Fall Armyworm attack: The damage done
The deadly but little understood crop pest, poses a threat to food security and livelihoods of millions as it ravages crops in Africa and now Asia
By the time the infestation was detected, it had already become malignant. Khemo Baghel, a farmer of Bade Chakwa village in Chhattisgarh’s Bastar district, took up maize cultivation for the first time early this year. He dug a borewell and was convinced that the return from maize would be better than any other crop. But hardly had the seeds sprouted, he saw some keedas (worms) slowly colonising his farm. “I detected them one morning. There was no trace of them the previous day. I think they landed at night,” he narrates. Within two months, the keedas had a firm grip on his farm, taking away 30 per cent of his maize crop.
Uncertainty hovers over the village as other maize farmers report the presence of this hitherto-unseen insect. Now agriculture scientists and extension officers frequent Bade Chakwa and neighbouring villages and they too are puzzled. But by now, the outlier has a local name: “American keeda”.
In January 2019, Chhattisgarh became the latest state to report the infestation of Fall Armyworm (FAW). As Down To Earth (DTE) reporter travelled across Bastar, a district ravaged by the decades old bloodbath between the Maoists and the security forces, the insect emerged as the focal point of most conversations. In Palari village, the American keeda has damaged the entire maize crop. “I have been farming for four to five years, but have never noticed this insect. Pesticides are not effective on them,” says Parmeshwar Pandey.
In just nine months since FAW was spotted in India in Karnataka last June, it has invaded crops in over 10 states. As if taking a pre-scripted route, FAW infestation has spread from Karnataka to all southern states; then to western Maharashtra and Gujarat; and now to eastern states. Besides advancing fast, the pest is also attacking new crops. Though it is being detected mostly in maize crops—a preliminary calculation estimates it has affected nearly 170,000 hectares (ha) of maize crops—there have been reports from states where it has infested paddy, sugarcane and sweet corn. Maize is the third most important cereal crop in India after rice and wheat. It accounts for 9 per cent of the total food grain production in the country.
Entomologists CM Kalleshwara Swamy and Sharanabasappa first detected FAW in the research fields of maize at the University of Agricultural and Horticultural Sciences, Shimoga, Karnataka. Just before the monsoon last year, a few maize farmers from Chikballapur district of the state reported a pest infestation to A N Shylesha, scientist at the National Bureau of Agricultural Insect Resources (NBAIR). Shylesha took it to be the True Armyworm infestation. But the severity in the infestation led him and his colleague SK Jalali to conduct a survey of the affected fields and collect samples in July 2018. At the end of the month came the confirmation, and a challenge in the form of the country staring at its first FAW infestation. The Fall Armyworm or Spodoptera frugiperda is more dangerous than the True Armyworm.
A sojourn out of its native
The up to 2-cm long pest “accidentally” landed in Africa in 2016 from the Americas, almost after 100 years. Since then, it has spread to over 50 countries in Africa and Asia ravaging crops, especially maize. In 2018, it invaded Asia through Yemen and India and has now spread to Bangladesh, Myanmar, Nepal and China (see 'At war'). A rapid breeder, the insect is known to eat 300 species of plants, most of which are major food crops. It has diversified its diet and can survive harsh conditions by migrating to different places or hiding, to spring back when conditions are favourable. Its wide dietary platter along with its phenomenal spread across two continents in just the last two years has made FAW an agent of global food production crisis.
In Andhra Pradesh’s Institute of Frontier Technology — an affiliate of the Acharya NG Ranga Agricultural University (ANGRAU) in Tirupati — crop researchers are a worried lot as the news of infestation has turned from a trickle to a deluge. It was first identified in Andhra Pradesh in August 2018 when it affected maize growing areas of East and West Godavari districts, Srikakulam and Vizianagaram. “With maize seed production being a major crop in Godavari district, it can have serious economic consequences. Being a major ingredient for the poultry and cattle feed, production losses in maize could cripple meat and milk production,” says M John Sudheer, principal scientist at ANGRAU.
