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Fall armyworm (Spodoptera frugiperda) — national status Photo: placeholder pending image-fill pass

Fall armyworm (Spodoptera frugiperda) — national status

Spodoptera frugiperda (J.E. Smith) is a polyphagous noctuid moth native to the Americas that was first reported on maize in India at Chikkaballapur, Karnataka, in May 2018. Within 16 months it spread to every maize-growing state and is now the single most damaging insect pest of Indian maize. ICAR-IIMR Ludhiana coordinates the national IPM response under AICRP-Maize, with CIMMYT-Asia and BISA supporting field protocols.

Identification and symptoms

Larvae are smooth-bodied, pale green to tan, with an inverted white "Y" on the head capsule and four black dots in a square pattern on the eighth abdominal segment. First-instar larvae scrape the leaf surface producing "window-pane" lesions; later instars bore into the whorl producing ragged-edged feeding holes and large quantities of moist frass. In tasseling crops larvae feed inside developing ears, contaminating grain with frass and predisposing it to Fusarium ear rot.

Hosts and life cycle

Maize is the preferred host but the pest also feeds on sorghum, sugarcane, paddy seedlings, cotton, several millets and fodder crops. The life cycle is completed in 30-40 days under Indian conditions: egg masses on the upper leaf surface (3-5 days), larva (14-22 days, six instars), pupa in soil (8-10 days), adult moth (10-15 days). Adults are strong fliers and disperse 100+ km in a few days, explaining the rapid 2018-19 country-wide spread.

Damage and economic impact

Untreated kharif maize crops in southern and central India have shown 30-60% grain-yield losses in pockets, with 100% defoliation on early-whorl-stage seedlings. Late-kharif and rabi crops face lower pressure because cool nights slow larval development. National-scale yield loss is estimated at 9-15% in kharif and 3-6% in rabi. Damage triggered the first mass approval of newer insecticide chemistries on maize in 2019.

Management

The ICAR-IIMR/CIMMYT-Asia IPM package combines:

  • Cultural: timely sowing within the agro-ecological window; deep summer ploughing to expose pupae; intercropping with pigeonpea or pulses; clean-cultivation of weed hosts.
  • Mechanical: pheromone traps (4-5/acre) for monitoring with FAW-specific lure; hand-collection and destruction of egg masses and gregarious first-instar larvae.
  • Biological: release of Trichogramma pretiosum @ 50,000/ha at egg stage; soil-applied or foliar Metarhizium anisopliae and Beauveria bassiana; Telenomus remus egg parasitoid where available.
  • Whorl application: sand + lime (9:1) by hand into the whorl for late-instar smothering — labour-intensive but effective on small plots.
  • Chemical (rotation): spinetoram 11.7% SC @ 0.5 ml/L, chlorantraniliprole 18.5% SC @ 0.4 ml/L, emamectin benzoate 5% SG @ 0.4 g/L. Avoid pyrethroid sprays — they flare FAW by killing natural enemies.

Limitations

Insecticide resistance to lambda-cyhalothrin and chlorpyrifos has been documented in Indian FAW populations by 2022. Spraying after the larva has bored into the whorl gives poor mortality; threshold is 5% damaged plants at early-whorl stage. Bt-maize (Cry1F, Cry2Ab) is not approved for commercial cultivation in India.

See also: Fall Armyworm Maize, Maize Crop Overview, Maize Bihar Rabi Cultivation, Dhm 117 Iimr Maize, Hqpm 1 Iari Quality Protein Maize, Pusa Qpm 5 Hybrid Maize.

Sources

  1. Fall armyworm IPM advisory. ICAR-Indian Institute of Maize Research, Ludhiana. https://iimr.icar.gov.in/?page_id=2392
  2. Fall armyworm management guide for South Asia, 2023. CIMMYT-Asia. https://repository.cimmyt.org/handle/10883/22617