objectives of forest entomology at the end of this section students should be able to: 1) appreciate...
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OBJECTIVES OF FOREST ENTOMOLOGY
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
The study of the Interrelationships of insects and trees
Includes damaging and beneficial species
Does not include all insects in the forest
Only those that affect health and use of trees
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 thriving and the utility of those wood plants with which the forester is concerned
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
F.P. Keen
W. G. Wellington
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
Agents of Forest Destruction and proportion of growth loss in saw timber – Hepting & Jemison 1958
0 10 20 30 40 50
Diseases
Insects
Fire
Weather
Animals
Other
Historical Aspects
Development of forest entomology
Forest Entomology
Taxonomic/natural history phase
Divergent phase
Population Dynamics
“Divergent” theories of population changesDensity Independent factorsDensity Dependent factors
Ecosystem analysis phase : Interrelationships of all environmental factors – Ecological webs, food chains, weather, etc
Predictive Modeling Phase
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
The Camphor Ambrosia Beetle:The Camphor Ambrosia Beetle: Xylosandrus mutilatusXylosandrus mutilatus
First found in Mississippi by Doug Stone and Evan Nebeker in 2002First found in Mississippi by Doug Stone and Evan Nebeker in 2002Found in Alabama in 2004 attacking living oak trees.Found in Alabama in 2004 attacking living oak trees.
Southern PineConeworm
Insects Cause Damage:To Seeds and Cones
Damage of Southern Pine Coneworm
Shield-backed Pine Seed bug
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
Beech Bark Disease is caused by a scale insect & fungus
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
Eastern Tent Caterpillar Adult
Egg Mass
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: Flies and Mosquitoes
Diptra: Cone gall midge and damage
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
Intermediate thinnings promote rapid growth and vigor and reduces stand susceptibility to southern pine beetle.
Insecticide Application in Seed Orchard
Spraying southern pine beetle infested logs
Use of pheromone“Repellent” verbenone to prevent bark beetleattacks
Mechanical removalof gypsy moth eggmasses
Removal of Ips and pine beetle killed trees
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?