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Beetle Battle

Meet the people going to war against forest-killing beetles

October 2017
By Alexa Kurzius
Joseph Benzel, Screening Aids, USDA APHIS ITP, Bugwood.org (redbay ambrosia beetle); David Cappaert/AGE Fotostock (emerald ash borer beetle); Steven Valley, Oregon Department of Agriculture, Bugwood.org (Mountain Pine Beetle); Erich G. Vallery, USDA Forest Service - SRS-4552, Bugwood.org (Southern Pine Beetle); Didier Descouens (Titan Beetle)

America’s forests are under siege. The culprit? Billions of beetles, many of which are no bigger than a grain of rice. The insects burrow into trees and kill them by cutting off their food and water supply. (But not all beetles do this. For more info, see “All About Beetles," below.)

Some tree-killing beetles are invasive species. This means they arrived in the United States from somewhere else. With no known predators in their new habitat, they can cause damage.

America’s forests are under attack. Billions of beetles are to blame. Many of these insects are no bigger than a grain of rice. They burrow into trees. Then they kill the trees by cutting off their food and water supply. (But not all beetles do this. For more info, see “All About Beetles," below.)

Some tree-killing beetles are invasive species. This means they arrived in the United States from somewhere else. They have no known predators in their new habitat. This means they can cause damage.

Other beetles are native to the U.S., but warmer weather patterns in recent years have led to a dangerous growth in their populations.

From developing an insect repellent for trees to importing beetles’ natural predators, scientists are battling tree-killing beetles in creative ways.

Other beetles are native to the U.S. But there have been warmer weather patterns in recent years. This has led to a dangerous growth in their populations.

Scientists are battling tree-killing beetles in creative ways. For example, they are developing an insect repellent for trees. They are also importing beetles' natural predators.

Appetite for Avocado Trees

Jason Smith’s biggest enemy is very, very tiny. The scientist at the University of Florida studies the redbay ambrosia beetle. This invasive species has killed more than 500 million trees in the U.S. since 2002. “It’s an epidemic,” he says.

Redbay ambrosia beetles are native to Southeast Asia. There they eat dead trees. But in the U.S., they’ve been attacking live trees. The beetles reproduce at lightning speed. The offspring from just one beetle can infest and injure a tree in just three weeks.

Jason Smith's biggest enemy is very, very tiny. Smith is a scientist at the University of Florida. He studies the redbay ambrosia beetle. This invasive species has killed more than 500 million trees in the U.S. since 2002. "It's an epidemic," he says.  

Redbay ambrosia beetles are native to Southeast Asia. There they eat dead trees. But in the U.S., they've been attacking live trees. The beetles reproduce at lightning speed. The offspring from just one beetle can infest and injure a tree in just three weeks.

N. F. Photography/Shutterstock.com (avocado tree); Screening Aids, USDA APHIS ITP, Bugwood.org (redbay ambrosia beetle)

Name: Redbay ambrosia beetle
Actual size: Abraham Lincoln’s nose on a penny
Victim: Trees in the Lauraceae family, including avocado and sassafras trees

Recently, redbay ambrosia beetles have begun to attack avocado trees. Smith estimates that the beetles have killed about 30,000 avocado trees in Florida since their arrival in 2002. If the beetle reaches California, the effects could be devastating. California farms produce 90 percent of the avocados grown in the U.S.

Smith is testing a special bug spray to keep the beetles off healthy trees. Farmers are also training dogs to sniff out infected trees. Then the farmers can dig up and destroy the diseased trees to stop the infection from spreading. So far, success has been limited. “It’s a complex problem,” Smith says.

Recently, redbay ambrosia beetles have begun to attack avocado trees. Smith estimates that the beetles have killed about 30,000 avocado trees in Florida. This has happened over time since their arrival in 2002. If the beetle reaches California, the effects could be devastating. California farms produce 90 percent of the avocados grown in the U.S.

Smith is testing a special bug spray. It will keep the beetles off healthy trees. Farmers are also training dogs. The animals will sniff out infected trees. Then the farmers can dig up and destroy the diseased trees. This will stop the infection from spreading. So far, success has been limited. "It's a complex problem," Smith says.

All About Beetles

There are more known species of beetles than any other group of organisms on Earth. Scientists estimate that there are more than 1 million beetles species!

Beetles are insects, so each has a head, a thorax, an abdomen, and six legs. Beetles have two set of wings. Their hardened front wings protect their delicate hind wings.

Beetle species can range in size from 0.3 millimeters to 167 millimeters in length, like the titan beetle below.

Beetles play an important role in the ecosystem. Most of them feed on plants and plant waste, including tree wood.

Many beetles eat other insects too. Ladybugs are one example. They eat insects that damage plants.

There are more known species of beetles than any other group of organisms on Earth. Scientists estimate that there are more than 1 million beetles species!

