**6. Preparation methods of ME formulation**

#### **6.1 Phase inversion method**

In phase dispersion method, dispersed phase is surfactant system along with active ingredient and water is the dispersant. The whole phase of inversion occurs in controlled temperature and other conditions for active kinetics (**Figure 9**).

**Characteristic features of ME**: ME formulation can effectively mask smell of the unpleasant active ingredients and protect pesticides from hydrolysis and oxidation. It enhances the solubility of water insoluble pesticides, regulates and slowdowns pesticide release, and increases bio-efficacy.

#### **6.2 Use of ME in agriculture**

Cyhalothrin ME was developed and found as the most promising pesticide formulation in China [23]. Carbendazim is another pesticide that was formulated as ME and its bio-efficacy was evaluated in *Rhizoctonia solani* [24]*.* Chlorpyriphos pesticide ME was successfully developed and found the most potent, safe, and environment-friendly pesticide formulations in comparison with conventional pesticide formulation in recent years [25].

Along with the synthetic pesticides, botanical-based microemulsions are well known in Asian agriculture. Essential oil in microemulsion form gives superior bioactivity as compared with emulsion forms [26]. In microemulsion system, spreading capacity and dispersion improves over applied plant surface. Therefore,

microemulsion system is the important vehicle for essential oil targeted delivery in a small quality without any losses [27, 28]. In addition, essential oil bio-constituents uniformly disperse after application over active targeted sites and offers improved bio-efficacy [29].

Clove (CO) and lemongrass oil (LGO) ME have investigated as efficient antifungal agents against *Fusarium oxysporum* f.sp. *lycopersici* without any phytotoxicity to main crop [30]. Previous studies in Asian region revealed that synthetic pesticide- and botanical-originated microemulsion could be an advanced, green, safe formulation against different crop pests. Therefore, microemulsion is the one of new-generation formulations for safest delivery system.

IPFT has developed different types of microemulsions of synthetic pesticides along with botanical pesticides. In addition to this, IPFT has prepared microemulsion system with inbuilt adjuvants and synergist, which will enhance the formulation efficiency and efficacy. There are different botanical-based microemulsions have been developed and formulation techniques transferred to various agrochemical industries.

#### **6.3 Nanoemulsion formulation**

Nanoemulsions are defined as nano-sized droplets dispersion in immiscible liquids (**Figure 10**). Different pesticides have been formulated as nano-formulation and researchers have quantitatively estimated the pesticide content by various characterization techniques [31]. This formulation exhibits the property of encapsulation and regulated release of pesticides for extended period of time as in controlled release formulations.

Characteristic features of nanoemulsion formulation techniques are small droplet size with low amount of surfactant and active ingredient. Similar to ME, NE can enhance solubility of active ingredient, increase bioactivity, and improve spreadability (during application). Moreover, it can reduce volatility and hydrolysis of active ingredient.

It has been evaluated that nanoemulsion formulation showed enhanced bioefficacy results compared with emulsifiable concentrates (EC) and microemulsions (ME). This study was conducted in third-instar larva of *Plutella xylostella* [32]. Indian Agriculture Research Institute (IARI), India, has developed nano-sulfur

**Figure 10.** *Diagrammatic representation of nano-formulation preparation 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*

formulation against *Erysiphe cichoracearum* (powdery mildew of okra) [33]. In addition to this, IARI has also developed nano-hexaconazole as effective fungicide [34]. Characteristic feature of this developed formulation is biosafety aspect, and after application of nano-hexaconazole, no impact was observed on soil nitrifiers such as blue green algae and cynobacteria species. Therefore, nano-formulations maintain the sustainable soil fertility and productivity compared with conventional formulations [35].

Many botanical-based nanoemulsions have been developed in recent years. In a study, *M. longifolia* oil nanoemulsion developed with droplet size 14 nm–36 nm. The results of study showed that in nanoemulsion formulation, its contact toxicity and durability increase. In a similar study, sea fennel (*Crithmum maritimum*) essential oil is formulated as nanoemulsion along with SiO2 nanoparticles and evaluated against *Spodoptera litura*. In other study, Eucalyptus oil NE prepared by emulsification method and insecticidal and repellent effect was evaluated against *Sitophilus oryzae*, *Rhizopertha dominica*, and *Tribolium castaneum* [36]. Nanoemulsion of *Piper aduncum* fruit extract has also been developed against cabbage pest *Crocidolomi apavonana*. Therefore, it has been concluded that botanical nanoemulsion formulation represents a new alternate for integrated pest management for organic farming promotion in Asian countries [37].

