nutrient recycling, decomposition pollination services ... · 1/2/2020 3 bacillus thuringiensis...
TRANSCRIPT
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Beneficial arthropods: Natural enemies and pollinators
Paula Shrewsbury, Ph.D.Department of Entomology
University of [email protected]
Landscape IPM Short Course January 2020
Insects provide critical ecosystem services
• Critical links in food webs and food chains
• Nutrient recycling, decomposition
• Pollination services
• Biological control
Insects provide critical ecosystem services
• Critical links in food webs and food chains
• Nutrient recycling, decomposition
• Pollination services
• Biological control
Insects provide critical ecosystem services
• Critical links in food webs and food chains
• Nutrient recycling, decomposition
• Pollination services
• Biological control
Habitat modification
Biological Control
• The use of predators, parasitoids, and pathogens to suppress pest populations below damaging levels
• Natural enemies
• Occur naturally, some commercially available
Syllabus – starting on pg. 159
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Specialist• an organism that feeds on only
one type (species, family) of prey or host
Ex. Wasp parasitoid that only attacks EAB eggs (Oobius agrili)
Generalist
• an organism that feeds on more than one type of prey or host
Omnivore• an organism that feeds on
both animal (insect prey) and plants (nectar and pollen, seeds)
Pathogens(Entomopathogenic)
• Microorganisms such as bacteria, viruses, fungi, and nematodes that cause disease in insects
• Occur in nature; commercially produced for pest managment
Pathogens• Enter insects through the
exoskeleton, body orifices, or by ingestion of food
• Multiplies within host insect and resulting disease kills host
• Spread when host’s body disintegrates or through feces
Pathogens
• Microorganisms such as bacteria, viruses, fungi, and nematodes that cause disease in insects
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Bacillus thuringiensis (B.t.)• Soil bacterium, common in nature• Over 30 subspecies and varieties• Produces a protein crystal• Crystal toxicity is insect specific• Produced and used commercially for many
years (formulated biological control)
Bacillus thuringiensis (B.t.)
• Most effective on young larvae• Mode of action
–Ingested by larvae
• Feeding inhibition in 1 hour• Death in 2 – 5 days
B.t. Varieties and Pests Controlled
• B.t. kurstaki or morrisoni– Caterpillar larvae
• B.t. israeliensis– Mosquito, black flies, fungus gnat larvae
• B.t. San Diego– Leaf beetle larvae
• B.t. galleriae– Scarab beetle grubs, adults; weevils; flat headed
beetles (beetleGONE; grubGONE; borerGONE)
Pathogens
• microorganisms such as bacteria, viruses, fungi, and nematodes that cause disease
Viruses
• In nature, greatest impact when caterpillars and sawflies are at very high populations
• Commercially not practical
Pathogens
• microorganisms such as bacteria, viruses, fungi, and nematodes that cause disease
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Entomopathogenic Fungi
Metarhizium anisopliaeBeauvaria bassiana
Commercial Products
• Best results seen in greenhouses against aphids, spider mites, and thrips
• Also used for white grubs, locusts, mosquitoes, others
Fungi Mode of Action• spores adhere to insects body
• spores germinate
• spore tube penetrates insect (enzymes)
• fungi enters circulatory system
• reproduces inside insect
• toxins produced and kills insect
• fungal hyphae emerge from insect
• infective spores are released
Image by N. Breisch and W. Fang, UMD
Wild type and genetically modified fungal strains
Pathogens
• microorganisms such as bacteria, viruses, fungi, andnematodes that cause disease
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EntomopathogenicNematodes
Steinernema species
Heterorhabditis species
Nematode and Bacteria
• Mutualistic association– Nematodes require bacteria as food to
grow and multiply
– Bacteria require nematodes to locate insect hosts in which they grow and multiply
• Steinernema spp. / Xenorhabdus sp.
• Heterorhabditis spp. / Photorhabdus sp.
Entomopathogenic nematode life cycle
Commercially Available Nematodes
NematodeS. carpocasae
S. glaseri
S. riobravis
S. scapterisci
S. feltiae
H. bacteriophora
H. megidis
Insect (major markets)Caterpillars (turf, mint, retail)
White grubs (turf)
Mole crickets (turf), Citrus weevils (citrus)
Mole crickets (turf)
Fungus gnats (ornamentals, mushrooms)
White grubs (turf), root weevils (ornamentals, citrus, berries)
Genera: Steinernema and Heterorhabditis
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Images from: NYS Ag. Exp. Station
Signs of attack by pathogen natural enemies
www.umassgreeninfo.org
Scale images from: www.walterreeves.com
Do insects defend themselves against pathogens?
