Insecticidal Activity of Ageratum conyzoides (Asteraceae) Aqueous Extracts against the Grasshopper Zonocerus variegatus (Orthoptera: Pyrgomorphidae)

Abstract

Ageratum conyzoides (Asteraceae) is an annual plant with insecticidal activity against some insect pests. The present study was designed to evaluate the insecticidal activity of aqueous extracts (infusion and maceration) of A. conyzoides against the pest grasshopper Zonocerus variegatus (Orthoptera, Pyrgomorphidae). Concentrations of 0, 10, 30, 100 & 300 µg/ml were prepared and administrated through injection to grasshoppers. Mortality rate was recorded for adult grasshoppers each day until the 9th day of treatment. Results revealed a significant increase (p < 0.05) of mortality rate with increasing concentrations of the two plant extracts. Plant extracts at 300 µg/ml induced 100.00 ± 0.00 percent mortality of adults Z. variegatus after 4 and 5 days for A. conyzoides infusion and maceration respectively. No mortality was registered after treatment with 0 & 10 µg/ml of the two plant extracts. Male mortality rate tended to be higher than that of female at the same concentration. Also, infusion tended to significantly increase (p < 0.05) mortality rate than maceration at the same concentration. Phytochemicals screening have shown that the presence of saponins, tannins, triterpenoids and alkaloids in the A. conyzoides aqueous extracts may be responsible for the insecticidal activity of this plant. These phytochemicals may therefore be exploited and serve as suitable alternatives to synthetic insecticides against the grasshopper Z. variegatus.

Evaluation of Toxicity of Some Tropical Flora, Clay and Permethrin against Sitophilus zeamais Motsch. on Stored Maize Grains

“…and Diaphania hyalinata. Furthermore, exposure of Zonocerus variegatus to 10 mg ml -1 to 300 mg ml -1 of A. conyzoides for 4 days to 5 days induced 100% mortality of the insect pest (Ingrid et al, 2020). Similar trials by Pintong et al (2020) indicated significant mortality of Aedes aegypti (dengue fever vector) to A. conyzoides.…”

Cytogenetic Toxicity and Infertile Properties of the Aqueous Extract of Cucumis melo Seeds (Cucurbitaceae) in Male Zonocerus variegatus Cell Model (Orthoptera: Pyrgomorphidae)

“…Similarly, the dose (0.05g / kg), for example 50 μg/mg of body weight was administered to grasshoppers. This dose is obtained after extrapolating from previous work in the research team [15]. Then, the work carried out by [15,23] led to the adoption of the intraperitoneal route of administration in Z. variegatus since the extract is placed directly in the hemocoel.…”

“…This dose is obtained after extrapolating from previous work in the research team [15]. Then, the work carried out by [15,23] led to the adoption of the intraperitoneal route of administration in Z. variegatus since the extract is placed directly in the hemocoel. Finally, a meiotic cycle corresponds to 24 hours, that is to say one generation of spermatozoa [23].…”

“…Meiotic chromosome smears were prepared by the method of [23] and examined using the FISHER binocular microscope with 40X and 100X objectives using Cedar wood immersion oil. Counting and examination of normal and/or abnormal parameters were performed on 250 follicles as described by [15], taking into account prophase-1 and anaphase-1 in meiotic division.…”

“…Secondary metabolites including alkaloids, flavonoids, phytosterols, glycosides, saponins and terpenes have been isolated in this plant [2,8]. Moreover, extracts of C. melo have shown antioxidant [9,10], anti-ulcer [11], anticancer [12,13], antidiabetic [14], antimicrobials and anthelmintics [15,16] properties. Ethnomedicine also reports that the seeds and their oils can be used against dysuria and gout or as purgatives and dewormers [1,11,17].…”