Fall Armyworm (Spodoptera frugiperda) 

Vegetable IPM Fact Sheet

Fall armyworm (FAW) is a pest that is resident in the southern United States. Adult moths migrate to the northeast in June, and remain there until freezing temperatures. In that time, FAW can be a serious problem in corn, damaging ears and greatly reducing yield.

In this fact sheet

  • Appearance of Fall armyworm
  • Signs and symptoms of Fall armyworm
  • Life cycle of Fall armyworm
  • Managing Fall armyworm
A FAW larva about the length of a quarter resting on a corn husk. The larva has a dark colored head marked with an inverted, pale “Y” between its eyes.
One of the most distinct features used to identify FAW larvae is the pale, inverted “Y” in the center of its darker-colored head.

FAW is a pest species that is a year-round resident in warmer areas, such as Florida, Texas, and the tropics of Central and South America. FAW moths migrate further north annually, arriving in the Northeast between early and late July. Depending on temperatures in the late summer and early fall in the Northeast, there may be a partial second generation following the first generation of FAW. Warming climate is contributing to greater frequencies of FAW outbreaks in the northern U.S., while expanding its winter range in the southern U.S. FAW feeds on a variety of crops, including corn, sorghum, small grains, and grasses. In corn, larvae feed on the whorl and ears, greatly reducing yields during years with high infestations.

Appearance of Fall armyworm

  • Eggs: FAW eggs are very small, with a diameter of less than 1/32 of an inch wide. They are laid by moths during the nighttime directly on corn plants in clusters of up to hundreds of eggs. The egg clusters are covered with fluffy hairs from the female moths. Eggs when first laid will have a pale yellow color, and darken to a black color closer to hatching.
  • Larvae: The larvae of FAW go through 6 to 7 instars before pupation, growing up to 1.5 inches long. The body color of the larvae can vary between greens, brown and black, but there are two distinct characteristics all larvae share. One is an inverted pale “Y” shape on the head capsule, and the other is 4 black dots arranged in a square at the rear of their body.
  • Pupae: Pupae of FAW have a reddish-brown color, similar to other armyworms and cutworms. They are about 1 inch in length, and are found below the soil surface.
  • Adults: Adult FAW are moths with hind wings that are grayish-white in color. The forewings are dark gray with mottled patches and a white spot at the tip of the wing. Their wingspan is typically 1.5 inches wide. 
Cluster of multiple FAW eggs on a corn leaf. The eggs are each about the size of a pine-head and have a yellow color. The eggs are covered with thin, wispy, gray hairs from the female moth.

Eggs laid by FAW moths are laid directly on the host plant’s leaves. Eggs hatch in about 4 to 5 days depending on the temperature. Their eggs also darken in color the closer they are to hatching.

Recently hatched black FAW larvae that are about the size of the tip of a pen. They are spread out across the surface of a leaf, with multiple clusters of brown, wispy egg clusters on the leaf’s surface.

The larvae of FAW are very small when they first hatch, being about 1/16 of an inch in length. This makes scouting for them hard until they grow larger.

A FAW larva on a yellow ear of corn. The larva has a brown body with a darker brown head. In the center of the face is a distinct inverted “Y” shape with a pale color.

FAW larvae can vary in body color from green to brown to black. But all color larvae have the “Y” shaped mark on their heads.

A green FAW larva about the length of a quarter resting on a corn leaf. The larva has a brown head with black pin-head sized dots along its body. Notably, there are four black dots in the shape of a square at the rear of its body.

Another one of the distinct identifying features of FAW larvae is the 4 dots arranged into a square at the rear of the body.

A brown FAW pupa about the size of a quarter. The surface of the pupa has a glossy, rigid, rust-colored surface. The bottom end of the pupa is tapered to a blunt tip, while the top of the pupa has the faint outline of the insect’s wings under the surface. The body is broken up into segments, and each segment has a single black dot on its right side.

Pupae of FAW are found buried in the soil, and appear very similar to other moth pests of sweet corn. They have a rust-colored body with a glossy surface.

A specimen of a FAW moth laid out flat with its wings fully spread out. Its wingspan is about the length of a house key. It has a brown, hairy body with white hindwings and brown forewings. The forewings have a hairy texture similar to the body.

