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Dr. Paula [email protected]
Department of Entomology
University of Maryland, College Park, MD
How to Attract Predators and Parasitoids to Improve Biological Control
Biological Control Conference
December 17, 2019
Today’s topics
• Arthropod services in managed environments
• Threats / factors that disrupt arthropods and their services that lead to pest outbreaks
• Concepts underlying conservation of natural enemies
• Practices to conserve natural enemies
• On-line resources
Insects provide vital ecosystem services
• Critical links in food webs and food chains
• Nutrient recycling, decomposition
• Pollination
• Biological control
Predators
Lady Beetle
Flower or Hover Fly
Diptera: Syrphidae
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M.J. Raupp
M.J. Raupp
Video by M.J. Raupp, UMD; Bug of the Week YouTube
Assassin bugsHemiptera: Heteroptera
Reduviidae
Video by M.J. Raupp, UMD; Bug of the Week YouTube
Parasitoids
www.obsessedbynature.com
C. Brodo, UMD
• More common in managed environments than natural ones…
• Why?
• How do we prevent or reduce pest outbreaks and their associated impacts?
Pest Outbreaks
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Factors disrupt arthropods by:
• Reduce abundance and diversity of natural enemies (habitat, food resources, movement, synchronization with host) herbivores perform better (top down factors)
• Effect plants so they are more nutritious and / or less defended herbivores perform better (bottom up factors)
• Result in pest outbreaks
Urbanization Gradient
• An environmental gradient with less
developed natural areas at one extreme
and highly developed areas dominated
by anthropogenic structures and inputs
at the other extreme
http://psahomes.com http://www.globalsiteplans.com
Threats to the sustainability of managed landscapes
1.Lack of plant and animal biodiversity
2.Substitution of exotic plants for native plants
3.Importation of exotic, invasive species
4.Climate change – the warming of our cities
5.Impervious surfaces – heat islands, water infiltration, compaction, stress
6.Anthropogenic inputs of nutrients and pesticides
Habitat modification
Conservation Biological Control and Conserving Beneficials
The deliberate attempt to maintain beneficial organisms (natural enemies, pollinators) in the nursery or landscape habitat
1. Enhancement of the habitat to promote beneficial survival and reproduction, and to attract and retain beneficials
2. Avoidance of activities that are harmful to or disrupt beneficials
Many natural enemies are pollinators
Many pollinators are natural enemies
R. Waterworth, UMDM. J. Raupp, UMD
P.M. Shrewsbury, UMD
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Many natural enemies are omnivores and need alternative food sources such as nectar, pollen and seeds
Today’s topics
• Arthropod services and pest outbreaks in managed environments
• Threats / factors that disrupt arthropods and their services
• Concepts underlying conservation of natural enemies
• Practices to conserve natural enemies
• On-line resources
Plant Diversity can be estimated different ways
•Species richness - number of plant species
•Structural complexity – vegetation found in a three dimensional space
Landscape biodiversity is important!
ground cover or turfherbaceous plants
shrubs
understory
overstory
Structural complexity
Shrewsbury and Raupp 2000, Environmental Entomology
Structural complexity = 70
Structural complexity = 225
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Number of Plant Species
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Plant and Arthropod Pest Species
P< 0.001, r2=0.18
Raupp et al. 2001
Increased plant species diversity
in a landscape results in more
potential alternate prey items to
support natural enemies.
Evidence shows that natural
enemies suppress pest
populations more often in the
presence of alternate prey
Why are there more predators and greater predator pressure in complex landscape habitats?
Additional food sources – alternate prey-Coriandrum sativum and Chrysanthemum maximum, increased alternate prey and
n.e. abundance and reduced survival of Stephanitis pyrioides – Shrewsbury, Lashomb,
Hamilton, Zhang, Patt, Casagrande
- Lobularia maritima, Coreopsis verticillata, and Panicum virgatum increased alternate
prey and n.e. abundance and reduced survival of Agrotis ipsilon - Frank and Shrewsbury
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Abundance in simple and complex landscapes
Complex landscapes have more alternate prey
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Do important predators respond to variation in prey abundance?