In addition to this, nanoemulsion formulation also been used as edible coating to improve the storability of fruits and vegetables in postharvest conditions for enhancing shelf life and prevention of microbial growth over fruits and vegetables [38].

IPFT has also contributed in developing many nanoemulsions of synthetic as well as bioactive pesticides and different essential oils for controlling various agriculture pests and micro-organisms. Besides this, IPFT has prepared nanoemulsion with botanical synergists and adjuvants to enhance the bioactivity and stability of nanoemulsion formulations. Moreover, combination of nanoemulsions is further developed for the amplified pest control applications in intense pest attacking conditions.

## **7. Emulsion in water formulation or oil in water emulsion (EW)**

Emulsion in water (EW) formulation is suitable for liquid or a liquid or oily active ingredient. These formulations are dispersion of active ingredient in aqueous continuous phase (**Figure 11**). The size of the dispersed droplets ranges generally from 0.5 to 4–5 μm. EW formulations are obtained by high-shear emulsification process. Principally, EW formulations contain pesticides dispersed in the form fine liquid droplets in water and form oil-in-water (O/W) emulsions [39].

#### **7.1 EW in agriculture**

Lambda-cyhalothrin is broad-spectrum synthetic pesticide widely being used to control diamondback moth, cabbage caterpillar, cotton bollworm, and other pests that damage main food crops such as vegetables, soybeans, peanuts, and cotton [40]. This pesticide is commonly used in Asian countries due to its moderate toxicity, high insecticidal activity, and a long-lasting effect. However, lambda cyhalothrin previously available as EC and ME formulations pollutes the environment, costly due to loads of surfactants and consume non-renewable resources in the form of petroleum solvents [41]. Therefore, there is an urgent requirement to replace these shortcomings to further take the benefit of this broad-spectrum pesticide.

EW formulations such as limonene, peppermint oil, and spearmint oil have been developed and bio-efficacy evaluation was done on *Pseudococcus longispinus*.

**Figure 11.**

*Diagrammatical representation showing key steps of emulsion in water formulation and its application.*

In a similar study, neem EW formulation was developed with palm oil methyl ester, RBD palm olein, and soybean oil for better adhesion and persistency. This formation was evaluated against golden apple snail. EW prepared with palm oil methyl ester showed better efficacies with LC50, 45.30 mg/l under field condition and have longer persistence t1/2 = 1.85; r2 = 97.75 on paddy leaves [42]. The formulation was found to be very effective against the pest with 90% mortality [43]. In another study, bio-larvicide *Lagenidium giganteum* have been formulated as EW formulation. It was investigated that in EW formulation of *L. giganteum* mycelium shelf life and delivery improved for good and prolonged bio-efficacy. In a similar study, entomopathogenic fungi have been formulated as emulsion in water formulation and found to be very effective against various agricultural pests. The study concluded that EW formulation showed good bio-efficacy and stability of entomopathogenic fungi over unformulated form. Hence, emulsion in water is the safe and economical formulation against agricultural pest.

In addition to agricultural field pest control, EW formulation can also be used in preparation of postharvest packaging films with anti-insect property. Recently, cinnamon oil (CO) anti-insect packaging film has been developed for repelling *Plodia interpunctella* (Hübner) larvae [44].

IPFT has contributed to Lambda Cyhalothrin EW, Chlorpyriphos 10 EW, etc. Recently, IPFT has optimized the neem EW formulation procedure by high shear mixing. The increase in shearing intensity reduced the droplet size and resulted in higher stability.

#### **7.2 Mixed formulations (Suspoemulsion, ZC, ZW)**

The combination formulations have broad-spectrum insecticidal activities and can be applied for insect control in different Asian countries. These mixed formulations have the user and environment-friendly applications over conventional formulations.

1.ZW (Capsulated Suspension (CS) + Emulsion in water (EW)

This formulation is the combination of two formulations with two different pesticides in water medium. In this, one pesticide is encapsulated inside the polymeric coating and other is in emulsified droplet form (**Figure 12**).

IPFT has developed ZW combination formulation of capsulated suspension (CS) of Lambda cyhalothrin with concentrated emulsion in water (EW) of chlorpyriphos, and this combination was termed as ZW [7, 8]. Main advancement of this formulation is that it is the combination of two pesticides in two different formulations, one broad-spectrum pesticide, that is, in EW formulation for quick action and lambda cyhalothrin CS for controlled release and will be effective for extended

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

**Figure 12.**

*Diagrammatical representation of ZC formulation and its application.*

period of time and give long-term pest control [45]. This combination formulation can be used for different pesticides with good compatibility index.

