Threat of wheat blast to South Asia’s food security: An ex-ante analysis
Threat of wheat blast to South Asia's food security: An ex-ante analysis
Khondoker Abdul Mottaleb 0 1
Pawan Kumar Singh 1
Kai Sonder 1
Gideon Kruseman 0 1
Thakur Prasad Tiwari 1
Naresh C. D. Barma 1
Paritosh Kumar Malaker 1
Hans- Joachim Braun 1
Olaf Erenstein 0 1
0 Socioeconomics Program, CIMMYT (International Maize and Wheat Improvement Center) , Texcoco, Mexico, 2 Global Wheat Program, CIMMYT, Texcoco , Mexico , 3 Geographical Information System Unit, CIMMYT , Texcoco, Mexico, 4 Country representative, CIMMYT, Dhaka , Bangladesh , 5 Wheat Research Centre , BARI , Bangladesh
1 Editor: Wujun Ma, Murdoch University , AUSTRALIA
New biotic stresses have emerged around the globe over the last decades threatening food safety and security. In 2016, scientists confirmed the presence of the devastating wheatblast disease in Bangladesh, South Asia±its first occurrence outside South America. Severely blast-affected wheat fields had their grain yield wiped out. This poses a severe threat to food security in a densely-populated region with millions of poor inhabitants where wheat is a major staple crop and per capita wheat consumption has been increasing. As an ex ante impact assessment, this study examined potential wheat-blast scenarios in Bangladesh, India, and Pakistan. Based on the agro-climatic conditions in the epicenter, where the disease was first identified in Bangladesh in 2016, this study identified the correspondingly vulnerable areas in India, Pakistan and Bangladesh amounting to 7 million ha. Assuming a conservative scenario of 5±10% for blast-induced wheat production loss, this study estimated the annual potential wheat loss across the sampled countries to be 0.89±1.77 million tons, equivalent to USD 132±264 million. Such losses further threaten an already-precarious national food security, putting pressure on wheat imports and wheat prices. The study is a call for action to tackle the real wheat-blast threat in South Asia.
Funding: This paper was supported by the CGIAR
research program on WHEAT agro-food systems
to GK and Australian Center for International
Agriculture Research (ACIAR) CIM/2016/170 to
PKS. The funders had no role in study design, data
collection and analysis, decision to publish, or
preparation of the manuscript.
Competing interests: The authors have declared
that no competing interests exist.
Wheat consumption in South Asia's traditional rice economies, such as Bangladesh, Nepal,
and India, has been steadily increasing since the Green revolution in the 1960s now oscillating
around 20 kg per capita per year in Bangladesh, 50±60 kg in Nepal and India; whereas, it has
long been around 100 kg in Pakistan (Fig 1). This increasing preference for wheat is not unique
to South Asia, as it has also become evident in the urban areas of sub-Saharan Africa in recent
]. The global population is projected to increase 25±33% by 2050 from the current
level  with more than 65% of the increase taking place in sub-Saharan Africa and South Asia
]. These trends imply significant increases in food demands in general, including major
staples, and wheat demand in particular [
Fig 1. Wheat consumption trends (kg/capita/year) in selected countries in South Asia. Source: own calculations based on FAOSTAT [
The need to supply more wheat and other food grains to meet the increasing and changing
demand in developing countries is increasingly challenging, given the rapidly-declining per
capita arable land and renewable fresh water in these countries  with the added stresses of
climate change. Additionally, new biotic stresses have emerged around the globe over the last
decades, threatening food safety and production and overall food security in developing
In 2016, the devastating wheat-blast disease caused by the fungus Magnaporthe oryzae
pathotype Triticum (MoT) was reported in Bangladesh, South Asia [7±12]. This is a significant
incident. First, it represents the first occurrence outside South America of this particularly
aggressive disease. Second, it entered South Asia, where wheat is a major staple for the masses.
In 2016, it was believed to be confined to Bangladesh, a densely-populated, land scarce country
with nearly 160 million people, of which 18% are extremely poor, living on less than USD 1.90
]. In 2017, wheat-blast-like symptoms were unofficially reported for the first time
from eastern India in various newspapers [
]. Although it has not been officially
confirmed these disease symptoms were blast, the likelihood of wheat blast passing across the
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Bangladesh border is high. Bangladesh shares a border of 2,217 kilometers only with West
Bengal, India, which cuts across the lower part of the Gangetic plains. This is an immense
contiguous densely-populated and intensively cultivated area that stretches from Bangladesh to
adjacent West Bengal up to north-western India and on to the Indus plains of Pakistan, home
to the rice-wheat systems and the staple basket for much of South Asia [16±17].
