Biological Control 1 Biological Control 2 Biological Control

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1 OPM_BC_2009.oo3 Biological Control 1 Biological Control Matthew J. Grieshop Michigan State University 2 Biological Control The use of one or more organisms to manage another. BC is the use of parasite, predator, pathogen, antagonist, or competitor populations to suppress a pest population, making the pest less abundant and less damaging than it would be in the absence of the BC agents BC can be applied to arthropods, weeds, or microbes Biological Control: Vocabulary Natural Enemy: A predator/parasite/disease that attacks a given pest Predator: An NE that consumes many prey over it's lifetime Parasite: An NE that lives off one or more hosts Parasitoid: A parasitic NE that consumes/kills a single host Hyperparasite: Parasite that attacks a primary parasite Antagonist: NE kills or hinders pest without consumption or direct competition Pathogen: NE that causes disease in a pest Competition: An ecological interaction with negative consequence for both parties Antibiosis: NE produces one or more deleterious compounds

2 Advantages/Disadvantages Stability Specificity Cost Effective (Classical) Slow Acting Rarely provides 100% control Easily Disrupted Expensive (Augmentative) 3 General Concept Biological often functions via two species population dynamics Because natural enemies can cycle with pests they can provide lasting control. When BC reduces pest populations below the ET then it is economically viable When it does not it is not economically viable 4 Biocontrol and Trophic Levels Top down relies on higher trophic levels Secondary, Tertiary Consumers Bottom up relies on same trophic levels Competition/Antagonism 5 Broad Function Bottom up: competition/interference Top down: predation/parasitism Different classes of pests are 6 Early History: Ants in China 7 Early History: Compost/Manure for Canker 8 Modern History: Cottony Cushion Scale

3 9 Post Modern History: Landscape Diversity Tscharke papers 10 Biological Control: Broad Types Classical: introduction of a natural enemy for management of an invasive species Accurate pest identification Assessment of pest life history Foreign Exploration in pest s home range Collection of potential NE s Host specificity testing Initial release and monitoring Redistribution and monitoring Augmentative: Mass release of natural enemies Accurate pest identification/monitoring Assessment of pest life history Purchase of appropriate NE s Release NE s and monitor success Repeat if necessary Mass release/biopesticide vs. innoculative Conservation: Environmental modification to enhance natural biological control Accurate pest identification/monitoring Assessment of pest life history Monitoring of NE s present in landscape Assessment of NE needs Moderation of disturbance Reduced risk pesticides, etc. Establishment of NE habitat

4 Conservation strips, cover crops, etc. Continued monitoring of NE s and pest Biological Control of Weeds: Leafy Spurge Important rangeland weed 3 million acres infested in 1990s Perennial with sexual and asexual reproduction Herbicides largely ineffective 12 Leafy Spurge Foreign exploration of Eurasia Many arthropods collected 10 Selected for release Chrysomelid beetles (Apthona spp.) successful Multiple species: Adults feed on foliage larva on roots Very successful 13 Weed Seed Predation Carabid beetles, Crickets, Vertebrates, Pathogens, Cover Crops Largely unquantified May account for up to 25% of weed seed 14 Biological Control of Pathogens Classical: Limited examples Augmentative: Very common Conservation: In it's infancy 15 Bio-Fungicides Serenade and Sonata B. subtilis Bacteria function by modifying substrates Out compete fungal pathogens

5 16 Compost Teas Function as parasites or competitors? Mode of action largely unknown May also function by providing nutrients to pre-existing beneficials 17 Predation of Sclerotia Sclerotinia S. scleotinia is an important pathogen of veggies and field crops Overwinters in Sclerotia Life cycle insert 18 Predation of Sclerotia Sclerotinia Fungus gnats and collembola Canadian study demonstrated reductions in sclerotia Muck Soils These insects may also be a problem Biological Control of Insects Classical: Many Examples Augmentative: Many Examples Conservation: Expanding Field 20 Classical Insect BC Cottony Cushiony Scale Gypsy Moth Russian Wheat Aphid Soybean Aphid 21 Augmentative Insect BC:Trichogramma Tiny egg parasitoids <.5mm Fast generation time Attack pest before it causes damage

6 Fairly easy to rear Have trouble in complex environments 22 Trichogramma and Indian Meal Moth IMM is a common stored product pest Corn meal packaged or unpackaged IMM eggs added then Trichogramma Larval parasitoid added later 23 Trichogramma and Indian Meal Moth Trichogramma good in packaged product Larval parasitoid good in both Why? Problems with this? 24 Conservation Insect BC BIODIVERSITY!! Producer diversity: Nectar sources also off season hosts Challenge to quantify STABILITY!! Provide favorable habitat Copclypeus example 25 Conservation Insect BC Reduced Risk Insecticides Allow higher trophic levels to exist Cover Crops Provide cover, food, and alternate hosts/prey 26 Biological Control and Thresholds BC is slower than Chemical control! BC cost is highly variable! BC can be density dependent

7 27 Biological Control Considerations How valuable is the crop? How picky is the consumer? How damaging is the pest? Is the Pest native or introduced? How stable is the agroecosystem? How diverse is the landscape? Biological Control and Organic Agriculture Type depends on the system... Perennial Fruit Low ET, Stable system, High biodiversity Field Crop Higher ET, Disturbed System, Low biodiversity Rangeland Highest ET, Stable system, mid biodiversity, Stored Product Lowest ET, Stable system, lowest diversity Greenhouse Variable ET, HIghest Disturbance, Low diversity