Nanopesticides: Scope and Threats in Agriculture

Abstract

 

Agriculture has now become versatile for it has broadened its purposes from producing more to maintaining the quality of produce, and from being extensive to achieving sustainability. This seems quite difficult, especially with the current level of limited resources left for us. Nanotechnology comes as a solution to this with its innovative offerings to us. Nanopesticides, formulated with specific pesticide ingredients, can be replaced by conventionally used pesticides. The advantages of using pesticides produced with particles of nano range include a lesser requirement, target specificity and lower toxicity. But, an opposite concern has also been raised that they might have the ability to contaminate the environment. Therefore, comprehensive research on nanopesticides has to be carried out to be aware of their overall advantages and environmental impacts and find ways to overcome the negative impacts.

 

Keywords: Environmental contamination, nanopesticides, target specificity, quality production

 

Introduction

 

Agriculture of recent times is getting more complicated day by day. One of the big reasons behind the loss in agriculture and the agricultural industry is to be blamed for a shortage in production due to the inefficient application of fertilizers and pesticides. Thus, there is a huge gap between the demand and supply of agricultural products. To bridge the gap, a lot of promising technologies have been suggested to be adopted, among which nanotechnology is the most emerging one. Nanotechnology is not a simple term as it needs to be known completely before mankind could even take the advantage of it. Application of nanoparticles like nanopesticides, nanofertilizers etc. not only needs the knowledge of the host crop, but also the complete understandings of the possible outcomes post their application. Nanopesticides are products formulated by implementing nanotechnology with the expectation of delivering pesticide-active ingredients. The use of nanopesticides could be a complete blessing as they are extremely target specific, thus reducing the risk of environmental contamination. Therefore, nano pesticides can also serve as an excellent replacement for the toxic pesticides used in the agricultural sector. Similarly, the target of agriculture to provide a larger amount of food with the assured quality might be achieved with the help of nanoparticles that help in growing crops resistant to pathogens and pests.

 

What are nanopesticides?

 

Nanopesticides, to be formulated, need engineering of substances with the property of pesticide or active ingredient of pesticide in nano form. Nanopesticides are a slow release of the active ingredient, thus taking a longer time to initiate its effectivity. The term ‘nanopesticide’ is used to describe any pesticide formulation that intentionally includes entities in the size range of nanoscale i.e., up to 1000 nm, and is designated with a ‘nano’ prefix such as nanohybrid, nanocomposite and so forth. Thus, a number of products are included under nanopesticides. The direct and intentional application of nanopesticides may result in negative environmental impacts (Kah et al., 2013). Thus, a complete understanding of the benefits and also the possible threats associated with short-term and/or long-term effects post the application of nanopesticides must be known.

 

Classification of nanopesticides, based on active ingredient (AI):

Nanopesticides, generally, are categorized into two types 

a. Organic molecular AI nano-carrier complexes: As the name suggests, these contain carriers. Polymers are an example of this category (Kah et al., 2016).

b. Inorganic nano-scale AI: These nano-pesticides do not contain carriers. Example includes Cu(OH)₂ nanopesticides (Zhang et al., 2019).

 

Possible functions of nanopesticides:

 

Nanopesticides are formulated with the hope of solving agricultural issues of recent times. They are expected to have functions like improving pesticide efficacy, enhancing the stability of active ingredients along with increasing their effective duration of the function, regardless of the type of nanopesticide formulation. To be able to reduce environmental loads of pesticides is also an important desirable function of nanopesticides making those more usable than the conventional one

 

Themes of nanopesticides:

 

I. Improvement of bioavailability – The first theme is concerned to improve the bioavailability of active ingredients of poor or low solubility to water. To make it successful, active ingredients are formulated in the form of nanoemulsions and dispersions.

II. Permeability – The second theme is based on permeability which involves the encapsulation of pesticide active ingredients within permeable nanoparticles.

