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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?