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Posts Tagged / Pest Management

  • Aug 16 / 2009
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Climate change and Pest Management in Agriculture  

Dr. G. V. Ramanjaneyulu, and Dr. T. A. V. S. Raghunath[1]

Insect populations like all animal populations are governed by their innate capacity to increase as influenced by various abiotic and biotic factors.  The changes caused by the natural evolutionary forces are accelerated with the human interventions.  After the changes like depletion of natural resources, environmental pollution, extinction of certain species of plants and animals, the Climate Change particularly caused by inadvertent anthropogenic disturbances has become more evident. Projected carbon dioxide levels in the twenty first century are two to four times higher than the pre industrial era.  Global climate change resulting in changes in temperature rise and precipitation patterns, could accentuate the vulnerability of agriculture.  IPCC (International Panel on Climate Change) predicted that global mean temperature would rise between 0.9 to 3.50 C by the year 2100 (IPCC, 2001).  Global warming may increase average water vapour and evaporation, increase in precipitation in high-altitude regions, significantly alter the Monsoon pattern resulting in long dry spells and heavy downpours and change in storm patterns which could influence the global movement of pests, especially pathogens.

In agricultural ecosystems, soil, plant and animal interactions are rarely persistent enough, in time and space, to provide the ecological stability but result in dynamic equilibrium.  Pest shifts are observed with changes in the ecological balance.  The natural balance between beneficial and harmful insects changes with the cropping patterns, pest management practices and variability in environment. Weather and Climate have an impact on the pest population.  ‘Weather’ is short term variation of the atmosphere at a given time with respect to temperature, pressure, wind moisture, cloudiness and precipitation.  ‘Climate’ is usually defined as the statistical collective of the weather of a specified area during a specific interval of time or as the prevailing or average weather conditions of an area over a long period.  Climate change leads to shifts in the pest incidence, migration and viability thresholds.  Today, farming and farmers lives are already effected by the pests and pest management practices they adopt. Hence, understanding the intricacies of climate change on pest management in agriculture is crucial.

Weather has both direct and indirect effects on the insect populations. The direct effects of weather on behavior and physiology are well documented.  Reproductive biology of an insect may be affected both positively and negatively which ultimately affect its populations.  Climate change would shift pest populations as it would shift important determinants of pest incidence, namely  temperature, precipitation distribution, and wind pattern.

Temperature: All life survives with a  certain narrow range of temperature.  Deviations from this in optimum range on either side is tolerated to some extent, depending on the physiological adaptations of the concerned species or populations.  Temperatures above or below these limits can prove lethal.  Exposure to lethal high or low temperatures may result in instant killing or failure to grow and reproduce normally.  Harmful effects of exposure to sub-lethal temperatures may be manifested at later critical stage like moulting or pupation.  rise in temperature might also have a negative effect on delicate natural enemies such as hymenopteran parasitoides and small predators.  This may effect natural enemy-pest relationship. For e.g. Brown Plant Hopper is 17 times more tolerant to 400 C than its predator Cyrtorrhynus lividipennis but wolf spider Paradosa pseudoannulata is tolerant to 40 0 C.

Moisture:  Most terrestrial insects live in an environment, which is dry.  The only source of water for insects is the water obtained with food material from their host plants.  These insects have, therefore developed a variety of mechanisms to conserve water.  In spite these mechanism, exceptionally dry air may prove lethal to most insects.  Likewise, excessive moisture may also adversely affect many insects by encouraging disease outbreaks, affecting normal development and by lowering their capacity to withstand lower temperatures.  The reproductive capacity of the insects is also affected by moisture but there are great differences in the capacity of different insects to tolerate conditions ranging from extreme dryness to near saturated environments.  For example, incidence of Rice Hispa in Telangana region has increased in the last two years due to prevailing dry situations.

