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Biological Control In The Field. Kris Braman University of Georgia. Why Use Natural Enemies?. Pests? Control Alternatives Why “go biological” ? The pesticide “treadmill” Target pest resurgence Secondary pest outbreaks Pesticide resistance Fewer pesticides available
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Biological Control In TheField Kris Braman University of Georgia
Why Use Natural Enemies? • Pests? • Control Alternatives • Why “go biological” ? • The pesticide “treadmill” • Target pest resurgence • Secondary pest outbreaks • Pesticide resistance • Fewer pesticides available • Human health and environmental concerns
What is a Pest, really?Some Pests are Bigger than Others!Key Pests
Integrated Pest ManagementIPM • Use of all available tactics to maintain pests at acceptable levels including: • Mechanical • Biological • Cultural • Chemical • Regulatory
Key Factors in Successful Pest Management • Scouting • Proper Diagnosis • Deciding on Control Tactic • Implementation • Follow-up Assessment
Wolf spider Tiger beetle Parasitoid Big-eyed bug Ground beetles Caterpillars Spittle bugs Grubs Chinch bugs Turfgrass Food Web
Ecological Basis of Biological Control Add density dependent mortality factor increase biotic pressure reduced carrying capacity
Conservation • Protection of existing biological control agents may be accomplished by: • Use of pesticides only when necessary • Spot sprays rather than blanket coverage • Choice of pesticide that is least toxic to beneficials • Avoid or be selective in applying broad spectrum or persistent pesticides • Planting a variety of flowering species to provide nectar and pollen sources and sources of alternative prey for predators • Providing shelter and moisture sources
Azalea Lace Bug (Stephanitis pyrioides) Azalea lace bug adult Azalea lace bug nymphs Azalea lace bug eggs
ALB feeding through stomates
Parasitic wasp that attacks and kills lace bug eggs Mymarid wasp next to An azalea leaf hair Parasitized lace bug egg next to leaf midrib. Wasp has chewed a circular hole in the lace bug egg and emerged
Azalea plant bug (Rhinocapsus vanduzeei) adult and nymph, a predator that feeds on lace bugs, thrips, other small insects and pollen
Azalea growth in response To azalea lace bug feeding Whole plant gas exchange measurements revealed that photosynthesis, carbon use efficiency and growth were not affected by lace bug injury < 13%
Augmentation • Release of additional beneficials when existing populations are too low • Inoculative release: small number released into an area of low pest infestation and progeny are sufficient to maintain low pest levels • Inundative release: large numbers of natural enemies are released often several times during a season
Augmentative Releases Augmentative releases of natural enemies Uses in the US: Predaceous mites Increasing in use Improved rearing still based on natural foodsImproved shipping and release systems envelopes with substrate, to place in plants Phytoseid mite consuming a spider mite
Mite predators L.Hull PHOTO: Max Verkooy
Importation (Classical) • Used most often against pests that have been accidentally introduced to the area where they are currently a problem • Natural enemies from the pest’s native region are introduced into the new area
Classical- Importation • In 1990 estimated that 722 biocontrol agents previously introduced into the US had resulted in suppression of 63 insect and mite pests • Most complete successes with Homopteran pests
PHM Parasite Release Program Media Covering Florida’s First Parasite Release
Ornamental Hibiscus Croton Allamanda Anthurium Heliconia Lantana Seagrape Bougainvillea Oleander Ixora Ginger lily Schefflera Ficus Pink Hibiscus MealybugHost Plants Vegetable • Tomato • Pumpkin • Okra • Lettuce • Beans • Cucumber • Peppers • Dasheen • Cabbage • Squash Fruits • Papaya • Sugar-apple • Golden apple • Pigeon pea • Carambola • Soursop • Cherry • Passion fruit • Avocado • Mango • Plum • Grape • Citrus • Breadfruit • Guava • Banana
California Mulberry = 96% Carob = 93% Bahamas = 82% (1 year) Florida = 98.7% Haiti = 97.2% Dominican Republic = 96.6% PHM Populations Reduced by Parasitoids • St. Kitts = 91.6 % • US Virgin Islands St. Thomas = 91.2% St. Croix = 97.1% • Puerto Rico = 92% • Culebra = 96.5% • Vieques = 97.8% • Belize = 96.6%
Identification and biology of some important predators • The first step in effectively using biocontrol is to correctly identify common natural enemies and to know what pests they are active against • Generalists vs. specialists • Knowledge of the life cycle is important; many natural enemies attack only a particular stage of a pest (egg, larva)
Turfgrass Cultivar Influences on Fall Armyworm Parasitism Tigers in the Turf S. Kristine Braman Department of Entomology University of Georgia Kris Braman University of Georgia