Is IPM sustainable in the Indian farming?

01 August 2022

Release of Anagyrus lopezi for the management of cassava mealybug at Yathapur, Tamil Nadu in June 2022 [Photo credit: NBAIR, Bangalore]

 

Long time ago, I was requested to deliver a Dr D Saharia Memorial talk on IPM at Assam Agricultural University, Jorhat. That was a year 2007 when I started studying and experimenting in a limited way what IPM is. As it encompassed vastness of environment and socio-economics, and specificity of crop or cropping system in relation to pest range, its complex nature started baring dynamically. And, the most common questions that I used to listen to were, how much area is under IPM? or why is that IPM area has not increased over the last five decades despite so much investment? And that most common answers are a magic figure of 10% of area under IPM, and the constraints like timely availability of quality biopesticides and lack of extension services to the farmers. We seem to have struck here for decades now.

A Background:

As early as 1939, Prof W M Hoskins at the University of California at Berkeley, USA and founder of insect toxicology as early as 1929 had a premonition about the adverse effects of pesticides on the environment and called for more discriminate use of pesticides. Imagine, those were the times when most of pesticides were inorganics, arsenicals or plant extracts which were available in limited amounts and only in some countries before an era of synthetic pesticides. During the ensuing decades, relative importance of abiotic and biotic factors in the regulation of pest (insect) population became a hotly debated topic amongst crop protection scientists, especially entomologists. Australians were more convinced of abiotic factors playing a major role, while Americans were forthright in elucidating role of biotic factors in the regulation of pest insect population.

Following discovery of insecticidal activity of DDT in 1939 and HCH in 1941, and availability of many more organic pesticides thereafter, reliance on pesticides increased, as their role in reducing yield constraints in agriculture and enhancing public health through control of arthropod vectors of human diseases became clear. With indiscriminate use of pesticides, pests evolved resistance to pesticides. In early 1940s, cases of resistance to DDT in the flies and bugs started appearing. This led to a treadmill situation wherein more pesticide had to be used for controlling resistant pests and eventually of different kinds too. The adverse impact of use of pesticides on the environment in terms of polluting soils as well as underground water resources became too evident. Besides, pesticides were found in the food chain affecting animals as well as humans. The harmful effects of pesticides on environment were highlighted with the publication of a book entitled “Silent Spring” by R Carson in 1962, that caused uproar, forcing some countries to severely restrict their use or even ban some.

The consequences of rampant use of pesticides justified a need for integrated control with both chemical as well as biological tactics [Stern et al. 1959 Integrated Control concept in Hilgardia 29:81]. The integrated control aimed at the usage of biocontrol agents as well as their conservation in the most compatible manner and at reduction in the use of chemical pesticides. With this integration, evolved a concept and practice of IPM that stretched to include holistic pest species targeting, cost-benefit analyses, societal reach and conservation of environment. Realising the importance of this approach to crop protection, Food and Agriculture Organization of the United Nations in 1972 stepped in to evolve a consensus and define it as management system that in the context of associated environment and population dynamics of pest species utilises all the tactics in the most compatible manner to keep population under the economic injury level. Over the years, this definition too is revised to be more comprehensive to include cost-benefit analyses that take in to account the interests of and impact on producers, society and the environment. Complexity of arriving at consensus in implementing the IPM as whole and reporting results that could be comparable has become too apparent. Furthermore, pest also means disease causing plant pathogens, weeds that compete for the same resources as the crop, affecting crop yields, and many others like rodents, birds and other animals. The latter means a different threshold to initiate strategies in view of nature of damage and biology of causal organisms. The concept of population dynamics as well as economic threshold levels that could be justified for pest insects is no longer applicable for diseases, weeds and other vertebrate pests. And decision making for use of fungicides and weedicides is more subjective and often preventive. Further, pest complex is in the state of flux especially for the seasonal and annual crops, and with change in climate. Despite these constraints, IPM strategies for some crops have worked well for some periods, but under the expert supervision. IPM project on cotton at Ashta in Maharashtra (1998-2001) prior to introduction of Bt cotton is one such success story. GM technology proved useful and facilitated IPM in cotton. Bt cotton effectively controlled bollworms. And in combination with seed treatment with neonicotinoids, Bt cotton crop controlled cotton sucking pests also. Decline in use of broad-spectrum pesticides led to abundance of natural enemies in the initial years. IPM in Bt cotton was at its best with these three interventions in the initial years. However, as the Bt cotton cultivation became too wide spread and intensified, IPM approach for other pest complex remained very limited. Like for cotton, IPM experts have to content with limited successes with available tactics for other crops. And, the holistic approach to IPM remains more often an exercise in academics than in practice. Consequently, academic biasness crept in with some talking and taking extreme stands, and advocating different variants of IPM, such as biointensive IPM, biocontrol based IPM, ecologically sound IPM, area-wide IPM, transgenics based IPM and so on, so forth.