Their immediate concern is whether the pest would start attacking millets and cereals like bajra, jowar, ragi and others. “The lifecycle of the worm can range from 30 to 45 days. In winter, the cycle can extend up to even 90 days. With continuous overlapping generations the worm can be seen in all stages at the same time. This makes it difficult to manage the pest,” says Sudheer.
K Bhupathi Reddy, a maize farmer in Mallayapalli near Tirupati in Chittoor district of Andhra Pradesh, always treated maize as a farmer-friendly crop. The investment is low and there is a ready market for the crop. After selling the maize, the fodder (45-50 tonnes per ha) can fetch Rs 2,000 per tonne from nearby cow shelters. “I have already spent Rs 20,000 for controlling these pests this season,” he says, adding that it is still not sufficient. Agriculture officials suggested crop rotation. But the infestation has jumped to other crops as well.
In Tamil Nadu, FAW has been confirmed in sugarcane crops in two districts, a first for the country. “Our entomologists visited Erode and Karur districts and have confirmed the presence of Spodopetra frugiperda. They also assessed the levels of damage to crop,” Bakshi Ram, director of the Coimbatore-based ICAR-Sugarcane Breeding Institute, stated in his letter to the State Directorate of Agriculture in December 2018. Speaking to DTE, Ram says, “Our team found FAW in four fields of the two districts. The infestation is not very serious and can be managed if farmers are made aware.”
In neighbouring Madhya Pradesh, FAW has infested crops in 13 out of the 52 districts. The worst affected are the agriculturally prosperous regions of Malwa, Mahakoshal and Baghelkhand. DTE reporter spoke to over 30 farmers over phone to gauge the extent of the damage. While all the farmers said that FAW is rapidly spreading, the state is yet to ascertain the scale of crop damage. Agriculture officials at the Krishi Vikas Kendras, however, confirm a gradual increase in the number of farmers reporting infestation in maize and soyabean crops.
Malvika Chaudhary from the Centre for Agriculture and Bioscience International (CABI) says, “Karnataka and Tamil Nadu are currently witnessing greater infestation. But taking into account environmental conditions and availability of host species the eastern side of India is more vulnerable to the pest in the near future.” Her forecast is already showing signs of coming true. During kharif 2018, the central government sent an alert to the agriculture department in Odisha saying that maize cultivation in some states had been attacked by FAW and the department needed to undertake a survey in maize-growing districts in the state. The Odisha government formed a committee under the chairmanship of agriculture director M Muthukumar to check the worm's spread. “The committee has taken a decision to regularly monitor and supervise the maize growing districts of the state and to create awareness among field level officials and farmers about the pest,” says Muthukumar.
In Maharashtra, FAW was first detected on August 29, 2018, in a maize field at Tandulwadi village in Solapur district by farmer Ganesh Babar. “Today, six months later, the infestation has spread across Maharashtra in Vidarbha, Marathwada and especially in western Maharashtra,” says Ankush Chormule, agronomist and entomologist of the 6th Grain Corporation. “In close to 15 districts of Maharashtra surveyed by the 6th Grain Corporation, the presence of the worm has been confirmed,” he adds.
“In India, FAW has already damaged crops in Karnataka, Andhra Pradesh, Telangana and Tamil Nadu. The damage caused by FAW is colossal as it has 30 to 40 days life cycle and one moth can lay up to 1,000 eggs at one time. The FAW larva scrapes out leaves causing a lot of damage to the crop,” says Chormule.
It is a double whammy for farmers. For one, there is a surge in expenditure and concurrently, there is a distinct fall in the crop yield. Babar, for instance, has suffered a 10 per cent loss in profit in the last year—translating into a production loss of 0.5 to 0.75 tonne per ha. Owing to this damage caused by the worm and the concurrent dearth, maize that earlier sold at Rs 12,000 per tonne is now being sold almost at Rs 19,000 per tonne. The yield has dipped drastically owing to drought and infestation. This is expected to continue, or get worse in 2019. As a result, India will have to increase the import of maize. The shift to imports in the world’s seventh largest maize producer, which typically exports to Asia, highlights the breadth of the crop losses due to FAW.
