**3. Conventional formulations and their limitations**

In Asia and Pacific regions, the most common formulations being used are dustable powders, emulsifiable concentrates, wettable powders, granules, soluble liquids, etc., for the control of insect pest and many pathogenic diseases [7, 8]. The most common conventional formulations are discussed below:


#### **Figure 1.**

*Schematic illustration showing key steps involved in dust formulation and its mode of application.*

**Figure 3.**

*Diagrammatical representation showing steps involved in WP formulation and its application.*


**Figure 4.**

*Schematic representation showing key steps involved in soluble powder formulation and its application.*

#### **Figure 5.**

*Schematic representation showing key steps involved in EC formulation and its application.*

*Vital Role of IPFT in Development of New-Generation Pesticide Formulation for Crop… DOI: http://dx.doi.org/10.5772/intechopen.101134*

suitable for the low melting point active ingredients, which are highly soluble in organic solvents. These formulations are developed by dissolving active ingredients in organic solvents along with emulsifying surfactants (**Figure 5**).

The main limitation is linked with the organic solvents that are mainly petroleum solvents being used in Asian countries. These petroleum solvents make the formulation flammable and cause dermal toxicity to the user. To rectify the problem associated with these conventional formulations, new formulations have been developed, which are improved and advance in terms of user and environment safety.

The major objectives of IPFT (India) to develop new formulation technologies are as follows:


#### **4. Recent advancements in agrochemical formulations**

**Water-dispersible granules (WDG):**-A WDG formulation is also termed as dry flowables (DF). These WDG formulations are non-dusty and disperse easily in water when added in spray tanks for its finer particle size in suspension. These are the safer and targeted delivery system for the various pesticides. Main uniqueness of these formulations is convenient application due to free-flowing nature and quick disintegration in water medium and applied as dilute suspensions. Size of the diluted suspended particles is very less, that is, 30–40 μm, therefore no nozzle clogging.

More advanced form of WDG is water-soluble bag-sealed WDG. In these packing bags, WDG are in partially disintegrated form, which can easily disintegrate in spray tanks (**Figure 6**).

Basic composition of WDG contains 50 to 90% pesticide (active ingredient) along with dispersing agents and wetting agents [10]. A dispersing agent is a type of surfactant that is added to formulations to improve the separation of the particles and inhibit particle size growth, and their settling or clumping. Pang et al. [11] reported lignosulfates as effective dispersing agent in water-dispersible granular formulations due to a high degree of sulfonation, high intrinsic viscosity property, and high molecular weights. Recently, sodium salt of methacrylic acid/styrene/ sodium p-styrene sulfonate copolymer (SMSS) has synthesized a novel dispersant by free radical polymerization mechanism. This new dispersant has strong resistance to hard water and showed high performance and show above 90% suspensibility in hard water [12].

IPFT has developed water-dispersible granules of liquid pesticide such as triazophos. Recently, IPFT developed neem WDG for mosquito control. Other WG

**Figure 6.**

*Schematic representation showing key steps involved WDG formulation and its application.*

formulations that have been developed by IPFT for agricultural usage are Captan 83WG, Isoproturon 75WG, Metamitron 70 WG, Mancozeb 75WG, Chlorothalonil 75WG, Endosulfan 75WG, Carbendazim 86WG, Divrinol 50WG, Thiram 80WG, Cypermethrin 40 WG, Thiamethoxam 25 WG, Deltamethrin 25 WG, and Triazophos 20 WG.

**Suspension concentrate:** Suspension concentrates are the stabilized dispersion of pesticides in water medium. This is the most popular formulation due to its safe and convenient use. The suspended particle size is very fine and provides good adhesion and penetration on target surface, which results in improved bio-efficacy. It has recently identified that SC formulations show less leaching of pesticides than conventional emulsifiable concentrate formulations. Similarly, another study has identified that in SC formulations, volatilization of active ingredient in environment reduced to 33.5% compared with conventional pesticide formulations [13]. Suspension concentrates have overcome the limitations associated with conventional organic solvent-based formulations (**Figure 7**).

**Figure 7.**

*Schematic key steps involved suspension concentrate formulation and its application.*

The main advantages of suspension concentrates are easy application, no organic solvent used, and free from any toxicity to users and environment.

Careful selection of surfactant system is necessary to prevent hetero-flocculation (agglomeration of solid particles and droplets) during storage. There are three types of instabilities identified in SC during storage due to particle size change and they are particle aggregation, Ostwald ripening, and particle sedimentation [14].