Wheat blast was first reported in the Parana state of Brazil in 1985 [
]. Later it spread to
the humid and warmer zones of Bolivia, Paraguay and north-eastern Argentina [
disease is so destructive that it reduced wheat yield in Sao Paulo, Brazil in 2005 by 14±32%, even
after two applications of fungicides [
]. In Bangladesh, in February 2016, wheat blast affected
nearly 15,000 ha (3.5% of the total 0.43 million ha of wheat area in Bangladesh), with wheat
yields in the affected fields reduced by 5±51% [
]. Any spread of wheat blast into the rest of
Bangladesh and particularly into India and Pakistan, could wreak havoc on wheat production
in South Asia and significantly threaten food security and the overall well-being of a region
with millions of poor wheat consumers who depend on wheat as their main source of dietary
The objective of this study was to examine wheat-blast scenarios in Bangladesh, India, and
Pakistan by applying an ex ante impact assessment framework to quantify the potential
impacts in South Asia's wheat areas, which are potentially vulnerable to wheat-blast
considering their favorable climate for the disease. This study intends to inform stakeholders of the
wheat-blast threat in South Asia and assess the implications.
The study is organized as follows: the next section gives a brief perspective on the spread of
wheat blast, its causes and implications; Section 3 includes the materials and methods section,
including the selection of wheat blast hotspots, the current status of land allocation to wheat
and wheat yield in the selected regions of the sampled countries; Section 4 presents simulation
results and Section 5 concludes and provides recommendations.
Wheat blast is usually classified as a spike disease (Fig 2). It can be found on all the aerial plant
parts of wheat [
], although leaf infection is seen only in highly-susceptible varieties [
Spike infection is the most notable symptom of the disease , which is often confused with
Fusarium head blight (FHB) infection; but rather than attacking individual spikelets and
conferring a salmon or pinkish tint to flames as FHB usually does, blast attacks the rachis, leading
to bleached spikelets above the point of infection and bright black spots on the rachis [
Grains from blast-infected heads are usually small, shriveled, deformed, and have low-test
weight. The highest yield losses happen when head infections start during anthesis or early
grain development stages [
The wheat-blast pathogen emerged only 32 years ago in South America, but has fully
adapted to its new host ± wheat ± and continues to spread and evolve genetically. The first
occurrence of this biotic stress outside South America represents a major event which, in turn,
may trigger a new selection pressure, from the Bangladesh outbreak epicenter, on this
highlyevolving fungus. Although the comparative genome analysis showed that isolates from diverse
wheat regions in Bangladesh appeared clonal [
], and pathogenomics analysis 
confirmed that the Bangladeshi wheat-blast most likely arrived from South America, a change in
pathogen population can be expected due to a new environment and hosts selection pressure.
Bangladesh and South Asian agro-ecology, as well as the host wheat germplasm and weeds are
quite different from that of South America. These differences will put different selection
pressures on the pathogen and the fungus will likely evolve and cope with the new environment,
which can trigger a new selection pressure in the pathogen population. Importantly, the strain
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Fig 2. Wheat-blast symptoms in Jhenaidah district, Bangladesh in February 2017. Panel A: Infected spikes; Panel
B: Infected field. Courtesy: Moksedul A. Arafat, Technical Officer, Jessore Hub, CIMMYT, Bangladesh, 2017.
identified in Bangladesh corresponds to a very aggressive type compared to MoT strains
collected in the early days of observation when the disease was considered an oddity, unable to
cause large and frequent epidemics [
7, 23, 24
]. In addition, wheat blast is a seed-borne disease
] and could potentially spread due to seed sharing between farmers, as frequently observed
in South Asia, and with wheat trade between countries. Moreover, it is also airborne [
can move relatively long distances during the cropping season. The 2016 detection of the
wheat-blast in Bangladesh could thus spread further into India and Pakistan, not least as
Bangladesh shares a long border with India. In 2017, unofficial media reported that spikes with
wheat-blast-like symptoms had been observed in West Bengal, adjoining the western borders
of Bangladesh [14±15].
At present, most of the commercially-grown wheat cultivars in South Asia are susceptible
to wheat blast. Although some cultivars tolerant or moderately resistant to wheat blast have
been identified in localized geographic areas, no durable resistant cultivar has been developed
until today [
]. The level of yield losses and speed of epidemics caused by MoT along with
the lack of resistance may require innovative approaches to manage this disease. Generally, the
known fungicides are ineffective under high disease pressure, and were only partially effective
under moderate to low infection of the wheat-blast isolates in Brazil . Moreover, the
pathogen has shown a rapid ability to develop resistance to certain classes of fungicides [
19, 23, 24
Still, there remains a role for protectant low risk fungicides, also as the pathogen's evolution
reflects the distinct selection pressure exerted by long term use of high risk fungicides (e.g.
QoIs, DMIs or SDHIs as the sole molecule). Indeed, the wheat-blast isolate in Bangladesh was
effectively controlled with Tebuconazole and Trifloxystrobin, which is widely available in
South Asia [Malakar, personal communication]. Nevertheless, the list of approved and locally
available fungicides in South Asia is limited and, therefore, testing the active-ingredient
efficacy is required. At present isolated incidences of fields affected by wheat-blast-like symptoms
are dealt with by burning the standing crop. This destructive method of dealing with the
disease can lead to severe production shortfalls if the disease becomes more pervasive. Moreover,
in addition to similar agro-climatic conditions across Bangladesh, India and Pakistan, the
changing global climate and the evolving pathogen (e.g. increasing aggressiveness, fungicide
resistance and sexual recombination) can further aggravate disease incidence with the likely
expansion to other major wheat-producing countries.
