In this article we will discuss about:- 1. Introduction to Pest Management 2. IPM (Springboard to Sustainable Agriculture) 3. Future Outlook.
Introduction to Pest Management:
The introduction and widespread use of high-external-input modern agriculture has caused many problems. Firstly, these problems are socio-economic in nature, i.e. technologies improved the condition of larger farmers and did not take enough care of small farmers; land tenure patterns became more skewed; position of women often became problematic as their role was not taken into consideration at all.
Secondly, problems were encountered in the areas of environment and health; the magnitude of these problems varied from direct poisoning of farmers by use/misuse of agrochemicals to deterioration in quality of air, water and food for human consumption.
The third and most recently talked about problem is that the green revolution approach in itself was not sustainable. After initial yield increases, introduction of green revolution packages often led to such disturbances in the agro-ecological system that subsequent yield reductions were inevitable.
The term ‘sustainable agriculture’ first appeared in the literature in 1978 but was formally introduced in 1985 when the US Congress “enacted the Food Security Act that initiated a programme in ‘low input sustainable agriculture’ to help farmers use resources more efficiently, protect the environment and preserve rural communities.”
Sustainable agriculture may be considered as an agriculture that can evolve indefinitely toward greater human utility, greater efficiency of resource use, and a balance with the environment that is favourable both to humans and to most other species. Sustainable agriculture emphasizes that agricultural systems must be economically viable and they must contribute to desirable environmental qualities over the long term.
IPM employs ecologically based management processes developed with an understanding of natural cycles and natural regulators of those species that compete with humans for resources in agricultural production systems. Therefore, successful IPM programmes are those that enhance agricultural enterprises and protect the environment for the indefinite future.
There have been considerable variations in pest management approaches from traditional to sustainable agriculture. The modern integrated pest management (IPM) approach aims at systemic adjustment, i.e., it looks for more efficient use of pesticides and product substitution (biorationals and botanicals in place of conventional pesticides) within an agricultural system that essentially remains unchanged.
However, sustainable agriculture aims at structural changes, i.e., it seeks to change the way we look at agriculture through better understanding of ecological processes and maximizing synergy between crops.
IPM (Springboard to Sustainable Agriculture):
The proponents of the sustainability concept for crop production have found great affinity with principles and approaches of IPM. Indeed, IPM provided both a conceptual approach and an implementation paradigm for sustainable agriculture. IPM and sustainable agriculture share the goal of developing agricultural systems that are ecologically and economically sound. IPM may be considered a key component of sustainable agriculture.
From an IPM perspective, the concept of sustainable agriculture provides a platform for launching IPM to higher levels of integration. Therefore, the future developments and successes in IPM are quite important to the sustainability of agriculture in the twenty-first century. The contributions of IPM are critical to meet the economic, environmental and social mandates in assuring sustainability of agricultural systems.
Economic Mandate:
Economic considerations basic to IPM are consistent with the requirement for profitability in sustainable agricultural systems. IPM is based on the concept that low population densities of pests usually do not threaten the profitable production of agricultural commodities.
This aspect of IPM philosophy has resulted from the development of concepts of ‘economic injury level’ and ‘economic threshold’. The sequence of sampling to assess the prevalence of pests followed by decision making using criteria of economic thresholds supports the basic tenet of both IPM and sustainable agriculture, i.e. production systems must be economically viable over the long term.
In this context, the economic injury level and economic threshold are the parameters that not only serve as criteria for decision making, but are also important for defining the contribution of effective pest management to the sustainability of production systems. As the frequency of pest occurrence at population densities exceeding the cost of available controls and the profitability of pest control measures are summarized over time, the value of pest management in production systems can be estimated.
Environmental Mandate:
The idea that profitability in agricultural production and protection of the environment are jointly attainable goals is central to the philosophy of IPM and sustainable agriculture. It is critical to sustainability that the use of off-farm inputs such as agrochemicals which may be potential pollutants, and farming practices such as tillage operations, which may contribute to soil erosion, be employed in a manner that does not result in the degradation of soil and water.
