Nabil El-Wakeil
National Research Centre, Egypt
Title: Medicinal Plants: An Entomological Point Of View
Biography
Biography: Nabil El-Wakeil
Abstract
Medicinal plants (MP) are variable and planting over the world in different geographical locations and climatic conditions. These plants are a rich source of novel natural substances that can be used to develop environmental safe methods. From entomological point of view, some of MPs have insecticidal activity however; others are subjected to insect attacks. Insecticidal activity of many plants against several insect pests has been demonstrated. These activities may include antifeedant, repellent, oviposition deterrent, growth regulatory, reduction of fecundity and fertility and lethal activities. In insecticide market, there are many products derived from MPs that approved to use in many countries worldwide. More than 1000 plant species belonging to different families and genera have been reported to contain potential toxic principles. Plants contain a large number of secondary metabolites and those categorized under terpenoids, alkaloids, glycosides, phenols and tannins play a major role in plant defense and insect control.
Medicinal plants like other plants are attacked by insects; leaf feeders, leaf miners, flower insects and soil insects. A study case: Chamomile Matricaria recutita (L.) is an ancient healing plant; it is used for a sore stomach, a mild laxative, anti-inflammatory and a gentle sleep aid. In a survey study in chamomile fields in central Germany throughout summer 2014, Chamomile plants are infested by chamomile stem-weevil Microplontus rugulosus (Col., Curculionidae) and chamomile smooth beetle Olibrus aeneus (Col., Phalacridae), which could lead to a high reduction in chamomile yield. In a study conducted on biological control of entomopathogenic nematodes (EPNs) were used to control M. rugulosus and O. aeneus. Management of both insects was conducted using three strains of EPNs. Three treatment dates were applied in 1000 IJ/ ml in May, June and July; the first date was mainly for controlling stem weevil, while the other two dates were for smooth beetle. The results showed that 70-80% of stems had damage and symptoms of stem weevils. Thirty percent from the investigated plants were larvae free of smooth beetle; whiles 70% was infested. Steinernema carpocapsae had more efficiency than S. feltiae and Heterorhabditis bacteriophora in controlling both insects.
In general, these products derived from MPs become more attractive alternative insecticides to organic farming. However, it requires a strong cooperation, committed, inter and multidisciplinary experts team consist of entomologist, ethnobotanist, expert in phytochemisty, microbiologist and eco-toxicologist, to progress from active ingredient to agricultural and commercial product lines. It also demands a strong as well as long-lasting joint venture between the scientific centers and the insecticide companies.
Keywords: Antifeedants, botanical insecticide, insects, lethal effect, medicinal plants, repellents