Inseticidal Oils From Amazon Plants in Control of Fall Armyworm

Abstract

-The potential insecticidal of oils from southwestern Amazon plants against Spodoptera frugiperda (J. E. Smith, 1797) (Lepidoptera: Noctuidae) was investigated. Initial bioassays were performed with undiluted oils from 11 plant species. The efficacy of the oils was evaluated against eggs and third-instar caterpillars of S. frugiperda. The oils of Copaifera sp. (Leguminosae), Orbignya phalerata (Arecaceae), and Carapa guianensis (Meliaceae) displayed a high efficacy against the caterpillars and were used in subsequent concentration-response bioassays, at concentrations established through preliminary tests. The highest nonlethal concentrations of oils and the lowest lethal concentrations were calculated. A completely randomized design was adopted in both bioassays. The LC 50 of the oils varied from 7.50 to 60.84% (v/v). Copaifera sp. oil had the highest toxicity and was 6.84-fold more toxic than O. phalerata oil and 8.11-fold more toxic than Carapa guianensis oil. In general, oils from Copaifera sp., O. phalerata, and Carapa guianensis were effective in controlling S. frugiperda caterpillars under laboratory conditions, and are good candidates for use in integrated management programs of corn pests.

Potential pesticide of three essential oils against Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae)

“…Rosemary pepper (L. origanoides) essential oil presented the fastest action and the highest pesticidal activity against the three evaluated instars, inducing in caterpillars, hyperactivity, tremor and rigid paralysis, possibly due to energy loss and neuromuscular fatigue induced by neuroexcitation mainly attributed to the action of carvacrol (30.37%), in addition to α-himachalene (10.38%), terpinolene (7.96%), α-pinene (5.08%) and β-myrcene (3.90%) (Dos Santos et al, 2016). Carvacrol has enormous insecticidal potential and is able to compete for nicotinic acetylcholine receptors (nAChRs), acting as an acetylcholinesterase (AChE) inhibitor (El-Wakeil, 2013), octopamine receptor blocker (Melo et al, 2018), or tyramine receptors (TyrR), which is a precursor of octopamine in cells of vinegar fly Drosophila melanogaster Meigen (Diptera; Drosophilidae) (Campos et al, 2018).…”

“…Exposure larvicidal activity bioassay was performed using filter paper discs (85 mm) impregnated with 0.8 mL essential oil's solutions or controls, placed in Petri dishes (90 × 15 mm) and allowed to stand 30 min (Olivero-Verbel et al, 2010;Dos Santos et al, 2016). After drying, the caterpillars were released in the center of the treated surfaces, providing an artificial diet fragment (Greene et al, 1976) to prevent starvation, and closing the plates with plastic film.…”

“…Essential oils are composed of complex secondary metabolites mixtures, which evolutionarily became the mechanisms of plant defense against insects and phytophagous mites, that extracted and exogenously applied can confer insecticidal, repellent or antifeedant activities (Isman, 2015). Plants of the genus Lippia, for example, have become important sources of insecticidal compounds, mainly by the presence of thymol (2-isopropyl-5-methylphenol) and carvacrol (2-methyl-5-(1-methylethyl)) (Regnault-Roger et al, 2012;Dos Santos et al, 2016). These aromatic monoterpenes are responsible for conferring to essential oils of Thymus vulgaris L. (Lamiaceae), wild marjoram Origanum vulgare L. (Lamiaceae) and rosemary pepper species such as Lippia sidoides Cham.…”

Research on the Bioactivity of Plant Essential Oils on Armyworm [Mythimna separata (Walker)] Larvae

“… Deletre et al (2016) found that the main compound of citronella essential oil may react with insect olfactory receptors, leading to insect avoidance behavior. Santos et al (2016) found that rosemary essential oil contained carvacrol (30.37%), α-himalayanene (10.38%), terpinene (7.96%), α-pinene (5.08%), and β-myrcene (3.90%), and other substances can cause symptoms such as hyperactivity, tremor, nerve paralysis, and muscle fatigue in caterpillars, resulting in a better insecticidal activity. El-wakeil, (2003) reported that carvacrol in essential oil had great insecticidal potential, which can compete with nicotinic acetylcholine receptors and can be used as an acetylcholinesterase inhibitor.…”

Plantas com potencial inseticida: enfoque em espécies amazônicas

“…Percebe-se, ainda, que o óleo da madeira de Copaifera sp. apresenta maior toxicidade para as lagartas do que as demais espécies (CL 50 = 7.50% (v/v), sendo 6,84 vezes mais tóxico que o óleo de sementes da Orbignya phalerata (CL 50 = 51.31% (v/v)) e 8,11 vezes mais tóxico que o óleo das sementes de Carapa guianensis (CL 50 = 60.84 % (v/v))(SANTOS et al, 2016).As espécies Banara guianensis, Clavija weberbaueri, Mayna parvifolia e Ryania speciosa apresentam efeito inseticida na concentração de 5 mg mL -1 sobre operárias de Atta laevigata. O extrato de M. parvifolia se destaca pela alta mortalidade, 82% em 72 horas, enquanto os extratos de Banara guianensis, Clavija weberbaueri e Ryania speciosa promovem a mesma mortalidade (68% às 72 horas após a aplicação)(GOUVÊA et al, 2010) Cerda et al (2019).…”