Fall Armyworm Management in Nepal: What Chitwan Maize Farmers Know and Do

What did the Chitwan fall armyworm survey find?

Maize growers in Chitwan district, Nepal, put fall armyworm (Spodoptera frugiperda) among the most important insect pests on their farms, but their response to it is narrow. In a household survey of 60 maize-growing households, 41.7% applied an insecticide, 35.0% did nothing at all, and not one respondent reported a cultural practice (such as adjusted sowing date, intercropping or residue destruction) or a biological control agent. Technical guidance came mainly from fellow farmers and agrovets, and no respondent named a public extension provider.

The study, published in Tropical Agrobiodiversity 7(2): 121–127 (2026), was led by Nirajan Bhandari as first author, with Bishal Neupane as second and corresponding author, and Sachin Chapagain, Ramesh Ayer and Bishal Dhakal as co-authors. It derives from a Learning Entrepreneurial Experience (LEE) report at Agriculture and Forestry University (AFU).

Why does fall armyworm matter for Nepal's maize?

Maize is the second most important cereal crop of Nepal. Fall armyworm, an invasive noctuid moth native to the Americas, was first recorded in Nepal in May 2019, where it is known locally as phauji kira ("army insect"), and it has since been reported from many maize-growing districts, Chitwan among them. The paper summarises why the pest is hard to manage with sprays alone: the larva feeds deep inside the whorl of young maize plants, where an insecticide applied over the canopy reaches it poorly, and later instars are less susceptible than early ones.

The authors argue that farmer practice, rather than the pest itself, is the useful thing to study. What farmers do against a new pest depends on what they know about it, how much damage they believe it causes, and what information reaches them. Chitwan is also a deliberately conservative case: it hosts a Prime Minister Agriculture Modernization Project (PM-AMP) maize zone and lies close to national research and extension institutions, so a gap in practice observed there is likely to be at least as large elsewhere.

How the study was designed

• Design: cross-sectional, descriptive household survey; each respondent reported on their most recent maize crop.
• Location: Bharatpur Metropolitan City (wards 5, 6, 7 and 12), Kalika Municipality (wards 5 and 6) and Ratnanagar Municipality (wards 14 and 15), Chitwan.
• Sample: 60 maize-growing households, selected purposively within purposively chosen wards; one decision-maker interviewed per household.
• Period: March to July 2024.
• Instrument: pre-tested structured interview schedule, administered face to face in Nepali, supplemented by two focus group discussions and key informant interviews.
• Analysis: frequencies and percentages in IBM SPSS and Microsoft Excel; constraints and pests ranked with a five-point weighted index of importance (scale values 1.0, 0.8, 0.6, 0.4, 0.2; index range 0.2–1.0). No inferential test was applied.

The paper is careful with its terms. "Perception" means only perceived relative importance on the priority scale. No knowledge test, attitude scale, or field measurement of incidence, severity or yield loss was made.

How farmers ranked fall armyworm

Insect pests were the top-ranked production constraint (index 0.86), ahead of erratic weather (0.76) and unavailability of irrigation and inputs (0.72). Among five insect pests, fall armyworm ranked second.

The authors read this as one high-importance band of three whorl- and stem-feeding pests rather than a meaningful gap between cutworm and fall armyworm. That matters in the field because damage from the three is easily confused, and a product chosen for one pest may be sprayed against another.

Among respondents familiar with the pest, 81.3% first noticed fall armyworm damage at the knee-high stage, 11.3% at the seedling stage and 7.5% at tasselling. The paper notes that the size of this subgroup was not recorded separately, so these figures indicate a pattern rather than precise prevalence.

What management practices did farmers use?

Farmers named insecticides in a multiple-response question that produced 80 product mentions. Emamectin benzoate (sold as Proclaim) made up 52.0% of mentions, spinosad (Conserve SC) 35.0%, chlorpyrifos (Terminal) 9.0% and spinetoram (Radiant) 4.0%. The botanicals named were jhol mol, a fermented preparation of plant material and cattle urine, and neem leaf extract, used mainly alongside insecticides.

The discussion raises two concerns. First, spinosad and spinetoram are both spinosyns, so switching between Conserve SC and Radiant rotates trade names, not modes of action; about 91% of mentions fall into just two modes of action, which the authors flag as avoidable selection pressure for resistance. Second, chlorpyrifos was banned in Nepal in December 2024, after the survey, so its appearance is a record of practice that is no longer lawful.

Where do farmers get advice?

Experienced fellow farmers were the main source of technical guidance for 65.0% of respondents, agrovets (private input retailers) for 26.7% and cooperatives for 8.3%. No respondent named a government extension service, the Agriculture Knowledge Centre or the PM-AMP maize zone, although all three operate in the district. The authors see this as the most likely explanation for the results: practices that are not already circulating among farmers have no route in, and advice from input retailers is mostly advice about products. Extension reach, not farmer willingness, appears to be the binding constraint.

What this means for farmers and extension workers

The paper closes with three specific recommendations for the agriculture sections of Bharatpur, Kalika and Ratnanagar, working with the Agriculture Knowledge Centre and the PM-AMP maize zone:

1. Field training on telling fall armyworm apart from cutworm and stem borer by symptoms and larval features, timed before the knee-high stage, because early recognition decides whether any control can work.
2. Introducing the cultural parts of the integrated pest management (IPM) package, such as sowing-date management, intercropping and residue destruction, through farmer field schools. These practices are absent from local use rather than rejected.
3. Bringing agrovets into extension planning, with dealer training on registered active ingredients, whorl-directed application and rotation between modes of action.

What this means for researchers

The study is descriptive by design and does not test which farmer characteristics predict adoption of a practice. The authors name this as the most useful next step: a follow-up that tests knowledge and models adoption. Students designing similar perception surveys may find the paper's handling of denominators useful (respondents versus product mentions) and its explicit separation of "perception" from measured incidence. Related survey work from the same group covers maize mechanisation in Gulmi and spring rice decisions in Rautahat.

Limitations

• One district and one recall season, so results describe Chitwan and cannot be generalised to Nepal.
• All data are self-reported; no field scouting, incidence or severity measurement was made.
• Sample of 60 gives a margin of error of about 12.6% at 95% confidence, which limits the precision of every percentage.
• Purposive sampling, possible recall and social desirability bias, and no formal back-translation of the Nepali instrument.
• Cross-sectional and descriptive, so no causal inference about adoption is possible.

How to cite

Bhandari, N., Neupane, B., Chapagain, S., Ayer, R., & Dhakal, B. (2026). Farmers' perception of fall armyworm (Spodoptera frugiperda) and its management practices on maize in Chitwan District, Nepal. Tropical Agrobiodiversity, 7(2), 121–127. https://doi.org/10.26480/trab.02.2026.121.127

The full list of Bishal Neupane's articles is on the publications page, and his survey and analysis methods are described on the methods page. Supervisors or collaborators working on pest management or extension in South Asia are welcome to get in touch through the contact page.