Fernando L C P, Aratchige N S, Peiris T S G
Coconut Research Institute, Lunuwila, Sri Lanka.
Exp Appl Acarol. 2003;31(1-2):71-8. doi: 10.1023/b:appa.0000005126.16574.3b.
Distribution patterns and numerical variability of the coconut mite Aceria guerreronis Keifer (Acari: Eriophyidae) and its predator Neoseiulus aff. paspalivorus DeLeon (Phytoseiidae) on the nuts of 3- to 7-month-old bunches of coconut palms were studied at two sites in Sri Lanka. At the two sites, coconut mites were present on 88 and 75% of the nuts but no more than three-quarters of those nuts showed damage symptoms. N. aff. paspalivorus was found more on mature nuts than on immature nuts. Spatial and temporal distribution of coconut mites and predatory mites differed significantly. The mean number of coconut mites per nut increased until 5-month-old bunches and declined thereafter. The densities of predatory mites followed a similar trend but peaked 1 month later. Variability in the numbers of mites among palms and bunches of the same age was great, but was relatively low on 6-month-old bunches. The results indicate that assessment of infestation levels by damage symptoms alone is not reliable. Sampling of coconut and/or predatory mite numbers could be improved by using several nuts of 6-month-old bunches. The effect of predatory mites on coconut mites over time suggests that N. aff. paspalivorus could be a prospective biological control agent of A. guerreronis.
在斯里兰卡的两个地点，研究了椰扁螨Aceria guerreronis Keifer（蜱螨亚纲：瘿螨科）及其捕食螨近纽氏钝绥螨Neoseiulus aff. paspalivorus DeLeon（植绥螨科）在3至7月龄椰果串上的分布模式和数量变异性。在这两个地点，88%和75%的椰果上有椰扁螨，但其中不超过四分之三的椰果表现出受害症状。近纽氏钝绥螨在成熟椰果上的数量多于未成熟椰果。椰扁螨和捕食螨的空间和时间分布存在显著差异。每个椰果上椰扁螨的平均数量在5月龄椰果串之前增加，之后下降。捕食螨的密度也呈现类似趋势，但峰值出现时间晚1个月。同一树龄的椰树和椰果串之间螨类数量的变异性很大，但在6月龄椰果串上相对较低。结果表明，仅通过受害症状评估侵染水平是不可靠的。通过采集6月龄椰果串上的多个椰果，可以改进椰扁螨和/或捕食螨数量的抽样方法。捕食螨对椰扁螨随时间的影响表明，近纽氏钝绥螨可能是椰扁螨的一种潜在生物防治剂。
