Olive Leaf Extracts Toxicity to the Migratory Locust, Locusta migratoria: Histopathological Effects on the Alimentary Canal and Acetylcholinesterase and Glutathione S-Transferases Activity

Abstract

The migratory locust, Locusta migratoria (Linnaeus), is the most widespread locust species. Frequent applications of insecticides have inevitably resulted in environmental pollution and development of resistance in some natural populations of the locust. To find a new and safe alternative to conventional insecticides, experiments were conducted to assess the effect of olive leaf extracts on L. migratoria fifth instar larvae. The methanolic extracts were prepared from the leaves sampled during four phenological growth stages of olive tree which are as follows: Cluster formation (Cf), Swelling inflorescence buds (Sib), Full flowering (Ff), and Endocarp hardening (Eh). The most relevant result was noted with the extract prepared from the leaves collected at the Sib-stage. Results showed that treatment of newly emerged larvae resulted in a significant mortality with a dose-response relationship. The olive leaf extracts toxicity was also demonstrated by histopathological changes in the alimentary canal resulting in a considerable disorganization and serious damage of the midgut, ceca, and proventriculus structure. Epithelial cells alterations, less dense and degraded striated border, disintegrated regeneration crypts, vacuolarized cells, extrusion of cytoplasmic contents, and rupture of muscular layer were evident in the midgut and ceca of treated larvae. Data of biochemical analyzes showed that olive leaf extracts induced a significant decrease of the hemolymph metabolites (proteins, carbohydrates, and lipids). In a second series of experiments, we showed that the olive leaf extracts reduced the activity of acetylcholinesterase and induced the glutathione S-transferases with a dose-response relationship.

Metabolic and Biochemical Profiling of Phenolic Compound and their Biosynthesis in Oil Crops

“…displays the most grounded movement noted for a plant metabolite and it is thought to be in charge of the release of phytoalexins which an anti-parasitic substance Kubo et al [59]; Abdellaoui et al [60]. It behaves as a multifunctional alkylator that acts as aperfect protein cross linker.…”

Insecticidal Effects and Chemical Composition of Lemongrass and Peppermint Essential Oils Against the Coconut Mealybug, Nipaecoccus nipae (Maskell), (Hemiptera: Pseudococcidae)

“…Due to their successful usage in plant protection as potential biocontrol agents, phytochemicals are botanicals that naturally occurring insecticides (botanical insecticides) (Ramya and Jayakumararaj 2009). In the context of integrated pest management programmes, using natural substances that can affect the physiology of insect pests is a possible alternative to chemical insecticides (La Pergola et al, 2017 andAbdellaoui et al, 2019). The purpose of this study is to investigate the effects of lemon grass (Cymbopogon citratus (DC.…”

DEAD-Box RNA Helicase DDX47 Maintains Midgut Homeostasis in Locusta migratoria

“…The migratory locust Locusta migratoria (Orthopetera) is a worldwide agricultural pest that represents a hemimetabolous model. Its midgut, originating from endoderm, consists of three cell types—regenerative cells, differentiated columnar cells, and endocrine cells [ 1 , 26 ]. Regenerative cells are located in the regenerative niche, and they can generate the other two cell types [ 1 ].…”