1/2/2020 1 Beneficial arthropods: Natural enemies and pollinators Paula Shrewsbury, Ph.D. Department of Entomology University of Maryland [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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Nutrient recycling, decomposition Pollination services ... · 1/2/2020 3 Bacillus thuringiensis (B.t.) • Soil bacterium, common in nature • Over 30 subspecies and varieties •
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Beneficial arthropods: Natural enemies and pollinators
• 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
White grubs (turf), root weevils (ornamentals, citrus, berries)
Genera: Steinernema and Heterorhabditis
Black vine weevil
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Control H. bacteriophora
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VW
Lar
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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
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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