5种植物提取物对小菜蛾的生物活性

Insecticidal Activity of Five Plant Extracts Against Plutella xylostella

植物源杀虫剂相较于化学农药,具有源于自然易分解、生物活性多样、害虫不易产生抗药性等优点。为研制高效低毒的植物源杀虫剂,为开发研究新型植物杀虫剂提供数据基础,从已报道的具有杀虫活性的5个科中选取丁香、甘草、独活、赤芍、八角5种植物,并在室内测定5种植物水醇提取物对小菜蛾3种虫态的生物活性。采用浸卵法、浸叶法和非选择叶盘法测定5种植物提取物对小菜蛾卵触杀、幼虫胃毒、成虫产卵忌避效果;并通过高倍显微镜观察5种植物提取物处理后小菜蛾卵的外部形态。结果表明,5种植物提取物对小菜蛾卵和幼虫均有显著的杀虫活性,对成虫具有产卵忌避活性,生物活性与剂量基本呈正相关;在植物提取物质量浓度为100 mg/mL时,对小菜蛾卵和幼虫的校正死亡率以及成虫产卵忌避率均在85%以上。丁香、甘草、独活、赤芍、八角提取物对小菜蛾卵的毒力LC50分别为9.57、16.16、20.42、9.00、7.57 mg/mL,对小菜蛾幼虫的毒力LC50分别为7.46、13.49、21.31、54.67、9.87 mg/mL。其中,丁香提取物对小菜蛾卵和幼虫的毒力最高;5种植物提取物处理后的小菜蛾卵发育受到影响,卵内组织器官发育受阻或虫体畸形。丁香、甘草、独活、赤芍、八角提取物具有作为植物源杀虫剂材料来源用于防控小菜蛾的潜在价值。

Compared with chemical pesticides,plant-derived insecticides have advantages such as natural origin,easy decomposition after application,diverse biological activities,and reduced likelihood of pest resistance.To develop highly effective and low-toxic plant-derived insecticides,and to provide a theoretical basis for the development of new plant-based insecticides for further research,in this study,five plants from five different families,all with reported insecticidal activity were screened.These plants are Eugenia caryophyllata,Glycyrrhiza uralensis,Angelica pubescens,Paeonia lactiflora,and Illicium verum.The hydroalcoholic extracts of the five plants were measured indoors for their biological activity against Plutella.xylostella.The effects of the five plant extracts on eggs,larval stomach toxicity,and female adult egg-laying(oviposition)deterring activity were determined using egg immersion,leaf immersion,and non-selective leaf disc methods.Furthermore,the external morphology of P.xylostella eggs,after treatment with the five plant extracts,was observed using high-magnification microscopy.The results showed that the five plant extracts exhibited effective insecticidal activity against eggs and larvae of P.xylostella,as well as strong oviposition-deterring activity on adults,and biological activityin a concentration-dependent manner increased with increasing concentration.When the mass concentration of the plant extracts was 100 mg/mL,the corrected mortality rate of eggs and larvae P.xylostella,as well as the oviposition-deterring rate of female adults,were both above 85%.The lethal concentration 50(LC50)for the extracts of E.caryophyllata,G.uralensis,A.pubescens,P.lactiflora,and I.verum were 9.57,16.16,20.42,9.00,7.57 mg/mL,respectively,for the eggs,and 7.46,13.49,21.31,54.67,9.87 mg/mL,respectively,for the larvae of P.xylostella.The highest toxicity of the extracts of E.caryophyllata was observed in both larvae and eggs,with the development of P.xylostella eggs being adversely affected by the treatment.The development of intrad egg tissues and organs was impaired or deformed.The results in this study proved that the extracts of E.caryophyllata,G.uralensis,A.pubescens,P.lactiflora,and I.verum hold great potential as phytogenic insecticides for preventing and controlling P.xylostella.This study provided a theoretical basis for the development of new plant-based insecticides for further research.