Duveiller et al. [
] reported that there are wheat-producing regions in the world, including
central India, Bangladesh and Ethiopia, where the disease had not yet been reported, but the
agro-climatic conditions are similar to regions in South America where the disease occurs.
The 2016 occurrence of wheat blast in Bangladesh fits the original prediction. Maciel [
expressed a similar concern, pointing out that wheat blast may spread to European countries,
Canada, and the USA under the scenarios of global warming due to climate change. Cruz et al.
] predicted that in the USA wheat blast could break out in 25% of the wheat area, with a
probability exceeding 70% in the warmer and more humid states. Hence a serious threat of
further wheat-blast expansion exists.
Wheat production in Bolivia is a notorious example of how wheat blast can destroy a
nation's wheat crop. In the early 1990s, Bolivia started an initiative to increase its national
wheat production, mainly to attain wheat food self-sufficiency [
]. The country managed to
increase wheat production from 10,865 tons in 1989 to 75,435 tons in 1994, and 120,414 tons
in 1997 [
]. However, the outbreaks of wheat blast in the subsequent years caused
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tremendous yield losses; consequently, the production volume dropped to 37,750 tons in 1999
from 172,892 ha [
]. Many resource-poor farmers were discouraged by the wheat-blast threat
and the area under wheat fell in subsequent years [
Materials and methods
We use a climate analogue model to first identify prospective wheat blast hotspots in South
Asia. As evidenced in South America, warm and humid areas are the most vulnerable to
wheat-blast incidence [
]. Bangladesh has a sub-tropical monsoon climate across its primarily
low-elevation landscape, with wide seasonal variations in rainfall, high temperatures and
humidity. Wheat is grown during the relatively cool and dry winter. In March 2016, the
emergence of wheat blast disease was first officially-recognized in Bangladesh, that reportedly
affected eight districts (Fig 1): Chuadanga, Meherpur, Jessore, Jhenaidah, Bhola, Kushtia,
Barisal and Pabna [
]. A team of Food and Agriculture Organization of the United Nations (FAO),
however visited 39 spots in seven districts and assessed the disease severity [
wheatblast affected sites in Bangladesh were identified using geo-referenced information from the
FAO-led field study [
]. These sites were used to generate an analogue climate map applying
the analogue tool. Using long term temperature and rainfall patterns (1960±1990) in the most
severely affected geo-spatial coordinates of the plots in four districts reported: Bhola,
Chuadanga, Jhenaidah and Meherpur [
], the present study characterizes the
wheat-blast-vulnerable agro-climate, and identifies the homologue areas (hotspots) in Bangladesh, India and
Pakistan by matching these characteristics during the wheat growing season (Fig 3).
The analogue climate approach has been utilized for a number of studies mainly focused on
climate change analysis [31±37]. The analogue tool used here is based on R code. It analyzes
climate variables at a given location and takes into account rainfall and average temperatures
as variables (in combination or each factor by itself) and uses spatial analysis to identify places
in the target areas that have a similar (analogue) climate based on a weighted similarity index.
Both variables can be weighted depending on the specific nature of the analysis needed (e.g.
disease risk, crop aptitude, biotic and abiotic stress-adapted landraces, representativeness of
trial sites, etc.). This analysis can be performed with the current climate data to identify current
spatial climate analogues as well as with predicted future climate data, be it looking forward or
backward to identify either the future climate of a location or where future predicted climate
can be found elsewhere . For the present study, we identified spatial analogue areas for
January and February's climate having the highest importance for the emergence of the
wheatblast disease for the Bangladesh outbreak. The spatial scope of the analysis was limited to
India, Pakistan and Bangladesh. The gridded outputs for all locations with similarity indices
above 0.6 (60%) were merged in a GIS and used to identify wheat-producing districts at risk of
wheat-blast infection (Fig 4).
The initial 2016 event in Bangladesh affected 5.4% of its potentially-vulnerable areas with
an average yield loss of 24.5% in the affected fields, representing an aggregate production
shock of 1.3% for the vulnerable areas. The 2016 event implied a particularly favorable scenario
for wheat blast in terms of high humidity and temperature at the right time of the wheat
growth stage (prior and during heading) with the initial presence of the blast inoculum. One
may assume that now having the disease endemic in South Asia increases the prospects of it
emerging again elsewhere in the region when the conditions are right. It also is likely that
wheat blast will persist in the presence of alternative hosts (e.g. wild grass species, non-wheat
crops), which undermine the prospects of eradicating the disease.
