OBJECTIVES OF FOREST INSECT MANAGEMENT At the end of this section students should be able to:

Have an understanding of the following ecological processes, concepts and pest management strategies.

The dynamic events associated with forest succession and the role of forest insects in the process.

The basic differences between forest insect management on federal forest lands versus on private lands.

The mortality quotient and the concept of economic damage.

The different insect pest management strategies including mechanical and physical control, chemical control, biological control, and some alternative methods of insect control.

The kinds of insecticides used in applied control and the different formulations of those chemicals.

The basic differences between density dependent and density independent control.

Principles of Forest Insect Pest Management

Hickory Horned Devil

Regal Moth - adult of HickoryHorned Devil

Philosophy of Forest Management

1) Federal/State/County Lands

2) Industrial and Private Forestry

Philosophy of Forest Management

Federal/State/Government Lands: Focus on Ecosystem Preservation

Approaches:Establish forest preservesLong rotationsEncourage recreation useProtect biodiversityProtect endangered species

Philosophy of Forest Management

Industrial and Private Lands: Focus on Intensive Forestry

Approaches:Genetic ImprovementShort rotationsThinning and pruningNew technology in wood utilization and harvesting

Long Range Forest Management Goals

Federal Forestry:Maintaining Forest Health

Industrial and Private Forestry:Protecting Investments

Ecological Roles of Insects:

Herbivores Defoliators Gypsy moth

Predators Checker beetles Mantids

Prey Southern Pine Beetles, Aphids

Detritivores termites, borers

Vectors Elm beetles & DED

Pollinators

What is a pest?

Pest status depends on population levels economic factors &objectives of stand.

(It is not your younger sibling)

Some Review Terms:

Equilibrium Position - The average population level of an insect species (EP).

Economic Threshold - The population level at which management action should be taken to prevent the pest from reaching the economic injury level (ET).

Economic Injury Level - The lowest number of insects that will cause economic damage (EIL).

Economic Damage - The amount of pest-caused damage that justifies the cost of applying pest control measures (ED).

Some Insects are never economic pests - the Equilibrium position (EP) is below the economic threshold (ET) or Economic Injury level (EIL)

Example: Eastern Tent caterpillar

Some insects are occasional pests and must be controlled at ET or they will reach EIL.

Example: Spruce budworm, Douglas-fir Tussock Moth

Some insects are regular and serious pests the Equilibrium position (EP) is above EIL all the time unless steps are taken to keep them low.

Example: Seed and cone moths in seed orchards

Economic considerations in PestManagement include:

Value of crop

2) Cost of control

3) Pest status - depends on point of view

Approaches to Pest Management:

Mechanical Control

Chemical Control

Biological Control

Integrated Pest Management

1)Mechanical Control:

Fly swatters

1) Mechanical Control:Fly swattersSalvage loggingSanitationWater treatment of cut logsKiln drying of lumber

2) Chemical Control:Effects on insects and humans

Characteristics of Pesticides:Specificity range of actionPersistence how long does it last?Toxicity How dangerous?Measures of ToxicityLD 50 dose (mg/kg) lethal to50% of test population - Oral or DermalPesticides are poisons!

Everyday ToxinsAcute oral LD 50s (mg/kg)* For a 170 lb. male

Table Sugar29,700Baking Soda3,500Malathion1,375Aspirin*1,000 (about 100 tablets)Table Salt400Caffeine*192 (about 100 strong cups of coffee)Gasoline150Nicotine53Vitamin D (pure)9.5

Mode of Action of Pesticides:Stomach Poisons Bacillus thuringiensisContact Poisons - MalathionSystemics - TemikFumigants Methyl bromideRepellents N,N-diethyl-meta-toluamide Attractants fire ant baits

Insecticide Chemical Groups:Nicotine tobacco plantsPyrethrum - chrysanthemumsRotenone tropical Derris plants

Characteristics: Quick knock downShort residual timeExpensivea) Botanicals

b) Organochlorines - also called Chlorinated hydrocarbons

DDTMethoxychlorLindaneChlordaneAldrin, Dieldrin, EndrinCharacteristics:Generally have long residueToxicity varies greatly

c) Organophosphates - Malathion, Parathion

All are Cholinesterase InhibitorsCharacteristics: Generally very effective Toxicity varies greatly - (Oral LD 50 Malathion 1375, Parathion 2 mg/kg) Short residual

CholinesteraseInhibition

d) Carbamates: carbyaryl (Sevin) or carbofuran (furdan)

*Cholinesterase Inhibitors Characteristics:Generally quite effectiveGenerally less toxic than OPCarbofuran is exception - Oral LD 50 8 mg/kgResidual limited, but longer than OP

e)Synthetic Pyrethroids Ambush, Warrior T, PounceCharacteristics:Much more effective than natural PryrethrumUsed at very low ratesRelatively safe - LD50 about 250 mg/kgResistance by insects has become a serious problem

Formulation and Application of Insecticides:

Sprays

Dusts

Wettable Powders (WP)

Emulsifiable concentrates (EC)

Ultra low volume sprays (ULV)

Pesticide Safety

Keep away from childrenRead the LabelLegal contract between the user, the producer and the State and Federal GovernmentsRemember these are poisons!