 

Properties of nanopesticides:

 

According to Bordes et al. (2009), nano-pesticides carry a number of properties, as mentioned below

 -Stiffness

 -Crystallinity

 -Permeability

 -Biodegradability

 -Larger surface area

 -Target specificity

 

Delivery techniques of nanopesticides:

 

The degree of effectiveness of nanopesticides is much dependent on their delivery techniques. Delivery techniques can slower release of active ingredients ensuring more effectiveness and environmentally friendly approaches. Some of those delivery techniques are mentioned below-

 

-Nanoemulsions

-Nanocages

-Nanoencapsulates and

-Nanocontainers

 

Recent status of nanopesticides:

Nanotechnology offers a wide range of applications in various fields. Agriculture is also supported by nanotechnology by means of the development of novel nano agrochemicals. While some serious concerns have been expressed considering the probable risks as a result of the introduction of the new products to the environment, many are hopeful to obtain a great future from the nanopesticides that could support the aim of increased global food production by sustainable means. The recent progress in the development of some nanopesticides with their probable functions is listed below-

 

-Fungicide activity by synthesized lipids of solid nature and polymers of nanocapsules

-Controlled release and enhanced herbicidal action of atrazine by poly (epsilon-caprolactone) nanocapsule

-Nanoemulsions of permethrin and neem oil for pesticidal activity

-Antimicrobial and insecticidal activity by different inorganic nanoparticles

-Development of bio-synthesized and eco-friendly nanoparticles to control phytopathogens and pests (Chhipa, 2017)

 

Risks associated with nanopesticides:

 

There has been a critical analysis of some recent reports on the determination of the safe limit to which nanoparticles differ from conventional products. Several studies on nanoparticles were reported but were found to lack nanospecific quality assurance and appropriate control measures. Nanopesticides, with the potential benefits for agriculture, are also considered to bring threats to agriculture by a group of scientists. According to various studies, nanopesticides can result in lots of harmful effects for their properties like the smaller size and others. The risks associated with nanopesticides could be their widespread use and thus release in the environment at an alarming rate, threats to agricultural production, risks to aquatic creatures through leaching of these products directly in water bodies, and eutrophication potential of different nanoparticles. Accumulation of nano-pesticides in the soil is very possible for their easy mixing nature. Crops also store those from which potential health risks might appear upon consumption of nano-pesticides treated crops. Thus, a contradiction in dealing with nanoparticles made pesticides or nano-pesticides is prominent. Currently, there is a lack of comprehensive studies to thoroughly evaluate the efficacy as well as environmental impacts of nanoagrochemicals under field conditions. Thus, this is a matter of proper investigation and sound evaluation of the representation of nanoagrochemicals and whether they could thrive better or not in comparison to the existing conventional products.

 

Conclusion:

 

The current level of limited acquaintance with nanopesticides does not provide a fair evaluation of the pros and cons that could result from the use of their application. Such assessments, to be successful, compulsorily require a better understanding of the effects post the application of nanopesticides and their ultimate destiny as well. A clear concept of regulations should also be made understandable so that refinements can be implemented if needed. Therefore, research on nanopesticides and their quality assessment are of utmost priority for ensuring the quality of food as well as environmental sustainability.

 

References:

 

Chhipa, H. (2017). Nanopesticide: Current Status and Future Possibilities. Agricultural Research and Technology, 5(1), 555651. https://doi.org/10.19080/ARTOAJ.2017.05.555651

 

Kah, M., Beulke, S., Tiede, K., & Hofmann, T. (2013). Nanopesticides: state of knowledge, environmental fate and exposure modelling. Crit. Rev. Environ. Sci. Technol. 43, 1823–1867. https://doi.org/10.1080/10643389.2012.671750

 

Kah, M., Weniger, A., & Hofmann, T. (2016). Impacts of (nano) formulations on the fate of an insecticide in soil and consequences for environmental exposure assessment. Environ. Sci. Technol. 50, 10960−10967.

 

Zhang, X., Xu, Z., Wu, M., Qian, X., Lin, D., Zhang, H., Tang, J., Zeng, T., Yao, W., Filser, J., Li, L., & Sharma, V. K. (2019). Potential environmental risks of nanopesticides: application of Cu(OH)₂ nanopesticides to soil mitigates the degradation of neonicotinoid thiacloprid. Environ. Int. 129, 42−50.