FAW moths are similar in appearance to other types of cutworm moths. Their hind wings have a gray color while the forewings have a brown color with a white spot near the wing tip.

Signs and symptoms of Fall armyworm

A stalk of corn that has leaves ridden with holes from FAW larval feeding. There is a brown FAW larva about the size of a quarter in the center of the whorl of leaves near the corn’s tassels. The larva is feeding on the tassel, leaving brown sandy frass behind.

FAW larvae feed on many parts of the corn plant, including the leaves and tassels. Evidence of FAW damage in corn include holes in the whorl of leaves, damaged stalks and damaged tassels.

Two green damaged stalks of corn in a field. Both stalks have holes of various sizes from FAW larval feeding in their whorls. The stalk on the left is only about knee-high, since its growth was stunted by FAW from having its top stem eaten.

FAW larval feeding can stunt the growth of corn plants from feeding on its tassels and the stem.

An ear of corn with its husk pulled back exposing its tip. There is a single brown FAW larva burrowed into the ear feeding on the kernels of corn. The ear already has evidence of larval feeding, with brown frass covering most of the tip where kernels used to be.

Later in the season, FAW larvae enter the corn ear to feed on the kernels. They either bore directly through the side of the ear, or enter the ear through the silk channel.

Life cycle of Fall armyworm

A circular clockwise diagram of the life cycle of fall armyworm in corn. Stage 1 is at the top with eggs, which hatch after about 5 days on leaves. Next at stage 2 is a larva, which will grow through 6 to 7 instars on the leaves, ears and whorls over about 20 days. Then at stage 3 is a pupa, where the larva will pupate into an adult moth in about 14 days in the soil. Finally at stage 4 is an adult moth, which has a life span of about 10 to 21 days in the field. Moths will lay eggs, completing the cycle.
  • Adult FAW migrate annually to the Northeast during the month of July. Female moths lay their eggs directly on the crop, with a single female producing up to 1,000 eggs in her lifetime (10 to 21 days).
  • Depending on the moth’s arrival time and temperatures from the end of summer to the beginning of fall, there may be one whole generation and a partial second generation of FAW.
  • Eggs once laid by moths will typically hatch in around 5 days, though this is also temperature dependent.
  • Larvae are the most destructive stage of FAW development to crops. Once hatched, larvae take around 20 days to fully grow, going through six or seven instars. In this time, the larvae first feed on the whorl of leaves in the center of the plant. This gives the leaves a ragged, hole-ridden appearance and stunts plant growth.
  • Later in the season once the ears develop, the larvae will feed on the ears, entering the ear through its silk channel or by boring a hole in the side. Years with heavy infestations will see a high percentage of corn ears in a field with this type of damage.
  • Pupation begins when fully grown larvae burrow into the soil near their host crop. This stage lasts for around two weeks until moths of the second generation emerge around September to early October in the Northeast
  • These newly hatched moths lay eggs for the second generation, which survive until freezing temperatures. Fall armyworm is unable to overwinter in the northeast.

Management of Fall armyworm

Pest monitoring

  • FAW larvae are hard to scout for initially during the season, since the early larval instars are very small and don’t do much damage to crops. It is still essential to scout for FAW at this stage because once larvae grow beyond 3/4 of an inch in length, their susceptibility to insecticides decreases.
  • Trap catches in New York State begin around mid-July for migrating moths, and peak around mid-September.
  • It is better to rely on green bucket pheromone or black light traps to monitor FAW populations. Spray intervals for FAW can be based on weekly trap catches.
  • After early arrivals of moths are trapped, regularly scout fields for whorl damage to estimate population levels. Action thresholds for FAW in corn are 15% of total plants damaged or 5% for silking corn.
  • For more information on monitoring FAW, see the Cornell Pheromone Traps for Sweet Corn fact sheet.
  • For more instruction on sweet corn trap monitoring, watch Cornell IPM’s Sweet Corn Pheromone Trap Network Setup and Monitoring video.
  • The Sweet Corn Pheromone Trapping Network has been monitoring FAW populations in NY since 1997. To get weekly trapping reports visit the IPM sweet corn network website. 