The present study uses a simple ex ante analysis to assess wheat-blast scenarios in South
Asia. We consider two scenarios applied across the prospective wheat blast vulnerable areas: a
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Fig 3. Original districts with wheat-blast in 2016 and new districts with wheat-blast like symptoms in 2017 wheat season in Bangladesh and
eastern India. Source: Bangladesh 2016 [
]; 2017 (authors' observations); India [
5% and a 10% wheat-blast-induced wheat-production shock in the vulnerable areas only; with
in each case no effect (0% loss) in the non-vulnerable areas. One can interpret the 5% scenario
as an average scenario; for instance, 10% of the vulnerable area could be affected by a 50%
yield loss; alternatively, 5% of the vulnerable area could be affected by a devastating 100% yield
loss, or variations thereof. Lacking further detailed insights for now, we assume the 5% and
10% production shocks to be reasonable scenarios within an ex ante impact assessment
An additional but important caveat is that these are potential wheat-blast-induced
production losses in the vulnerable areas during affected years. These scenarios depict specific
situations where the season's agro-climatology favors an outbreak of blast in the vulnerable areas
(i.e. the simultaneous combination of high humidity and temperature at the right time in the
wheat season and in the presence of blast inoculum). Such conducive instances for wheat blast
do not occur in all years, even in the vulnerable areas. The scenarios thereby represent
Fig 4. South Asia wheat-blast vulnerability map. Source: Authors' own estimation.
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occurrences that may happen in one particular year simultaneously across South Asia±but not
necessarily every year in the vulnerable areas. Even if it occurs, the disease may present itself as
is the case in the 2016±17 wheat season in Bangladesh, which was less propitious for wheat
blast and hence was less badly affected than in the preceding 2015±16 season. However, even
though losses in the 2016±17 cycle were less than in 2015±16, the occurrence of the disease in
Bangladesh indicates that wheat blast is now established, and occurs even though the weather
was not conducive (relatively dry, limited rain).
In Bangladesh, matching with the climate in the original four severely wheat-blast affected
districts, the present study identifies 0.28 million ha (out of a total 0.43 million ha under wheat
production) , as vulnerable to wheat blast located in 46 districts (out of total 64 districtsÐ
Table 1). Applying the same historical weather-variable matching technique, this study shows
that, in India, out of 30.96 million ha of actual wheat area , 6.57 million ha are found to be
vulnerable to wheat-blast disease located in 138 districts in 11 states. In contrast, out of 9.52
million ha of the total wheat area in Pakistan, only five districts located in Sindh Province with
an approximate area 0.14 million ha , are vulnerable to wheat-blast disease.
The vulnerable area, therefore, stretches in a broad band across the sub-tropics of the
Indian sub-continent: from the southern half of Bangladesh into India's West Bengal and on
to India's Gujarat in the West and into Pakistan's southern Sindh (Fig 4). The vulnerable area
represents a vast wheat-producing area totaling 7 million ha. Still, most of the
wheat-producing areas across the Indo-Gangetic plains remain relatively spared due to their more northern
location and correspondingly cooler winter season.
Potential wheat loss
(`000 ton) (million
USD) under different
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Table 1 also presents the wheat-blast vulnerability indicators for Bangladesh, India and
Pakistan, including current wheat indicators, predicted vulnerability indicators and the
potential wheat loss from wheat blast for two scenarios (assuming 5% and 10% wheat-blast-induced
wheat-production shocks in the vulnerable areas). Table 1 shows that Bangladesh is the most
vulnerable to wheat blast in South Asia: 65% of the total wheat area is vulnerable, reflecting the
sub-tropical climate. Still, Bangladesh is the much smaller wheat producer among the three
South Asian countries in terms of area and production. This would potentially result in an
estimated wheat loss of 43±85 thousand tons in affected years under the 5±10% scenarios,
equivalent to USD 6.3±12.7 million when valuing wheat at USD 149/ton.
Compared to Bangladesh's 65%, only 21% of India's total wheat area is vulnerable to wheat
blast (Table 1), reflecting that wheat is more widely grown in the colder northern latitudes.
Still, the sheer size of India's wheat area and production implies, that even a fifth being
vulnerable has potentially dire consequences, were wheat blast to spread across India. This would
result in an estimated potential wheat loss of a whopping 0.8±1.6 million tons in the affected
years under the 5±10% yield loss scenarios, equivalent to USD 122±244 million (again valuing
wheat at USD 149/ton).
Table 1 shows that Pakistan is the least vulnerable to wheat blast in South Asia: 1.6% of the
total wheat area could be vulnerable, reflecting the more northern latitude of its wheat
production with the vulnerable area confined to Sindh in the south. Therefore, although wheat is the
major staple in Pakistan and its wheat area and production is second to India in South Asia,
potential blast-induced losses are the lowest for Pakistan. Wheat blast could potentially result
in an estimated wheat loss of 23±45 thousand tons in affected years under the 5% and 10%
scenarios, equivalent to USD 3.4±6.8 million.
Across South Asia, the wheat-blast-induced wheat-yield loss scenarios of 5±10% imply a
potential wheat loss of 0.89±1.77 million tons in affected years, equivalent to USD 132±264
million. The threat of wheat blast increases the pressure on the already-precarious national
food security in South Asia, and potentially adds pressure on wheat imports and wheat prices.
