bees, pesticides, and politics · 2018. 7. 21. · bees pollinate our gardens and plants that...
TRANSCRIPT
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7/18/2018
Pesticide Applicator Recertification Credit
Check in at the table in the back of the room for special instructions.
The following states offer credit for this session:
Daniel A. Potter, ProfessorDept. Of Entomology, Univ. of Kentucky
Bees, Pesticides, and PoliticsChallenges and Opportunities for the
Horticulture Industry
Early one June 2013 morning at an Oregon shopping center parking lot……
Shortly later, as shoppers begin to arrive…
50,000 dead and dying bees
Oregon Dept. of Agriculture officers
Endangered species conservation biologists
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More backlash…..
“This product is highly toxic to bees… Do not apply or allow it to drift to blooming crops or weeds if bees are visiting the treatment area”
The Oregon bee kill resulted from a label violation
Why all this attention on bees?
What challenges and opportunities does this issue for the Horticulture Industry?
Growers, Garden Centers, Landscapers
Land Care Industry
Why care about bees?
Bee pollination services to US Agriculture valued at $20 billionper year
Cherries
Tomatoes
Melons, squash
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Without bees, they’ll all be off the menu
The California almond industry alone requires use of 1.4 million honey bee colonies!
Why conserve urban bees?
Bees pollinate our gardens and plants that provide food for urban wildlife
Pollinator‐Friendly Plants and Land Care Benefit the Industry
Honey bees are not native to America
Brought here by early colonists in the 1600s 4000 species of native bees also provide pollination services in the USA!
Besides honey bees…
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Sweat bees (Halictidae)Mason, resin, & leafcutter bees (Megachilidae)
Bumble bees (Apidae) Mining bees (Andrenidae)
Some Familiar Native Bees Bees and Wasps are NOT the same
Mason bee nest
Feeding time!
Bees feed their young on pollen and nectar
Fuzzy, with branched hairs
Body adapted to carry pollen
Bees and Wasps are NOT the same
Wasps have little to no hair
Wasps feed their young on meat!
Honey bees are docile unless hive is threatened, and native bees rarely sting
Most stings in urban settings are from wasps!
Honey bees and native pollinators have been having a tough time of it Why are bee populations
declining?
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Most scientists agree that there is no single cause for declining bee populations
Rather, interactions between multiple stresses are involved
Varroa mites: #1 pest of honey beesSuck blood and transmit deadly bee diseases
Yikes!!
Nosema fungus causes “dysentery” in bees
Exotic bee diseases
Deformed wing virus
Why are honey bees declining?
Honey bee diseases are spilling over into native bee populations
Why else are honey bees declining?
Good Not good
Real honey boosts baby bees’ immune systems
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Why are honey bees declining? Why are honey bees declining?
Travel stress!
Didn’t I use to live here?
Why are ALL bees declining?Habitat loss
Why are ALL bees declining?Environmental stressors
Less varied, less nutritious pollen & nectar
Acute or chronic exposure to pesticides
DiseasesParasitic mites
Habitat LossStressful management practices
Acute and chronic pesticide exposures
Parasites, diseases
Insecticide exposure
Other stressors
One stress can increase bees’ vulnerability to others
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Varroa mites, diseases, management stress, habitat loss
It is hard to recover from a concussion…
Insecticide exposure
If you are also being kicked in the head
Public perception is that pesticides, esp. neonicotinoid insecticides are the main cause of bee decline
Conflicting studies and media coverage… What are neonicotinoids and why does the Land Care Industry use them?
Treated
Not Treated
Neonicotinoids are relatively long‐lasting so they can provide extended pest control
Emerald ash borer
White grubs
TreatedNot Treated
Neonicotinoids are systemic insecticides
They move upward in the plants’ vascular system to all parts of the plant
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Systemic applications are often more practical and less hazardous than sprays
This…… Or this…
Psyllids
Lace bugs
Scale insects
Neonics are very effective for systemic control of:
Leaf miners
Whiteflies
Aphids
Urban landscapes account for a tiny fraction of neonicotinoid use
Douglas & Tooker Environ. Sci. Technol. 2015
Turf & landscape (purple line)
But… the Horticulture Industry is “low‐hanging fruit” in the debate about banning pesticides
The “bee issue” has become the new driver for those pressures
Managing Pests Safeguarding Pollinators
Growers and Land Care Professionals
Between the Devil and the Deep Blue Sea……..
… that does not mean that neonics are harmless to bees!
Although it is very unlikely that horticultural use of neonics is impacting bee populations….
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Bees can potentially be exposed via contact orsystemic transference into pollen and nectar
At high enough dosages, neonicotinoids can kill bees outright and also impair colony function
The research shows:
Emerald Ash Borer Impact: Toledo Ohio
Before (2006) After (2009)
Fact: All current effective insecticides for EAB are systemic and intrinsically toxic to bees.
