Enhanced insecticidal activity of isoparaffin by ozone as an adjuvant

Recently, concerns have been raised regarding control methods for
domesticated sanitary pests. For many years, we have relied on chemical
pesticides for control, but their negative effects on the human body and
increased insecticide resistance have been reported, highlighting the
necessity to develop new control technologies. Therefore, we focused on
insect respiratory systems, for which it is considered difficult to
develop insecticide resistance. In this study, the synergistic effects of
isoparaffin and ozone were tested. The insect mortality rates (%) were not
significantly different, reaching almost 100 percent when sprayed with SS
(spray substance) and SS+O3 (SS containing Ozone). However, death times
(minutes) were noticeably different. In cockroach P. fuliginosa, the death
times were 10.5 ± 2.6 min. and 1.6 ± 0.5 min. (mean ± SD) for SS and
SS+O3, respectively. The Asian tiger mosquito A. albopictus exhibited a
death time of 13.5 ± 20.7 min from SS and 1.6 ± 1.4 min from SS+O3.
Insects sprayed with SS+O3 died significantly faster, at speeds up to 6
times those observed in SS treatment alone. SEM observation indicated
death was caused when the spiracles of the insects were covered with
isoparaffin degraded by ozone, resulting in suffocation. From these
results, we conclude the combination of isoparaffin and ozone offers a
promising new insecticide against pest insects.

近年来，居家卫生害虫的防控手段引发了诸多关注与担忧。长期以来，我们依赖化学农药开展害虫防控，但已有研究报道其对人体存在负面影响，且害虫会产生日益严重的抗药性，这凸显了开发新型防控技术的必要性。因此，我们将研究重点聚焦于昆虫呼吸系统——这类系统被认为难以产生抗药性。本研究针对异链烷烃（isoparaffin）与臭氧的协同防控效果展开测试。经喷施处理后，SS（喷雾基质，spray substance）组与SS+O3（含臭氧的SS）组的昆虫死亡率（%）无显著差异，均接近100%。但致死时长（单位：分钟）存在显著差异。在黑胸大蠊（P. fuliginosa）样本中，SS组与SS+O3组的致死时长分别为10.5 ± 2.6分钟与1.6 ± 0.5分钟（均为平均值±标准差，mean ± SD）。亚洲虎蚊（A. albopictus）经SS处理后的致死时长为13.5 ± 20.7分钟，经SS+O3处理后则为1.6 ± 1.4分钟。喷施SS+O3的昆虫致死速度显著快于单独喷施SS组，最快可达后者的6倍。扫描电子显微镜（SEM）观察结果显示，昆虫死亡的原因是经臭氧降解后的异链烷烃覆盖了其气门，导致窒息死亡。基于上述结果，我们认为异链烷烃与臭氧的组合为害虫防控提供了一种极具潜力的新型杀虫剂。