In Telangana, it is an unheard of situation. Though it is one of India’s traditionally non-maize areas, to earn more in face of drought farmers switched to maize in a big way: 0.5 million ha are under this crop. It is also covered under the government’s minimum support price (MSP) regime. FAW has infested maize crops in all the districts. Mora Sudarshan Patel of Kuntala village in Nirmal district has destroyed 0.8 ha of his maize crops while Kadam Avadhuta Rao of Penchikalapadu village destroyed crop in 1.2 ha to arrest FAW infestation. “Once we reaped good harvest of chili. Vagaries of market played havoc with us. We adopted maize which looked promising. FAW has upset the precarious economy of small and marginal farmers,” says Patel.
The situation in Nizambad district is worse. The farmers here have been on warpath demanding MSP for red jowar and turmeric—a replacement crop for maize lost to FAW. At the time of writing of this article on February 16, thousands of farmers from Armoor and Nizambad division laid siege to National Highway 44 demanding procurement of red jowar and turmeric by the government. Aleti Naveen Reddy of Mantena village, who also took part in the agitation, is planning a fast unto death to put pressure on the state government to deliver the promise it made at the time of the Assembly elections.
What is alarming is that FAW has started hopping to other crops as well. The DNA bar-coding test of 44 samples collected from as many as eight districts has conf irmed that paddy (Karimnagar), chickpea (Adilabad), jowar (Vikarabad) and groundnut (Nagarkurnool) are under attack.
C Parthasarathi, principal secretary, agriculture says that the maize crop damage was observed in about 15 districts. During rabi season 2018-19, the incidence of pest ranged from 5 per cent to 45 per cent. “FAW was noticed in maize in extent of 17,394 ha out of 462,322 ha actual sown area in kharif 2018. During rabi 2018-19 the pest was noticed in 22,072 ha out of 78,982 ha of actual sown area,” Parthasarathi informs. Though the extent of crop loss is not available officially, Ramanjaneyulu, scientist and director, Centre for Sustainable Agriculture, who studied the pest extensively, from the economic perspective, puts the loss at 30 per cent in kharif. “Prolonged monoculture, supported by powerful pesticides have destroyed the natural enemies of the pest. Long dry spells coupled with too many bouts of overcast sky have made maize susceptible to pest attack. Enough is enough, the government should encourage farmers to migrate to pulses and oil seeds before it is too late,” Ramanjaneyulu says.
Parthasarathi says the foreign pest has thrown up a challenge before the scientific community. “The pest behaviour varies from region to region and season to season. The scientists should study the behaviour of the pest in different environments and come up with a forecast for every season,” he says, forewarning that the outbreak of FAW might not confine to maize alone and it could invade other crops as well once the maize harvest is completed. “The ball now is in the court of agricultural scientists,” he says.
Small farmers are the most vulnerable
Tackling the moth is vital for food security and livelihood needs
The arrival of FAW in India has made it clear that the pest will cause destruction globally. Just two years after it entered Africa, the pest reached its second continent—Asia. It will now enter other Asian countries including China, the second largest maize-producing country. “FAW could have a devastating impact on Asia's maize and rice producers—mostly small-scale farmers who depend on their crops for food and to make a living. This is a threat that we cannot ignore,” says Kundhavi Kadiresan, FAO assistant director- general and regional representative for Asia and the Pacific. Maize is a staple crop essential for food security in large parts of Asia and Africa. In early 2016, strains of FAW were first spotted in Nigeria, after the moth probably crossed the Atlantic in cargo containers or airplane holds before being dispersed by the wind, a 2017 report, Fall Armyworm: Impacts and Implications for Africa, by the Centre for Agriculture and Bioscience International (CABI) says. Now, the pest has spread to 44 African and six Asian countries.
Trail of destruction
Even before FAW ravaged maize fields in Africa, COOPROMASA—a maize farmers’ cooperative in eastern Rwanda—had warned of a major pest attack. In 2015, tentatively a year before the pest officially arrived, the cooperative’s officials found that the production of maize had reduced from 4 tonnes per ha to 3 tonnes per ha. Two years later, the moth was identified at Mushishito Marshland in Nyamagabe district of Rwanda. Due to limited research and the absence of early detection, it spread quickly. By the end of April 2017, outbreak was reported in all 30 districts where the pest had infested an estimated 40 per cent of maize crops.
