Evaluation of Bacillus thuringiensis Berliner as an alternative control of small hive beetles, Aethina tumida Murray (Coleoptera: Nitidulidae)

Small hive beetles, Aethina tumida Murray, are parasites and scavengers of honeybee colonies, Apis mellifera L., and have become an invasive species that can cause considerable damage in its new distribution areas. An effective subspecies of Bacillus thuringiensis Berliner (=Bt) would provide an alternative to chemical control of this pest. Therefore, we tested three different Bt strains [B. thuringiensis, var. aizawai (B401^®), B. thuringiensis var. kurstaki (Novodor^®) and B. thuringiensis var. San Diego tenebrionis (Jackpot^®)] and Perizin^® (3.2% coumaphos), each applied on combs with a pollen diet fed to pairs of adult beetles. This evaluates the products for the suppression of successful small hive beetle reproduction. While none of the tested Bt strains showed a significant effect on the number of produced wandering larvae, we could confirm the efficacy of coumaphos for the control of small hive beetles. We further show that it is also efficient when applied with a lower concentration as a liquid on the combs. We suggest the continued search for efficient Bt strains naturally infesting small hive beetles in its endemic and new ranges, which may become a part of the integrated management of this pest.     

气相色谱法测定蝇毒磷溶液（蚕用）中蝇毒磷的含量

为了使蝇毒磷溶液（蚕用）检测方法更为准确简便,本实验对蝇毒磷溶液（蚕用）的含量测定行了方法学考察。采用气相色谱法,氢火焰检测器。线性范围在0.2525～8.0801 mg/mL,蝇毒磷和内标物的峰面积与浓度均呈良好的线性关系,相关系数分别为0.9998和0.9999,总回收率为99.8%, RSD为0.34%。本试验各项目设计科学合理,检测快速准确。     

Toxicological and biochemical characterization of coumaphos resistance in the San Roman strain of Boophilus microplus (Acari: Ixodidae)

The San Roman strain of the southern cattle tick, Boophilus microplus, collected from Mexico was previously reported to have a high level of resistance to the organophosphate acaricide coumaphos. An oxidative detoxification mechanism was suspected to contribute to coumaphos resistance in this tick strain, as coumaphos bioassay with piperonyl butoxide (PBO) on larvae of this resistant strain resulted in enhanced coumaphos toxicity, while coumaphos assays with PBO resulted in reduced toxicity of coumaphos in a susceptible reference strain. In this study, we further analyzed the mechanism of oxidative metabolic detoxification with synergist bioassays of coroxon, the toxic metabolite of coumaphos, and the mechanism of target-site insensitivity with acetylcholinesterase (AChE) inhibition kinetics assays. Bioassays of coroxon with PBO resulted in synergism of coroxon toxicity in both the San Roman and the susceptible reference strains. The synergism ratio of PBO on coroxon in the resistant strain was 4.5 times that of the susceptible strain. The results suggested that the cytP450-based metabolic detoxification existed in both resistant and susceptible strains, but its activity was significantly enhanced in the resistant strain. Comparisons of AChE activity and inhibition kinetics by coroxon in both susceptible and resistant strains revealed that the resistant San Roman strain had an insensitive AChE, with a reduced phosphorylation rate, resulting in a reduced bimolecular reaction constant. These data indicate a mechanism of coumaphos resistance in the San Roman strain that involves both insensitive AChE and enhanced cytP450-based metabolic detoxification.     

Small hive beetle diagnosis and control in naturally infested honeybee colonies using bottom board traps and CheckMite + strips

The efficacy of bottom board traps and CheckMite + strips using Coumaphos, for small hive beetle (SHB) diagnosis and control was studied in Australia. Colonies in three apiaries (N = 10 each) were surveyed for SHB. In two apiaries, colonies received bottom board traps (cardboard or plastic) with CheckMite + strips and in the control apiary, traps without strips. After 5 days, all colonies were surveyed again, killed and dissected to quantify non-detected SHB. Significant differences in the number of live SHB were found between apiaries after treatment, supporting the fact that Coumaphos traps are efficient (trap mortality: 94.73 ± 0.06% cardboard and 99.53 ± 0.01% plastic). However, mortality assessment at the colony level (53.29 ± 31.30%), showed that only a limited SHB proportion was affected. Post mortem colony inspections revealed that 14.06 ± 10.53% SHB were undetected, which should be considered for quantitative diagnosis. Bottom board traps provided a first estimate of infestation levels (43.03 ± 27.02%).     

气相色谱法同时检测蜂蜜中溴螨酯、蝇毒磷、氟胺氰菊酯和氟氯苯氰菊酯残留

本文建立了同时测定蜂蜜中溴螨酯、蝇毒磷、氟胺氰菊酯和氟氯苯氰菊酯等四种农药残留的分析方法.蜂蜜样品用水溶解后经正己烷-二氯甲烷提取,Oasis HLB固相萃取柱萃取净化,正己烷-二氯甲烷洗脱吹干后,用内标溶液定容,采用气相色谱电子捕获检测器进行测定.在0.004mg/kg～0.160mg/kg添加水平,四种农药的回收率在70%～110%之间,各农药的检出限在0.004mg/kg～0.008mg/kg之间.