Government stance:

In India, as early as 1985, the National Agriculture Policy stipulated the importance of IPM and called for use of biocontrol agents in order to minimise use of indiscriminate and injudicious of pesticides. Indian farmers were becoming more dependent on pesticides during 1970s and 1980s. At one time in 1980s, annual pesticide (technical) production peaked up to about 85,000 metric tons or more, with cotton and rice using a major share to be followed by vegetables and fruits. And this forced to thinking of limiting their use. Presently, about 60,000 tons of pesticides are used in the country. The use of pesticide per unit area [about 450 gm/ha] remains low as compared to some developed countries in the world. Since minimal use of chemical pesticides is a laudable objective in the policy, it does not convey as to how crop loss or pest incidence will be reduced to minimum without pesticides? Further, it weans away from the aim of high yields which leads to ambiguity as to what our goal is or should be.                       

As a concerted effort to implement IPM in practice, the Government of India has established as many as 36 central IPM centres in 28 states and 2 union territories to supply biocontrol agents and monitor the pest incidence. During 1994-95 and 2021-22, pest monitoring covered over 32 million hectares while release of biocontrol agents and efforts at their augmentation and conservation covered an area of 20.4 million hectares. At present, annually about a million hectare of area is covered with release of biocontrol agents through this network. Besides, ICAR’s institutes played a significant role [photo 1]. This level of use of biological agents is inadequate in view of annual cropping area of about 175 million hectares. We will need greater participation of other stakeholders, especially farmers and village level entrepreneurs to increase area under IPM.

Recent attempt to introduce the pesticide management bill to replace Insecticide Act 1968 did little to clarify as to what we aim at? Regulating pesticides or achieving IPM? As pesticides are integral part of IPM, pesticide management bill does offer some solace to steer the course smoothly in the broad vision of IPM. A stalwart of pesticide industry however dubbed it as ‘old wine in new bottle’.  In view of recent emphasis of the Government on natural or organic farming or /and zero budget natural farming, IPM strategies are likely to be very limited and under great stress to evolve and be compatible with farm practices as well as expectation of high yields in the context of food security.

IPM technologies worldwide need to be made available to the Indian farmers. The Government has recently allowed genome editing products based on limited changes related to SDN1 and SDN2. Genome editing technologies may not offer much help for control of pest insects. The Government is dithering over approval of other GM technologies or other Bt crops except its approval of Bt cotton two decades ago. Further, there are lot of limitations in importing biological technologies like natural enemies, as it may contradict Destructive Insects and Pests Act and the National Biodiversity Act.

Nitty gritty of IPM:

IPM will succeed only if it also contributes to high yields or high economic returns. IPM comes into play only at the time when pest attains the economic threshold level. Thus, it assumes that some damage to the crop is inevitable. These thresholds are more verbose and have not been revised in the recent past, as costs of inputs and price of produce have increased and pest complex changed. Will farmer accept this situation? Only seldom. Unfortunately, expected benefits of quality pesticide-free produce fetching higher prices do not seem to be a case often, as farmers have limited scope to market them in niche areas. IPM farmers may lose price-wise if they have to compete with the organic farmers who are better organised.

Will IPM help in reducing cost of crop protection? Is that a significant factor in the cost of crop production?