Insect Growth Regulators:

Development Juvenile Hormone (JH) Methoprene.

Synthetic ecdysone interferes with normal development

Cuticle formation - Diflubenzuron disrupts cuticle formation, inhibits molting process

Behavioral chemicals = semiochemicals

Pheromones = chemicals used forcommunication within species

Sex Pheromones

Aggregation pheromones

Anti-aggregation pheromones

Behavioral chemicals = semiochemicals

Specific insect pheromones collected, analyzed and synthesized.

Synthetic pheromone impregnated into rubber septum.

Wendell Roel of (Cornell University)did much of the pioneering work in this field.

Pheromone may be used in insect control and pest management:

1. Detection and monitoring

2. Trap outs Protection

3. Attracticides

4. Confusants

1. Detection and monitoring: Turf beetle

2. Trap outs /Protection: German Bark beetles

3. Attracticides: pheromone plusinsecticide

Insects are attracted to the material and killed. Many ants are killed in this manner; Amdro, etc.

4. Confusants: German Grape berry Moth

Biological Control:

a)Action of natural enemies

b)Predators

c)Parasites (Parasitoids)

d)Pathogens

Biological Control:

Usually density dependent - the percentage of hosts killed increases with population density

In contrast, natural control factors (like weather) are density independent

Kill the same percentage of the pests regardless of population density

Native and Introduced biological control agents

Predators Preying mantidsLady bird beetles (ladybugs)Lacewing larvae and adultsGround beetles

LacewingadultPreyingmantid

Lady bird beetle(ladybug)Larva eating aphids

Parasitoids

Chalcid waspsCynipid waspsIchneumonid waspsNumerous Diptera

Value of Parasitoids vs. Predators

ParasitoidsGenerally very host specificWell synchronized with host biology

PredatorsNot host specific, can switch prey when food is scarcePopulations do not die out when one prey is gone

Pathogens

Bacteria Bacillus thuringiensis, Bt Controls many insect pestsFungi Entomophthorales spp. Infects Gypsy Moth larvaViruses NPV Nuclear Polyhydrosis virus (Gypsy Moth & other larva). GV Granulosis Virus (Douglas-fir Tussock Moth)Protoza Nosema Fall Webworm

Approaches to Biological Control

Importation from other countries

Conservation that protect habitats of any biocontrol agents that may be present

Enhancement: Artificial rearing of agent for release to increase or enhance existing biocontrol populations

Advantages of Biological Control

Control is self-perpetuating

Control is selective and density dependent

Does not create new problems - normally

Disadvantages of Biological Control

Not effective against Direct Pestswhere any damage is unacceptable

Some level of damage occurs and must be acceptable

Must be implemented over large areas

May take years to become effective

Other Approaches to Insect Control:

Host Resistance--

Preference/non-preference

Antibiosis

Tolerance -

Other Approaches to Insect Control:

Legislative Control:

Laws made to prevent entry or spread of pests. Quarantine against pine shoot borer.

Integrated Forest Pest ManagementThe combination of all suitabletechniques to reduce or manipulatepest populations so that they remain below economically important levels

Questions to for Principals of Forest Insect Management:

1) What are the basic differences in management philosophy between those in Federal forestry and the private forestry companies?2) Why is control of seed orchard pests so important? Why is the approach used in seed orchards said to be similar to pest management in agriculture?3) What are the basic approaches to pest management used in forestry?4) What are the basic characteristics of commonly used insecticides?5) What is the LD 50 of a pesticide?6) What is the basic mode of action of the organophosphate and carbamate insecticides?7) What are semiochemicals and how can they be used in forest pest management?8) What is the difference between density dependent and density independent pest control?9) What type of biological agent was used in the control program of the larch casebearer? Would you characterize this as a program of introduction, conservation or enhancement?10) Why is Bacillus thuringensis used so often in control of forest Lepidoptera?11) What are the basic types of viruses used in control of forest pests?12) Explain why biological control agents are not effective at eradicating a pest species.