**Propesticides and Their Implications**

**Propesticides and Their Implications**

Shaon Kumar Das and Irani Mukherjee Shaon Kumar Das and Irani Mukherjee Additional information is available at the end of the chapter

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.71532

#### **Abstract**

With increasing knowledge of the biochemistry and genetics of major pest insects, weeds, and agricultural pathogens, the design of such selectivity becomes a part of pesticide development and is achieved by appropriate structural modification of the parent lead molecule which is called as propesticide. In a strict sense, a propesticide is a biologically inactive compound requiring structural transformation(s) after application to become pesticidally active. Various pesticides have come to the limelight of being a propesticide by carrying out studies on their metabolic fate in organisms. Studies on the metabolic fate of diafenthiuron in vitro by liver microsomes from various vertebrates revealed a variety of possible transformations of the thiourea. Few have been developed by reversibly masking the active ingredients. Fluorinated N-acylaziridine behaves as a propesticide of the fluorinated carboxylate and the hydrolysis of the former to 2-methylaziridine and carboxylate being activation pathway. Imidacloprid and the thiazolylmethyl analogue masked with oxodioxolyl group decomposed with half life of 15.4 and 11.4 h in alkaline and physiological salt solutions, respectively, releasing imidacloprid quantitatively. New propesticide with two effects of both benzoylphenyl ureas and carbamates were designed and synthesized.

DOI: 10.5772/intechopen.71532

**Keywords:** propesticide, biologically inactive, lead molecules, oxodioxolyl, xenobiotics, selective agrochemicals

#### **1. Introduction**

Pesticide as an input in agriculture has seen changes at different stages in very few decades. Pesticides as such according to FAO may be defined as any substance or mixture of substances intended for preventing, destroying or controlling any pest, including vectors of human or animal disease, unwanted species of plants or animals causing harm during or otherwise interfering with the production, processing, storage, transport or marketing of food, agricultural commodities, wood and wood products or animal feedstuffs, or substances which may be administered

Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons

to animals for the control of insects, arachnids or other pests in or on their bodies [1]. The term includes substances intended for use as a plant growth regulator, defoliant, desiccant or agent for thinning fruit or preventing the premature fall of fruit, and substances applied to crops either before or after harvest to protect the commodity from deterioration during storage and transport.

in disruption of activating enzyme [7]. The activating enzymes, present in the tissue of target organism, are carrying out certain biochemical function in the body of target organism. When active toxophore are released from the proinsecticide their normal functions are discontinued resulting in killing of organisms. This is also known as suicide inactivation as their natural process is being inactivated [8]. Likewise, there also takes place the

Propesticides and Their Implications http://dx.doi.org/10.5772/intechopen.71532 109

By detoxification system we meant the various processes carried out by the target organisms to detoxify any xenobiotics compound [9]. These are usually degradation processes and it includes oxidation, reduction, hydrolysis or conjugation reactions. Here, the xenobiotic compounds, i.e., propesticides are acted upon by these processes resulting in production of a

Most of the insects harbor symbiotic or parasitic microorganisms in their guts or hemolymph which posses enzymes lacking in them [10]. The various endogenous xenobiotic processes can be brought under control to activate proinsecticidal agents in such organism specific

In this path enzymes are not involved. Here, the activation process is not metabolic but results

Propesticides can be classified in two ways like based on the number of activation steps involved and based on the type of pest to control [11]. Based on the number of activation steps involved propesticides are classified as single step activation and multiple step

• The term juvenogen is used to indicate a new class of the complex chemical compounds which generate products with juvenile hormone activity in response to certain biotic or

in toxicity because a change in the propesticide occurs in biological milieu.

**a.** Disruption of secondary enzyme system in the same tissue.

**b.** Disruption of enzyme at other target tissue.

**3.2. Activation by detoxification system**

more toxic material than the original one.

**3.3. Activation by symbiont metabolism**

**3.4. Activation by symbiotic routes**

**4. Classification of propesticides**

following:

fashion.

activation.

*4.1.1. Juvenogens*

**4.1. Single step activation**

environmental factors.

Present day pesticides which are common and widely used have number of adverse affects on non-target organisms. The consequences lead to environment toxicity affecting ecosystem [2]. Therefore safer insecticide deserves attention. A propesticide is a biologically inactive compound requiring structural transformation(s) after application to become pesticidally active. Activation process for propesticides can be one of or a combination of the three following types: (a) chemical (nonenzymatic); (b) biochemical (enzymatic); or (c) physical, e.g., photochemical [3]. In practice, however, propesticidal substances are sometimes active without chemical modification when measured *in vitro*; nevertheless, their metabolites contribute significantly to the overall biological activity of the applied material.