In the studies on evaluation of IPM practices in tomato and cabbage at ICAR-NCIPM, while IPM reduced expenditure on crop protection, it also affected yields. And, the net profit per hectare in IPM trials was marginally but not significantly better than non-IPM trials. Similar study on biointensive IPM in brinjal involving six releases of Trichogramma chilonis and three sprays of 5% NSKE did not show any significant increases in yield nor net profit over the farmers’ practice of chemical pesticides during two years of 2015 & 2016 at Jorhat.

However, studies carried out on IPM in sugarcane showed significantly less damage due to the Plassey borer, higher yields and higher net returns during 2015 to 2018 at Jorhat. This shows that long standing crops with vegetative growth as their produce or fruit crops are better suited for IPM.

Most of the IPM studies often reported low cost of crop protection, probably due to use of natural enemies and other biopesticides which were either highly subsidized and/or under-priced. Besides, reduction in use of chemical pesticides lowered the cost of crop protection. And this helped in tilting the scale towards higher cost-benefit ratios. Further, as production did not increase, overall cost of production too did not increase as harvesting costs in comparison to the farmers’ practice, with prices of produce more or less static.

For IPM to be sustainable at the farmer’s level, it has to be cost-effective at the crop protection as well as production levels. Dr R Peshin of Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu in 2013 reported four most important drivers for IPM adaption in cotton viz., relative economic advantage, benefit visibility, compatibility with past experiences and (un)complexity. Experimental studies on IPM in Bt cotton have definitely shown economic advantage and all crop cultivation practices were more or less in synchrony with the past experience. Benefits in term of improving quality of environment were not visible, as they were not of monetary nature. Significant reduction in bollworm damage increased yields significantly in the first decade of Bt cotton. However, benefits weathered as the pest evolved resistance to Bt toxins and the new technology was not available to counter this problem as well as emergence of sucking pests as major ones. As far as complexity of explaining and implementing IPM in Bt cotton is concerned, it is well taken care of in cotton with infrastructure and mission mode projects often in continuum, and in view of significant contribution of cotton to the Indian economy. Of course, this is not the case with other crops.

Key factors in complexity and sustainability of IPM

Pests are the major constraints for achieving maximum crop yields. Although the estimates of crop losses are reportedly in billions of rupees, farmers tend to realise their importance in relation to other constraints and crop recovery that is likely to take place. Most farmers tend to spray crop before the pest damage, without regular survey of pest incidence or crop damage and assessment of likely impact on yields. Since the pesticides tend to be effective for short time, congenial conditions may bring back pest incidence. And hence, pesticides remain a cure for short term, but other tactics need to be used in conjunction and in continuum to sustain the benefit of pest control. Further, pests have evolved resistance to pesticides which has pushed up cost of crop protection. Pesticide resistance management is now being considered important so that pesticide benefits are sustained for a long time and is not exclusive of IPM.

Over the years, biocontrol agents have been in use, increasingly so. Of these, microbial pesticides are predominant. As many as 13 microbials are being produced to the extent of about 0.5 million tons valued at Rs 8 to 10 billion annually. As these are effective and storable, their use has been on increase. However, the limited and timely availability, efficacy and restricted range of activity of natural enemies like parasites and predators have become a constraint to achieve crop protection area-wide. Often, this frustration has given rise to the concept of conservation of natural enemies by manipulating crop ecosystem especially mixed or intercropping and reducing use of pesticides. Besides, selective pesticides that do not harm biocontrol agents are being promoted. This approach has been more successful than the one exclusively depending upon the biocontrol agents which needs to be regularly released in the biointensive or biological IPM. Some fruit crops as well as those with long duration like sugarcane have shown successes with bio-intensive IPM. However, this approach largely remained restricted in view of limited monetary benefits for most agricultural crops.