Although wheat is one of the major and increasing sources of dietary calories in Pakistan,
India and Bangladesh. Pakistan and Bangladesh are already regular importers of wheat over
the last decade and, in 2016, even India resorted to imports. A potential wheat-blast-induced
reduction of wheat production would have a significantly negative impact on the overall food
security in the region and on international trade, potentially feeding into international
wheatprice increases and threatening the food security of the poorest wheat consumers.
The yearly per capita consumption of wheat in Bangladesh, India and Pakistan in 2013 was
17.5 kg, 61 kg and 114 kg respectively (Table 2). Bangladesh, to meet wheat demand, imported
2.84 million tons [
] of wheat, on average, from 2009 to 2013. Under the potential
wheat-blastinduced production losses of 5% and 10%, to maintain the consumption at the 2013 level,
Bangladesh needs to import 1.5±3.0% more wheat. Pakistan, a net importer of wheat based on the
net average wheat trade statistics, imported 0.22 million tons of wheat [
] from 2009 to 2013.
To maintain wheat consumption at the 2013 level in Pakistan, under the potential
wheat-blastinduced production losses of 5±10%, the country needs to increase wheat imports by 10±21%.
In contrast, based on the average of net wheat trade from 2009 to 2013, India was a net
exporting country of wheat, exporting a yearly average of 2.24 million tons of wheat. Under India's
2009±13 wheat trade balance, the potential wheat-blast-induced production losses of 5% and
10% would reduce wheat exports by 37±73%. In 2016 India resorted to importing wheat, but
normal circumstances would keep India as net exporter, although wheat-blast-induced losses
could jeopardize India's reserve stocks.
An increase in wheat imports by Bangladesh and Pakistan, and decreases in India's exports
may increase the price of wheat on the international market. Such increases in price can lead
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to an increase in the number of people at risk of hunger, not only in South Asia, but also in
other countries where wheat is a major staple and they depend on wheat imports. Worryingly,
the largest wheat-producing Sub-Saharan African country, Ethiopia, is also vulnerable to the
wheat-blast threat due its climatic conditions. In due time, the wheat-blast impacts are likely to
reach beyond the already-significant impacts in South Asia.
Conclusion and policy implications
In 2016, the devastating wheat-blast disease was found in Bangladesh ± its first occurrence
outside South America. The disease is now endemic in the densely-populated region, presenting
potentially devastating negative impacts on wheat production, income and livelihoods of
wheat farmers, and the overall food security in Bangladesh.
This study first identified the area vulnerable to wheat blast in South Asia by matching the
historical weather variables across Bangladesh, India and Pakistan to those in the 2016
epicenter. The study identified a total of seven million ha of wheat in these countries that are
vulnerable to the wheat-blast disease. The study then used two scenarios applied across the vulnerable
areas: a 5% and 10% wheat-blast-induced wheat production shock. Across South Asia, the
wheat-blast-induced wheat-yield loss scenarios of 5±10% imply a potential wheat loss in
affected years of 0.89±1.77 million tons, equivalent to USD 132±264 million. Such losses
further threaten the already-precarious national food security, adding pressure to wheat imports
and wheat prices. The increase in wheat prices can escalate the number of people facing hunger
by lowering their purchasing power, which can ultimately impair the food security of the entire
The study is a call for action to tackle the now real wheat-blast threat in South Asia and calls
for both short-term and long-term action plans to mitigate the threat. In the short term,
investments are needed in research and development to better understand the disease and its
implications in the South Asia setting, and to monitor its re-occurrence and resort to immediate
control measures to check the spread and damage. Since this is a new disease, awareness
creation among wheat growers and all stakeholders is equally important in the short term.
Therefore, it is important to develop strategies to manage the disease, such as developing and
deploying appropriate fungicides to ensure effective chemicals are available in the hands of the
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farmers at an affordable price and at the right time, especially during wheat-blast-conducive
environments, along with the knowledge of the appropriate use of these fungicides. However,
only fungicide application, which is a short-term solution, is not enough as the rapid
development of fungicide resistance was observed in Brazil. To prepare for the long term, a concerted
effort and long-term assured investments are needed immediately to develop and disseminate
blast-resistant wheat varieties, including their targeting to vulnerable areas, and reliable and
timely surveillance and disease forecasting to ensure wheat food security for the masses.
