Integrated Pest Management (IPM) concepts and grower training needs in Hawaii’s

tropical fruit industry

Is IPM a sustainable approach to managing pests?[Sustainable: “method of using a resource so that the resource

is not depleted or permanently damaged”]

Pest Control – often creates its own problems – can lead to permanent “damage”.

Pest Management vs. Pest Control

• Pest management aims to maintain insect populations below a threshold;

• Emphasis is not on eradication.

The UH IPM Verification Program

IPM Implementation on 75% of Hawaii's Crop Acres by the Year 2001. Our highest priority is implementation to meet President Clinton’s goal for IPM implementation on 75% of the nations crop acres.

http://www.extento.hawaii.edu/IPM/

Verification is based on points allocated for:

• Development and implementation of IPM procedures;

• Monitoring, application of various options, justification for each action.

• Farmer provides documentation for annual audit.

Insects – prevalent features of our environment

• Number of species;

• Interactions in

ecosystems and

with us;

• Our major competitors.

Understanding insect numbers

• May be explosive outbreaks

• Seasonal changes in numbers;

• What are the causes of changes in abundance?

• Insect ecology examines dynamics of insect numbers temporally and spatially;

• Phenology and diversity are also important;

• Interactions with plants and other insects.

• Ecology aims to explain how environment (biotic and physical) affects abundance, phenology and diversity of insects;

• Therefore ecology forms the basis for pest management.

• Understand both ecology and economy to implement IPM

Some history: Dealing with pests

• Pre-insecticide era: 2500 B.C.: Sulfur, herbs and oils used to protect seeds and stored grain.

• 300 B.C.: Plant phenology recognized as a means of avoiding pests; Chinese started using natural enemies of insects.

• By 1101, Chinese used soaps to control pests;

• Late 1600’s: tobacco infusions , arsenic used.

• 1700’s: Importance of temperature summation in determining insect phenology discovered!

Plant resistance used in the USA;

Botanical insecticides rediscovered.

• 1800’s: inspection and quarantine became important;

• 1920 - 1930’s: Depended on crop sanitation, timing of planting, minor use of insecticides.

• Insecticide era: ~1939 - 1962: DDT was discovered; Organophosphates later.

• Purely insecticide-based approach to pest problems emerged.

• 1962: Silent Spring by Rachel Carson

• The concept of Integrated Pest Management was developed.

• Emphasized the selective use of insecticides, and conservation of natural enemies.

Emphasis shifted from control to management.

Tolerance, rather than decimation encouraged.

Elements of IPM:

• Multiple tactics used in a compatible manner;

• Pest numbers below levels that cause economic damage;

• Consideration of environmental impact.

IPM = Sustainable Pest Management?

Aims of IPM:

• Reduce pest populations to levels below those causing economic impact, using multiple, compatible techniques;

• Reduce environmental impact of pest management.

Economic injury level

Lowest number of insects that will cause economic damage.

Economic / Action threshold:

Number of insects that should instigate management action

Economic decision levels - thresholds

• Usually expressed as number of insects per area, plant, or sampling procedure

• Sometimes use extent of plant damage

• Include biological and economic information

Gain threshold

• Expresses the beginning point of economic damage.

• Insecticide application would have to save 5 bushels per acre to be profitable

ueMarket val

costs Management holdGain thres =

acreper bushels 5 bushel / $2

acre / $10 GT ==

Economic threshold

• Also called Action Threshold – Insect density that would justify intervention

• May be a fixed economic threshold: e.g. if EIL is 6 insects per plant, intervene at 4 insects per plant;

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Economic loss

No loss

Non-economic loss

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Economic injury level:

Economic threshold

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IPM Options:

• Biological control

• Physical control

• Cultural control

• Chemical control

Monitoring insect numbers is the cornerstone

of IPM

Approaches to monitoring:

Various methods:

• Direct counts

• Traps

• Damage estimates

• Prediction: degree-days

Benefits of monitoring:

• Track numbers of pests and natural enemies;

• Able to target insecticide applications at the correct time;

• Enhances conservation of natural enemies;

• Indicate efficacy of treatments.

Biological control:• Natural enemies of pests cause mortality;• Can maintain pest population at below-threshold levels

Predators

Parasitoids

Pathogens

Types of BC:

• Import natural enemies - establish in field - Classical BC;

• Augmentative releases: inundative or inoculative releases each season;

• “Conservation” BC: depend upon local natural enemies.

• All these approaches require conservation of natural enemies to be effective.

Conserving natural enemies

Reduce insecticide use;

Use softer chemicals;

Manipulate habitats, e.g. intercropping.

Concerns: Biological Control

• Non-target effects?

• “Necessary evils: murder, drugs and biological control” (Lockwood 1999)

• Host specificity testing

• Risk assessment protocols?

Insecticides

• Insecticides as resources:

Huge financial investment for development;

Potential for Use or Abuse of this resource;

Can play an important role in providing options for pest management.

Problems with insecticides:

• Kill or disrupt natural enemies

• Secondary pests

• Residues on produce

• Build-up of resistance – insecticide “treadmill”

• Environmental concerns

Build-up of resistance:

1 2

3 4

Dealing with resistance

Wrong approach:• Raised concentrations of active ingredients!• Increased frequency of application!

Correct approach:• Reduce reliance on chemicals.• Alternation of chemical groups.• Targeted insecticide applications.

Organophosphates Carbamates

Pyrethroids

CHC’s“Organics”

IGR’s

Example of rotation program:

Benefits of insecticides:

• Can be effective if used correctly• Can provide an immediate solution• New formulations are safer • Target-specific modes of action are being

developed• Effective chemicals should be conserved as a

component of sustainable pest management programs.

Summary

• IPM requires pest and beneficial insect identification;

• Need effective means of managing these;

• Require economic information;

• Require training to encourage adoption.

Are fruit growers interested in IPM training and verification?

• What are the needs of growers in terms of training?

• Would verification be valuable to you?

• Should we proceed to develop verification guidelines?

Mark G. Wright

Department of Plant & Environmental Protection Sciences, CTAHR, UHM

Tel: 808 956-7670

Email: markwrig@hawaii.edu

Website: http://www.ctahr.hawaii.edu/wrightm