Ecological manipulation/engineering has entered the jargons of farming and has often been evoked by the advocates of organic farming. It is essentially a kind of habitat management by growing mixed crops or intercrops or border crops that offer complexity for pests to live in. This approach of crop diversity does not offer advantage to any pest species to be dominant and the overall pest complex is in its equilibrium with their natural enemies, unless drastically altered through pesticide use. However, this advantage is not often realised in view of small size of crop area, dominance of single crops, high cropping intensity, lack of rotation and inoperability of interculturing as well as marketing of produce in view of diversity. This approach has not been found economical as labour is becoming costlier and marketing difficult. Ecological manipulation with pheromones has offered a distinctive merit, but mostly for monitoring the pest population, similar to survey or surveillance of pest and damage incidence in the crop. And this approach has been in use for timing effectively control tactics. Some successes have been recorded with mass trapping as well as mating disruptions on the area-wide scale. In recent years, availability of sex pheromone of the pink bollworm of cotton for mating disruption has helped in controlling pest damage and increasing yields.

Crop resistance to pest species has been the classical method of pest control. Spectacular successes were seen in case of control of diseases. However, as plant pathogens circumvented crop resistance, this approach too suffered setback. Although, several sources of insect resistance have been reported in many crops, but their utilization in insect-resistance breeding programs have been to a limited extent, and fewer numbers of insect-resistant varieties have been released for commercial cultivation. Furthermore, these traditionally bred resistant varieties often have yield penalties, which limit the popularity amongst the farmers. Thus, this approach for control of pest insects did not offer much promise across many crops, except in the recently introduced plant incorporated protectants, such as Bt crops where crop protection does not interfere with yields. Transgenic crops expressing Bt toxins performed well in controlling specific target pest insects. As some of these crops were able to control damage of target pest insects, other tactics like selective pesticides and bioagents played an important role in imparting overall crop protection. In India, with the commercialization of Bt cotton in 2002, crop resistance to target pest insects like bollworm controlled boll damage and enhanced yields. With reduction in pesticide use, bioagents played their role for control of other pests at least in the first decade.

There has been an emphasis on natural and organic farming, and zero budget farming under the Paramparagat Kheti Vikas Yojana. About 2.77 million hectares of farmland is under organic farming in India. As the farming in the olden days used to be natural or organic, the input costs were mostly related to seeds or/and occasional use of fertilizers which were minimum. Further most of labour came from farm families. And yields were considered providential. With intensification of farming for more yields and precision farming, inputs as well as physical labour are costly. With natural or organic farming, IPM strategies are highly limited as use of pesticides, growth promotors and fertilizers is not desired, while biotic constraints remain constant threat as against expectation of high yields. Furthermore, some of concoctions with plant and microbial extracts are promoted in the form of seed dressers as well as plant sprays which may have safety concerns for environment and humans.

Sustainability of IPM has to be greatly underlined with the profit that the technology offers. Unfortunately, high cost of cultivation in recent times is largely due to manual labour, as the labour on farm is scarce. Further, prices of pesticides and fertilisers have increased significantly over the years. Over the generations, land holding per capita is on decline, with those having < 2 hectares being most predominant. These farmers find farming uneconomical and have to supplement their income by working outside the farms. Most have to grow crops in succession like rice-rice or rice-wheat, cotton-wheat/chickpea, sugarcane, soybean; with intercrops or mixed crops in some of them which has affected soil in terms of its nutrient as physical traits. With such cropping intensity, incidence of pest has increased over the years. Sucking insect pest menace is constant. Besides, there are invasive pests or sporadic pests of importance.

Lack of IPM extension in the overall context of integrated farming is one constraint that impeded spread of IPM amongst the farmers. Digitization and ICT services are lacking in the vernacular languages for the farmers to understand. Dr C D Mayee of South Asia Biotechnology Centre using both conventional as well as digital means of communication successfully demonstrated reach of these means for management of invasive pest, fall armyworm on maize during 2019 and 2020 within a year of its invasion.

Under these circumstances, IPM sustainability will remain impacted unless the farmers are in position to mechanise the farm, and predict the risks well in advance and manage them on time with economical and effective tactics, and grow crops that give them assured returns and/or get in return subsidies/incentives for environmental conservation. 

Thanks Dr M K Dhillon for his critical comments