The present study has a few limitations. First, data and the associated assumptions
intrinsically limit this study. More detailed data sets and enhanced understanding of the disease in the
South Asia context could provide the foundation for more rigorous and advanced models in
the future (e.g. ). This study assumes the potential disease spread in areas based on a
similarity of 60% or higher in terms of rainfall and temperature to the 2016 epicenter in
Bangladesh. In reality, wheat blast can spread in more restricted or more extended areas than the
present homologue areas considered, depending on the local micro-climate conditions which
can be more or less favorable to the development of the disease. Using daily climate data for
the growing season of the 2016 outbreak sites in Bangladesh would allow the potential
highrisk wheat-blast areas to be narrowed down with more precision and allow the establishment
of early warning systems to give research institutions, farmers and extension services in the
region the ability to react quickly with plant protection measures in wheat fields or spot
eradication if needed. Currently, regional coverage of daily data is limited for near real-time
warning systems, but investment in the expansion of weather station networks with automated
online availability such as is currently being undertaken by the Government of Bangladesh is
crucial. Long-term climate conditions were assumed for the analysis, even given the anomaly
of the rainfall events leading to the outbreak. However, the reappearance of the pathogen in
2017 shows that, once established, the disease can cause damage even under relatively normal
weather conditions similar to the large outbreak in 2009 in South America.
Second, this study assumed some factors to remain constant. For instance, that there will be
no gain in virulence in the pathogen, i.e. the disease epidemic in 2016 remains the base. It did
not consider any change in acreage of wheat production or its economics due to the presence
of the disease and additional costs related to fungicide application and potential price effects.
Finally, the origin and pathway of wheat blast into Bangladesh and the pathogen nomenclature
are beyond the scope of the present study, although a few studies have linked the Bangladesh
introduction with South America [
], probably associated with wheat imports from Brazil. A
rigorous establishment of the source and pathways of the wheat-blast disease into Bangladesh
and beyond is needed not least to identify the role of quarantine failure and leakages and
associated policy learnings and implications to avoid such costly re-occurrences of disease
introductions in an ever more connected world.
This study was supported by the CGIAR research program on WHEAT agro-food systems and
the Australian Center for International Agriculture Research (ACIAR). The funders had no
role in study design, data collection and analysis, decision to publish, or preparation of the
manuscript. The views expressed here are those of authors and do not necessarily reflect the
views of the funders or associated institutions. The usual disclaimer applies and the authors
are responsible for any remaining errors and inferences.
Conceptualization: Gideon Kruseman.
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Data curation: Kai Sonder.
Formal analysis: Khondoker Abdul Mottaleb.
Investigation: Paritosh Kumar Malaker.
Software: Kai Sonder.
Supervision: Gideon Kruseman, Hans-Joachim Braun, Olaf Erenstein.
Validation: Thakur Prasad Tiwari, Naresh C. D. Barma, Paritosh Kumar Malaker.
Writing ± original draft: Khondoker Abdul Mottaleb, Pawan Kumar Singh, Kai Sonder.
Writing ± review & editing: Gideon Kruseman, Hans-Joachim Braun, Olaf Erenstein.
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1. Mason N.M. , Jayne T.S. and Shiferaw B. ( 2015 ). Africa's Rising Demand for Wheat: Trends, Drivers, and Policy Implications . Development Policy Review , 33 ( 5 ): 581 ± 613 .
2. Mottaleb K.A. , Rahut D.B. , Kruseman G. , Erenstein O. ( 2018 ). Wheat production and consumption dynamics in an Asian rice economy- The Bangladesh case . European Journal of Development Research . https://doi.org/10.1057/s41287-017-0096-1.
3. UN (The United Nations). ( 2015 ). World population prospects, the 2015 revision . New York: Department of Economics and Social Affairs. Available from URL: http://esa.un.org/unpd/wpp/Download/ Standard/Population/, [Accessed 06, April 2016 ].
4. FAO (Food and Agriculture Organization of the United Nation) . ( 2011 ). The State of the World's Land and Water Resources for Food and Agriculture: Managing system at risk . Rome: FAO. Available from URL: http://www.fao.org/docrep/015/i1688e/i1688e00.pdf, [Accessed 07 April , 2016 ].
5. FAO (Food and Agriculture Organization of the United Nations) . ( 2016 ). FAOSTAT: Crop and livestock products and Crops . Rome: Food and Agriculture Organization of the United Nations . Available from URL: http://www.fao.org/faostat/en/#data/QC, [accessed January 10, 2016 ].
World Bank. ( 2016 ). World Development Indicators: Arable land (hectare/capita), internally renewable fresh water (cubic meter/capita) . Washington DC: World Bank. Available from URL: http://data.
worldbank.org/indicator/NY.GDP.PCAP.CD?view=chart, [Accessed 06, April 2016 ].
7. Malaker P.K. , Barma N.C.D. , Tiwari T.P. , Collis W. J. , Duveiller E. , Singh P.K. , et al. ( 2016 ). First report of wheat blast caused by Magnaporthe oryzae pathotype Triticum in Bangladesh . Plant Disease , 100 ( 11 ): 2330 .
