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Fruit and Vegetable Pest Management

Sheriden Hansen

Assistant Professor | Horticulture

USU Extension | Davis County

INTEGRATED PEST MANAGEMENT

• What is integrated pest management (IPM)?• A philosophy of pest control founded on

ecological principles

• Involves using SEVERAL control tactics based on:• Knowledge of the CROP, PESTS, and associated

NATURAL ENEMIES

• Goal is to AVOID CROP LOSS and MINIMIZEharmful effects on the environment.

INTEGRATED PEST MANAGEMENT

• More tolerant approach to pest control than traditional insect-based programs.

• Conserves natural enemies

• Does not eliminate all of the pests

• Some damage (usually to foliage) is tolerated, less tolerance on fruit

BENEFITS OF IPM

• Greater survival of natural enemies

• Slower development of resistance

• Less pest resurgence

• Fewer outbreaks of secondary pests

• Less negative impact on the environment

• Safer for gardeners and those eating produce

HISTORY OF IPM

• Synthetic pesticide era launched after WWII

• In 1936 there were 30 registered pesticides

• By 1972 there were more than 900

• Chemicals were EFFECTIVE, EASY TO USE, and INEXPENSIVE

HISTORY OF IPM

• Broad spectrum pesticides were the answer to most pest problems

• Sprays were being used on a routine, preventative basis whether they were needed or not

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RESISTANCE

• Insects began to develop RESISTANCE to insecticides

• RESISTANCE is a significant decrease in sensitivity to a pesticide

• A population is made up of individuals that vary in genetic make-up. Dogs come in many variations such as lab, border collie, husky, pug – but all are dogs

RESISTANCE

• Resistance is the ability of one of the variants in the population to survive pesticide exposure

• All of the dogs are susceptible to the chemical, except the Labrador

• The Labrador then has puppies that are also resistant

• Now you can’t control the Labradors…

RESISTANCE

• In the population of squash bugs that you have on your squash plant, one or two may be unaffected by the application of chemicals.

• Surviving members are referred to as RESISTANT to the pesticide

RESISTANCE

• Resistance is the NATURAL ABILITY of a variation of the organism to survive exposure to a pesticide that would normally kill an individual of that species.

• This occurs with INSECTS, WEEDS, FUNGI, and other pests.

HOW DOES RESISTANCE OCCUR?

• The resistant pest survives the repeated exposure and reproduces, creating more resistant pests

• The population of this organism can become dominated with this resistant variation

• The pesticide is no longer effective

BUT…

• If resistance is MANAGED from the beginning using IPM, pesticides remain effective and useful

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BACK TO OUR STORY…

• Pests that had been naturally kept in check before the pesticide era were now becoming pests… WHY?

• Natural enemies were being eliminated with the application of chemicals

• Populations of pests were RESURGING• killing natural enemies, leads to an increase in

the target population

CHEMICAL CONTROL CYCLE

• Growers then applied MORE TOXIC products to control SECONDARY PEST outbreaks• Some pesticides promote pest activity

• Carbaryl and imidacloprid are known to INCREASE spider mite reproduction

• Growers were trapped in a cycle of using more and more chemicals to treat a single pest problem

CONVENTIONAL PEST MANAGEMENT

• This reliance solely on chemical control is called Conventional Pest Management

• Annual sprays are done based on a calendar date only

• There is no thought about the chemicals being used

• Lacks a system-wide perspective

MITE CONTROL LED TO IPM

• In the 1950’s and 1960’s mite populations were out of control in apple orchards

• Quickly developed resistance to miticides

• If predatory mite populations were allowed to rise at the right time, they controlled the spider mites

SUCCESS OF INTEGRATED MITE CONTROL

• Integrated mite control became so successful that orchardists in the Pacific Northwest have not had to apply miticidessince the 1960’s

IPM DEFINITION

• IPM is a SUSTAINABLE APPROACHto managing pests by COMBININGbiological, cultural, physical, and chemical tools in a way that MINIMIZES economic, health and environmental risks

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COMPONENTS OF IPM

• KNOWLEDGE• Of the pest

• The pest biology

• The host plant

KNOWLEDGE• The pest?

• Mite

• The pest biology?• Overwinter under leaf bud scales

• Emerge in the spring

• Many generations over the summer

• Will reduce apple size and decrease photosynthesis

• The plant? • Apple

KNOWLEDGE• What to do?