The judicious use of chemical pesticides in agricultural production systems has been central to the development of IPM since its inception.
Through IPM, the judicious use of chemical pesticides is emphasized to:
(i) Preserve natural control agents, such as entomophagous insects and beneficial microorganisms,
(ii) Decrease the potential for mortality of an array of non-target organisms such as wildlife species, and
(iii) Limit the accumulation of toxic residues in the environment.
Social Mandate:
Health and well-being are highly valued in societies all over the world, resulting in demands for a safe, wholesome food supply that is produced without harm to the environment or hazards to those who work in agriculture. Clearly, the demands of people around the world for safe, abundant food supply can be met only by the development of sustainable agricultural systems that can effectively combine pest controls with profitability and the maintenance of a safe environment and human food supply.
In addition to providing a safe and effective means for reducing damage to commodities by all types of pests, IPM is also the primary means by which hazards of both chemical and microbial contamination of food commodities may be greatly decreased.
The perception of an unlimited supply of cheap food that exists in many countries could rapidly be provided an illusion if effective means of pest management are not maintained through judicious use of existing control technologies and consistent investment in research to develop new avenues for pest control for the future.
Through deliberate and persistent educational efforts, the public must come to appreciate the development and implementation of IPM, even when programmes involve the use of products of biotechnology such as genetically modified crops, are a sound investment of resources in support of sustainable agricultural production of the future.
Future Outlook of Pest Management:
The global population reached 7 billion in 2011, increasing from 5 billion in 1987 to 6 billion in 12 years in 1999. The world population stood at 7.24 billion in mid-2014. Although the overall growth rate has declined from 2.1 per cent per year in late 1960s to 1.2 per cent at present, the population is still growing, particularly in Asia and sub-saharan Africa. It is entirely possible that that 8th billion would be added in 12 years as well.
This would place us squarely in the middle of history’s most rapid population expansion. Therefore, strenuous efforts will have to be made to increase world food supplies to ensure environment and food security. Ecostrategies are likely to play a prominent role to achieve the above objectives. In this context, integrated pest management, which relies on suppression of pest problems while causing minimum disruption to the agro-ecosystem, is one of the viable alternatives.
The current methodology for assessing insect damage to undertake control measures is cumbersome, and the farmers are not able to properly understand and practice the methods. Simple techniques to assess insect damage and population density would be useful for timely application of appropriate control measures.
There is a need to develop economical high-resolution environmental and biological monitoring systems to enhance our capabilities to predict pest incidence, estimate damage, and identify valid economic thresholds. Economic threshold levels (ETLs) are available for a limited number of insect species. ETLs developed without taking into consideration the potential of naturally occurring biological control agents and levels of resistance in the cultivars to the target pests are of limited value.
The ETLs have to be developed for specific crop-pest-climatic situations. The ETLs developed in one region are not applicable in other areas where the crop-pest and socioeconomic conditions are different. Simple methods of assessing ETLs could help avoid unnecessary pesticide applications.
Nanotechnology is a promising field of research which has opened up a wide array of opportunities and is expected to give major impulse to technical innovations in future. These include enhancement of agricultural productivity involving nanoporous zeolites for slow release and efficient dosage of water and fertilizer, nanocapsules for herbicide delivery, and vector and pest management, and nanosensors for pest detection.
Nanoparticles help to produce new pesticides and insect repellents. Nanoencapsulation (a process through which a chemical is slowly but efficiently released to a particular plant), with nanoparticles in the form of pesticides allows proper absorption of the chemical into plants unlike in the case of larger particles. This process can also deliver DNA and other desired chemicals into plant tissues for protection of host plants against insect pests.
It is known that aluminosilicate filled monotube can stick to the plant surfaces while nanoingredients of nanotube have the ability to stick to the surface hair of insect pests, and ultimately enter the body and influence certain physiological functions. Nanoencapsulation is currently the most promising technology for protection of crop plants against insect pests.