8. Callway E. ( 2016 ). Devastating wheat fungus appears in Asia for the first time . Nature , 532 : 421 ± 422 . https://doi.org/10.1038/532421a PMID: 27121815
9. Islam M.T. , Croll D. , Gladieux P. , Soanes D.M. , Persoons A. , Bhattacharjee P. , et al. ( 2016 ). Emergence of wheat blast in Bangladesh was caused by a South American lineage of Magnaporthe oryzae . BMC Biology , ( 2016 ) 14 : 84 . https://doi.org/10.1186/s12915-016 -0309-7 PMID: 27716181
10. Sadat A.M. , Choi J . ( 2017 ). Wheat Blast: A new fungal inhabitant to Bangladesh threatening World . Plant Pathology Journal , 33 ( 2 ): 103 ± 108 . https://doi.org/10.5423/PPJ.RW. 09 . 2016 .0179 PMID: 28381956
11. Saharan M.S. , Bhardwaj S.C. , Chatrath R. , Sharma P. , Choudhary A.K. , Gupta R.K. ( 2016 ). Wheat blast diseaseÐAn overview . Journal of Wheat Research , 8 ( 1 ): 1± 5 .
12. Choudhary A.K. , Saharan M.S. , Aggrawal R. , Malaker P.K. , Barma N.C.D. , Tiwari T.P. , et al. ( 2017 ). Occurrence of wheat blast in Bangladesh and its implications for South Asian wheat production . Indian Journal of Genetics and Plant Breeding 77 ( 1 ):1± 9 .
13. World Bank. ( 2017 ). World Development Indicators 2017 : Poverty headcount ratio at USD1.90 a day (2011 PPP) % of population . Washington D.C.: The World Bank. Available from URL: http://databank. worldbank.org/data/reports.aspx?source=world-development-indicators, [accessed January 10 , 2017 ].
14. Das , S. 2017 . Wheat Blast disease enters India from Bangladesh, ICAR official says damage contained . The Financial Express, March 6 , 2017 . Available online: http://www.financialexpress.com/india-news/ wheat-blast-disease-enters-india-from-bangladesh-icar-official-says-damage- contained/576247/ [accessed March 28 , 2017 ].
15. The Hindu Business Line (India) . 2017 . Deadly wheat blast disease hits Bengal . March 09 , 2017 . Available online: http://www.thehindubusinessline.com/economy/agri-business/ deadly-wheat-blast-diseasehits-bengal/article9578083 .ece, [accessed March 28 , 2017 ].
16. Timsina J. , Connor D.J. ( 2001 ). Productivity and management of rice-wheat cropping systems: issues and challenges . Field Crops Research 69 , 93 ± 132 .
17. Erenstein O. , Thorpe W. ( 2011 ). Livelihoods and agro-ecological gradients: A meso-level analysis in the Indo-Gangetic Plains, India . Agricultural Systems 104 , 42 ± 53 .
18. Igarashi S , Utiamada C.M. , Igarashi L.C. , Kazuma A.H. , Lopes R.S. ( 1986 ). Pyricularia em trigo. 1 . Ocorrência de Pyricularia sp. no estado do Parana. Fitopatol Bras 11 : 351 ± 352 .
19. Duveiller E. , He X. , and Singh P.K. ( 2016 ). Wheat Blast: An Emerging Disease in South America Potentially Threatening Wheat Production . World Wheat Book, Volume 3. A History of Wheat. Bonjean A. and van Ginkel M. (Eds.) Pages 1107 ± 1122 . Lavoisier , Paris, France.
20. Urashima A.S , Grosso C. , Stabili A. , Freitas E. , Silva C. , Netto D. , et al. ( 2009 ). Effect of Magnaporthe grisea on seed germination, yield and quality of wheat . In: Advances in Genetics, Genomics and Control of Rice Blast Disease. Springer, Pages 267 ± 277 .
21. Maciel J.L.N. 2011 . Magnaporthe oryzae, the blast pathogen: current status and options for its control . In: Hemming D (ed) Plant Sciences Reviews. CABI , UK, pp 233 ± 240 .
22. Farman M. , Peterson G. , Chen L. , Starnes J. , Valent B. , Bachi P. , et al. ( 2017 ). The Lolium pathotype of Magnaporthe oryzae recovered from a single blasted wheat plant in the United States . Plant Disease , 101 ( 5 ): 684 ± 692 .
23. Gaulart A.C.P. , Paiva F. de. A. ( 1990 ). Transmission of Pyricularia oryzae by wheat (Triticum aestivum) seeds . Fitopatol Brasileira , 15 : 359 ± 362 .
24. Maciel J.L. , Ceresini P.C. , Castroagudin V.L. , Zala M. , Kema G.H. , McDonald B.A. ( 2014 ) Population structure and pathotype diversity of the wheat blast pathogen Magnaporthe oryzae 25 years after its emergence in Brazil . Phytopathology, 104 ( 1 ): 95 ± 107 . https://doi.org/10.1094/PHYTO-11-12-0294 -R PMID : 23901831
25. Cruz CD , Peterson GL , Bockus WW , Kankanala P , Dubcovsky J , Jordan KW , et al. ( 2016 ) The 2NS translocation from Aegilops ventricosa confers resistance to the Triticum pathotype of Magnaporthe oryzae . Crop Sci 56 : 990 ± 1000 . https://doi.org/10.2135/cropsci2015. 07 .0410 PMID: 27814405
26. CastroagudÂõn V.L. , Ceresini P.C. , de Oliveira S.C. , Reges J.T.A. , Maciel J.L.N. , Bonato A.L.V. , et al. ( 2015 ). Resistance to QoI fungicides is widespread in Brazilian populations of the wheat blast pathogen Magnaporthe oryzae . Phytopathology , 105 ( 3 ): 284 ± 294 . https://doi.org/10.1094/PHYTO-06-14-0184 - R PMID : 25226525
27. Duveiller E , Hodson D , Sonder K , von Tiedemann A. 2011 . An international perspective on wheat blast . Phytopathology 101 : S220 .