2.ZC formulation (Capsulated formulation (CS) + Suspension Concentrates (SC))

The ZC formulation is the stable aqueous suspension of polymeric-encapsulated microcapsules and solid-suspended fine particles of two different pesticides. Both formulations are homogeneously mixed by wet milling and gentle shear mixing (**Figure 13**).

Chlorantraniliprole and thiamethoxam SC, lambda cyhalothrin and chlorantraniliprole ZC, thiamethoxam and lambda cyhalothrin ZC, beta-cyfluthrin and imidacloprid SC, and flubendiamide and thiacloprid SC efficacy have been evaluated against spotted pod borer. The study was found that ZC formulations gave superior results on the management of *M. vitrata* and *Spodoptera litura* over simple SC formulations [46].

In addition to enhanced bio-efficacy, this combination formulation has been investigated for non-targeted effects. ZC (thiamethoxam and lambda cyhalothrin under trade name Alika 247 bio-efficacy) was evaluated against Pest of Tea in West Bengal, India. The study reported that Alika 247 ZC was safe for the important natural predators found in the tea ecosystem relative to conventional formulations like EC [47]. Similarly, thiamethoxam and lambda cyhalothrin ZC impact was investigated on Population of Lady Bird Beetles in maize crop ecosystem in Gujarat, India [48].

This combination formulation has fast and quick knockdown and extended control of foliar insect pest. This formulation is basically developed for soybean aphids, Japanese beetle, grasshopper, corn rootworm beetle, stinkbugs, etc.

Institute of Pesticide Formulation Technology (IPFT) has developed Lambda cyhalothrin 14 CS with Diflubenzuron 10SC. The unique specialty of this developed ZC formulation is effective against early stages and adult stages simultaneously. The combined pesticide provides improved and synergistic activity. Besides this, formulation is suitable for immediate as well as for prolonged pest control practices.

**Figure 13.** *Diagrammatical representation of ZC formulation and its application.*

**67**

#### **Figure 14.**

*Diagrammatical representation of suspoemulsion formulation and its application.*

3.Suspoemulsion (Suspension concentrate (SC) + Emulsion in water (EW))

Suspension (SE) is the combination of two active ingredients one in suspension concentrate (SC) and concentrated aqueous emulsion (EW) (**Figure 14**). Suspoemulsion is the stable colloidal suspension with fine droplets with a high degree of electrostatic, steric, and hydrophobic interactions and with lesser degree of Ostwald ripening [49].

Main advancing features are different active ingredients with different solubility or melting points can be incorporated, providing broad-spectrum pest control, and tank mixing is not required. Suspoemulsions are the most convenient formulation for the farmers to apply the correct quantity of pesticides and tank mix incompatibility problems have been removed. Surfactants and thickeners were added in suspoemulsion to prevent flocculation and separation of the dispersed phases [50].

IPFT has contributed suspoemulsion of fipronil 5% SC + Soyabean oil as Adjuvant 5% EW. The main characteristic feature of this formulation is high stability and shelf life along with good bio-efficacy to agricultural pest in Asian countries.

#### **7.3 Botanical formulations**

Different bioactive phytochemicals have been identified for good bio-efficacy. These bioactive ingredients in formulated form will play a very significant role in promotion of organic farming in Asian countries in a safe and sound way. Followings botanical formulations have been formulated by IPFT.

New generation botanical-based formulations developed in IPFT, India, are as follows:


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

Highly volatile bioactive pesticides encapsulated in a thick polymeric coating by cross-linking. Therefore, these formulations are efficient for an extended period of time.


Institute of Pesticide Formulation Technology (IPFT), Gurugram in India is the only institute devoted for the development of safe and environment-friendly new-generation insecticide formulation technology. There are some new formulated products of natural insecticides such as controlled release formulations, nanoformulations, or water-based formulations, which enhance 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 also on their commercialization.

## **8. Future considerations for the promotion of safe and green biopesticides**

Currently, IPFT is working toward the development of safer alternatives to banned or going to be banned agrochemicals. Research is in the process of development to safer formulations with potentially low-risk user and environment-friendly novel formulation development of various broad-spectrum pesticides that are in the verge of banned have been attracting global attention. In this context, public and private sectors cooperation is necessary to facilitate the formulation development of safe and environment-friendly improved and advanced alternative. Novel formulations improve the delivery of agrochemicals and boost up the agricultural system in near future. Most important aspect along with the development is the cost of safe formulation. Maintaining low cost of novel formulations to farmers for a given product quality and availability, particularly in developing countries, is also important. Though, new formulation strategies could give out a very promising and potential option for pest control but to attain this objective, more field research is required to assess the efficacy on specific pest problems and over rising pest problems in various cropping systems. Therefore, it is a necessary requirement for strengthening the research in this safe and green formulation technology development.