Question: Would saving these trees have been justified?
Photos: D. Herms, OSU
Is there an acceptable threshold for bee hazard from insecticides in urban landscapes?
If so, how should it be balanced against the pest management benefits?
Question: Can we establish Best Management Practices for integrated pest and pollinator management (IPPM)?
Model system for lawn studies:
White clover intermixed with cool‐season turf
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Eusociality when first workers emerge
Queens overwinter, each starts a new colony in early spring
New queens seek overwintering sites, colony dies out
Midsummer switch to producing new queens and males
More workers produced, colony grows
Gynes emerge, mating and outcrossing
Solitary Phase(first few weeks)
Neonicotinoids
We compared lawn insecticides from two chemical classes:
Clothianidin
Imidacloprid
Anthranilic diamide
Chlorantraniliprole
Applications were at typical timing for preventive grub control
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
MASKED CHAFERLIFE CYCLE
MASKED CHAFERLIFE CYCLE
Insecticides were applied at label rate and watered in; bees were introduced 1 day later
Hives started with queen & 20 workers
30 open‐bottom cages
When colonies were checked after 6 days’ exposure we saw:
58% fewer live bees3‐fold more dead bees
No adverse effects
GaineswayHorse Farm
Colonies then moved to safe foraging site and left for 6 weeks
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Weighing colonies in the field
Get him!!
Get him!!
Larson et al PLOS One 2013
Colonies that had foraged for 6 days on neonic‐treated weedy turf struggled to grow Evaluating Colony Health
Non‐treated or Acelepryn‐treated
Neonicotinoid ‐treated
The neonic‐exposed colonies were too weak to reproduce (i.e., no new queens)
Larson et al. 2013
Will bees avoid sprayed flowers?
Larson et al PLOS One 2013
Spraying plots Counted bees for each day for 1 week
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Will bees avoid sprayed flowers?
NO!
Untreated
Take home points:
Direct exposure to neonic residues on flowering lawn weeds is harmful to bees!
Our research did identify some ways to reduce neonic bee hazard in lawn care:
Mow flower heads before or after treatment
Granular formulations pose less hazard than sprays
Hooray!
Another key point:
Acelepryn is an effective, non‐neonic lawn insecticide that is non‐hazardous to bees
This work has been shared with thousandsof practitioners and is helping the industry to adopt more “bee‐friendly” lawn care
How can we reduce systemic insecticide hazard to bees on woody landscape plants?
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Foster holly Clethra
Residue Studies on Woody Landscape Plants
2 neonics
3 treatment timings
Hawthorn
Post BloomNovember Pre-bloom
imidacloprid dinotefuran
200‐300 flowers = 1 sample
Twigs with blooms mounted in tubes
Extracting Nectar for Residue Analyses
Collecting flowers Prepping flowers
Spin out the nectar
The research showed:
Probably OK if applied post‐bloom
Hazard remains the following spring even if used post‐bloom
Take‐home point:
Avoid using neonicotinoids on bee‐attractive plants unless there is no other way to protect the plant
Or, prune to remove flower buds
Treat ASAP after bloom
If you must treat bee‐attractive woody plants with systemic insecticides….
Controls caterpillars, beetles, and sawflies
What are some alternatives?
Short‐residual products should be OK so long as not applied during bloom:
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New EPA Bee Advisory Box An harder question:
Do neonicotinoids impact bee health at the landscape level?
Hazard = Toxicity x Exposure
High exposureHigh hazard
Low exposureLow hazard
Urban bees visit many types of plants, only a small fraction of which are ever treated
High risk of exposure Much lower risk
Consumer attractive plants
Bee attractive plants
Treated plants
Relatively few plant species meet all three criteria
Linden
‘Single’ roses Hawthorn BoxwoodsHybrid roses
Ash treesCherrylaurel
Conifers
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Keep the Cost/Benefit in Perspective!
Emerald Ash Borer Impact: Toledo Ohio
Before (2006) After (2009)
Pollinator‐friendly land care is good for the industry
Lots of folks want to help the pollinators
My granddaughters Adele and Evie; Halloween 2017
The best way to help urban pollinators is to give them more and better food!
Best Trees and Shrubs for Bees A single tree or shrub can provide 1000s of flowers with high‐quality pollen and nectar
Kentucky yellowwood
Summersweet (Clethra)
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Listmania!We sampled 75 species of woody landscape plantsFive sites (replicates), 250 bees per plant species>18,750 bees identified
375 Sample Sites!
Municipal and Institutional landscapes
Cemeteries Home landscapesArboreta
Street trees
We compared plants’ attractiveness to bees by timed “snapshot counts”
Then we collected and identified 250 bees from 5 sites per plant species
Different woody ornamentals attract unique bee assemblages
Flowering crabapple Fuzzy Deutzia
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Bee diversity and species richness vary by plant species
Mock Orange (Philadelphus)
Chaste tree(Vitex)
Non‐nativeNative
Chelosoma philadelphi
Flower Form Matters!
