biological control in the field kris braman university of georgia
TRANSCRIPT
Why Use Natural Enemies?
Pests?Control AlternativesWhy “go biological” ?
The pesticide “treadmill”Target pest resurgence Secondary pest outbreaksPesticide resistance
Fewer pesticides availableHuman health and environmental
concerns
Integrated Pest Management
IPMUse of all available tactics to
maintain pests at acceptable levels including:
MechanicalBiologicalCulturalChemical Regulatory
Key Factors in Successful Pest Management
Scouting Proper Diagnosis Deciding on Control Tactic Implementation Follow-up Assessment
Turfgrass Food Web
Chinch bugs
Spittle bugs Caterpillars
Grubs
Big-eyed bug Parasitoid
Wolf spider
Groundbeetles
Tiger beetle
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 (Azalea Lace Bug (Stephanitis pyrioidesStephanitis pyrioides))
Azalea lace bug adult
Azalea lace bug eggs
Azalea lace bug nymphs
Parasitic wasp that attacks and kills lace bug eggs
Parasitized lace bug egg next to leaf midrib. Wasp has chewed a circularhole in the lace bug eggand emerged
Mymarid wasp next toAn azalea leaf hair
Azalea plant bug (Rhinocapsus vanduzeei)adult and nymph, a predator that feeds on lace bugs, thrips, other small insectsand pollen
Azalea growth in responseTo azalea lace bug feeding
Whole plant gas exchange measurements revealed thatphotosynthesis, carbon useefficiency 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 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
Augmentative Releases
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 Media Covering Florida’s First Parasite ReleaseRelease
Pink Hibiscus MealybugHost PlantsFruits
Papaya Sugar-apple Golden apple Pigeon pea Carambola Soursop Cherry Passion fruit Avocado Mango Plum Grape Citrus Breadfruit Guava Banana
Ornamental Hibiscus Croton Allamanda Anthurium Heliconia Lantana Seagrape Bougainvillea Oleander Ixora Ginger lily Schefflera Ficus
VegetableTomatoPumpkinOkraLettuceBeansCucumberPeppersDasheenCabbageSquash
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%
CaliforniaMulberry = 96%Carob = 93%
Bahamas = 82% (1 year)
Florida = 98.7% Haiti = 97.2% Dominican Republic =
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
S. Kristine BramanDepartment of Entomology
University of Georgia
Tigers in the Turf
Kris BramanUniversity of Georgia
Managing Naturally Occurring Parasites and Predators
Choose selective rather than broad-spectrum insecticides May be slower, but long term control
is better achieved by using methods that conserve natural enemies
Monitor for beneficial arthropods as you would for pest insects If ratio of pests to natural enemies is
low, then spraying can be delayed