Promotion of Bio-Agrochemicals for the Sustainable Pest Management: A Safe Approach

TABLECREATED

Table 1: Most common plant families, which has pesticidal property.

Botanical insecticides are classified into toxicants, repellents, antifeedent, ovipositional deterrent and growth inhibitors according to the pest behavior after application [6]. Botanical plant extract and essential oils are the main sources of these plant have been used for crop protection for last so many years [7,8]. These botanical bioactive agents (phyto-chemicals) can effectively replace the presently available synthetic pesticides against mosquito. At present, natural insecticides shares only 5% of global usage but it is increasing 10% every year. It is expected that the global market of these natural insecticides will further increase if these insecticides successfully substitutes the synthetic insecticides in a safe manner.

These phyto-chemicals have high degree of biodegradation so; these are environmentally sound control agents. These phytochemicals will be popular in near future, due to ever increasing public interest and awareness toward the environment, in both developed and developing countries.

Factors Affecting Usage of Botanical Pesticides

1. Raw material for pilot scale up of the botanical is not available.

2. Botanical extracts contain complex mixture of chemicalconstituents so, characterization and optimization is not simple.

3. Different chemical compounds of various plant species and their plant part are soluble in different Solvent types. Therefore, extraction procedure is very complex and time consuming.

4. Botanical constituents are easily degraded at slight variation in temperature, moisture or light.

5. Botanical pesticide registration is not easy task because plenty of data is required for registration.

6. The public perception has a negative effect in the utilization of botanicals, due to their slower and nontoxic pest control compared with conventional insecticides so, market demand is very less.

7. Weather conditions affect the synthetic pathways of various phyto-chemicals therefore same plant shows different chemical composition in different weather conditions. Therefore, consistency in chemical composition is not possible.

Currently, a very few natural insecticides registered by India due to scarcity of complete and systemic reports. In this context, more research work is required for discovery of new green products and their formulation and delivery mechanism. This will boost up the commercialization of green insecticides in future. Moreover, for promotion of these green insecticides co-operation of public and private sector is necessary. Additional research and development is necessary for common pilot production of green insecticides and accessibility for farmers at low cost, complete data for registration of low risk insecticide products. These all development will facilitate the promotion of safe insecticide products and enhances the availability at the market level and slow down the demand of synthetic chemical insecticides in near future.

Role of Formulation in Promotion of Botanical Pesticides

1. Increase the shelf life of botanicals by adding some stabilizers

2. Enhanced the bio-efficacy by adding synegists

3. Concentration of botanical can be fixed

4. Easy to apply

5. Provide diverse mode of application

6. Limit the wastage of botanical and give a targeted delivery mechanism.

Botanical Pesticide Formulations

Conventional formulations

A. Granules: A granular formulation is a product with a size range (250-1,000 microns). The active ingredient concentration is usually from 1-40% and the granules are free flowing and disintegrate in the soil to release the active ingredient (Agrow Report, 1995).

B. Wettable Powders (WP): Wettable powders are finely divided solid pesticide formulations, which are applied after dilution and as a suspension in water. The powders are prepared by wetting and dispersing agents and inert carriers or fillers along with botanical extract up to 50%. Wettable powders contain many particles of less than 5 microns and all the particles should pass through a 45-micron screen [9].

C. Dustable Powder: It consists of active ingredients (botanical powders) along with inserts and carriers like china clay. Active ingredient either solid or liquid is gradually added in china clay. After complete addition of the active ingredient, it is ground in a mixer to get a uniform composition. It is easy to formulate and use.

D. Emulsifiable Concentrate (EC): They are formulated by dissolving the botanical extract or extracted botanical chemical constituents solubilize in organic solvent and then emulsifying agent added. EC formulations give a stable “milky” emulsion after dilution with water. Stable emulsion has very little creaming and no oil separation and droplets up to about 10 microns are formed when the product is diluted in water in the spray tank [10]. IPFT has developed various botanical EC formulations.

