Fall armyworm, destroyer of maize farms, causes concern in India

  • After ravaging cornfields of sub-Saharan Africa, the fall armyworm arrived in India in 2018. The pest infestation has already spread to most parts of the subcontinent and has been reported from maize farms in 20 states.
  • A native of America, the fall armyworm has spread through trade routes to Africa and Asia. There is no single solution to get rid of this voracious eater of maize plants, and scientists suggest a multi-pronged approach depending on geographical location and extent of the infestation.
  • Maize monoculture and overuse of pesticides that increase resistance have turned the fall armyworm into a serious pest. A shift towards agro-ecological approaches like organic and natural farming, and multiple cropping systems could help in managing the outbreak.

Maize farmers in many parts of Karnataka were taken by surprise in July last year when an unknown caterpillar attacked their crop. It didn’t take scientists long to identify the new pest. By the second week of July, researchers from the National Bureau of Agricultural Insect Resources (NBAIR), an institute under the Indian Council for Agricultural Research, said the new pest was the Fall Armyworm (FAW).

Spotted in a maize field in Chikkaballapur, some 60 km from state capital Bangalore, the appearance of FAW in India is a cause for serious concern. Native to tropical and subtropical regions of the Americas, the dreaded caterpillar appeared and spread rapidly in Africa in 2016, and has since then devastated millions of hectares of maize crop in all parts of sub-Saharan Africa.

Read more: Pest responsible for food crisis in Africa reaches Karnataka

And sure enough, the worm spread very fast through the maize fields of India as well. In a matter of months, more than 14 states in the country reported the infestation last year, seriously compromising the corn harvest. The infestation has since spread even wider this year to 20 states, with the northeastern parts of the country the worst affected.

The caterpillar stage of a moth, the FAW (Spodoptera frugiperda) is a voracious eater of maize plants and has been termed as an invasive species by scientists. It’s not a picky eater though. Besides corn, it likes to feed on the leaves and stems of more than 350 plant species, including rice, sorghum, sugarcane and wheat.

An adult female moth can lay up to a thousand eggs in her lifetime. They are also terrific fliers and can travel up to 100 km in a single night.

The moth stage of fall armyworm on a maize plant. The pest infestation has been reported from maize farms in 20 states in India. Photo from Plantix.

Fast spread

The spread of FAW through the Indian subcontinent has been particularly fast. In 2019, the pest has spread as far as Mizoram in the northeast, Uttar Pradesh in the north, Gujarat in the west, Chhattisgarh in central India, and several states in the south. This year, the biggest victims so far have been farmers in the northeastern states, where a cumulative of 10,772 hectares of maize crop has been affected. The pestilence has been reported from 20 states in India.

Read more on fall armyworm invading northeast India

Scientists are not surprised at the fast transmission of FAW. “We have already seen in Africa that the infestation spread from one country, Nigeria, to almost half of the continent in a matter of two years (2016-2018),” said Malvika Chaudhry, regional coordinator, Plantwise Asia, Centre for Agriculture and Bioscience International (CABI).

The northeastern states with their “high humidity and moderately high temperatures” are suitable for the spread of FAW. Its metabolic rate is well supported in these conditions, sometimes even leading to “intensification of infestation,” said Chaudhry. It means that the pest is able to complete its lifecycle in a shorter period of time, resulting in more pests, more quickly.

Farmers and scientists are now fighting to contain the infestation. Maize is India’s third most important cereal crop after rice and wheat. In 2016, 25.9 million metric tons of maize was produced in India. In 2017, that number rose to 28.7 million tons. In 2018, however, production fell by 3.2% to 27.8 million tons. It is expected that the net production will decline further in 2019 due to the pest attack.

Fall armyworm (Spodoptera frugiperda) larva on maize cob. The larvae, which are marked with a distinct inverted "Y" on the front of the head, feed on a wide variety of plants. Photo by Phil Sloderbeck/Kansas State University/ (CC BY-NC 3.0 US)
Fall armyworm (Spodoptera frugiperda) larva on maize cob. The larvae, which are marked with a distinct inverted “Y” on the front of the head, feed on a wide variety of plants. Photo by Phil Sloderbeck/Kansas State University/ (CC BY-NC 3.0 US)

Cascading effect

Although corn is not a staple in India, it serves an important role as feed for poultry. The growth in the poultry industry has resulted in a concomitant increase in the area cultivated under maize since the turn of the millennium. The decrease in maize production thus has a cascading effect on the poultry industry.

