Insecticidal Activities of Atriplex halimus L., Salvia rosmarinus Spenn. and Cuminum cyminum L. against Dactylopius opuntiae (Cockerell) under Laboratory and Greenhouse Conditions

Abstract

The wild cochineal Dactylopius opuntiae (Hemiptera: Dactylopiidae) is one of the major insect pests of the prickly pear Opuntia ficus-indica (L.) in Morocco, a well-known fruit and vegetable crop of arid and semi-arid regions around the world. The present study investigated the insecticidal potential of six extracts (three aqueous and three hydroalcoholic (MeOH/H2O, 20/80 (v/v)) from Atriplex halimus (leaves), Salvia rosmarinus (leaves) and Cuminum cyminum (seeds) to control nymphs and adult females of D. opuntiae under laboratory and greenhouse conditions. Out of the tested samples, A. halimus aqueous extract showed the highest activity, inducing mortality rates of 67.04% (after 4 days) and 85% (after 8 days) on nymphs and adult females of D. opuntiae, respectively, at a concentration of 5% under laboratory conditions. It also showed the highest mortality rate of nymphs with 100% (4 days after application) and 83.75% of adult females (7 days after the second application) at a concentration of 5% when combined with black soap at 10 g/L under greenhouse conditions. The difference in the toxicity of plant species of the study was correlated with their saponin content. A total of 36 of these triterpene glucosides were suggested after a comprehensive LC-MSn profiling of the most active extract, A. halimus, in addition to phytoecdysones and glycosylated phenolic acids and flavonoids. These findings provided evidence that the aqueous leaf extract of A. halimus could be incorporated in the management of the wild cochineal as an alternative to chemical insecticides.

Lavandula angustifolia Mill. Essential Oil Exhibits Distinct Insecticidal Activities Against Pea Leaf Weevil Adults on Faba Bean under Laboratory and Growth Chamber Conditions

“…angustifolia EO using ingestion assay and growth chamber experiments. These results are in agreement with several reports identifying the great potential of essential oils as well as their individual components against harmful insects and mites in fields, greenhouses, and storage conditions. − Essential oils derived from Illicium pachyphyllum, Lavandula dentata, Citrus aurantifolia, Ocimum basilicum, Mentha piperita, and others from different families were reported as one of the best for controlling a wide variety of insects in the Curculionidae family. − L. angustifolia essential oil is widely reported for its broad range toxicity against different field and storage insect pests at different mode of application. , L.…”

“…The compounds identification was conducted using NIST 2017 database. The retention indices (RIs) of the isolated components were calculated against a set of standard n -alkanes that were separately analyzed under the same chromatographic conditions …”

“…Only individuals that failed to move their legs after pushing each adult with a camel hairbrush were considered dead. 21 2.3.2. Ingestion Assay.…”