Hydrangea paniculata
Hydrangea arborescens
Prairie rose
Hybrid tea rose
Good!
Pretty useless
Are natives best for bees?
Not necessarily!!
Non‐natives and natives can be equally attractive!
Non‐native plant
Average Snapshot Counts
Both can attract diverse bee assemblages
Beebee tree
Higan cherrySeven sons flower tree
Devil’s walking stickAmerican yellowwood
Bottlebrush buckeye
Winged sumac
Eastern redbud spiraea
Cornus mas
Native Non‐native
Chaste tree
Some GREAT shrubs for bees
Sweetspire (Itea)
Glossy abelia
Winterberry holly
SummersweetClethra
Dwarf fothergilla
Buttonbush
Virginia spiraea
Fuzzy deutzia
St. John’s Wort
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Spring Early Summer Late Summer
Serviceberry Bottlebrush buckeye Bee bee tree
Crabapple Climbing prairie rose Winged sumac
False Indigo Clethra Glossy abelia
Eastern redbud Hydrangea paniculata Seven son flower tree
Cornelian cherry St. John's wort Chaste tree
Winter king hawthorn Winterberry Devil's walking stick
American yellowwood Golden rain tree Buttonbush
Foster's holly Amur maackia
Flowering cherry Virginia spirea
How to Build a Bee‐Friendly Landscape(Choose some from each column)
On Horticultural Research Institute Website……
Marketing opportunities for growers and retailers
Many of the best “bee magnets” are also nearly pest‐free!
False Indigo St. John’s Wort Bee Bee Tree Chaste Tree
Glossy abelia Seven‐Son Flower Amur Maackia Black gum
Native plants are good, but mixing in some (non‐invasive) exotics can buffer bees from seasonal gaps in flower availability
Early spring Summer Autumn
Cornelian cherry dogwood
Bottlebrush buckeye
Seven sons flower tree
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Monarch butterfly: a beloved, iconic species
Monarchs migrate to and from overwintering grounds in Mexico
The eastern migratory population of monarchs is in serious decline
Billions of stems of milkweed have been lost from the monarch breeding grounds in the US Midwest
Planting milkweed is key to the North American Monarch Conservation Plan
Seed Kit: $16
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Demand for milkweed transplants is booming
Butterfly Milkweed Common MilkweedSwamp Milkweed Narrow‐leaved
Milkweed
Green Milkweed Showy MilkweedWhorled MilkweedBroad‐leaved Milkweed
Which Milkweeds are Best?
Common MilkweedSwamp Milkweed Showy Milkweed
Best Milkweeds for Monarchs
Yum!Best Milkweeds for Bees
Butterflyweed(Asclepias tuberosa)
Whorled milkweed(Aclepias verticillata)
New study confirms monarchs quickly find and use milkweeds in small urban gardens!
What Garden Design Attracts More Monarchs?
Milkweed Outside Milkweed Inside Mixed
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Milkweed around perimeter
Place the milkweeds around the perimeter, set off by mulch
Garden Design Matters for Monarchs! Cultivars with double blooms or covered with sterile sepals often have little value to pollinators
Do horticulturally‐selected milkweed cultivars have the same conservation value as straight species?
Asclepias incarnataSwamp Milkweed
‘Soulmate’ ‘Ice Ballet’ ’Cinderella’
Asclepias tuberosaButterfly Milkweed
‘Hello Yellow’ ‘Gay Butterflies’ ‘Blonde Bombshell’
Are horticulturally‐selected milkweed cultivars as good as straight species?
So far, the research says “yes!”
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One last example: Operation Pollinator for Golf Courses
Seed mix developed for Ohio Valley Region
Primary species:
Lanceleaf Coreopsis Bergamot Black‐eyed Susan New England Aster
Prairie coneflowerPlains Coreopsis Purple coneflower
And…. smaller amounts of others to add variety and interest
Establishing KY Operation Pollinator Plots
Scalp Herbicide
Scarify and rake
Seed
June 2013 July 2013
Lakeside GC, Lexington (same site)
We documented 49 types of bees and butterflies, including three declining bumble bee species, in our plots on KY golf courses
‐ Dobbs and Potter 2014
Operation Pollinator has been implemented on hundreds of golf courses in 30 states
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Take home point: Conserving pollinators benefits urban habitats
Take Home Points:
Diversify landscapes with pest‐resistant flowering plants
[Both natives and non‐natives can help to support pollinators]
Pollinator‐Friendly Plants and Land Care Benefit the Industry!!
Can the public’s empathy for pollinators help turn these…………. into these?
Research Supported by: Thanks!
Nursery/Landscape Endowment Fund