Control

  • Cultural control: Planting earlier or using earlier-maturing varieties can help crops escape peak FAW pressure, reducing the risk of severe damage. Controlling grassy weeds and volunteer cereals near fields removes alternative hosts that can support early FAW larvae before they move into the crop.
  • Biological control: Common beneficial organisms such as ground beetles, soldier bugs, birds and rodents are known to prey on FAW. They are often unable to suppress outbreaks of large populations of FAW, and other control methods must be used instead.
  • Bt corn hybrids: Certain field and sweet corn hybrids are available that possess resistance to FAW. These hybrids contain the Bt trait, which enables the plant to produce insecticidal proteins that help protect against FAW feeding. Refer to seed company guidelines when using Bt or other corn hybrids.
  • Chemical control: Refer to your local Cornell Cooperative Extension or state guidelines when applying insecticides to crops.
    • Responsible pesticide application should be planned when applying any insecticide to crops. This ensures that resistance to pesticides is minimized in the targeted pest population, while minimizing damage to beneficial insects and pollinator populations. 

Use the EIQ (Environmental Impact Quotient) calculator to assess the environmental and health impacts different pesticides have before selection.

Any time you use a pesticide, you must read and follow the label directions and comply with all applicable laws and regulations related to pesticide use. Also be sure that any pesticide used is approved for use in your country and state/province.

A green plastic FAW trap shaped like a bucket. It is suspended off the ground from a pole and is placed next to a field. A raised lid is attached to the top of the trap. There is a hole in the top of the trap under the lid to capture and collect FAW moths.

FAW bucket traps are used to monitor moth populations next to fields. They contain a pheromone lure that attracts the male moths. Moths enter through the top and get trapped. An insecticidal strip kills them allowing the dead moths to be collected in the bottom of the trap and counted.

A sealed white packet of FAW insecticide about the size of an index card. The main text on the packet reads HERCON VAPORTAPE II. Inside the packet is a strip laced with insecticide for use in traps.

Insecticidal strips come in seal pouches for use in FAW traps. They are placed at the bottom of traps, and release vapors that kill moths that enter.

A green bucket trap used to collect FAW adult moths and monitor their population. A red strip of insecticidal tape is attached to the inner wall of the bucket to kill FAW moths that enter the trap. There is a pile of about 50 FAW moths in the bottom of the bucket that entered inside and died from the insecticide.

FAW moths are collected in these traps and are monitored on a weekly basis. This gives farmers an idea of population levels in their area and if action needs to be taken to control FAW populations.

Authors

  • Marion Zuefle
    Vegetable IPM Coordinator, Cornell Integrated Pest Management

  • Lukas Rood
    Temporary Program/Extension Aide, Cornell Integrated Pest Management

Last updated: February 2026

Modified from an article written by A.A. Muka: Muka, A. A. (1983). Fall armyworm. Cornell University Library eCommons. https://hdl.handle.net/1813/42368

This factsheet was developed in part with funding support from the New York State Department of Agriculture and Markets.

  • One of the most…—photo by Ken Wise, Cornell IPM
  • Eggs laid by FAW…—photo by Abby Seaman, Cornell IPM
  • The larvae of FAW…—photo by Ronald Smith, Auburn University
  • Another one of the…—photo by Abby Seaman, Cornell IPM
  • FAW larvae can vary…—photo by Marion Zuefle, Cornell IPM
  • Pupae of FAW are…—photo by Daniel Reiland, North Carolina State University
  • FAW moths are similar…—photo by Lyle Buss, University of Florida
  • FAW larvae will feed…—photo by Marion Zuefle, Cornell IPM
  • FAW larval feeding can…—photo by Marion Zuefle, Cornell IPM
  • Later in the season…—photo by John C. French Sr., Retired, Universities:Auburn, GA, Clemson and U of MO
  • FAW bucket traps are…—photo by Keith Waldron, Cornell IPM
  • Strips laced with insecticide…—photo by Julieta Brambila, USDA APHIS PPQ
  • FAW moths are collected…—photo by Marion Zuefle, Cornell IPM

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