• Encourage predatory mites

• Application of dormant oil before leaf bud break

• Can combine with carbaryl

• Application of sulfur (not with dormant oil)

KNOWLEDGE

• The Pest?• Coryneum Blight

• The pest biology?• Fungus• Overwinters in infected

buds and cankers• Wet springs – moisture on

leaves and fruit

• The plant?• Stone fruits

• What to do?• Prune out infections• Application of a fungicide at

shuck fall (one time!)

HOW DO I KNOW WHAT I AM DEALING WITH?

• Unsure?• Every state has a plant pest diagnostic laboratory

• In Utah: Utah Plant Pest Diagnostic Lab (UPPDL) on campus in Loganwww.utahpests.usu.edu/uppdl

• Call your county extension office and ask for help• Davis 435-919-1336 (Diagnostic clinic: Thursdays 9-noon, Mid-April to Oct.)

Email: usudavishotline@gmail.com

• Weber 801-399-8200• Box Elder 435-695-2542• Salt Lake 385-468-4828 (Diagnostic clinic hotline)

COMPONENTS OF IPM

• KNOWLEDGE• Of the pest

• The pest biology

• The host plant

• Monitoring for insect or disease occurrence• Visual observation

• Trapping

• Determining a Biofix

• Degree day model for estimating insect activity and treatment

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WHY MONITOR?

• Provides early warning of potential pest problems

• Determines which life stage is active for both pathogens and insects

• Helps determine if you should treat

• Determine if your management strategies are working

WHEN TO MONITOR?

• SPRING TO SUMMER• Once per week

• LATE SUMMER• Every other week

WHAT DO I NEED TO MONITOR?

• Hand lens is helpful• Helps see tiny insects (like mites)

• Helps see signs of disease

• 10x – 30x

• Search online for “Jeweler’s Loupe” or “Hand Lens”

HOW DO I MONITOR?

Brown Marmorated Stink Bugs Hatching

Visual observations

• Check under leaves, at the base of plants, look for small clusters of eggs or insects

• Look for signs of disease, fuzzy growth, wilting plant parts, discolorations, oozing, etc.

• Can remove eggs and insects as you see them

HOW DO I MONITOR? TRAPPING

Traps• Sticky traps (many colors)

• Many contain attractants or pheromones

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TRAPPINGSticky Traps

• Can be used in orchards, gardens, greenhouses

• Monitor for first arrival of certain insects

• Helps you know the severity of the problem

Western Cherry Fruit Fly Apple Maggot Walnut Husk Fly

TRAPPING

Pheromone Baited Traps

• Pheromones are sex-hormones

• Secreted by one sex (usually the female) to attract to other

• Insects fly in a zig-zag pattern following pheromones

PHEROMONE TRAPS

• Why use them?• To monitor the population over time

• To get BIOFIX (biological fix)

• Biofix is the FIRST DATE at which moths consistently fly, or when more than two moths have been caught in a trap over two consecutive nights.

Peach Twig BorerCodling Moth Greater Peach Tree Borer

DEGREE DAY MODEL

• What are degree days?• Measurement of heat units over time

• Insect life cycles are dependent on temperature

• Specific range for specific insects

• Helps you pinpoint right stage/time to treat

DEGREE DAY MODEL

• USU Monitors degree days for a number of insects

• You can get alerts on when to spray and treat based on this model:

• Utah TRAPs app for android or iOS

• Website for pest advisories: https://pestadvisories.usu.edu/

KNOWING AT WHAT LEVEL TO TREAT

• Threshold Levels• How much damage are you willing to tolerate?

• Determines when you treat

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KNOWING AT WHAT LEVEL TO TREAT

Threshold for spider mites is 10 mites per leaf.

TIME TO TREAT!

USING AN INTEGRATED APPROACH

• Cultural control

• Sanitation

• Encourage natural biological control

• Select least-toxic pesticide option first

CULTURAL CONTROL

• Proper water management

• Mulches or groundcovers

• Optimal fertilization

• Using resistant varieties

• Good soil management

Tomato spotted wilt virus (TSWV)

SANITATION

• Clean field equipment• Sanitize pruners between cuts

(fireblight)

• Removing diseased/damaged tissue

• Quick removal of infested trees and plants

Tobacco mosaic virus

Early blight

BIOLOGICAL CONTROL

• Predators: seek out and eat multiple prey specimens

• Parasitoids: specialized insects that deposit egg(s) inside a host, eggs hatch and larva(e) develop, eventually killing the host