Shrewsbury and Raupp 2006, Ecological Applications
Structural complexity
Plant species richness
Refuges
Microclimates
Alternate food sources
(prey, nectar, pollen)
Is it possible to design or modify landscapes and nurseries with increased diversity to:- Reduce pests
- Increase natural enemies and pollinators
- Enhance ecosystem services
How could you do it?
Add flower and plant diversity
• What do we know already?
• What do we need to think about?
• How can you apply this information to increase biological control in systems where you work?
Add flowers
to landscapes
Shrewsbury et al. 2004, IJEES
RefugesMicroclimates
Alternate food sources(prey, nectar, pollen)
Shasta daisy and coriander around azaleas
Conclusions:
Azaleas with flowers
planted around them
had:
• Greater abundance of alternate prey
• Greater abundance of natural enemies
• Lower survival of azalea lace bug
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Conservation strips in Golf Courses
Tee
Green
Fairway Rough
Frank and Shrewsbury 2004, Enviromental Entomololgy
Nursery Ecosystems
P. Shrewsbury, UMD
P. Shrewsbury, UMD
• Nursery manipulations to increase structural complexity and plant species diversity, and favorable management practices
– Cover crops
– Grass alleys with flowers
– Hardwood mulch groundcover over weed cloth
– Pot-in-pot planting method
– Conservation strips / flowering plants
Benefits of cover crops
•Attract and retain natural enemies (biological control)•Floral resources, summer and winter habitat, alternate prey
•Reduce insect / mite pest damage
•Suppress plant parasitic nematodes
•Weed suppression
•Increase organic matter for soil improvement
•Root penetration to alleviate soil compaction
•Improve water movement
•Reduce soil erosion
•Addition of nitrogen (N) by N-fixing legume cover crops
•Alters nitrogen cycling by taking up N in the fall (likely reducing N leaching) and releases it in the spring when trees and shrubs need N
Nursery Cover Crop Project
Experimental design• Cover crops will be evaluated in 4 types of areas
common to most field nurseries 1) tree row bare zones 2) tree row fallow areas 3) grass alleyways4) open field areas
• Treatments– Cover crop species,combinations, and planting time
Tre
e
Row
Grass Alley
Grass Alley
Grass Alley
Bare Zone
Fallow Area
Tre
e
Ro
w
Tre
e
Row Fallow Area
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Bare Zone Tree Row Study
Forage radish, Raphanus sativus (Brassica)
Fall 2008
Bare Zone Tree Row Study
Crimson clover, Trifolium incarnatum (Legume)
Spring 2009
Bare Zone Tree Row Study
Alyssum, Lobularia maritima (Brassicaceae)
Summer 2009
Bare Zone Tree Row Study
Buckwheat, Fagopyrum esculentum (Polygonaceae)
Summer 2009
Nursery Cover Crop ProjectSunnhemp, Crotalaria juncea ‘Tropic Sun’ (Legume)
Fixes N, 5000 lb/acre dry weight, 100 lb
N/acre, adapted to infertile soils, grows well
with 8-16 weeks warm weather
Nursery Cover Crop ProjectOpen Field Areas: Percent of Ground with Cover
Crop, Weeds, and Soil
Nursery Oct. 2008
Forage Radi sh Sunn Hemp Conventi onal
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Note: Sunn hemp was killed by frost
prior to Nov. sampling
Forage radish seeded: 8/31/08
Sunn hemp seeded: 9/4/08
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Efforts towards the conservation of natural
enemies and pollinators
Obj. To evaluate the impact of beds of
flowering plants (conservation strips) in
production nurseries on:
• Pollinator abundance and diversity
• Natural enemy abundance
and diversity
• Biological control services
R. Waterworth, UMD
Shrewsbury and Waterworth, current study, 2017-18
Raemelton Farm and Ruppert Nursery
Efforts towards the conservation of natural
enemies and pollinators
• Seed mix of annual and perennial
flowers, native and exotic
– 19 species
– Select percentage seed of each
species
• Based on research that
demonstrated attraction of
pollinators and/or natural enemies (ex. attract parasitoids that attack scale
insects)
• Commercially available seeds
• Something blooming throughout the
season
Shrewsbury and Waterworth, current study, 2017-18
Colias sp on Symphyotrichum novae-
angliae
Results: # of Pollinator Species Collected by Plant
Common Name Plant Species #
Coreopsis Coreopsis lanceolata 20
Cornflower Centaurea cyanus 16
Butterfly milkweed Asclepias tuberosa 11
Grey-headed coneflower Ratibida pinnata 10
Cup plant Silphium perfoliatum 14
Spotted beebalm Monarda punctata 11
Sulfur cosmos Cosmos sulphureus 17
Rigid goldenrod Solidago rigida 4
New England aster Symphyotrichum novae-angliae 13
Smooth Aster Symphyotrichum laevis 18
Shrewsbury and Waterworth, current study, 2017-18
Size and arrangement of landscape beds
• How big do the conservation beds have to be?
