Old World bollworm larva (Antoine Guyonnet, 

Lépidoptères Poitou-Charentes, Bugwood.org)

Old World bollworm adult (Julieta Brambila, USDA APHIS PPQ, Bugwood.org)

Old World bollworm adult (Gyorgy Csoka, Hungary 

Forest Research Institute, Bugwood.org)

The Old World bollworm can feed on 

crops, such as corn, cotton, small 

grains, soybeans, peppers, and 

tomatoes. Damage occurs when the 

larvae bore into the host’s flowers 

and fruit and feed within the plant; 

the larvae may also feed on the 

leaves of host plants. This invasive 

pest can be found both in field and 

greenhouse settings. 

Distribution and Spread

Old World bollworm is found in 

many areas of Africa, Asia, Europe, 

Australia, and the islands of the 

Western Pacific Region. It has also 

been reported in Brazil and may be 

present in other South and Central 

American countries. Old World 

bollworm was found on a single farm 

in Puerto Rico in September 2014. 

This was the first time the pest has 

been detected in the United States. 

Adults can fly up to 6 miles to find 

sufficient host material on which to 

lay eggs. They can be carried longer 

distances by wind. In Europe, for 

instance, the Old World bollworm 

migrates annually into Scandinavia 

from the Mediterranean.

Description

The Old World bollworm has four life 

stages: egg, larva, pupa, and adult. 

Eggs are very small with ribs that run 

lengthwise across their surface. They 

change from yellowish-white to dark 

brown just before hatching. Larvae 

can measure up to 1.7 inches long 

and range in color from bluish green 

to brownish red, darkening after each 

molt. Pupae are dark tan to brown 

Pest Alert Animal and Plant Health Inspection Service

Plant Protection and Quarantine

Old World Bollworm (Helicoverpa armigera)

in color and 0.6 to 0.9 inches long. 

Adults have a wingspan of 1.4 to 

1.6 inches and vary in color. Males 

are usually yellowish-brown, light 

yellow, or light brown, and females 

are orange-brown.

Related Species

Old World bollworm is similar to many 

other species of cutworms, including 

the corn earworm (Helicoverpa 

zea). Based on looks alone, it is not 

possible to tell them apart. A qualified 

entomologist must dissect the insect 

or use DNA analysis to accurately 

identify the species. 

United States Department of Agriculture

Life Cycle

Adults emerge from late March to 

June and lay eggs on a variety of 

host plants. Larvae go through five to 

seven developmental stages. Once 

mature, the larvae drop to the ground 

and pupate to overwinter in the soil, 

emerging as moths in the spring.

This species can have overlapping 

generations, meaning different life 

stages can be present at the same 

time. The number of generations 

per year can vary greatly depending 

on climate. Typically, this pest can 

have 2 to 5 generations per year in 
Old World bollworm damaging tomato (Central Science Laboratory, Harpenden Archive, British Crown, 

Bugwood.org)

APHIS 81-35-025

Revised June 2018

USDA is an equal opportunity provider, 

employer, and lender.

Old World bollworm damaging corn (Antoine Guyonnet, Lépidoptères Poitou-Charentes, Bugwood.org)

temperate regions, and as many as 

11 generations per year in tropical 

regions. 

Symptoms and Signs

Look for Old World bollworm adults, 

larvae, or signs of damage on the 

flowers, fruits, and leaves of host 

plants and report any suspect 

findings. In some cases, it may be 

necessary to cut open the fruit to 

detect the pest. 

The symptoms and signs of Old World 

bollworm may vary depending on the 

crop. In tomato, Old World bollworm 

larvae bore into the young fruit, 

causing it to fall from the vine. Larger 

larvae may also bore into the older 

fruit. In corn, the bollworm lays its 

eggs in the silks. Once hatched, the 

larvae bore into the ear and eat the 

developing grain, damaging the end 

of the ear. In cotton, the larvae bore 

holes into the base of flower buds, 

hollowing them out and causing the 

bracteoles (small, leaf-like structures) 

to spread out and curl downwards. 

Larvae also bore into young bolls, 

causing them to fall, and larger larvae 

may bore into maturing green bolls. 

Larvae may also eat the leaves and 

shoots of cotton plants.

Control

Old World bollworm can be effectively 

controlled using commercially 

available insecticide sprays and 

genetically modified crops that 

contain Bt insecticidal properties. 

Both Bt cotton and corn are widely 

used in the United States. In 2016, 

86 percent of commercial cottonproducing acres were planted with Bt 

cotton, and 80 percent of commercial 

corn-producing acres were planted 

with Bt corn. Many of the best 

management practices for controlling 

other cutworm species, such as 

the corn earworm (H. zea) which 

is widely distributed in the United 

States, should also control Old World 

bollworm, with few modifications.

Report Your Findings

It is important to properly identify Old 

World bollworm, given its similarity to 

many other species. Growers can use 

a commercially available pheromone 

lure to detect this pest. However, nontarget insects, including the native 

corn earworm, are also attracted to 

this lure.

If you observe signs of damage or 

find an insect that you suspect is the 

Old World bollworm, please contact 

your local Extension office or State 

Plant Regulatory Official as soon 

as possible. To locate an Extension 

specialist near you, go to the U.S. 

Department of Agriculture (USDA) 

website at www.nifa.usda.gov/

Extension. A directory of State Plant 

Regulatory Officials is available on 

the National Plant Board website 

at www.nationalplantboard.org/

membership.