PDF(Pubmed)
Abstract：
Fall armyworm, Spodoptera frugiperda (FAW) is a cosmopolitan crop pest species that has recently become established in sub-Saharan Africa and Southeast Asia. Current FAW control is almost entirely dependent on synthetic pesticides. Biopesticides offer a more sustainable alternative but have limitations. For example, pyrethrum is an effective botanical insecticide with low mammalian toxicity but is highly UV labile, resulting in a rapid loss of efficacy in the field. Beauveria bassiana is an entomopathogenic fungus that is more persistent, but there is a time lag of several days before it causes insect mortality and leads to effective control. The combination of these biopesticides could mitigate their drawbacks for FAW control. Here we evaluated the efficacy of pyrethrum and B. bassiana as individual treatments and in combination against 3rd instar FAW. Four different combinations of these two biopesticides were tested, resulting in an antagonistic relationship at the lowest concentrations of B. bassiana and pyrethrum (1 × 104 conidia mL-1 with 25 ppm) and an additive effect for the other 3 combined treatments (1 × 104 conidia mL-1 with 100 ppm and 1 × 105 conidia mL-1 with 25 ppm and 100 ppm pyrethrum). Additionally, a delay in efficacy from B. bassiana was observed when combined with pyrethrum as well as a general inhibition of growth on agar plates. These results appear to show that this particular combination of biopesticides is not universally beneficial or detrimental to pest control strategies and is dependent on the doses of each biopesticide applied. However, the additive effect shown here at specific concentrations does indicate that combining biopesticides could help overcome the challenges of persistence seen in botanical pesticides and the slow establishment of EPF, with the potential to improve effectiveness of biopesticides for IPM.
摘要：
秋季粘虫，Spodopterafrugiperda（FAW）是一种世界性作物害虫，最近在撒哈拉以南非洲和东南亚建立。目前，一汽的控制几乎完全依赖于合成农药。生物农药提供了更可持续的替代品，但有局限性。例如,除虫菊是一种有效的植物源杀虫剂，具有低哺乳动物毒性，但对紫外线高度不稳定，导致该领域的功效迅速丧失。球孢白僵菌是一种昆虫病原真菌，更持久，但是在导致昆虫死亡并导致有效控制之前，有几天的时间滞后。这些生物农药的组合可以减轻它们对一汽控制的缺点。在这里，我们评估了除虫菊和球孢芽孢杆菌作为单独治疗和联合治疗对三龄FAW的疗效。测试了这两种生物杀虫剂的四种不同组合，在最低浓度的玄武岩和除虫菊（1×104分生孢子mL-1，25ppm）下产生拮抗关系，并对其他3种联合处理（1×104分生孢子mL-1，100ppm和1×105分生孢子mL-1，25ppm和100ppm除虫菊）产生累加效应。此外,当与除虫菊组合时,观察到来自球孢芽孢杆菌的效力延迟以及琼脂平板上的生长的一般抑制。这些结果似乎表明,生物农药的这种特定组合对于害虫控制策略不是普遍有益或有害的,并且取决于所施用的每种生物农药的剂量。然而,此处在特定浓度下显示的加性效应确实表明，结合生物农药可以帮助克服植物源农药中的持久性和EPF缓慢建立的挑战，具有提高生物杀虫剂对IPM的有效性的潜力。
