven distribution of some species. Seed coating could not lead to the decrease of the diversity and evenness of the arthropod community. When the population of target pest, Rhopalosiphum maidis, occurred at high level, the diversity and evenness in seed coating areas could be increased by inhibiting the target pests. The effects of imidacloprid FSC on the dominant species differed with maize growth stages in different years. In 2015, R. maidis occurred at higher population density, the dominant species of the phytophagous insects and predators in seed coating plots were similar to that in control plot at early growth stage of maize, while Pseudaletia separata and Erigonidium graminicolum were the dominant species in plots of 2 times and 4 times doses of maximum recommended doses(MRD). In 2016, when R. maidis occurred at lower population density, Ostrinia furnacalis and Helicoverpa armigera were dominant phytophagous species, and Propylea japonica and Harmonia axyridis became the dominant species of predators. The dominance degree showed similar change trend to dominant concentration index. The impact of seed coating on ear-feeding lepidopteran larvae was complex. For example, the population density of O. furnacalis in the treated plots was higher than or equivalent to that in the control plots during early and middle grain-filling, and the density of Dichocrocis punctiferalis larvae also increased significantly at the early grain-filling stage, but decreased at the middle grain-filling stage. For P. separata, the density in seed coating plots increased significantly than that in control plot at middle filling stage, while the density of H. armigera in seed coating plots differed from the check plots with no remarkable degree. The results of the two-year investigations showed that the density of O. furnacalis, D. punctiferalis and P. separata had an increasing trend in seed coating plots, but it was not closely related to the dosage of seed coating agent of 600 g·L^-1 imidacloprid. 【Conclusion】It is recommended that lepidopteran pests should be prevented or controlled in the maize field with application of imidacloprid coating agent.
出处
《中国农业科学》
CAS
CSCD
北大核心
2017年第24期4735-4746,共12页
Scientia Agricultura Sinica
基金
国家公益性行业(农业)科研专项(201303030)
河南省现代农业产业技术体系(玉米)(S2015-02-G05)
关键词
吡虫啉
种衣剂
玉米
节肢动物群落
非靶标害虫
imidacloprid
seed coating agent
maize
arthropod community
non-target pests