• How close do the conservation beds have to be?
– Habitat patches that are bigger and closer to other patches tend to be better than smaller, isolated patches
– However, every plant counts
– Clumps of plants of the same species, within patches tend to be better than single plants
Plant Origin – Native or Exotic
• Function of the plant
– Will it survive / thrive in the habitat?
– Quality and availability of the pollen and nectar
– What does it attract and support?
• Avoid invasive or aggressive species
Plant Selection: Bloom period
From: Xerces Society – Pollinator-Friendly Plants – Mid-Atlantic Region at: http://www.xerces.org/pollinator-conservation/plant-lists/
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Sweet Alyssum
Coreopsis
Switchgrass
Plant Selection: Floral and Plant Architecture
Gaillardia
Liatris Yarrow
Plant Selection: type and species
• Plant / flower species– Research-based information
• Trees, shrubs, vines, wildflowers, herbs, perennials, annuals– Annuals tend to not be good sources of nectar and pollen, but there are exceptions (see: Protecting and enhancing pollinators in urban landscapes…)
• Diversify!
“Protecting and enhancing pollinators in urban landscapes for the US North Central Region”
-Provides information for landscapers and gardeners who want to attract pollinators and protect them when implementing pest management tactics-Plant lists-Timing of pesticide trts
http://msue.anr.msu.edu/resources/how_to_protect_and_increase_pollinators_in_your_landscape
Frank, Shrewsbury, & Esiekpe, 2008 Environmental Entomology (37:2)
MD Native plant species tested to determine
their attractiveness to natural enemies
Common name Scientific name Family
Common milkweed Asclepias syriaca Asclepiadaceae
Butterfly weed Asclepias turberosa Asclepiadaceae
Threadleaf coreopsis Coreopsis verticillata Asteraceae *
Hyssopleaf thoroughwort Eupatorium hyssopifolium Asteraceae *
Spotted horsemint Monarda punctata Lamiaceae *
Narrowleaf mountain mint Pycnanthemum tenuifolium Lamiaceae *
Skullcap Scutelaria integrifolia Lamiaceae
Switchgrass Panicum virgatum Poaceae
Indiangrass Sorghastrum nutans Poaceae
Little bluestem Schizachyrium scoparium Poaceae
Frank, Shrewsbury, & Esiekpe, 2008 Environmental Entomology (37:2)
www.croatianworld.net
Coreopsis verticillata
Eupatorium hyssopifolium
www.ct-botanical-society.org
Monarda punctata
groups.ncf.edu
Pycnanthemum tenuifolium
www.ct-botanical-society.org
“Winners” -
MD Native
Insectary
Plants
Frank, Shrewsbury, & Esiekpe, 2008 Environmental Entomology (37:2)
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Eupatorium perfoliatum L.
Monarda punctata L.
Silphium perfoliatum L.
Potentilla fruticosa auct. non L.
Coreopsis lanceolata L.
Spiraea alba Duroi
Agastache nepetoides (L.)
Kuntze
Anemone canadensis L.
Angelica atropurpurea L.
