Plant compounds insecticide activity against Coleoptera pests of stored products

Abstract

-The objective of this work was to screen plants with insecticide activity, in order to isolate, identify and assess the bioactivity of insecticide compounds present in these plants, against Coleoptera pests of stored products: Oryzaephilus surinamensis L. (Silvanidae), Rhyzopertha dominica F. (Bostrichidae) and Sitophilus zeamais Mots. (Curculionidae). The plant species used were: basil (Ocimum selloi Benth.), rue (Ruta graveolens L.), lion's ear (Leonotis nepetifolia (L.) R.Br.), jimson weed (Datura stramonium L.), baleeira herb (Cordia verbenacea L.), mint (Mentha piperita L.), wild balsam apple (Mormodica charantia L.), and billy goat weed or mentrasto (Ageratum conyzoides L.). The insecticide activity of hexane and ethanol extracts from those plants on R. dominica was evaluated. Among them, only hexane extract of A. conyzoides showed insecticide activity; the hexane extract of this species was successively fractionated by silica gel column chromatography, for isolation and purification of the active compounds. Compounds 5,6,7,8,3',4', 5,6,7,8,3'-pentamethoxy-4',5'-methilenedioxyflavone and coumarin were identified. However, only coumarin showed insecticide activity against three insect pests (LD 50 from 2.72 to 39.71 mg g -1 a.i.). The increasing order of insects susceptibility to coumarin was R. dominica, S. zeamais and O. surinamensis.Index terms: natural insecticide, pest management, alternative control, secondary metabolites. Compostos de plantas com atividade inseticida a coleópteros-praga de produtos armazenadosResumo -O objetivo deste trabalho foi selecionar plantas com atividade inseticida, para isolar, identificar e avaliar a bioatividade de compostos inseticidas presentes nessas plantas, contra as seguintes pragas de produtos armazenados da ordem Coleoptera: Sitophilus zeamais Mots. (Curculionidae), Rhyzopertha dominica F. (Bostrichidae) e Oryzaephilus surinamensis L. (Silvanidae). As espécies de plantas usadas foram: anis (Ocimum selloi Benth), arruda (Ruta graveolens L.), cordão-de-frade (Leonotis nepetifolia L.), datura (Datura stramonium L.), erva baleeira (Cordia verbenacea L.), hortelã (Mentha piperita L.), melão-de-são-caetano (Mormodica charantia L.) e mentrasto (Ageratum conyzoides L.). Avaliou-se a toxicidade dos extratos hexânico e etanólico dessas plantas sobre R. dominica. Somente o extrato hexânico de A. conyzoides apresentou atividade inseticida. O extrato hexânico desta planta foi fracionado, sucessivamente, por cromatografia de coluna de sílica gel, para isolamento e purificação dos compostos ativos. Os compostos 5,6,7,8,3',4', 5,6,7,8,5'-metilenodioxiflavona e cumarina foram identificados. Entretanto, somente a cumarina apresentou atividade inseticida às três espécies de insetos (DL 50 de 2,72 a 39,71 mg g -1 de i.a.). A ordem crescente de suscetibilidade à cumarina foi R. dominica, S. zeamais e O. surinamensis.Termos para indexação: inseticida natural, manejo de pragas, controle alternativo, metabolito secundário.

Insecticidal activity of the ethanolic extract from Croton species against Plutella xylostella L. (Lepidoptera: Plutellidae)

“…On other hand, insecticidal activity is associated with the solvent, which can make an extract more efficient depending on the insect tested (Moreira et al, 2007).…”

Topical Toxicity of Esenbeckia pumila Extracts on Leaf-Cutting Ants Atta laevigata and Acromyrmex balzani

“…A few specific flavonoids are known to act as antifeedant agents, for example, ermanin and rutin (Echeverri et al, 1991;Silva et al, 2016) and insect growth inhibitors (Simmonds, 2003), most likely as they interfere with the neural mechanisms whose toxic actions are influenced by the chemical structure of each specific compound. The coumarin is known to inhibit the electron transport chair (Neal & Wu, 1994) and also compromises the detoxification capacity of insects, which reduces, for example, their tolerance to xenobiotics (Moreira et al, 2007). The cardioactive glycosides (terpenoids) are well-recognized drugs that influence vertebrate cardiac muscles (Taiz & Zeiger, 2004), but they have not yet specifically been investigated in insects.…”

The mortality of Oryzaephilus surinamensis Linnaeus, 1758 (Coleoptera: Silvanidae) induced by powdered plants

“…in the form of oils, water, and alcohol extracts, and their combinations) on the saw-toothed grain beetle are being tested (Shaaya et al 1991;Moreira et al 2007;Shah et al 2008;Ebadollahi et al 2010;Benelli et al 2012;Madkour et al 2013;Padin et al 2013;Najafabadi et al 2014). The above-described studies indicate that herbs used in various forms may be potential insecticides/ allies in the combat against storage pests.…”