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 grain.

B.C

.: Sulfur, herbs and oils used to protect seeds and stored • 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.

Gain thres hold  Management costs Market val ue GT  $10 / acre $2 / bushel  5 bushels per acre • Insecticide application would have to save 5 bushels per acre to be profitable

Economic threshold

• Also called

Action Threshold

– Insect density that would justify intervention • May be a 6 insects per plant, intervene at 4 insects per plant;

fixed

economic threshold: e.g. if EIL is

12 Economic loss 10

Non-economic loss

8 6 4 2

No loss

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Time

12 10 Economic injury level: 8 6 4 Economic threshold 2 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Time 15 16 17 18 19 20 21 22 23 24 25

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

natural enemies to be effective.

of

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

1

Build-up of resistance:

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.

Example of rotation program: Pyrethroids IGR’s Organophosphates Carbamates “Organics” CHC’s

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: [email protected]

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