MI Native Beneficial
Insectary Plants
Cup plant
Silphium
perfoliatum L.
http://nativeplants.msu.edu
Canada anemone
Anemonecanadensis L.
Shrubby cinquefoil
Potentilla fruticosa auct. non L.
Meadowsweet
Spiraea alba Du Roi
Yellow giant hyssop
Agastache nepetoides (L.) Kuntze
Angelica
Angelica atropurpurea L.
MI Native Beneficial
Insectary Plants
http://nativeplants.msu.edu/pdf/E2973.pdf
-Native plants
-Pollinators and natural enemies
-Table of plants, bloom times, and rating of attractiveness to natural enemies and pollinators
From: MSU – Attracting Beneficial Insects with Native Flowering Plants at: http://nativeplants.msu.edu/pdf/E2973.pdf
Plant Selection: Plants to conserve beneficials
Impervious Surfaces
Disrupt movement and
colonization of herbivores
and/or natural enemies
Creation of heat islands
Host quality and accessibility
•Vary dramatically across urban gradients, fragment habitats, affect
plant density, alter thermal regimes and plant-water relations, and
inhibit movement of herbivores and their natural enemies
Reduced connectivity of green space
Urban green space
-types: residential gardens, parks, motorways, traffic
circles, green roofs / walls, community gardens
-design: connectivity and spacing, number / amount of
green space, plant selection
-benefits: sustain biodiversity (plants, arthropods,
wildlife) and ecosystem services, movement, reduce
arthropod outbreaks, reduce heat island effects, rain
water impacts (erosion, runoff), carbon sequestration,
improved mental health / quality of life
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Habitat Manipulation -Recommendations:• Increase structural complexity
– More plants at different vegetational strata– More green space
• Increase plant biodiversity– More plant species, families– Include trees, shrubs, vines, perennial flowers and herbs
• Add flowers– vary architectural complexity– provide overlapping and season long bloom
• Select plants based on proven attractiveness and the natural enemies and pollinators they attract
• Provide nesting and egg laying sites
• To provide:– a community of plant species that attracts diverse natural
enemy and pollinator taxa and provide habitat, nectar and pollen throughout the season
Do insecticide reduce abundance and disrupt activities of natural enemies resulting in loss of top-down regulation?
Secondary pest outbreaks associated with insecticide applications in urban areas
Target pest: Outbreaking pests:
Japanese beetle citrus red mite, woolly whitefly, purple scale
Mosquitoes pine needle scale
Filth flies European fruit lecanium
Hemlock woolly adelgid spruce spider mite, hemlock rust mite
Asian longhorned beetle Scheonei spider mite
Unknown (cover sprays) euonymus scale, white prunicolascale, pine needle scale
Impacts of a neonicotinoid, neonicotinoid–pyrethroid premix, and anthranilic diamide
insecticide on four species of turf inhabiting beneficial insectsJ.L. Larson, C.T. Redmond, D.A. Potter, 2014, Ecotoxicology
Compared the impact of:
– a neonicotinoid (clothianidin [Arena])
– a premix (clothianidin [Arena] / bifenthrin [Talstar])
– an anthranilic diamide (chlorantraniliprole [Acelepryn])
Four species of beneficial insects:
• Harpalus pennsylvanicus, an omnivorous ground beetle
• Tiphia vernalis, an ectoparasitoid of scarab grubs
• Copidosoma bakeri, a polyembryonic endoparasitoid of black
cutworms
• Bombus impatiens, a native bumble bee
Impacts of a neonicotinoid, neonicotinoid–pyrethroid premix, and anthranilic diamide
insecticide on four species of turf inhabiting beneficial insectsJ.L. Larson, C.T. Redmond, D.A. Potter, 2014, Ecotoxicology
Results:Clothianidin (Arena) or the premix (clothianidin / bifenthrin
(Talstar))
• Ground beetles suffered high mortality
• Reduced parasitism by Tiphia vernalis
• Copidosoma bakeri wasps suffered high mortality
• Reduced numbers of workers in bumble bee colonies
Chlorantraniliprole (Acelepryn)
• No apparent adverse effects on any of the beneficial species
