Botanical Pesticides or natural insecticides are organic and natural pesticides that are derived from plants and minerals, that have naturally occurred defensive properties. These types of pesticides have become more popular since they do not release toxins as they decompose. Also, they have proven to be more useful than conventional insecticides as insects become more resistant to synthetic pesticides.
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Plants use self-created pesticides as a form of defense against diseases, herbivores, and insects. These botanical pesticides include chemicals such as nicotine or urushiol and oils like citrus oils. The insecticides made with these natural pesticides have minimal to no toxic effects on the environment while acting fast to tackle insects. Explore more knowledge about Botanical Pesticides with Pritish Kumar Halder.
Botanical pesticides are derived from plants belonging to different families and are either utilized as plant extracts, essential oils, or both. Plant parts used to make botanical pesticides include barks, leaves, roots, flowers, fruits, seeds, cloves, rhizomes, and stems. The plant part used is dependent on the targeted bioactive compounds and their abundance within that particular part.
Plants that are sources of botanical pesticides are easily available in the environment and most of them have multiple uses such as medicines, spices, ornamentals, food, and or as feed. Their availability makes them inexpensive and hence they are easily incorporated into agricultural production systems.
Commercialized pesticides from plants such as pyrethrum, neem, and sabadilla are some of the least toxic, especially to non-target organisms such as pollinators and fish. This attribute makes botanical pesticides effective, reliable, and acceptable in sustainable crop protection.
They interfere with insect behaviour, physiological activities, biochemical processes, morphology, and metabolic pathways. The activity of the metabolites is specific in their effect on the pest, for example, terpenes block glucose on chemosensory receptor cells in the mouth of lepidopteran larvae while some plant essential oils have chemo sterilant activity.
Acceptance, adoption, and utilization of botanical pesticides have been reviewed by various authors. Sufficient evidence and information regarding the chemistry and efficacy of botanical pesticides are needed to satisfy the pesticide registration regulations. This is in addition to information on their formulation, degradation, longevity, and toxicity
Integration of botanicals in agricultural production systems ensures major benefits to the farmers including food safety, reduced pest levels, improved quality of produce which fetches higher prices, and guaranteed market access. The consumers in lucrative markets are willing to pay higher prices for organically produced foods, thereby creating market opportunities for botanical pesticides
The increasing interest in natural plant products in medicine, agriculture, and the food industry has spurred research into the composition of compounds in various plant families. The common bioactive compounds in botanical pesticides are majorly secondary metabolites such as steroids, alkaloids, tannins, terpenes, phenols, flavonoids, and resins that possess antifungal, antibacterial, antioxidant, or insecticidal properties.
The specific compounds found in given species of plants make them effective against a given category of pests. The bioactive compounds found in plants also dictate their mode of action on the target pests.
The bioactive compounds in botanical pesticides have varied modes of action against different pests including insects, fungi, bacteria, nematodes, and plant host cells infected by viral pathogens. The modes of action include repellence, inhibition, denaturation of proteins, and other effects depending on the type of botanical compound and pest.
For instance, pesticides from pyrethrum target the nerve cells of insects leading to paralysis and later died while neem-based pesticides have antifeedant and repellent properties, induce molting abnormalities, hinder oviposition and disrupt the endocrine system. Synthetic pesticides are more specific in their targets and are mostly neurotoxicants with similar results as botanical pesticides. For more information about botanical pesticides please visit Pritish Kumar Halder’s page.
Understanding the mode of action including the physical, biological, and chemical interactions between the pest and pesticide is vital in pest management as it dictates the management strategy to be adopted. The sections hereunder contain descriptions of modes of action of botanical pesticides against specific groups of agricultural pests.
Mode of action
Most plant extracts act on insects by repelling, deterring feeding and oviposition, toxicity, lethal activity, and interfering with physiological activities. The multi-active role of botanical insecticides on insect pests makes them more popular in the market.
For example, commercialized products from plants such as pyrethrum have been reported to possess among others neurotoxicant effects on insect pests causing paralysis and knockdown and consequently mortality. Botanical pesticides also interfere with the production of important enzymes such as those responsible for moulting thus inhibiting growth and development.
The biological nature of botanical pesticides makes their degradation swift and therefore, does not accumulate in the environment such as in water and soils, therefore, eliminating the chances of pollution. Their exposure to air, sunlight, moisture, and high temperatures is enough to break down their constituents.
Integrated pest management (IPM) is an approach that combines several strategies to achieve sustainable pest management. The objective is to sustainably reduce pests, and attain high and profitable yields while keeping the environment safe.
Despite the availability of proof of the efficacy of botanical pesticides against a wide range of crop pests, they are still not well represented in the pesticide market. Commercialization of botanical pesticides is dependent on the availability of the source plants in large quantities and the plants should be readily cultivated. The source plants are either grown for other uses such as food, medicinal, shade, ornamental, or growing naturally in forests and another uncultivated land.
Conclusion and research needs
The natural environment is a rich source of a wide range of plants, some of which have been used to cure human, animal, and plant diseases. Following concerns of human health, environmental safety, and strict regulations on pesticide residues in agricultural produce, the use of synthetic pesticides needs to be done judiciously and only when necessary.