Distribution of entomopathogenic nematodes in Southern Cameroon
Distribution of entomopathogenic nematodes in Southern Cameroon
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DOI：
10.1016/j.jip.2011.09.008
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发表时间：
2012-01-01
影响因子：
3.4
通讯作者：
Moens, Maurice
中科院分区：
文献类型：
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作者：
Kanga, Francoise Ngo;Waeyenberge, Lieven;Moens, Maurice
2007年和2008年在喀麦隆南部的三个农业生态区进行了昆虫病原线虫（EPN）的第一次调查。从251个土壤样品中回收到26个昆虫病原线虫，回收率为10.4%。共发现3种线虫，分别为鲍氏异小杆线虫（Heterorhabditis baujardi）、斯氏线虫属（Steinernema sp. A）和斯氏线虫属（Steinernema sp. B），其中2种为未定种。在阳性样品中，23份样品仅含H。baujardi（88.5%），其中2株含有与H. baujardi（7.7%），斯氏线虫属（Steinemema sp.）B（3.9%）。H. baujardi在森林和水果作物（可可和油棕榈种植园）中很常见。Steinernema sp. A在柚木种植园中发现，Steinernema sp. B在森林栖息地中发现。线虫主要存在于pH值为3.7至7.0的酸性土壤中。在桑迪壤土、桑迪粘壤土、桑迪粘土和粘土中记录到最高的EPN存在。EPN在砂、壤土和粘壤土中未被回收。利用主成分分析方法，提取了4个因子，可解释总变异的73.64%。因素是地理（纬度，经度，海拔），土壤（pH值，含量的沙子，淤泥和粘土，有机碳，质地），水分（萎蔫点，田间容量）参数以及气候参数（平均年降雨量，平均气温）的组合。Logistic回归和冗余分析（RDA）显示，土壤pH值，经度，有效水和海拔高度与EPN的存在和不存在。Logistic回归和RDA均表明，随着海拔高度的降低，土壤pH值和经度的增加导致含有昆虫病原线虫的样品的百分比增加。(C)2011 Elsevier Inc. All rights reserved.
A first survey of entomopathogenic nematodes (EPN) was conducted in three agro-ecological zones of Southern Cameroon in 2007 and 2008. Entomopathogenic nematodes were recovered from 26 of 251 soil samples (10.4%). Three species, Heterorhabditis baujardi, Steinernema sp. A and Steinernema sp. B were found. The two steinernematids were considered unidentified species. Among the positive samples, 23 samples contained only H. baujardi (88.5%), two contained Steinernema sp. A co-occurring with H. baujardi (7.7%), and one sample contained Steinemema sp. B (3.9%). H. baujardi was frequent in forest and fruit crop (cocoa and oil palm plantations). Steinemema sp. A was found in a tree plantation of teak, Steinernema sp. B in a forest habitat. Nematodes were mostly present in acidic soils with pH ranging from 3.7 to 7.0. The highest EPN presence was recorded in sandy loam, sandy clay loam, sandy clay and clay soils. EPNs were not recovered in sand, loamy sand and clay loam soils. Using principal component analysis for elucidating the major variation patterns among sampling sites, four factors explaining for 73.64% of the overall variance were extracted. Factors were a combination of geographical (latitude, longitude, altitude), soil (pH, contents of sand, silt and clay, organic carbon, texture), and moisture (wilting point, field capacity) parameters as well as climatic parameters (mean annual rainfall, mean air temperature). Logistic regression and redundancy analyses (RDA) revealed that soil pH, longitude, available water and altitude were associated with presence and absence of EPN. Both logistic regression and RDA indicated that, increasing soil pH and longitude, associated with decreasing altitude, led to higher percentages of samples containing entomopathogenic nematodes. (C) 2011 Elsevier Inc. All rights reserved.