Occurrence of the diamondback moth (Plutella xylostelia L.) and its parasitoids in Ethiopia:: influence of geographical region and agronomic traits
Occurrence of the diamondback moth (Plutella xylostelia L.) and its parasitoids in Ethiopia:: influence of geographical region and agronomic traits
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DOI：
10.1111/j.1439-0418.2006.01078.x
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发表时间：
2006-08-01
影响因子：
1.9
通讯作者：
Go, C. K. P. O.
中科院分区：
文献类型：
--
作者：
Ayalew, G.;Go, C. K. P. O.
2001年在埃塞俄比亚的芸苔产区进行了调查，以确定小菜蛾（diamondback moth， DBM）的地理分布和严重程度以及本地寄生蜂的发生情况。采用主成分分析方法，分析了DBM密度、不同寄生蜂种（Oomyzus sokolowskii、Diadegma spp、Apanteles sp.）的寄生率和总体寄生率、种植制度、农药用量、施药频率和海拔等9个参数的重要性。共访问了13个不同地区的194块芸苔田。主成分分析表明，9个主成分中的前两个（主要是DBM密度和农药使用）占数据集变化的70%。较高的DBM数与农药用量和间作的总体寄生率有关。共记录到8种寄生蜂，其中3种寄生蜂在寄生蜂的分布和寄生水平上均具有重要意义。其中包括乌尼祖斯(Hym。，蛭形蝇科)，蛭形蝇属（姬蜂科）和大翅虫（小翅虫科）。茧蜂科)。总体寄生率为3.6% ~ 79.5%，地区间差异较大。Apanteles sp.和Diadegma sp.主要局限于杀虫剂使用最少的埃塞俄比亚西南部。Ooniyzus sokolowski主要分布在东非大裂谷和埃塞俄比亚北部使用杀虫剂较多的地区。该研究表明，重复的杀虫剂处理和农艺措施对DBM的严重程度和寄生蜂有很大影响。
Surveys were carried out in 2001 in brassica-producing areas of Ethiopia to determine the geographic distribution and severity of diamondback moth (DBM) and occurrence of indigenous parasitoids. Principal component analysis was used to analyse the importance of nine parameters - DBM density, parasitism by different parasitoid species (Oomyzus sokolowskii, Diadegma spp., Apanteles sp. and overall parasitism), cropping systems, pesticide use, frequency of pesticide application and altitude. A total of 194 brassica fields in 13 different areas were visited. Principal component analysis showed that the first two of the nine principal components (largely DBM density and pesticide use) accounted for 70% of the variation in the data set. Higher DBM numbers were associated with pesticide usage and higher overall parasitism with intercropping. Eight parasitoid species were recorded of which three species were important both in distribution and level of parasitism. These include Ooniyzus sokolowskii (Hym., Eulophidae), Diadegma spp. (Hym., Ichneumonidae) and Apanteles sp. (Hym., Braconidae). Overall parasitism ranged from 3.6% to 79.5% with big differences between areas. Apanteles sp. and Diadegma spp. were largely confined to the south-western part of Ethiopia where insecticide use is minimal. Ooniyzus sokolowskii is mainly distributed in areas of the Rift Valley and northern Ethiopia with relatively heavy insecticide use. This study indicated a huge impact of repeated insecticide treatment and agronomic practices on DBM severity and its parasitoids.