Research on nanoparticles and insect control should be directed towards production of faster and ecofriendly pesticides to deliver into the target host tissue through nanoencapsulation. This will control pests efficiently, prolong the protection time and lead to sustainable crop protection. Thus, nanotechnology is likely to revolutionize agriculture in general and pest management in particular in the near future.
Foods derived from genetically modified plants are now appearing in the market and many more are likely to emerge in the future. It is important to ensure the safety of food derived from transgenic crops based on the principle of nutritional equivalence. Strenuous efforts should be made to make this technology available to farmers who cannot afford the high cost of seeds and chemical pesticides in developing countries.
Transgenic crops would play a significant role in integrated pest management in future reducing the number of pesticide applications and pesticide residues in food. Concerted efforts are required involving international and advanced research institutes, and the national research organizations to harmonize the regulatory requirements to assess the biosafety of the food derived from genetically engineered crops and their effects on non-target organisms for sustainable crop production and food security.
The goals of the future IPM programmes are to improve the economic benefits related to the adoption of IPM practices and to reduce potential human health risks and unreasonable environmental effects from pests and from the use of pest management practices.
i. A major determining factor in the adoption of IPM programmes is whether the economic benefit outweighs the cost to implement an IPM practice. Conducting a “cost benefit” analysis of the proposed IPM strategies is not based solely on the monetary costs; it is based on four main parameters, i.e. monetary, environmental/ecological health and function, aesthetic benefits, and human health.
While there may be many benefits from adoption of IPM practices, if new 1PM programmes do not appear to be as economically beneficial as practices already in place, they are not likely to be adopted. Evaluation of the short and long term risks and benefits is needed. Therefore, improving the overall economic benefit to humans and the broader natural systems, resulting from the adoption of IPM practices, is a critical component of the future IPM programme.
ii. IPM programmes need to be designed with the goal of reducing potential human health risks by reducing exposure of both the general public and workers to pests as well as high- risk pest management practices, whether mechanical, chemical or biological in nature. IPM protects human health through its contribution to food security by reducing potential health risks and enhancing worker safety.
In the past, success in achieving the goal of reduced risk from pest management practices was generally measured by tracking changes in the annual amount of pesticides used. However, when used alone it is a poor indicator of human health risk, and more advanced systems of measurement are required.
iii. IPM programme should be designed to protect agricultural, urban and natural resource environments from the encroachment of native and non-native pest species while minimizing unreasonable adverse effects on soil, water, air and beneficial biological organisms. For example, in agriculture, IPM practices should promote a healthy within crop environment, and conserve organisms that are beneficial to agricultural systems, including natural enemies and pollinators.
By reducing off-target impacts, IPM should help to maximize the positive contributions that agricultural land use can make to watershed health and function. Greater IPM efforts are required to maintain functional and aesthetic standards in natural and recreational environments such as lakes, streams, parks and sport facilities.
Classical integrated management programmes for apple pests in Canada and cotton pests in Peru provided some of the early models for successful implementation of IPM in the field. The FAO subsequently provided the coordination to spread the IPM concept in developing countries.
The success of an IPM programme in rice in Southeast Asia was based on linking outbreaks of the brown planthopper with application of broad-spectrum insecticides, and the realization of the fact that the brown planthopper populations were kept under check by the natural enemies in the absence of insecticide applications. Much of the impact of this programme was brought out through field demonstrations, training programmes, and farmers’ field schools.
Subsequently, many more developing countries launched their own national IPM programmes. The success of some of these programmes has led to the establishment of the Global IPM Facility, under the auspices of FAO, UNDP and the World Bank, which will serve as a coordinating and promoting entity for IPM worldwide. Currently many IPM programmes have been developed in which different control tactics are combined to suppress pest numbers below a threshold.
These vary from judicious use of insecticides based on ETLs and regular scouting to ascertain pest population levels to sophisticated systems using computerized crop and population models to assess the need, optimum timing, and selection of insecticides for sprays. The increase in our knowledge about insect-plant-environment interactions and advances in modern technologies like biotechnology and nanotechnology, would give further impetus to IPM in the future.