Farmers need to worry as the female moth lays between 1,000 and 2,000 eggs on crop leaves that give birth to destructive caterpillars. Rwanda’s agriculture minister Geraldine Mukeshimana says that the pest still poses a threat to farmers, though many have learnt to deal with it. One of the ways is to destroy the caterpillars by hand. Spraying on infested crops is another measure. But it is expensive. Farmer John Muvara from Nyagatare district of Rwanda applied pesticides on 12 ha of maize which cost him over $1,100. In March 2018, the government, along with FAO, launched a campaign to install pheromone traps to lure and catch the male moths to control their population.
Kenya also took measures to contain the pest. In December 2017, government authorities at Embu, located 120 km northeast of Nairobi, hired men to manually kill the caterpillars. FAO also partnered with the government in a pilot project to try out new control methods. None of the measures, however, proved effective. Overall, 43 of the 47 counties reported the presence of the moth. The country lost up to 20 per cent of its projected maize yields, equivalent to 7.5 to 8 million bags of grains. This was enough to feed the citizens for two long months.
In Ethiopia, more than 0.6 million ha of maize was damaged last year. Uganda was infested too. By mid-2017, the worm was present in all its 127 districts, causing 15 to 75 per cent crop loss. An estimated 450,000 million tonnes of maize worth $192 million was hit.
Weather determing factor
Though a major threat, the moth needs conducive weather conditions to survive. It cannot tolerate extreme temperatures or excess rainfall. In sub-Saharan Africa (SSA), Lesotho has been saved due to cold temperatures. The pest cannot resist Sahara's heat either. Kenya got respite by the onset of heavy rains in March 2018. “The rains seemed to have broken the lifecycle of the moth, which usually attacks crops during its larval stage,” Miltone Ayieko, director, Tegemeo Institute of Agricultural Policy and Development, a research think-tank of Egerton University in Kenya, told Down To Earth.
According to FAO, the worm feeds on 80 crop species. But it seems to thrive on maize. Stephen Mugo, principal scientist at the International Maize and Wheat Improvement Centre’s Africa unit in Nairobi, explains that regions in the north eastern part of Kenya and neighbouring Somalia and Ethiopia, which do not grow maize, did not report the pest.
Tackling FAW infestation is vital for food security in Africa. In SSA, a region already ravaged by drought and food shortage, the larvae attack can leave 300 million people hungry, warns Bukar Tijani, FAO assistant director-general and regional representative for Africa. To prevent the moth from spreading to northern Africa, southern Europe and the Near East, a massive campaign is needed to train over 0.5 million farmers in pest management in SSA.
If farmers' yields dip, it would result in deficit of 16 million tonnes of maize, worth nearly $5 billion. CABI says that in the absence of proper control methods, the moth has the potential to cause yield losses between 8.3 and 20.6 million tonnes per year in 12 of Africa’s major maize-producing countries.
Anatomy of the worm
The pest's ability to adapt and the changing local weather are emerging as two important aspects requiring microscopic research
In the initial reports from Karnataka the cobs were not infested but in later stages the cobs were also infested by the larvae. The adult moths also feed on the plants. “FAW moths are nocturnal in habit. They gather together in large numbers like an army and go to cultivated fields and cut the stems and feed on the leaves. They also completely defoliate (make leafless) the fields so only the veins remain after the infestation. This also leads to rotting of the produce as it gets infected by other fungus,” says AK Chakravarthy, former head of entomology at the Indian Institute of Horticultural Research (IIHR).
Two characteristics make it a dangerous pest. First is its ability to spread quickly over vast areas. Some scientists have speculated that it might have travelled to India with the monsoon winds from Africa. The adult moth is a fast flyer and can cover 100 km a night and winds are not an impediment. But it’s not possible that the insect could have flown the distance of roughly 7,000 km between South America and Africa. It might have spread because of the entry of contaminated cargo in Nigeria from America. Now experts like Shylesha’s team at the NBAIR are conducting molecular DNA analysis to ascertain how exactly it got here. This study will also inform about the strain of the worm that has entered India.
