Insecticidal effects of Moroccan plant extracts on development, energy reserves and enzymatic activities of Plodia interpunctella

Abstract

The aim of this work was to study the effects of methanol extracts of ten plant species used in traditional medicine in Morocco (Peganum harmala, Ajuga iva, Rosmarinus officinalis, Lavandula stoechas, Lavandula dentata, Cistus ladanifer, Cistus salviaefolius, Cistus monspeliensis, Centaurium erythraea and Launaea arborescens) on Plodia interpunctella Hübner (Lepidoptera: Pyralidae) larvae. Firstly, we studied the effects of the ingestion of these extracts at 500 ppm on post-embryonic development parameters. Most plant extracts provoked a notable decrease of larval weight 8 days after treatment (up to 33% weight loss with C. erythraea) and caused significant alterations on pupation (ranging from 5% to 85%) and adult emergence (below 2.5% with R. officinalis, C. erythraea and A. iva). The plant extracts that showed strongest effects on post-embryonic development were selected to test their effects on the following physiological parameters: larval reserve substances (at 500 ppm); and midgut activities of hydrolytic and detoxification enzymes (at 500, 750 and 1000 ppm). All treatments provoked a significant reduction of protein and carbon hydrate larval contents, the inhibition of proteases and α-amylase activities in a dose depended manner, and the induction of glutathione S-transferase and esterase (using MtB as substrate) activities, whereas the activity of cytochrome P450 monooxygenases and esterases (using 1-NA as substrate) increase or decrease depending on the extract concentration and the plant analyzed.

Synthesis of thymyl esters and their insecticidal activity against Spodoptera litura (Lepidoptera: Noctuidae)

“…Similar results were reported by Kumrungsee and Caballero, who found that both GST and CE activities were significantly increased in thymol‐treated larvae, and the GST activity was not significantly increased by the treatment of limonoid mixtures at a concentration below 1000 ppm, respectively. The increase in carboxylesterase activity may have been due to the uptake of the active compound by the insect, which progressively increased the amount of active components in the insect's body or a general induction of detoxification genes in response to secondary metabolites in the early stage of exposure . Our results showed the potential of thymyl cinnamate to induce toxicity in S. litura larvae but also increased the level of detoxification enzymes that may indicate the possibility of resistance development.…”

“…Generally, the herbivorous insects use detoxification enzymes to metabolize xenobiotics . However, these enzymes can be induced by natural and synthetic insecticides that is one of the mechanisms responsible for the resistance development in insect populations . GST and CE are common detoxification enzymes that metabolize pesticides or secondary plant compounds in arthropods .…”

“…[40][41][42] However, these enzymes can be induced by natural and synthetic insecticides that is one of the mechanisms responsible for the resistance development in insect populations. [43][44][45] GST and CE are common detoxification enzymes that metabolize pesticides or secondary plant compounds in arthropods. 46,47 GST is mainly a cytosolic enzyme that catalyzes the conjugation of electrophile molecules with reduced glutathione so that potentially toxic substances become more water soluble and, generally, less toxic.…”

Effect of Medicinal Plant Extracts on the Blood Sugar Trehalose of the Pulse Beetle Callosobruchus Chinensis (Coleoptera: Bruchide)

“…The relation between trehalose and insects was ignored until the substance was rediscovered in insects in the mid-fifties [14] and its metabolism was extensively studied in the following years. The reaction involved in the synthesis and degradation of trehalose in insects are now well understood.…”

Bio Efficacy of Atalantia monophylla (L) Correa (Rutaceae) against Spodoptera litura Fabricius (Lepidoptera: Noctuidae)

“…Cistus ladanifer L. (Cistaceae), Peganum harmala L. (Zygophyllaceae), Ajuga iva L. and Rosmarinus officinalis L. (Lamiaceae) extracts reduced the larval weight, pupation and adult emergence and decreased the protein, carbohydrate, lipid of Plodia interpunctella [6]. Baskar and Ignacimuthu [7] stated that ononitol monohydrate derived from Cassia tora (L.) Roxb.…”