Pereira M de C
Departamento de Parasitologia, Universidade de São Paulo, Brazil.
J Econ Entomol. 1998 Feb;91(1):153-8. doi: 10.1093/jee/91.1.153.
Among several methods used to estimate the efficacy of an acaricide is the Drummond adult test, based on formulas which permit the assessment of the reproductive capacity of treated female ticks in comparison with controls. A constant value of 20,000 is normally used in these formulas, because this figure approximates the number of larvae that will hatch from 1 g of eggs. In laboratory studies conducted on large numbers of ticks, egg counting is a time-consuming and fastidious operation. Therefore, in quantitative studies, sampling techniques are more convenient. The use of the weight of egg masses laid by ixodids is adequate because eggs congregate in clusters. Experimental results have demonstrated that the analysis of the mean daily weight of egg aliquots in comparison with actual counts, from the 1st to the 20th d of oviposition, did not permit rejection of the hypothesis that 20,000 would be a representative number of eggs contained in 1 g. When aliquots were weighed only on the 20th or the 30th d of the oviposition-incubation period, and the results were analyzed in comparison with egg counts, the value of 20,000 no longer was reliable to express the number of Boophilus microplus (Canestrini) eggs contained in 1 g.
在用于评估杀螨剂功效的几种方法中，有德拉蒙德成虫试验，该试验基于一些公式，这些公式能够通过与对照组比较来评估经处理的雌性蜱的繁殖能力。在这些公式中通常使用20000这个固定值，因为这个数字接近从1克卵中孵化出的幼虫数量。在对大量蜱进行的实验室研究中，计数卵是一项耗时且繁琐的操作。因此，在定量研究中，抽样技术更为便捷。使用硬蜱产下的卵块重量是合适的，因为卵会聚集在一起。实验结果表明，在产卵的第1天到第20天，将等分卵的平均每日重量与实际计数进行分析比较时，无法否定20000是1克卵中所含代表性卵数这一假设。当仅在产卵 - 孵化期的第20天或第30天对等分卵称重，并将结果与卵计数进行分析比较时，20000这个值就不再能可靠地表示1克微小牛蜱（卡内斯特里尼）卵的数量。
