Corn EarwormsCorn Earworms

Laramie Kettler

Charlie Barnhill

Dexter Knox

Brendan Mills

Presentation By:

From Gatesville IntermediateFrom Gatesville IntermediateGatesville, TexasGatesville, Texas

The corn earworm is known as the tomato fruit The corn earworm is known as the tomato fruit worm or cotton bollworm.worm or cotton bollworm.

Pictures 1 & 2 are from http://ow.csisd.org/usda/cornearjpg

The Life of a Corn EarwormThe Life of a Corn Earworm

The life of a corn earworm starts with an egg.

The female adult

moth smells the silk of a corn. Moths can smell corn silk from miles away.

The moth flies The moth flies toward the corn toward the corn to lay her eggs. to lay her eggs. When the eggs When the eggs hatch, they will hatch, they will find food and find food and shelter inside shelter inside the corn ear.the corn ear.

Depending on the temperature, the eggs should hatch in 2 to 6 days after being laid.

The larvae follow the silk channel to the tip of the developing ear where they feed on kernels and grow.

ObservationsObservationsThe worms come in a variety of colors:

green, tan, brown, pink, maroon, or nearly black.

Pictures 1 and 3 from http://firstep.coe.tamu.edu.

Look what the worms did. Look what the worms did. A cup of frass! (Worm excrement)A cup of frass! (Worm excrement)

Picture Number 2 from Http://ow.csisd.org/usda/cornear.jpg

We tested the following foods in our experiment: corn, tomatoes, potatoes, strawberries, and apples.

Experiment #1

What do earworms eat?

Colton Taylor was watching Colton Taylor was watching what his worm ate.what his worm ate.

Dexter is spying out the worm. Dexter is spying out the worm. Which food is best?Which food is best?

Rhett’s worm likes the tomato.Rhett’s worm likes the tomato.

Megan’s worm is trying out the Megan’s worm is trying out the potato.potato.

Jake’s worm keeps crawling away.Jake’s worm keeps crawling away.

These worms are trying out the corn, These worms are trying out the corn, potato, tomato, strawberry, and apple.potato, tomato, strawberry, and apple.

Results from Experiment Onepotatoes

7%

tomatoes20%

strawberries11%

Corn37%

apple25%

potatoes

tomatoes

strawberries

Corn

apple

ConclusionsConclusions

The worms liked the corn, apple, and tomato the best.

Photo from: Http://ow.csisd.org/usda/cornear.jpg.

As the worms grew, we measured them. This As the worms grew, we measured them. This one measured about 31mm.one measured about 31mm.

The worms went from an egg to a pupa in about 21 days.

Picture from http://firstep.coe.tamu.edu

Worm MeasurementsWorm Measurements

3/29/05 4/4/05 4/7/05 4/11/05 4/12/05

Very small, gray

larger Pinkish

larger

Red stripe forms

larger

1mm 15mm 26mm 30mm

Lots of

frass.

31mm

Experiment Number TwoExperiment Number Two..

Would worms eat anything outside?Would worms eat anything outside?

We tried to see if the corn We tried to see if the corn earworm would eat bluebonnets.earworm would eat bluebonnets.

Do Corn Earworms like grass?Do Corn Earworms like grass?

Do corn earworms like hackberry Do corn earworms like hackberry trees?trees?

Are wildflowers a part of their Are wildflowers a part of their diet?diet?

Are weeds on the Are weeds on the menu for pink corn earworms?menu for pink corn earworms?

Results of Foods OutsideResults of Foods Outside

Bluebonnets Grass Hackberry Trees

Wildflowers Weeds

No NO NO None NO

ObservationsObservations

The students noticed that the worms at this The students noticed that the worms at this stage wanted to fall off and burrow. They had a stage wanted to fall off and burrow. They had a

hard time keeping the worm on the plant.hard time keeping the worm on the plant.

To the PUPA!To the PUPA!!!!!!!!!

It took 21 days for our corn earworms to start metamorphosis.

The Transformation from Worm The Transformation from Worm to Pupae to Pupae

The larva will go through five The larva will go through five moltings before pupating.moltings before pupating.

The larva burrows under its own The larva burrows under its own castings to pupate. It creates a castings to pupate. It creates a

shell around its body.shell around its body.

Views of the pupae with theViews of the pupae with theIntel microscope.Intel microscope.

The Pupa MagnifiedThe Pupa Magnified

10X 60 X 200X

Egg2-5 days

Larvae14-18 days

Pupa 12-18 days

AdultMoth

8-15 days

Life Cycle

Is the moth a male or female?

Hold the moth and gently squeeze the abdomen. The females will have a brownish small part pop out. They are usually less active and have shorter, fatter abdomens than the males. Females are usually darker.

Drawing from http://ow.csisd.org/usda/procedur.htm

Laramie is using the microscope Laramie is using the microscope to find the sex of the moth.to find the sex of the moth.

Which pupa is male or female? Which pupa is male or female?

The moth emerging from the The moth emerging from the pupa must struggle to spread pupa must struggle to spread

its wings.its wings.

The moths continue to emerge.The moths continue to emerge.

The corn earworm moth has a The corn earworm moth has a wing span of 1 ½ inches. It is wing span of 1 ½ inches. It is

buff colored with irregular spots buff colored with irregular spots and markings on the wings.and markings on the wings.

The front wings have a dark, The front wings have a dark, comma shaped spot that is more comma shaped spot that is more

prominent on the males.prominent on the males.

A new generation of moths lays A new generation of moths lays eggs on fresh corn silk, and the eggs on fresh corn silk, and the

cycle begins again.cycle begins again.

SourcesSources

Http://firstep.coe.tamu.eduhttp://ow.csid.org/usda/procedur.htmhttp://hgic.clemson.edu/factsheets/HGIC22

05.htmFoster. Rick,” Corn Earworm”,

Vegetables.E-32-W. Pages 1-3.