Beetles are insects, so each has a head, a thorax, an abdomen, and six legs. Beetles have two set of wings. Their hardened front wings protect their delicate hind wings.

Beetle species can range in size from 0.3 millimeters to 167 millimeters in length, like the titan beetle below.

Beetles play an important role in the ecosystem. Most of them feed on plants and plant waste, including tree wood.

Many beetles eat other insects too. Ladybugs are one example. They eat insects that damage plants.

All About Beetles

There are more known species of beetles than any other group of organisms on Earth. Scientists estimate that there are more than 1 million beetles species!

Beetles are insects, so each has a head, a thorax, an abdomen, and six legs. Beetles have two set of wings. Their hardened front wings protect their delicate hind wings.

Beetle species can range in size from 0.3 millimeters to 167 millimeters in length, like the titan beetle below.

Beetles play an important role in the ecosystem. Most of them feed on plants and plant waste, including tree wood.

Many beetles eat other insects too. Ladybugs are one example. They eat insects that damage plants.

There are more known species of beetles than any other group of organisms on Earth. Scientists estimate that there are more than 1 million beetles species!

Beetles are insects, so each has a head, a thorax, an abdomen, and six legs. Beetles have two set of wings. Their hardened front wings protect their delicate hind wings.

Beetle species can range in size from 0.3 millimeters to 167 millimeters in length, like the titan beetle below.

Beetles play an important role in the ecosystem. Most of them feed on plants and plant waste, including tree wood.

Many beetles eat other insects too. Ladybugs are one example. They eat insects that damage plants.

Hunting for Predators

Vanessa Lopez loves talking about beetles. “They’re my favorite animals!” she says. Lopez is an entomologist, or person who studies insects. She works for the U.S. Forest Service studying invasive beetle species.

Lopez and other scientists have been studying the emerald ash borer for a number of years. It’s been killing ash trees all over the U.S. since it came from Asia in 2002.

Vanessa Lopez loves talking about beetles. "They're my favorite animals!" she says. Lopez is an entomologist. That’s a scientist who studies insects. She works for the U.S. Forest Service. There, she focuses on invasive beetle species.

Lopez and other scientists have been studying the emerald ash borer for a number of years. It's been killing ash trees all over the U.S. The beetles came from Asia in 2002.

Iowa State University, Extension (Ash Tree); David Cappaert/AGE Fotostock (emerald ash borer beetle)

Name: Emerald ash borer
Actual size: Width of a pencil eraser
Victim: Ash trees throughout much of the U.S.

Attempts to get rid of the pest have failed so far. So the U.S. government has imported four wasp species from Asia that eat only the emerald ash borer.

Scientists have to be careful when considering whether to introduce a new species. They must run tests to make sure the species won’t alter the ecosystem. “Before we can release any natural enemy, we have to make sure it only attacks the insect we’re targeting,” Lopez says.

Attempts to get rid of the pest have failed so far. So the U.S. government has imported four wasp species from Asia. They eat only the emerald ash borer.

Scientists have to be careful when considering whether to introduce a new species. They must run tests. That’s to make sure the species won't alter the ecosystem. "Before we can release any natural enemy, we have to make sure it only attacks the insect we're targeting," Lopez says.

Gemini2525 (Western U.S. Pine Trees); Steven Valley, Oregon Department of Agriculture, Bugwood.org (Mountain Pine Beetle)

Name: Mountain pine beetle
Actual size: Point of a pencil
Victim: Pine trees in the western part of North America

Small Successes

Not all beetle problems are caused by invasive species. Scientist Robert Rabaglia studies native insects with the U.S. Forest Service. 

Some, like the mountain pine beetle, have killed more than 20 million acres of trees across the West from 2000 to 2014. “There is only so much you can do when there is an outbreak,” he says.

Not all beetle problems are caused by invasive species. Scientist Robert Rabaglia studies native insects. He works for the U.S. Forest Service. 

Some, like the mountain pine beetle, have killed more than 20 million acres of trees across the West from 2000 to 2014. "There is only so much you can do when there is an outbreak," he says.

Manana Skhiladze/EyeEm/Getty Images (Southern U.S. Pine Trees); Erich G. Vallery, USDA Forest Service - SRS-4552, Bugwood.org (Southern Pine Beetle)

Name: Southern pine beetle
Actual size: Height of 3 stacked credit cards
Victim: Pine trees in the southern part of the U.S.

But with dedicated forest management, it’s possible to make the outbreaks less severe. That has been the case with which lives in the southeastern United States. 

These beetles prey on weak trees. Since 2003, the Forest Service has partnered with landowners to cut down weak trees, so that the remaining trees can grow stronger and healthier. “Keeping trees healthy is the best way to prevent an outbreak,” Rabaglia says.

But with dedicated forest management, it's possible to make the outbreaks less severe. This worked with the southern pine beetle. The insect species lives in the southeastern United States. 