• Behaviorally – grooming
• Chemically – stink bugs, bed bugs
Parasitoid• generally a small insect that
slowly kills and consumes a larger insect called the host
• develop in or on its host
Common Parasitoid Groups
• Hymenoptera - Wasps
• Diptera - Flies
Wounding of scale by parasitic wasp
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Host feeding on scale by parasitic wasp
Endoparasitoid
• a parasitoid that develops and feeds inside its host
Ectoparasitoid
• a parasitoid that develops outside of its host while feeding through the host’s cuticle
Aphid mummies
Estimating Parasitism Rate
• Small, mobile, hard to “see”• Hosts exhibit characteristic symptoms• Changes in host color, size, shape
–Ex. Swelling of aphids into “mummies”, melanization of soft-scales and whiteflies, circular exit holes
• Use symptoms to estimate level of parasitism
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Hymenoptera
Parasitic wasp
Exit holes in scale covers- sign
www.hydro-gardens.com
M.J.Raupp
Tachinid Fly
Diptera: Tachinidae
Ectoparasitoid
• a parasitoid that develops outside of its host while feeding through the host’s cuticle
www.entomology.cornell.edu
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www.uky.edu
Predator• generally a large, active insect
that quickly kills and consumes many smaller, insects called prey
• require many prey to complete development
Common Predator Groups• Coleoptera:
– Coccinellidae - lady beetles– Carabidae – ground beetles– Staphalynidae – rove beetles
• Neuroptera: – Chrysopidae - lacewings
• Diptera: – Syrphidae – flower or hover flies
• Hemiptera: – Reduviidae – assassin bugs
• Acari: – Phytoseiidae - predatory mites
• Araneae:– Thomisidae, Salticidae, others - spiders
Lady Beetle
Video by M.J. Raupp, UMD
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Citrus mealybug
(pest)
Mealybug destroyer
(ladybeetle, predator)
Hyperaspis Lady Beetle
adult and larva
Spider Mite Destroyer
Coccinelidae
Predatory Mites (Acari: Phytoseiidae)
Green Lacewing Neuroptera: Chrysopidae
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Debris carrying lacewing
Flower or Hover Fly
Diptera: Syrphidae
M.J. Raupp
M.J. Raupp
Video by M.J. Raupp, UMD
cropwatch.unl.edu
Hemiptera: Heteroptera: Anthocoridae
Minute Pirate Bug
Assassin bugsHemiptera: Heteroptera
Reduviidae
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Hemiptera: Heteroptera: Nabidae
Damsel Bug
Soldier beetleColeoptera: Cantharidae
www.pbase.com/dougsmit/
Coleoptera: Staphylinidae Rove Beetle
Coleoptera: Carabidae
Ground Beetle
Photo Credit: Jeff Hahn
Araneae: Anyphaenidae
Araneae: Salticidae
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FloridaNature.org
Araneae: ThomisidaeP. Shrewsbury
Black and Yellow Garden Spider
Egg sac
Black and Yellow Garden Spider vs Brown Marmorated Stink Bug
Video by M.J. Raupp, UMD
www.geocities.com
www.geocities.com
Praying Mantis
Mantodea: Mantidae
bugs.bio.usyd.edu.au/
Insects provide critical ecosystem services
• Critical links in food webs and food chains
• Nutrient recycling, decomposition
• Pollination services
• Biological control
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Insects provide critical ecosystem services
• Critical links in food webs and food chains
• Nutrient recycling, decomposition
• Pollination services
• Biological control
Many natural enemies need alternative food sources = nectar and pollen = pollination
Images by M.J. Raupp, UMD
Many natural enemies are pollinators
Many pollinators are natural enemies
R. Waterworth, UMDM. J. Raupp, UMD
Beetles
Who are the pollinators?
Flies
Butterflies and Moths
Video by M.J. Raupp, UMD
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Wasps are important pollinators too
http://www.honeybeehaven.org/content/bees-101
Sarah Greenleaf photos
(Photo by Kathy Keatley Garvey)
Honey bees
Bumble bees
Ground nesting bees
Plasterer beesDigger beesMiner bees
Ground nesting bees - Sweat or halictidbees
B.Castro, TAMU
www.westerngardeners.com
Hole nesting bees –Leaf cutter bees
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Many natural enemies are pollinators
Many pollinators are natural enemies
• Practices to conserve natural enemies and pollinators should be similar
R. Waterworth, UMD
M. J. Raupp, UMD
Need to give natural enemies and pollinators a helping hand!
Biological Control Approaches
Classical / Importation
Augmentation
Formulation
Conservation
Goal of Biological Control
• to reduce pest densities to non-damaging levels – not to eradicate pests
Classical / Importation
• the importation and establishment of new species of natural enemies from the original home of introduced pests to control those pests
• USDA APHIS, State Dept. of Agriculture, University scientists
Researchers determine:
•Successful establishment of natural enemies (NE)
•Numbers of NE needed for establishment
•Site conditions required for establishing NE populations
•Interactions among exotic and native NEs
•NE dispersal rates
•Impacts on EAB populations and ash survival or recovery
•Effects on non-target species
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Formulation
• pathogens or entomopathogenic nematodes may be formulated into a product that is applied in a method
similar to conventional pesticides
B.t. Varieties and Pests Controlled
• B.t. kurstaki or morrisoni– Caterpillar larvae
• B.t. israeliensis– Mosquito, black flies, fungus gnat larvae
• B.t. San Diego– Leaf beetle larvae
• B.t. galleriae– Scarab beetle grubs, adults; weevils; flat headed
beetles (beetleGONE; grubGONE; borerGONE)
Commercially Available Nematodes
NematodeS. carpocasae
S. glaseri
S. riobravis
S. scapterisci
S. feltiae
H. bacteriophora
H. megidis
Insect (major markets)Caterpillars (turf, mint, retail)
White grubs (turf)
Mole crickets (turf), Citrus weevils (citrus)
Mole crickets (turf)
Fungus gnats (ornamentals, mushrooms)
White grubs (turf), root weevils (ornamentals, citrus, berries)
Genera: Steinernema and Heterorhabditis
Black vine weevil
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Control H. bacteriophora
Nu
mb
er o
f B
VW
Lar
vae
a
b
Effect of H. bacteriophora on
BVW Infesting Bergeniaa
Augmentation
• when existing natural enemy populations are low or absent at a site, additional predators or parasitoids may be purchased from a commercial insectary and released
BC sources: Syllabus on pg. 178
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P.M. Shrewsbury, UMD
Green lacewing larva feeding on azalea lace bug nymph
0
10
20
30
40
50
60a
b
Effects of Lacewings, Beauvaria, and Acephate on ALB
cc c
6 days post-release -
2 of 150 glw recovered
P.M. Shrewsbury and D.C. Smith-Fiola. 2000
Challenging in outdoor environments
Add food and habitat to retain augmented natural enemies
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