SPATIAL-DISTRIBUTION OF PREIMAGINAL BEMISIA-TABACI (HOMOPTERA, ALEYRODIDAE) IN COTTON AND DEVELOPMENT OF FIXED-PRECISION SEQUENTIAL SAMPLING PLANS
SPATIAL-DISTRIBUTION OF PREIMAGINAL BEMISIA-TABACI (HOMOPTERA, ALEYRODIDAE) IN COTTON AND DEVELOPMENT OF FIXED-PRECISION SEQUENTIAL SAMPLING PLANS
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DOI：
10.1093/ee/23.2.254
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发表时间：
1994-04-01
影响因子：
1.7
通讯作者：
FLINT, HM
中科院分区：
文献类型：
--
作者：
NARANJO, SE;FLINT, HM
研究目的是检查两种陆地棉品种 Gossypium hirsutum L. 和一种美国皮马棉 G. barbadense L. 上烟粉虱 (Gennadius) 卵和若虫的分布模式，并制定有效的抽样计划来估计未成熟个体的密度。以每平方厘米为基础，卵和若虫均等分布在由主叶脉划分的四个叶区中。这种模式与叶子的节位置、品种或采样日期无关。然而，根据对叶柄附近 3.88 cm2 圆盘的计数，卵和若虫都聚集在每个扇区的近端。圆盘和全叶计数之间的关系随节位置和品种的不同而变化。最大数量的卵和若虫分别出现在节点 2-4 和 4-7（主茎终端 = 节点 1）的主茎叶上。这种模式随着时间的推移略有变化，但三个品种之间的情况相似。最低的变异系数分别与卵和若虫的节点 4-5 和 5-6 的叶子计数相关。基于方差划分和采样成本分析，第五个主茎节叶第二扇区基部的单个 3.88 cm2 圆盘被确定为估计卵和若虫密度的最有效样本单元。使用 Green (1970) 方法计算该样本单元的顺序采样停止线。使用蒙特卡罗模拟进行的样本计划验证表明，实际精度水平（SEM/平均值）低于未成熟群体低密度下指定的精度水平，但优于高密度下指定的精度水平。进一步的模拟表明，当卵或若虫密度分别为每个叶盘 100 个时，指定精度 0.20、0.25 或 0.30 的停止线将保持 0.25 的平均精度。这些采样计划可以有效监测害虫管理应用，并将有助于研究棉花中烟粉虱的种群动态。
Studies were conducted to examine distributional patterns of Bemisia tabaci (Gennadius) eggs and nymphs on two cultivars of upland cotton, Gossypium hirsutum L., and one American Pima cotton, G. barbadense L., and to develop efficient sampling plans for estimating densities of immatures. On a per square centimeter basis, both eggs and nymphs were equally distributed among the four leaf sectors delineated by the major leaf veins. This pattern was independent of the nodal location of the leaf, cultivar, or sampling date. However, based on counts on 3.88-cm2 disks near the petiole of the leaf, both egg and nymphal were aggregated at the proximal end of each sector. The relationship between disk and whole leaf counts varied with nodal position and cultivar. The greatest number of eggs and nymphs were found on mainstem leaves from nodes 2-4 and 4-7 (mainstem terminal = node 1), respectively. This pattern changed slightly with time but was similar among the three cultivars. The lowest coefficients of variation were associated with leaf counts from nodes 4-5 and 5-6 for eggs and nymphs, respectively. Based on variance partitioning and sampling cost analysis, a single 3.88-cm2 disk from the base of the second sector of the fifth mainstem node leaf was determined to be the most efficient sample unit for estimating egg and nymphal densities. Sequential sampling stop lines were calculated for this sample unit using Green's (1970) method. Sample plan validation using Monte Carlo simulation indicated that actual levels of precision (SEM/mean) were poorer than those specified at low densities of immatures and better than specified at high densities. Further simulations indicated that stop lines for specified precisions of 0.20, 0.25, or 0.30 would maintain an average precision of 0.25 when egg or nymphal densities are 100 per leaf disk, respectively. These sampling plans allow efficient monitoring for pest management application and will aid the study of B. tabaci population dynamics in cotton.