New Generation Formulations

A. Microemulsion: Microemulsions are thermodynamically stable formulation and droplet size have very fine size less than 0.05 microns (50 nanometers). There are three main component of micro emulsion active ingredient, water and surfactant/co-surfactant. These components form a single phase containing relatively large ‘‘swollen micelles’’ [11]. Neem oil based microemulsions were successfully developed at IPFT, Gurgaon [12].

B. Nanoemulsions: These are very fine oil-in-water nanoemulsions with droplet size ranging from 5-100 nm [13]. They are thermodynamically and kinetically stable stabilize systems of botanical along with surfactants [14]. Eucalyptus oil nanoemulsion with karanja and jatropha aqueous filtrates as a pesticide by making a nanoemulsion for the control of Tribolium castaneum, a secondary pest of stored grains [15].

C. Controlled Release Formulations (CRF), Microencapsulation: This technology regularize the release of active constituents and reduce the toxicity [16]. Polymeric coating by interfacial polymerization mechanism is the popular microemcapsulation technique. Release kinetics of active ingredient depends upon the thickness of the polymeric coating. Botanical pesticides with high volatile chemical constituents needs to be polymerize with thick polymeric coating with high degree of cross-linking and reverse for less volatile bio-constituents.so, these formulations are effective for extended period of time.

D. Suspension concentrates Suspension Concentrate (SC) of water insoluble botanical extracts is well known [17]. SC is a finely ground, botanical active ingredient dispersed in water along with various surfactants. Particle size distribution in the range of 2-20 μm. These small particles improves the bio-efficacy as smaller the particle size translocation will be easier. SC formulations are eco-friendly, user friendly and economical as well. Hence, botanical suspension concentrates are most suitable formulation for botanicals to detain their greener characteristics.

E. Oil Dispersions (OD): These formulations are the same as SC, main difference is in dispersion medium, and here dispersion medium is oil instead of water as in SC. Therefore, OD formulations have good spreading and permeation. The Oil dispersion can be most suitable for hydrolytically unstable botanicals. In addition to this oil, dispersions give synergist effects with the botanicals and broaden the pest control. Most common oil dispersion medium being used is soyabean oil [18].

F. Capsule suspension (CS): these formulations are in the suspension forms in which stable suspended microcapsules with active ingredient. Biopesticides are encapsuled in various polymers like cellulose, starch, gelatin ect. Fungal biopesticide has been formulated by CS formulations [19,20]. Various stabilizers and thickners used to stabilize the encapsulated microspheres in the suapension. These formulations are very less in demands inspite of great efficacy due to their high production cost [21].

Institute of pesticide formulation technology, Gurugram in India is the only Institute of its kind devoted to the development of safe and environment friendly new generation insecticide formulation technology. There are some new formulated products of natural insecticides like controlled release formulations, Nano-formulations or water based formulations which enhances the efficacy of natural pesticides against insect pest. The work carried out at IPFT, greatly emphasizes on the development and promotion of environment and user-friendly pesticide formulations, also biodegradable, with the incorporation of latest technologies, and on their commercialization.

Future Considerations for the Promotion of Safe and Green Biopesticides

Biopesticides have long been attracting global attention as a safer strategy than chemical pest control, with potentially less risk to humans and the environment. To this end, co-operation between the public and private sectors is required to facilitate the development, manufacturing, and sale of this environmentally friendly alternative. In this context, discovery of new substances and research on formulation and delivery would boost commercialization and use of biopesticides. Additional research on integrating biological agents into common production systems is necessary. Maintaining low cost to farmers for a given product quality and availability, particularly in developing countries, is also important. Moreover, regulations that promote registration of low-risk compounds with provision of Agriculture incentives could also facilitate commercialization and availability of biopesticides in the market. While new substances could serve as a promising option for use in pest control, more field research is required to assess the efficacy on specific pest problems in various cropping systems. Microencapsulation based on nanotechnology could improve the residual action of biopesticides, and this could increase their field use.

Therefore, it is very necessary for strengthening the research in these safe and green insecticides.

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