Food loss prevention during postharvest storage is critical from a financial standpoint. Postharvest infestation control with chemical (contact/residual) insecticides and fumigants is now commonly acknowledged as part of integrated pest management.
By Danyal Haider Khan, Usama Fareed, M. Zaryab Khan, M. Ashir
Because of the residual problem and health concerns to consumers, synthetic chemical insecticides are either prohibited or handled with caution. Plant-based pesticides are getting a lot of traction as a result of the recent rise in the usage of green insecticides..
Losses in stored grain due to pest:
According to current estimates, insect pests cause a loss of up to 25% in rice and maize, 5% in wheat, and 15% in pulses in India. More than 20,000 species of field and storage pests are responsible for the destruction of almost one-third of the world’s food output, which is worth more than $100 billion each year. India, as a tropical country, suffers 20–30% damage to stored food In the temperate zone, only around 5–10% of grain products are lost to insect pests. In the year 2010-2011, India’s food grain output was estimated to reach 250 million tons, with stored grain insect pests causing damage to approximately 20–25 percent of the grain. According to a World Bank research, storage bugs cause the loss of 12-16 million tons of agricultural grains If not stopped, one-third of the world’s population would be fed. As a result, there is a pressing need to find effective, cost-effective, and ecologically sustainable solutions for controlling and managing pests in stored products.
Use of botanicals for stored product pest management:
The idea of storing various household things in natural sources stems back to a time when there were no contemporary alternatives. Ancient civilizations utilised ash, sand, herbs, and medicinal plants to increase the storage life of various foods. Many of these techniques retain their validity in the contemporary day since they are cost-effective and long-lasting. The presence of essential oils, which are lipophilic volatile secondary metabolites, is responsible for the majority of the action. Many spices and herbs, as well as their extracts, have insecticidal qualities, which are commonly found in the essential oil fraction. Botanical insecticides now account for less than 1% of the global pesticide business.
Plant products as new chemotherapeutants in plant protection have recently gotten a lot of interest in different regions of the world. Plant products have the potential to be useful in pest control because of their non-phytotoxicity, systemicity, simple biodegradability, and stimulatory nature of host metabolism. The utilisation of plant compounds, particularly those of natural origin with minimal mammalian toxicity, has grown in popularity during the last few decades. Pest control chemicals have been employed with a variety of tropical medicinal plants and spices. Plant products such as ash, vegetable oils, and powdered plant parts are frequently claimed by peasant farmers and researchers to be effective in insect pest management. The utilisation of plant compounds, particularly those of natural origin with minimal mammalian toxicity, has grown in popularity during the last few decades. Pest control chemicals have been employed with a variety of tropical medicinal plants and spices. Plant products such as ash, vegetable oils, and powdered plant parts are frequently claimed by peasant farmers and researchers to be effective in insect pest management. Biologicals are biodegradable and leave no harmful residues or by-products because of their natural origin..
Classification of Botanical Insecticides
Based on their effect on insects, we may divide plant components into six categories: repellents, feeding deterrents/antifeedants, toxicants, growth retardants, chemosterilants, and attractants.
Repellents: Repellents are low-impact chemicals that stimulate olfactory or other receptors in insects to keep them away from treated objects. Some historically beneficial Ghanaian plant materials, such as Ocimum viride and Chromolaena odorata, have also been found to reduce the survival of stored product insect pests to less than 25% after 10 days of treatment at concentrations of 0.1 mg ml1 and higher. Essential oils from the Lamiaceae (mint family), Poaceae (aromatic grasses family), and Pinaceae (pine and cedar family) families are widely utilised as insect repellents across the world.
Antifeedants/Feeding Deterrents: Antifeedants are compounds that make the treated materials unappealing or unpleasant to insects, therefore inhibiting or disrupting their eating. Glycosides of steroidal alkaloids, aromatic steroids, hydroxylated steroid meliantriol, triterpenehemiacetal, and other antifeedants are among the most common naturally occurring antifeedants. Secondary metabolites like as alkaloids, phenolics, and terpenoids are used to make antifeedants, with the latter being the most effective. The most prevalent anti feedants include limonoids from neem (Azadirachta indica) and chinaberry (Melia azedarach) plants, such as azadirachtin and toosendanin, as well as limonin from citrus species..
Toxicity:
The chemical makeup of essential oil, the source from which it was collected, the season and ecological circumstances, the technique of extraction, the period of extraction, and the plant component utilised all influence the toxicity of the oil. The volatile toxicity of C. sativum essential oil was discovered in stored product insects. Nicotine, an active component of Nicotiana tabacum, has been described as a potent organic poison with contact-stomach poisoning and insecticidal characteristics, as well as human toxicity. Many Ocimum species, as well as their oils, extracts, and bioactive components, have been shown to have insecticidal properties against a variety of insect species.
Fumigant toxicity:
Horseradish oil, mustard oil, and Foeniculum fruit extract have been shown to have insecticidal action using a fumigation approach with 100 percent mortality in sealed containers. In open containers, there is a 2-4 percent mortality rate.
Reproduction Inhibitors: Plants and their different components have been found to affect insect oviposition, egg hatchability, postembryonic development, and progeny generation when combined with grains. Botanicals induce theovariole in female flies to misfire. Oviposition inhibition occurs when females die before depositing their eggs after coming into touch with botanical materials, or when living females fail to lay eggs.
Plant-based bio insecticides are now gaining popularity as a result of modern commercialization strategies and government efforts. Farmers and extension workers must be taught about the usage and value of botanicals, and extensive effort must be done to develop their efficacy for large-scale and long-term application. Subsidies and programmes should be provided by the government, and efforts should be made to encourage the adoption of such items.
Authors: Danyal Haider Khan, Usama Fareed, M. Zaryab Khan, M. Ashir