Schulz Johanna, Berk Jutta, Suhl Johanna, Schrader Lars, Kaufhold Stefan, Mewis Inga, Hafez Hafez Mohammed, Ulrichs Christian
Institute of Animal Welfare and Animal Husbandry, Friedrich-Loeffler Institut, Celle, Germany.
Parasitol Res. 2014 Sep;113(9):3167-75. doi: 10.1007/s00436-014-3978-6. Epub 2014 Jun 8.
Poultry red mite infestation still is an unsolved problem in poultry farms. Legal regulations, residue risks, and resistances limit chemical control of mites. Alternatives to chemical acaricides for control of poultry red mite are silica-based products, which have as a main constituent silicon dioxide. The acaricidal effect is attributed to sorptive properties of the particles, which result in the mite's death by desiccation. In the present study, the acaricidal efficacy of 12 products containing natural or synthetic silica, 9 in powder form, and 3 for liquid application was tested under laboratory conditions. Mite mortality was measured at several intervals and the mean lethal time (LT₅₀) determined by Probit analysis after Abbott's correction. The LT₅₀ values of the products significantly differed (Tukey's HSD p < 0.05). LT₅₀ values of powdery formulations ranged from 5.1 to 18.7 h and overlapped with those of the fluid ones which ranged from 5.5 to 12.7 h. In order to explain the differences in efficacy of the tested silica products, further characterizations were carried out. X-ray fluorescence, specific surface, cation exchange capacity (CEC), and water absorption capacity (WAC) were measured. Furthermore, electron microscopy was conducted and different products compared. Silicon dioxide content (ranging from 65 to 89% for powders and 57 to 80% for fluids) had no significant impact on efficacy, while specific surface and CEC (2.4-23.2 mEq 100(-1) g(-1) for powders and 18-30.8 mEq 100(-1) g(-1)) were positively and WAC (1.3-4.4 wt% for powders and 3.3-4.8 wt% for fluids) negatively related to the acaricidal efficacy. Influence of these parameters on acaricidal efficacy was significant according to the results of a stepwise regression analysis (p < 0.01).
家禽红螨感染仍是家禽养殖场中一个尚未解决的问题。法律法规、残留风险和抗药性限制了对螨类的化学防治。用于防治家禽红螨的化学杀螨剂的替代品是硅基产品，其主要成分是二氧化硅。杀螨作用归因于颗粒的吸附特性，这会导致螨因干燥而死亡。在本研究中，在实验室条件下测试了12种含有天然或合成二氧化硅的产品的杀螨效果，其中9种为粉末形式，3种为液体剂型。在几个时间间隔测量螨的死亡率，并在经阿伯特校正后通过概率分析确定平均致死时间（LT₅₀）。产品的LT₅₀值有显著差异（图基检验p＜0.05）。粉末制剂的LT₅₀值范围为5.1至18.7小时，与液体制剂的LT₅₀值范围（5.5至12.7小时）重叠。为了解释所测试的二氧化硅产品在功效上的差异，进行了进一步的表征。测量了X射线荧光、比表面积、阳离子交换容量（CEC）和吸水容量（WAC）。此外，进行了电子显微镜观察并比较了不同产品。二氧化硅含量（粉末为65%至89%，液体为57%至80%）对功效没有显著影响，而比表面积和CEC（粉末为2.4 - 23.2 mEq 100⁻¹ g⁻¹，液体为18 - 30.8 mEq 100⁻¹ g⁻¹）与杀螨功效呈正相关，WAC（粉末为1.3 - 4.4 wt%，液体为3.3 - 4.8 wt%）与杀螨功效呈负相关。根据逐步回归分析结果，这些参数对杀螨功效的影响是显著的（p＜0.01）。