In Africa there are two strains — one that mostly affects maize and the second that mostly affects rice. As of now the Indian strain has not been identified but this brings us to another looming and major threat. As it travels into new climates and geographies, FAW might be slowly modifying itself genetically, though it has not been confirmed as yet. Shylesha says that we need more research to find out if the species is indeed diversifying. "The initial assessment will take another two-three months while the complete analysis might take more than a year," he says.
The second reason that makes FAW dangerous is its reproductive capacity. A single female can lay 600 to 700 eggs. Under African conditions a female is known to lay 1,600 eggs. The number of eggs increases when there are alternate hosts, which is now the case in India. Warm and humid conditions also help its reproductive capabilities. Temperatures ranging from 15 to 300° Celsius are optimum for egg laying, growth and spread. Extreme temperatures, either hot or cold, are not favourable for the pest but this is where it acts to protect itself. During the harsh winters in northern United States the moths travel down south to warmer states like Texas and Florida and return when the conditions become congenial.
From the initial infestation of maize, the moth has spread to sugarcane, sorghum, different varieties of millets and its diet might further increase as it spreads. The biggest scare is its infestation of rice and unconfirmed reports of that happening have been received by digital platforms like the Plantix app operated by Germany-based artificial intelligence and agriculture start up, Progressive Environmental and Agricultural Technologies (PEAT). The type and extent of infestation depends on the stage or the age of the crop.
“FAW is capable of eating very heavily, more than its body weight. It is also a polyphagous pest, which means that it can feed on more than one species of plants and also diverse species of plants. This is because they have been able to incorporate and digest multiple nutrients and chemical compounds,” explains Chakravarthy. He adds that all monocot plants which have only one embryonic leaf or cotyledon are at risk of infestation. Most food grain crops like maize, rice and millets and other economically important crops like sugarcane are monocots.
Climate change might also be playing a role in the increased risk from FAW. “Under the global warming scenario in India FAW is going to feed more. This will lead to more generations of the insect and early completion of its lifecycle,” says Chakravarthy. The pertinent question is if this notorious pest can be brought under control? Experts feel that this can be done through early detection and subsequent pest management. The Plantix app is helping out farmers all over India with the early detection part. The app gets its inputs from the farmers through photographs of the infestation from the field. Then it uses image recognition and analysis carried out by an artificial intelligence machine to identify the pest correctly. It tells the farmer if the pest that she is looking at is FAW or not. And even if it is not able to give this exact information it gives a list of possible pests which then can be confirmed by a local expert. “Around 6,500 farmers have approached us with photographs through the app and in 90 per cent of the cases we have been able to inform them correctly about the pest,” says Korbinian Hartberger, co-founder of PEAT.
“Wherever FAW infestation is very severe we are recommending the use of Emamectin Benzoate (0.4 grams per litre of water). Where it is mild we are recommending neem formulations. Apart from these we are asking farmers not to use any other chemicals. If timely management practices are initiated, the pest can be controlled, and as of now, in India it has not affected the yield as it did in Africa,” says Shylesha.
(With Inputs from: Africa - Kenya: Maina Waruru, Uganda: Lominda Afedraru, Ethiopia: Abbcha Sew, Rwanda: Christophe Hitayezu; India - Andhra Pradesh: Ram Mohan G, Odisha: Priya Ranjan Sahu, Madhya Pradesh: Anil Ashwani sharma and Harinarayan Gupta, Maharashtra: Gajanan Khergamker, Chhattisgarh: Purusottam Singh Thakur, Telangana: Jinka Nagaraju)
(This story was first published in the March 1-15, 2019 issue of Down To Earth)
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India Environment Portal Resources :
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- Nonsensical choices? Fall armyworm moths choose seemingly best or worst hosts for their larvae, but neonate larvae make their own choices
- Adaptive potential of Fall Armyworm (Lepidoptera: Noctuidae) limits Bt Trait durability in Brazil
- First report of outbreaks of the Fall Armyworm Spodoptera frugiperda (J E Smith) (Lepidoptera, Noctuidae), a new alien invasive pest in west and central Africa