BIOLOGICAL CONTROL

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BIOLOGICAL CONTROL

• Pathogens: nematodes, viruses, bacteria, fungi, protozoans

BIOLOGICAL CONTROL

DEVELOP HABITAT

• Develop a habitat to promote beneficial insects

• Make it native, low-maintenance, and drought tolerant

USE AN INTEGRATED APPROACH - PESTICIDES

• “Reduced Risk” pesticides• Materials that the EPA has determined to be safer for humans and the

environment • Some are made from plants and plant derivatives

• Others are just considered “softer”

• https://www.epa.gov/pesticide-registration/reduced-risk-and-organophosphate-alternative-decisions-conventional

• Biopesticides• Made from micro-organisms or from their metabolites

• Avoid “broad-spectrum” pesticides

USE AN INTEGRATED APPROACH - PESTICIDES

• Application times:• Dormant

• Delayed dormant (starting at bud swell)

• Spring to summer cover sprays

RECORD-KEEPING• Keep a record of what you

applied

• When you applied it

• Rate that it was applied

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INSECT EXAMPLES - APPLE & PEAR CODLING MOTH

• Primary pest of apple and pear

• Damage occurs when larvae burrow into fruit to feed on seeds

• Can potentially infest 100% of the fruit on a tree or in an orchard

CODLING MOTH CODLING MOTH

CODLING MOTH

• Overwinter in silken cocoons under loose tree bark

• 7 to 30 day development period depending on temperature

• Three generations per year in Utah

• MONITOR!!!

• Moths fly at night

CODLING MOTH MANAGEMENT

• Cultural controls:• Thin fruit to one apple/cluster

• Remove unmanaged trees

• Clean and remove all unharvested or dropped fruit all season (sanitation)

• Monitor with traps (alerts from app)

• Insecticides (horticultural oils, Bt, spinosad, see fact sheet)

https://digitalcommons.usu.edu/cgi/viewcontent.cgi?referer=https://www.bing.com/&httpsredir=1&article=1879&context=extension_curall

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SAN JOSE SCALE

• Fruit tree pest

• Severe infestations can kill limbs, deform fruit, reduce yields, and kill trees

• Can be difficult to control, timing is key

• Delayed dormant period is when you would apply chemical control

SAN JOSE SCALE

SAN JOSE SCALE

• Armored scale – hard bodies

• Phase called “crawler phase” where they are soft bodied

• Crawlers resemble spider mites but have antennae

• Crawlers congregate at new growth

SAN JOSE SCALE MANAGEMENT

• Scout for infestations during dormancy (pruning is ideal time)

• Males can be monitored with pheromone traps (females don’t fly)

• Traps should be placed at PINK stage of apple bloom

• OR wrap double sided sticky tape around trunk to detect crawlers

• Traps app for biofix dates and alerts for crawler emergence and spray dates

SAN JOSE SCALE MANAGEMENT

• Chemical control at crawler stage• Horticultural oil combined with an insecticide

(delayed dormant)

• For list of chemicals see fact sheet: • http://extension.usu.edu/files/publications/publi

cation/san-jose-scale'97.pdf

• Biological control• Keep populations of natural enemies high

• Lady beetles and parasitoids

• Supplement with chemical control

SAN JOSE SCALE MANAGEMENT

• Pruning• Good pruning practices reduce scale

problems

• Prune out infested limbs and watersprouts

• Open canopy to allow for good spray coverage in the top of canopy

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INSECT EXAMPLES - VEGETABLES APHIDS

• Many different species (over 500 in Utah)

• Attack multiple vegetables and fruits (some host specific)

• Soft bodied, pear-shaped

• Multiple colors (green, red, purple, yellow, black)

• Can be winged or wingless

APHIDS

• Suck the phloem out of plants

• Mouthpiece called a proboscis (like a straw)

• Can reduce crop yields

• Can cause leaf twisting, rolling, galls or unsightly cottony masses

• Exude honeydew which can encourage fungal growth

APHIDS

• Do NOT need to mate to reproduce

• Give birth to live young in the summer

• Lay eggs in the fall that overwinter

APHID MANAGEMENT

• Tolerate certain levels of insects

• Encourage beneficial insects

• Wash off with a strong stream of water

• Apply insecticidal soaps to nymphs and adults

• Apply systemic insecticide (neonicitinoid) in the spring

• Apply a cover spray (pyrethroids) when aphids are present

https://utahpests.usu.edu/ipm/ornamental-pest-guide/arthropods/aphids-adelgids/other-aphids