Impacts of a neonicotinoid, neonicotinoid–pyrethroid premix, and anthranilic diamide
insecticide on four species of turf inhabiting beneficial insectsJ.L. Larson, C.T. Redmond, D.A. Potter, 2014, Ecotoxicology
Recommendations:• Adjust application timing and avoid seasonal activity of adult parasitoids
• Do not apply to blooming, pollen-shedding, or nectar-producing parts of
plants that may be visited by bees
• Control spring-flowering weeds:
o mow to remove flower heads before or immediately after the
application OR
o wait until after weeds have finished blooming
• Use granular formulations, as opposed to sprays, to reduce exposure of
residues to bees and above-ground parasitoids
• Use target-selective insecticides. Compared to neonicotinoids,
chlorantraniliprole (Acelepryn) has no adverse effect on beneficials, and:
o similar strong efficacy against scarab and billbug larvae
o better activity against caterpillars
o less active against sucking pests
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EPA Reduced Risk Pesticides
• Acequinocyl – miticide
• Bifenazate – miticide
• Pymetrozine – aphids, whiteflies
• Spinosad – caterpillars, sawflies, leafmining flies
• Tebufenozide – caterpillars
• Acetamiprid – many sucking insects
• Chlorantraniliprole – caterpillars, grubs, lace bugs, clearwing borers
• Cyantraniliprole – aphids, lace bugs, Jap. beetles, leaf beetles, caterpillars, leafminers, soft scale, thrips, whitefly
Organic Materials Review Institute (OMRI)
• OMRI - a nonprofit organization founded in 1997.
• Provides organic growers, manufacturers, and suppliers
an independent review of products intended for use in
certified organic production, handling, and processing.
• Acceptable products are OMRI Listed® and appear on
the OMRI Products List© or OMRI Canada Products
List©.
• OMRI lists 184 insecticides for a wide variety of pests
including those in landscapes
“Protecting and enhancing pollinators in urban landscapes for the US North Central Region”
-Provides information for landscapers and gardeners who want to attract pollinators and protect them when implementing pest management tactics-Plant lists-Timing of pesticide trts
http://msue.anr.msu.edu/resources/how_to_protect_and_increase_pollinators_in_your_landscape
• Choose pesticides wisely!
– Low toxicity, selective, short residual activity, IGR
– EPA Reduced Risk or OMRI listed pesticides
– Read and follow label directions carefully!
• Integrate alternative control measures (IPM)
– Cultural, mechanical, or biological tactics
Recommendations
Threats to the sustainability of managed landscapes
1.Lack of plant and animal biodiversity
2.Substitution of exotic plants for native plants
3.Importation of exotic, invasive species
4.Climate change – the warming of our cities
5.Impervious surfaces – heat islands, water infiltration, compaction, stress
6.Anthropogenic inputs of nutrients and pesticides
Why we want to attract and retain natural enemies in managed environments…
Video by M.J. Raupp, UMD; Bug of the Week YouTube
Wheel bug stalking a caterpillar
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2020 ADVANCED LANDSCAPE IPM PHC SHORT COURSE
January 6 - 9, 2020University of Maryland Entomology Department & Maryland Extension Service
Description
• The annual Advanced Landscape IPM PHC Short Course is a recertification short course for arborists, landscape supervisors, IPM monitors, advanced gardeners, and others responsible for urban plant management.
Location
• Entomology Department in Room 1140 Plant Sciences Building on the University of Maryland campus in College Park, MD.
Dates
• Monday, January 6 - Thursday, January 9, 2020
Time
• Lecture: 8:00am - 3:00pm
• Lab (optional): 3:30 - 5:30pm (Note: Lab is full)
https://landscapeipmphc.weebly.com/
Contact for information:
Amy Yaich, Admin. Assist. II
Department of Entomology
University of Maryland
Phone: 301-405-3911
E-mail: [email protected]
THANK YOU!
Paula Shrewsbury, Ph.D.
University of Maryland
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