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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: [email protected]
• 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!!!