Earlier in August, poultry farmers in Karnataka and Maharashtra urged Narendra Singh Tomar, India’s farm minister, to urgently import maize to meet a shortfall. Due to the deficit, maize prices have shot up, resulting in an increase in production cost for chicken and eggs.

Its not just the feed and starch industries that are feeling the heat. Maize farmers maize are too facing additional challenges in continuing to grow the crop. They’ve had to endure crop losses and bear the additional cost of rescuing their crop from FAW and preventing further infestation.

“The input cost of growing maize has gone up,” said Bhagirath Choudhary, founder-director of South Asia Biotechnology Centre (SABC), a New Delhi-based scientific organization. In addition to the usual input cost, farmers have to spend on pheromone traps, safety kits, botanical and biological control methods and more pesticides.

In addition to their price, most of these items attract high taxes to the tune of 18 percent. Only botanical and biological controls are taxed at five to 12 percent. For farmers, especially smallholders, these costs are punitive. “The SABC has submitted a request to the Union Minister of Finance, Nirmala Sitharaman, to either completely exempt GST (Goods and Services Tax), or reduce it to the lowest slab on these items,” said Choudhary.

Worryingly, FAW seems to have spread to crops other than maize as well. For example, scientists noticed FAW infestation on sorghum and bajra (millet) in the fields of an agricultural research station at Ananthapuramu in Andhra Pradesh in October 2018. The researchers noted that the pest was gradually spreading to other millets grown in Ananthapuramu district.

In another report, researchers from Maharashtra noted FAW’s presence in sugarcane and sorghum. A statement by the Ministry of Agriculture and Farmer Welfare on June 25 confirmed FAW infestation on sorghum and ragi (finger millet). The only consolation of sorts is that the spread in these crops has not been as rapid as than in corn.

Fall armyworm larvae feeding on a maize crop. Photo from Plantix.
Fall armyworm larvae feeding on a maize crop. Maize monoculture and overuse of pesticides that increase resistance have turned the fall armyworm into a serious pest. Photo from Plantix.

Stopping FAW’s march

In 2018, when the pest attack first started, most farmers were unfamiliar with FAW. On Plantix, an AI-based farmer assistance mobile application where farmers can ask questions, farmers in 2018 were mostly asking to identify the pest, according to Sairekha Kadirimangalam, who works for Plantix in Hyderabad. However, as FAW starting spreading in India, the nature of queries changed. Maize farmers are now looking for solutions to stop the pest from damaging the crop, Kadirimangalam said.

There is no silver bullet to stop FAW in its tracks. A good monitoring system and farmer awareness about the pest are the first steps, said Chaudhry. “Sometimes, when confronted with the pest suddenly, farmers tend to panic and spray their fields with an array of chemicals,” she said. “This panic response is not just ineffective but also leads to broad-spectrum resistance in the pest, and should be avoided.”

“The first thing they (farmers) should do is to contact the nearest Krishi Vigyan Kendra (agricultural extension center) or state department’s agriculture officials,” said A.N. Shylesha, principal scientist, Entomology, NBAIR. Based on geography and extent of infestation, ICAR recommends a variety of solutions, which include mechanical, biological and chemical measures. For example, the infestation is in its early stages can be controlled by using bio-control agents like Trichogramma and Telenomus, and providing good nutrition to the plants. It is only when the infestation is severe that chemicals are recommended.

As FAW continues its march across India and other Asian countries, the need for effective protective measures will only grow stronger. “Increasing monoculture of maize around the year and wrong pest management practices with excessive dependence on chemical pesticides, which increased the resistance in the insect to pesticides, have contributed to FAW becoming a serious pest,” said G.V. Ramanjaneyulu, executive director of the Centre for Sustainable Agriculture, which works with smallholder farmers. “Any pest is always a function of practices followed and local weather conditions. Therefore, a shift towards agro-ecological approaches like non-pesticidal management, organic or natural farming, and multiple cropping systems are the ways to manage such pest outbreaks.”

Banner image: A native of America, the fall armyworm has spread through trade routes to Africa and Asia. Photo from Plantix.

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