SQUASH BUGS

• Pest of squash and pumpkin

• Plant damage includes:• Necrosis (tissue death)

• Scarred fruits, sunken areas

• “Sudden Wilt”

• Piercing, sucking mouthparts

• Can transmit diseases (vector)• Curcurbit Yellow Vine Disease (CYVD)

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SQUASH BUGS

• Prone to developing resistance to insecticides

• Preventative, cultural, and mechanical controls should be the first line of defense

• One egg cluster per plant is the treatment threshold

SQUASH BUG

• One generation per year

• Spend the winter as unmated adults in protected sites• Under plant debris

• Compost piles

• Around building foundations

• A female can lay up to 250 eggs

• New, summer generation of adults appears in June/July

SQUASH BUGS

• Eggs are small, long, oval shaped

• Can be yellow brown to brick red in color

• Laid in clusters on the underside of leaves• Spring to late summer

• Hatch in 10-14 days

SQUASH BUG MANAGEMENT

• Cultural Practices• Maintain healthy plants• Appropriate site selection• Soil preparation, fertilization• Irrigation

• Sanitation• Minimize populations of overwintering

adults

• Resistant Varieties• See fact sheet• https://extension.usu.edu/files/publica

tions/factsheet/ENT-120-08.pdf

SQUASH BUG MANAGEMENT

• Trap Crops and Traps• Includes squash varieties that are

attractive to overwintering squash bugs• Treat trap crops

• Trap insects with wooden boards, shingles, heavy cardboard

• Turn over and kill bugs in the mornings

• Crop Rotation

• Row Covers• Floating row covers or fabrics

SQUASH BUG MANAGEMENT

• Mechanical Destruction• Hand picking • Squashing eggs

• Promoting beneficial insects• Parasitoid wasps

• Insecticides• Should NOT be used as first

management• Combine with other strategies• See fact sheet• https://extension.usu.edu/files/publicati

ons/factsheet/ENT-120-08.pdf

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DISEASES – FIRE BLIGHT

• Bacterial disease of rosaceous plants Erwinia amylovora

• Most serious on apples and pears

• Spread by:• Insects• Splashing water• Contaminated tools• Wind

• Must have an opening in the plant • Blossom, fresh pruning cut, open wound

FIRE BLIGHT

• Signs and Symptoms • Scorched leaves, blossoms, and shoot

tips

• Wilting “shepherd hooking”

• Tissue turns black

• Cankers

• Oozing of an amber liquid (infectious)

• Progresses quickly and can cause whole plant death

FIRE BLIGHT MANAGEMENT

• Practices that promote excessive new growth should be avoided• Be careful with fertilization of fruit trees

• Frequent assessment of trees in the spring (1-2 x/week)

• Immediate removal of any blighted blossoms or twigs

• Prune any infections 8-12 inches below the infection

FIRE BLIGHT MANAGEMENT

• Dormant pruning • Look for cankers and prune out

• Remove suckers at base of the tree

• Sanitize pruners• Between cuts

• 10% bleach solution

• Remove disease hosts near trees• Cotoneaster, hawthorn, crabapple,

pyracantha

FIRE BLIGHT MANAGEMENT

• Do not wet tree canopy• Adjust sprinklers

• Avoid excessive watering to reduce humidity

• Plant less susceptible varieties• Geneva™ rootstocks for apples are

resistant

• See fact sheet for more resistant varieties

FIRE BLIGHT MANAGEMENT

• Delayed dormant Copper-plus-oil sprays• Silver tip to green tip

• Bordeaux mixture

• See fact sheet:• https://digitalcommons.usu.edu/cgi/viewconte

nt.cgi?referer=https://www.bing.com/&httpsredir=1&article=1900&context=extension_curall

• Agricultural antibiotics • For commercial operations

• Timing of application is critical

• Get alerts with TRAPS app

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IN CONCLUSION

• IPM promotes BEST practices

• Combines cultural, mechanical, biological, sanitation, and pesticide application practices to provide the best treatment

• Protects beneficial insects

• Safer for humans

• Pesticides are used in combination with other practices or as a last resort

A WORD OF CAUTION…

NEVER USE A CHEMICAL PESTICIDE IN A MANNER THAT IS INCONSISTENT

WITH ITS LABELED INSTRUCTIONS, IT IS A VIOLATION OF FEDERAL LAW.

THE LABEL IS THE LAW!

QUESTIONS?

Can bees fly in the rain?

NOT WITHOUT THEIR LITTLE YELLOW JACKETS!!!