Pesticidal compounds from higher plants

Abstract

Higher plants offer an excellent source of biologically active natural products. Over the centuries numerous plants have been exploited as sources of insecticides, but nowadays traditional botanical insecticides play only a minor role in world agriculture. Nevertheless, plant natural products still have enormous potential to inspire and influence modern agrochemical research.Few plant natural products will ever reach the market as products per se, but others will provide lead structures for programmes of synthetic chemistry and hopefully follow the success story of the synthetic pyrethroids. Structurally complex compounds, which are not amenable to synthetic chemistry programmes, may also have a role to play by validating new modes of action for pesticides.Examples are presented of compounds exhibiting insecticidal, fungicidal and herbicidal effects. Consideration is also given to the development of screening programmes to detect new compounds with interesting biological properties. Careful experimental design and thorough recording of procedures and data are crucial to success. Badly designed programmes afford only weakly active compounds or show effects which cannot be reproduced at a later date.Natural product chemistry, whether based on higher plants, micro-organisms or other sources, is a very difficult science, but there is little doubt that dedicated research will eventually be rewarded with exciting new lead structures for industrial application.

Antifungal Activity of Essential Oils from Some Medicinal Plants of Iran against Alternaria alternate

“…In an attempt to reduce the use of synthetic pesticides, over the past two decades extensive investigations have been made into the possible exploitation of plant compounds as natural commercial products, that are safe for humans and the environment [7] Although essential oils from various wild plants have been reported in the past to be effective against a wide range of micro-organisms in vitro [6] , these essential oils failed to inhibit pathogen growth in vivo [5] and failed to control diseases under field conditions in most cases. Although in vitro screening of plant extracts is an important first step in identifying plants with potential application in agriculture, in vivo confirmation of this potential is essential in the search for plant derived preparations with the potential to be commercialized [13] .…”

Insecticidal, repellent, antimicrobial activity and phytotoxicity of essential oils: With special reference to limonene and its suitability for control of insect pests

“…Generally, plants can produce a diverse range of secondary metabolites such as terpenoids, phenolic compounds and alkaloids (Benner 1993). Terpenoids are among the vast reservoir of secondry compounds produced by higher plants evolved in defence against herbivores and pathogens (Duke et al 1991).…”

In vitroantifungal activity of terpinen-4-ol, eugenol, carvone, 1,8-cineole (eucalyptol) and thymol against mycotoxigenic plant pathogens

“…However, the development of new pesticides is of interest to struggle with the evolution of resistant pathogens and to replace the compounds lost due to the new registration requirements (Dayan et al 2009). Plant extracts and essential oils have been investigated for their antimicrobial activity (Bakkali et al 2008;Isman 2000), starting from the idea that the secondary metabolism of plants have evolved to oppose pathogens (Brenner 1993 (Angelini et al 2006;Bishop and Reagan 1998;Bowers and Locke 2000;Inouye et al 2000). In a previous study we have examined the effects of TTO and of its major purified components (terpinen-4-ol, γ-terpinen and 1,8-cineole) on two mycotoxigenic fungi, i.e.…”