There is a shift observed from the leaf/fruit eating caterpillars to sucking pests in the recent years.  While monoculture of crops/varieties and chemical pest management practices understood to have resulted resulted in such pest shifts, climate change also have also contributed for such shift.  For example in cotton there is a shift towards sucking pests (mealy bugs, jassids) particularly after the introduction of Bt cotton.  Similarly, Aphid incidence in Groundnut, Thrips and yellow mites in chillies are observed.  Most of the sucking pests are also vectors of viral diseases. With increasing incidence of sucking pests viral diseases are also increasing e.g., Budnecrosis in Groundnut, Tobacco Streak Virus incidence in Cotton, and similar viral problems in most of the fruit crops, vegetables.

Other impacts of Climate change on pest incidence

a. Increases in UV-B radiation is likely due to depletion of ozone layer resulting in increased production of plant metabolites that might change the host-pathogen relationships and the status of the individual pest.

b. Under changed climatic condition, cropping pattern and intensity may be changed and to cope up the situation new varieties,  or new methods of pest control or new chemicals to kill a pest may be released which might have either positive or negative impact on pests.

Ecological Pest management

Pest is not a problem but a symptom. Disturbance in the ecological balance among different components of crop ecosystem (biotic and abiotic) makes certain insects reach pest status.  These problems of increasing pest incidences and pest shifts can be tackled only with better  environmental friendly pest management practices.  Ecological approaches to pest management should be based on knowledge and skill based practices to prevent insects from reaching damaging stages and damaging proportions by making best use of local resources, natural processes and community action’.

  • Understanding crop ecosystem and suitably modifying by adopting suitable cropping systems and crop production practices. The type of pests and their behavior differs with crop ecosystem. Similarly the natural enemies’ composition also varies with the cropping systems.
  • Understanding insect biology and behavior and adopting suitable preventive measures to reduce the pest numbers.
  • Building Farmers knowledge and skills in making best use of local resources and natural processes and community action. Natural ecological balance which ensures that pests do not reach a critical number in the field that endangers the yield. Nature can restore such a balance if it is not meddled with too much.

In Andhra Pradesh such initiative implemented through Federations of Women Self Groups across the state in 18 districts in more than 3000 villages covering more than 14 lakh acres in 2008-09 in the name of ‘Non Pesticidal Management’ has shown that such eco-approaches can bring in both ecological and economic benefits to the farmers.  This program started in 2004-05 with technical support from Centre for Sustainable Agriculture and financial and administrative support from Society for Elimination of Rural Poverty (SERP).  The farmers in the villages are grouped into Field Schools and trained by the local civil society organisations.  The regular and incidental technical support is institutionalized and community managed.  The learning from this program are now considered by the ‘National Mission on Sustainable Agriculture’ as part of National Action Plan on Climate Change to be implemented across the country during the 11th five year plan.

[1]    The aurthors can be contacted at Centre for Sustainable Agriculture, 12-13-445, Street no-1, Tarnaka, Secunderabad-500 017 ramoo@csa-gmail.com, http://www.csa-india.org

  • Feb 12 / 2008
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Integrated Pest Management versus Non Pesticidal Management

Dr. G. V. Ramanjaneyulu, Centre for Sustainable Agriculture

The attempts to overcome the serious economical and ecological problems of the chemical pesticides have given rise to alternative systems to manage pests and pesticides.

Integrated Pest Management

In an attempt to slow the development of pest resistance, improve the financial basis for agricultural production, and improve the health of the farming population, systems of Integrated Pesticide Management have been introduced around the world. IPM is an ecological approach to plant protection, which encourages the use of fewer pesticide applications.

