OBJECTIVES OF FOREST ENTOMOLOGY

Chapters 17-18

At the end of this section students should be able to:

1) Appreciate the damage caused by forest insects.2) Understand the multifaceted role of forest entomology and some of

the factors involved in protection of forests and urban trees and the role of insects in the ecosystem.

3) Describe the development of forest entomology in Europe and North America.

4) Describe the contributions of the pioneers of forest entomology.5) Identify the major trends of the profession.6) Know some of the major sources of information on forest insects.7) Discuss the scientific contributions and current research of the U.S.

Forest Service.8) Outline the current role of forest entomology in private and public

Definition of Forest Entomology

Influence of Germans

J. C. Schaffer - Early studies of Gypsy Moth

J.T.C. Ratzeburg – Father of Forest Entomology

J.T.C. Ratzeburg

The study of forest insects which have an influence on the health and the utility of those wood plants with which the forester is concerned.

1830-1850: “Die Foresteinsketen”

Forest Entomology in U.S. and CanadaA. D. Hopkins - Considered Father of U.S. Forest Entomology: Bark Beetle Specialist

F.C. Craighead (left) and J.A. Beal - 1926

Why Insects are Important in the Forests

Their activities result in damage

In 1950, Craighead estimated annual losses to be:

Bark beetles -----------------------$20 millionDefoliators -------------------------$20 millionForest Product pests --------------$60 millionShade and ornamental pests ----$100 million

F.P. Keen

W. G. Wellington

Historical Aspects

Development of forest entomology

Forest Entomology1. Taxonomic/natural history phase

2. Divergent phase

“Divergent” theories of population changesDensity Independent factorsDensity Dependent factors

3. Ecosystem analysis phaseInterrelationships of all environmental factors –

Ecological webs, food chains, weather, etc

4. Predictive Modeling Phase

Models developed from divergent and ecosystem phases.

Economic Impact of Forest Insects

• Mortality – reduce growing stock

• Delay stocking levels – Reproduction– Seeds, cones, seedlings

• Reduce radial/axial growth– Defoliation of leaves/killing of buds

• Deterioration– Loss of product value

Southern Pine Beetle Spot

Insects Cause Damage: To trees

Southern PineConeworm

Insects Cause Damage:To Seeds and Cones

Damage of Southern Pine Coneworm

Insects Cause Damage:To seedlings

White Grub Adult

White Grub Larva

Pales Weevil and Damage on Pine Seedling

Insects Cause Damage: To Wood Products

Termites Damage Wooden Structures

Carpenter Ant & Damage

Southern Pine Beetle andBlue Stain Fungus

Insects also Spread Disease

Dutch Elm Disease – vectored by Bark Beetles

Oak wilt causes tree mortality spread by Picnic Beetles

Insects are Important in the Forest

Beneficial:

As plant pollinators in the forestAs natural enemies of pest insects

Hover Flies Pollinate Many Flowers

Preying Mantid feeding on a katydid

Larva of Lady beetle feeding on aphids

Insects also provide fodder for Gary Larson and his cartoon humor

Important Insect Groups in the Forest

Lepidoptera : The butterflies & Moths

Eastern tent caterpillar & tent

Eastern Tent Caterpillar Larva

Coleoptera: The Beetles

Asian Longhorned Beetle

Anoplophora glabripennis

Family Cerambycidae

Hymenoptera: Bees, Wasps, Ants & Sawflies

Pine Sawfly Ovipositing

Carpenter Bee

Carpenter Ant

Yellow Jacket Wasp

Homoptera-Hemiptera: Aphids, Adelgids, leafhoppers, & true bugs.

True bugs

Leafhoppers

Aphids

Orthoptera: Grasshoppers, Katydids, & Walking Sticks

Katydid

Grasshopper

Walking Stick

Diptera: Cone gall midge and damage

Diptera: Flies and Mosquitoes

Isoptera: Termites

Termite Reproductives swarming

Termite soldier and workers

Insects Cause Damage Many Ways:

FeedingNest BuildingOviposition

Tree Mortality caused by feeding of Adelgids

Nest buildingdamage bycarpenter ants

Oviposition damage causedby 13-YearCicada

Twig Mortality caused by 13-YearCicada

Approaches to Insect Control

Natural Control Factors

Weather

Natural Enemies

Cultural Control

ResistanceStand ManagementChemical Control

Mechanical Control

Aphid lion (lacewing larva) and victim

Longleaf Pine is resistant to many insect enemies includingSouthern Pine Bark Beetles

Insecticide Application in Seed Orchard

Use of pheromone“Repellent” verbenone to prevent bark beetleattacks

Mechanical removalof gypsy moth eggmasses

Buffer zone stops/slows southern pine beetle advance

Forest Entomology – Applied Ecology

• Detection

• Identification

• Forecast – what will happen?

• Assessment – risk to forest

• Analysis of outbreak

• Recommendations/Management

Questions for Introduction to Forest Entomology:

1) Why did damage caused by forest insects in North America prompt development of forest entomology as an important discipline within silviculture?2) Describe the evolution of forest entomology in Europe and later in North America.3) What are the basic reasons insects are important in the forests?4) In what ways do insects cause damage to forest trees?5) What are the most important insect groups in the forests?6) How does natural control differ from cultural control?7) Why is chemical control not used more often to control forest pests?8) Why will the future use of pesticides likely decline in the control of forests pests?9) Describe how forest pest management will change in the future. What key biological or mathematical disciplines will be most important in pest management?