Faculty of Life Sciences, Division Urban Plant Ecophysiology, Humboldt-Universität zu Berlin, Lentzeallee 55, 14195, Berlin, Germany.
Botany Department, National Research Centre, 33 EL Bohouth St. Dokki, Cairo, 12622, Egypt.
Exp Appl Acarol. 2020 Oct;82(2):243-254. doi: 10.1007/s10493-020-00541-y. Epub 2020 Sep 8.
Four silica-based acaricides were examined in laboratory tests for their effectiveness against poultry red mite, Dermanyssus gallinae. All acaricides resulted in 100% mite mortality. Two groups of active ingredients could be differentiated. The products Silicosec and Ewazid, based on naturally occurring diatomaceous earth (DE), killed 100% of adult D. gallinae within 48 h exposure time. The time to kill 50% of the mites (LT) was calculated to be 31.7 and 34.9 h, respectively. The other two products, containing aggregates and agglomerates of pyrogenic synthetic amorphous silicon dioxide as active ingredients, killed the mites in a significantly shorter time: LT was 6.3 h for the liquid product Fossil Shield Instant White and 11.8 h for the powdery product Fossil Shield 90.0 White. This is more remarkable as the quantities of active ingredients used for the DE treatments were several folds higher. The effectiveness of all tested products was also shown in practical tests. A professional company treated five chicken houses on one farm in the Berlin-Brandenburg region with the test products, three houses with Fossil Shield Instant White and one each with Ewazid and Silicosec. Over a period of 46 weeks after stocking, the mite development in the houses was assessed. Only in one of the houses, treated with Fossil Shield Instant White, the mite population remained permanently low. In two houses treated with Fossil Shield Instant White, small mite colonies appeared in week 36, which were controlled by a follow-up spot treatment in week 41. In the houses treated with DE, the first mite colonies appeared 12 weeks after stocking. The number increased continuously over the experimental period and in week 31 after stocking there were clearly visible colonies (2-3 cm diameter) and the first mites could also be detected on the chicken eggs. At this time both houses were treated again with a follow-up spot-treatment, which only led to a slight improvement in one house and to a stabilization of the infestation in the other house. In week 41, large mite colonies were detected in both houses. A spot treatment at this point was ineffective in reducing the infestation. The tests showed faster acaricidal action of the products with the synthetic active ingredients compared to the natural DE-based products. This matches the shorter killing times under laboratory conditions. The experiments in a commercial chicken farm showed that it is possible to control the mite population for a period of 46 weeks by using physically effective SiO-based products. These products are therefore an effective alternative to the use of chemical acaricides.
四种基于二氧化硅的杀螨剂在实验室测试中被评估了对鸡血红螨（Dermanyssus gallinae）的有效性。所有杀螨剂都导致螨虫死亡率达到 100%。可以区分出两组有效成分。基于天然硅藻土（DE）的 Silicosec 和 Ewazid 产品在 48 小时暴露时间内杀死了 100%的成年 D. gallinae。杀死 50%螨虫所需的时间（LT）分别为 31.7 和 34.9 小时。另外两种产品，含有聚合和团聚的热解合成无定形硅作为活性成分，在更短的时间内杀死了螨虫：液体产品 Fossil Shield Instant White 的 LT 为 6.3 小时，粉状产品 Fossil Shield 90.0 White 的 LT 为 11.8 小时。这更值得注意，因为 DE 处理中使用的活性成分数量高出数倍。在实际测试中，所有测试产品的有效性也得到了证明。一家专业公司在柏林-勃兰登堡地区的一个农场用测试产品处理了五座鸡舍，三座用 Fossil Shield Instant White，一座用 Ewazid，一座用 Silicosec。在饲养后 46 周内，评估了鸡舍中的螨虫发育情况。只有在一座用 Fossil Shield Instant White 处理的鸡舍中，螨虫数量保持在低水平。在两座用 Fossil Shield Instant White 处理的鸡舍中，在第 36 周出现了小的螨虫群，第 41 周通过后续局部处理控制了这些螨虫群。在用 DE 处理的鸡舍中，第 12 周后首次出现螨虫群。在实验期间，数量不断增加，饲养后第 31 周出现了明显的螨虫群（直径 2-3 厘米），并且在鸡蛋上也可以检测到第一批螨虫。此时，两座鸡舍都再次进行了后续局部处理，但只有一座鸡舍的情况略有改善，另一座鸡舍的螨虫数量仍保持稳定。在第 41 周，两座鸡舍都检测到了大的螨虫群。此时进行局部处理对降低螨虫数量没有效果。实验表明，与基于天然 DE 的产品相比，具有合成活性成分的产品具有更快的杀螨作用。这与实验室条件下更短的杀灭时间相匹配。在商业养鸡场的实验表明，通过使用物理有效的基于 SiO 的产品，可以控制螨虫种群 46 周。因此，这些产品是化学杀螨剂的有效替代品。