The field experiences gave rise to several paradigms of IPM which agriculturists presently adhere to. The most up-to-date paradigm of IPM is ecology based approach which is promoted by FAO world wide in the form of Farmers Field Schools (FFS).  Through interactive learning and field-experimentation, FFS programs teach farmers how to experiment and problem-solve independently, with the expectation that they will thus require fewer extension services and will be able to adapt the technologies to their own specific environmental and cultural needs (Vasquez-Caicedo et al., 2000). Extension agents, who are viewed as facilitators rather than instructors, conduct learning activities in the field on relevant agricultural practices. In the FFS, a method called “agro-ecosystem analysis” is used to assess all beneficials, pests, neutral insects and disease, and then determine if any intervention like a pesticide spray is needed. Economic Threshold Levels are discussed in the FFS, but crop protection decisions are based on conserving beneficial insects/spiders.

The Indonesian tropical wet rice ecosystem the IPM field school experience (Kenmore, 1980, Way and Heong, 1994 and Settle, et.al., 1996) shows that

  • Beneficial insects/spiders comprise the majority of species in healthy ecosystems. 64% of all species identified were predators (306 species) and parasitoids (187 species); neutrals (insect detritivores, plankton feeders) comprise 19% (Settle et.al., 1996) and Rice pests constitute only 17% of species.
  • Beneficials are extremely effective in controlling major rice pests; very substantial reduction of pesticide applications does not threaten rice yield.
  • Contrary to previous understanding, beneficials typically enter the tropical wet rice ecosystem before pests, and feed on detritivores and other “neutral” insects, e.g., Springtails (Collembola) and Midge larvae (Chironomidae) already present in the rice paddy. Beneficials are therefore present from the start of the crop season and effective in pest control from an earlier stage than had previously been assumed (Settle, et. al., 1996; Wu et. al., 1994)

The learnings from IPM projects and FFS experiences worldwide should have led to research on the complex interaction between crop ecology, agronomic practices, insect biology, and climate change to develop effective methods to manage disease and insect control strategies.  Similarly the farmers’ knowledge on using the local resources could have been captured and the principles could have been standardized.  But FFS mostly remained as a paradigm shift in agricultural extension: the training program that utilizes participatory methods “to help farmers develop their analytical skills, critical thinking, and creativity, and help them learn to make better decisions”.  The agriculture research and extension system worldwide still continue to believe in chemical pesticide based pest management in agriculture.

The effectiveness of the IPM FFS could have been enhanced by broadening the focus from a single crop to a broader systems approach, to address other matters, such as water management, crop rotation, crop diversification and marketing (Mancini, 2005).

Though FFS is seen as a knowledge intensive process, main focus was on taking external institutional knowledge to farmers.  Proper space was not provided for traditional knowledge and practices or grass root innovations by farmers. In a study by Mancini (2006) evaluating the cotton IPM FFS in Andhra Pradesh, farmers reported that their confidence in implementing the new management practices was not strong enough to translate into a change in behaviour.  This supports the argument that an effective, empowering learning process is based on experience, rather than on simple information and technology transfer (Lightfoot et al., 2001).

Pesticide industry is aware of the growing pest resistance towards their pesticides.  Many of the pesticides become useless as the pests develop resistance and loose their market before they can recover the costs involved in developing the product leaving aside the profits. This situation has forced the pesticide industry to come up with their paradigm of IPM called ‘Insecticide Resistance Management’ (IRM) which is a proactive pesticide resistance-management strategy to avoid the repeated use of a particular pesticide, or pesticides, that have a similar site of action, in the same field, by rotating pesticides with different sites of action. This approach will slow the development of one important type of resistance, target-site resistance, without resorting to increased rates and frequency of application and will prolong the useful life of pesticides. This resistance-management strategy considers cross-resistance between pesticides with different modes of action resulting from the development of other types of resistance (e.g., enhanced metabolism, reduced penetration, or behavior changes) (PMRA, 1999).

Though pesticide industry states that it fully supports a policy of restricted pesticide use within an IPM programme, it perceives a clear need for pesticides in most situations. Furthermore, its practice of paying pesticide salespeople on a commission basis, with increased sales being rewarded with increased earnings, is unlikely in practice to encourage a limited use of pesticides (Konradsen, 2003).