28. Cruz C.D. , Magarey R.D. , Christie D.N. , Fowler G.A. , Fernandes J.M. , Bockus W.W. , et al., 2016 . Climate suitability for Magnaporthe oryzae Triticum pathotype in the United States . Plant Disease 100 , 1979 ± 1987 .
29. ANAPO (AsociacioÂn de Productores de Oleaginosas y Trigo). 2012 . Manual de recomendaciones teÂcnicas±Cultivo de trigo, 2012 . Santa Cruz (Bolivia): ANAPO (AsociacioÂn de Productores de Oleaginosas y Trigo): 120 .
30. FAO (Food and Agriculture Organization of the United Nations) . 2016 . Wheat blast in South-Western Bangladesh . Field visit report. Unpublished document . Dhaka: FAO.
31. Burke M.B. , Lobell D.B. , Guarino L. , 2009 . Shifts in African crop climates by 2050, and the implications for crop improvement and genetic resources conservation . Global Environmental Change , 19 ( 3 ): 317 ± 325 .
32. Thornton P.K. , Jones P.G. , Ericksen P.J. , Challinor A.J. , 2011 . Agriculture and food systems in subSaharan Africa in a 4ÊC+ world . Philosophical Transitions of the Royal Society A , 369 : 117 ± 136 .
33. Leibing C. , Signer J ., van Zonneveld M. , Jarvis A. , Dvorak W. , 2013 . Selection of provenances to adapt tropical pine forestry to climate change on the basis of climate Analogs . Forests 2013 , 4 ( 1 ): 155 ± 178 .
Webb L.B. , Watterson I. , Bhend J. , Whetton P.H. , Barlow E.W.R. 2013 . Global climate analogues for winegrowing regions in future periods: projections of temperature and precipitation . Australian Journal of Grape and Wine Research , 19 ( 3 ): 331 ± 341 .
35. Berry P. , Ramirez-Villegas J. , Bramley H. , Mgonja M.A. , Mohanty S. , 2014 . Regional impacts of climate change on agriculture and the role of adaptation . In Jackson M. , Ford-Lloyd B. and Parry M . (eds.) Plant Genetic Resources and Climate Change . Wallingford (UK): Cabi International.
36. Kellet J. , Hamilton C. , Ness D. , Pullen S. , 2015 . Testing the limits of regional climate analogue studies: An Australian example . Land Use Policy 44 : 54 ± 61 .
37. Pugh T.A.M. , Muller C. , Elliott J. , Deryng D. , Folberth C. , Olin S. , et al., 2016 . Climate analogues suggest limited potential for intensification of production on current croplands under climate change . Article number: 12608. Nature Communications 7 . https://doi.org/10.1038/ ncomms12608 RamÂõrez-Villegas J. , Lau C. , KoÈ hler A-K. , Signer J. , Jarvis A. , Arnell N. , et al. 2011 . Climate analogues: finding tomorrow's agriculture today . Working Paper no. 12 . Cali , Colombia: CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS) . Available from URL: https://ccafs.
cgiar.org/sites/default/files/assets/docs/ccafs-wp-12 - climate-analogues-web.pdf, [accessed January 28 , 2017 ].
Bangladesh Bureau of Statistics (BBS) . 2014 . Estimates of Wheat, 2013 ± 14 . Dhaka: Agriculture Wing, Bangladesh Bureau of Statistics, Ministry of Planning, Bangladesh. Available from URL: http://203.112.
218.65/WebTestApplication/userfiles/Image/Agriculture/wheat2013- 14 .pdf, [Accessed December 14 , 2016 ].
Government of India . 2017 . Crop Production Statistics for Selected States , Crops, and Range of Years.
Crop Production Statistics Information System. Special Data Dissemination Standard Division . New Delhi: Directorate of Economics & Statistics, Ministry of Agriculture and Farmers Welfare. Available from online: http://aps.dac.gov.in/APY/Public_Report1.aspx, [accessed on June 27 , 2017 ].
Government of Sindh (Pakistan) . 2016 . Final Estimates of Wheat Crop of Sindh Province for Year 2014 ± 15 . Karachi (Pakistan): Agriculture, Supply and Prices Department , Agriculture Department, Government of Sindh. Available from URL: http://www.sindhagri.gov.pk/wheats.html, [Accessed December 15 , 2016 ].