These beetles prey on weak trees. Since 2003, the Forest Service has partnered with landowners. Together, they cut down weak trees. This allows the remaining trees can grow stronger and healthier. "Keeping trees healthy is the best way to prevent an outbreak," Rabaglia says.

Didier Descouens

The titan beetle 

MATH TALK:

What are some situations in which insect scientists might work with fractions and decimals?

MATH TALK:

What are some situations in which insect scientists might work with fractions and decimals?

Ordering Decimals

Ordering Decimals

A student draws the following number line with fractional values to show the length in centimeters of a mountain pine beetle. Express the number on the number line as a decimal.

A student draws the following number line with fractional values to show the length in centimeters of a mountain pine beetle. Express the number on the number line as a decimal.

Southern pine beetles are 0.40 centimeters long. Plot this value on the number line. Is it longer or shorter than the mountain pine beetle? 

Southern pine beetles are 0.40 centimeters long. Plot this value on the number line. Is it longer or shorter than the mountain pine beetle? 

Use decimal fractions to write a number sentence with an inequality symbol comparing the lengths of both beetles. 

Use decimal fractions to write a number sentence with an inequality symbol comparing the lengths of both beetles. 

A scientist collects 3 redbay ambrosia beetles that measure the following lengths in centimeters: 19 hundredths, 201 thousandths, 2 tenths. On a separate sheet of paper, draw a place value chart with these numbers in decimal form.

A scientist collects 3 redbay ambrosia beetles that measure the following lengths in centimeters: 19 hundredths, 201 thousandths, 2 tenths. On a separate sheet of paper, draw a place value chart with these numbers in decimal form.

Which beetle is the largest? 

Which beetle is the largest? 

Ladybugs are a common type of beetle. They can range in length from 0.70 cm to 1 cm. On your separate sheet of paper, create a number line for the range 0.50 to 1.

Ladybugs are a common type of beetle. They can range in length from 0.70 cm to 1 cm. On your separate sheet of paper, create a number line for the range 0.50 to 1.

A scientist collects 4 beetles that measure 0.85 cm, 0.75 cm, 0.60 cm, and 0.51 cm. Plot these numbers on the number line. Which of these fall into the size range of ladybugs? 

A scientist collects 4 beetles that measure 0.85 cm, 0.75 cm, 0.60 cm, and 0.51 cm. Plot these numbers on the number line. Which of these fall into the size range of ladybugs? 

The largest titan beetle ever measured was 16.7 cm long. Four other titan beetles have the following measurements:

        Beetle A is 16.46 cm long

        Beetle B is 15.79 cm long

        Beetle C is 16.07 cm long

        Beetle D is 16.305 cm long

The largest titan beetle ever measured was 16.7 cm long. Four other titan beetles have the following measurements:

        Beetle A is 16.46 cm long

        Beetle B is 15.79 cm long

        Beetle C is 16.07 cm long

        Beetle D is 16.305 cm long

Order the four other beetles from shortest to longest. 

Order the four other beetles from shortest to longest. 

Which beetle is closest in length to the longest titan beetle ever measured? 

Which beetle is closest in length to the longest titan beetle ever measured? 

Adult Goliathus goliatus beetles measure a maximum of 11 cm. Their larvae can measure a maximum of 11.5 cm. Which goliath beetle specimens in the chart could not be adult beetles? Explain your reasoning.

Adult Goliathus goliatus beetles measure a maximum of 11 cm. Their larvae can measure a maximum of 11.5 cm. Which goliath beetle specimens in the chart could not be adult beetles? Explain your reasoning.

Number & Operations
Comparing Decimals
predators

Animals that live by hunting other animals for food. Lions, sharks, and hawks are types of predators.
place value chart

A chart that labels a number based on each digit’s location (or place value)

Example: a place value chart for 175 would label 1 in the hundreds place, 7 in the tens place, and 5 in the ones place
ecosystem

A community of living things. A forest is an ecosystem, with a community of plants, animals, and other microscopic organisms.
number line

Numbers are marked at intervals and can be used to show fractions, decimals, whole numbers, or increments of time.

Example: A horizontal or vertical number line between 0 and 1 might have markings at 0, 1/4, 2/4, 3/4, and 1.
complex

Very complicated
estimate

A calculation that is not exact. Estimates are often used when making calculations quickly or with large number or decimal numbers

Example: To estimate 19.8 x 3, you can round the expression to 20 x 3. This means your estimate is 60
siege

A persistent or serious attack
number sentence

A mathematical phrase that includes numbers and an equal sign. It is also known as an equation.

Example: 5 + 5 = 10
decimal

A number that contains a decimal point. The decimal portion of a number consists of the place values to the right of the decimal point.

Example: 8.7 is a decimal number. The decimal separates the whole number part from the decimal part. That number can be read as 8 and 7 tenths
infest

To be present in large numbers in a way that causes harm or disease
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