Right from the time of the Rio Earth conference, India has been highlighting this IPM policy in all its official documents. The ICAR had also established a National Centre for Integrated Pest Management in 1998.  In India a total of 9,111 Farmers’ Field Schools (FFSs) have been conducted by the Central Integrated Pest Management Centres under the Directorate of Plant Protection, Quarantine & Storage from 1994-95 to 2004-05 wherein 37,281 Agricultural Extension Officers and 275,056 farmers have been trained in IPM. Similar trainings have also been provided under various crop production programmes of the Government of India and the State Governments (Reports of Government of India available on http://www.agricoop.nic.in).

IPM is sought to be made an inherent component of various schemes viz., Technology Mission on Cotton (TMC), Technology Mission on Oilseeds and Pulses (TMOP), Technology Mission on Integrated Horticultural Development for NE, J & K, Himachal Pradesh, Uttaranchal, Technology Mission on Coconut Development etc. besides the scheme “Strengthening and Modernization of Pest Management” approach in India being implemented by the Directorate of PPQ&S [Plant Protection, Quarantine & Storage].

The problems with chemical pesticides also prompted the research systemsandindustry to look for alternatives.  Several schemes and projects have been initiated to research, produce and market biopesticides and biocontrol agents which are recommended as non chemical approaches to pest management.

Today, there is much data generated by the agriculture research establishment in India to show that non-chemical IPM practices across crops have yielded better results in terms of pest control and economics for farmers. However, the field level use of pesticides has not changed much. The official establishment usually claims that pesticide consumption in the country has come down because of the promotion and deployment of IPM practices on the ground by the agriculture research and extension departments [as was informed to the Joint Parliamentary Committee in 2003]. However, the actual progress of IPM on the ground has been quite dismal and small.

Further, the government often fails to take into account the fact that even if pesticide consumption has decreased in terms of quantities due to a shift to consumption of low-volume, high-concentration, high-value pesticides, the real picture in terms of number of sprays and costs involved is still the same for the farmers.

The Integrated Pest Management (IPM) initiatives which have come up as alternative though largely debates about the effects of pesticide on human health and on environment still believe that pesticides are inevitable, at least as a last resort and suggests safe and ‘intelligent use’.   On the other hand, replacing chemical products by biological products by itself may not solve the problem of pest management with restoration of ecological balance.

While the inevitability of pesticides in agriculture is promoted by the industry as well as the public research and extension bodies, there are successful experiences emerging from farmers’ innovations call for a complete paradigm shift in pest management.

Shifting Paradigms: Non Pesticidal Management

 The ecological and economical problems of pests and pesticides in agriculture gave rise to several eco-friendly innovative approaches which do not rely on the use of chemical pesticides. These initiatives involved rediscovering traditional practices and contemporary grass root innovations supplemented by strong scientific analysis mainly supported by non-formal institutions like NGOs. Such innovations have begun to play an important role in development sector.  This trend has important implications both for policy and practice.  One such initiative by Centre for World Solidarity and Centre for Sustainable Agriculture, Hyderabad was Non Pesticidal Management.

The ‘Non Pesticidal Management’ which emanates from collaborative work of public institutions, civil society organizations and Farmers in Andhra Pradesh shows how diverse players when come together to work in generating new knowledge and practice, can evolve more sustainable models of development.

Pest is not a problem but a symptom. Disturbance in the ecological balance among different components of crop ecosystem makes certain insects reach pest status.    From this perspective evolved the Non Pesticidal Management which is an ‘ecological approach to pest management using knowledge and skill based practices to prevent insects from reaching damaging stages and damaging proportions by making best use of local resources, natural processes and community action’.

Non Pesticidal Management is mainly based on

  • Understanding crop ecosystem and suitably modifying by adopting suitable cropping systems and crop production practices. The type of pests and their behavior differs with crop ecosystem. Similarly the natural enemies’ composition also varies with the cropping systems.
  • Understanding insect biology and behavior and adopting suitable preventive measures to reduce the pest numbers.
  • Building Farmers knowledge and skills in making best use of local resources and natural processes and community action. Natural ecological balance which ensures that pests do not reach a critical number in the field that endangers the yield. Nature can restore such a balance if it is not meddled with too much. Hence no chemical pesticides/pesticide incorporated crops at all. For an effective communication to farmers about the concept effectively and to differentiate from Integrated Pest Management which believes that chemical pesticides can be safely used and are essential as lost resort it is termed as ‘Non Pesticidal Management’.


Kenmore, Peter. 1980. Ecology and Outbreaks of a Tropical Insect Pest of the Green Revolution: The Rice Brown Planthopper, Nilaparvata lugens (Stal). Berkeley: University of California, Graduate Division.

Kenmore, Peter. 1996. Integrated pest management in rice. in Biotechnology and Integrated Pest Management 76–97, (Ed. G. Persley). Wallingford: CAB International.

Kenmore, Peter. 1997. A Perspective on IPM, LEISA Magazine, December, 1997

Konradsen Flemming A, Wim van der Hoekb, Donald C Cole C, Gerard Hutchinson Hubert Daisley D, Surjit Singh E, Michael Eddleston F.G. 2003. Reducing acute poisoning in developing countries—options for restricting the availability of pesticides, Toxicology 192 (2003) 249–261

Lightfoot, C., Ramirez, R., Groot, A., Noble, R., Alders, C., Shao, F., Kisauzi, D. and Bekalo, I. 2001. Learning OurWay Ahead: Navigating Institutional Change and Agricultural Decentralisation. Gatekeeper Series no. 98. London: IIED.

Mancini Francesca, Ariena H. C. Van bruggen, Janice I. S. Jiggins, Arun c. Ambatipudi, Helen Murphy. 2005. Acute Pesticide Poisoning among Female and Male Cotton Growers in India, Vol 11/No 3, Jul/Sep 2005 www.ijoeh.com

PMRA -Regulatory Directive DIR99-06, 1999. Voluntary Pesticide Resistance-Management Labelling Based on Target Site/Mode of Action, published by Pest Management Regulatory Agency, Canada www.hc-sc.gc.ca, http://www.irac-online.org/

Settle, W.H., H. Ariawan, E.T. Astuti, W. Cahyana, A.L. Hakim, D. Hindayana, A.

Sri Lestari, Pajarningsih, and Sartanto. 1996. Managing Tropical Rice Pests through Conservation of Generalist Natural Enemies and Alternate Prey, Ecology, 77 (7). Pp. 1975-1988.

Vasquez-Caicedo, Gloria, Julio Portocarrero, Oscar Ortiz, and Cristina Fonseca. 2000. Case Studies on Farmers’Perceptions about Farmer Field School (FFS) Implementation in San Miguel Peru: Contributing to Establish the Baseline for Impact Evaluation of FFS Report to the DECRG from the World Bank, May. As quoted in by Godtland Erin, Elisabeth Sadoulet, Alain de Janvry, Rinku Murgai and Oscar Ortiz (2003) The Impact of Farmer-Field-Schools on Knowledge and Productivity: A Study of Potato Farmers in the Peruvian Andes, Department of Agricultural & Resource Economics, UCB CUDARE Working Papers (University of California, Berkeley)

Way, M.J. and Heong, K.L. 1994. The Role of Biodiversity in the Dynamics and Management of Insect Pests of Tropical Irrigated Rice: A Review. Bulletin of Entomological Research, 84. Pp. 567-587.

Wu, J., G. Hu, J. Tang, Z. She, J. Yang, Z. Wan, and Z. Ren. 1994. Studies on the Regulation Effect of Neutral Insects on the Community Food Web in Paddy Fields.  Acta Ecologica Sinica 14 (4).