Transcript Pest Update: Rockbridge County

Making IPM Work:
Key Components in Action
Presented by
Amber D. Vallotton
Crop and Soil Environmental Science Agent
Rockingham County
Integrated Pest Management
A sustainable approach to manage pests by
combining biological, cultural, physical, and
chemical tools in a way that minimizes
economic, health, and environmental risks
-- National Coalition on IPM
ASSUMPTIONS about IPM:
• Is one component of the total crop production
system
• Uses a broad interdisciplinary approach to reduce
pest populations
• Emphasizes suppression rather than elimination
Review of Key IPM Principles
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Correct Pest Identification  Foundation of all Decision-making
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Understanding Pest Biology and Crop Dynamics
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Window of vulnerability in crop = When does pest cause feeding
damage? How much is tolerable?
Treatment window = When crucial to treat?
Planning Preventive Strategies
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Cropping practices to reduce pest attack? = tillage, crop rotation, time
of planting?
Pest-resistant plants?
How to prevent pest pops from exceeding economic levels?
Any natural control agents?
Monitoring
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Periodic assessment of pests, natural controls, crop, and
environmental factors = sampling, field scouting, traps
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Decision-making  To Act or not to Act?
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Using monitoring information to assess benefits vs. risks of action or
inaction
Estimating pest population size compared to “Economic thresholds” or
“Action thresholds” => Is damage potential of pest more costly than
the control?
Selection of Optimal Pest Control Tactics
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Looking at all cultural, physical, biological, and chemical tools to
manage pests while minimizing economic, health, and environmental
risks
Implementation of Options
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Using tools in a timely manner with precision and completeness
Evaluation of Pest Control Actions
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Follow-up to determine if choice of controls were appropriate
What went right and what went wrong?
Changes in future to improve effectiveness if same pest problem
occurs?
Changes to production system to get better suppression?
2007 Crop Pest Update
Brief snippets emphasizing some of the
IPM principles just discussed…
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Alfalfa - Potato Leafhopper
Grasses - Billbug
Soybean - Rust
Corn - Slugs
Insect Resistance Management
Survey
Alfalfa
Potato leafhopper
• After about 8-10 years, particularly
troublesome this year…WHY?
• Persistent drought with higher temps
meant greater PL migration northward
coupled with stressed plant conditions
• Nymphs and adults inject saliva during
feeding that causes “V”- shaped yellowing
of leaflet tips (i.e. “hopperburn”)
• Infestations are highly variable from field
to field and from year to year  crucial to
monitor individual fields to be able to
make sound pest management decisions
Monitoring Essential to PL Control
• Depending on stem height, economic
threshold changes
• Taller alfalfa can withstand higher
numbers of PL:
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14” critical height
– Less than 14”  number PL dictates
spraying or re-scouting in 7 days
– Greater than 14” and PL no. above
threshold, harvest rather than spray!
– Fields just cut more susceptible to damage
b/c feeding pressure on young growing plant
tissue
– Second through fourth cuttings particularly
vulnerable
– Even more damage when drought stressed
Key to successful PL
management is effective
scouting program
• 15 year VCE Scouting Program
shows scouting pays off!
• Scout mid-late May through midAugust
Grasses
Billbug (hunting and bluegrass)
• Adults overwinter along
fencerows, & in Spring lay
eggs in leaf sheath above
crown
• Larvae feeding in stem and
crown causes browning &
plant death
• In 2006, north SV hit by BB
• Little presence this year, but
important to be on lookout in the
future  IDENTIFICATION
Soybeans
Soybean Rust
• Out of five southeastern
VA counties sampled, SR
confirmed present in Isle of
Wight and Virginia Beach
counties on 10/26/2007
• Cooler weather & rains =
favorable conditions for
rust development on green
leaves
• Good news: Crops
mature (> R6) so no yield
loss 2007
• http://www.ppws.vt.edu/ipm/soybeanrust/index.htm
• Into late Fall (before frost) and with
Spring green-up, scouting of kudzu
crucial  overwintering host for SR
• Monitoring will continue across VA and
other states
– Sentinel plots in Southeast US (10)
– Random detection surveys
– Commercial plots (when rust detected
within 100 miles, or after tropical storm
movement)
– Spore traps (proviso: not definite only that
spores MAY be present)
• On-going resistant variety trials
• Next year’s crop  Monitor and scout
leaf undersides; stay updated with statewide SR monitoring
Corn
Slugs
• Some issues this year with slugs in
fields with heavy residue or weed
cover under cool, wet weather
conditions
• With droughty conditions not as
problematic, and if damage not too
severe can be outgrown when
temperatures rise, fields dry off,
and growing conditions improve
• Injury: pre-emergence damage to
seeds in partly closed seed slots
and defoliation of young seedlings
• Important to monitor!
- Can inspect by turning over
clods of dirt and residues then
counting
- Lay out old roof shingles as
trap area
• Some strategies that may help
- Mechanically remove trash
from furrow to reduce refugia
- Delay planting until warmer
temperatures
- If warranted b/c high numbers,
some baits available but costly
Insecticide Resistance Management
• IRM is COMPLEX stuff
 Focus on BASICS!
• Use of GMO Bt corn
varieties steadily
increasing, offering
effective control of
several major corn insect
pests
• However, overuse poses
some potential risks
because of selection
pressure for superbugs
Bt Resistance Management
How insecticide resistance develops
Complex process but here’s the
simple version:
• Insecticide is applied
• Sometimes, there are individuals
unaffected by insecticide (resistant)
• Resistant individuals pass on their
genes to next generations
• Over time, more and more individuals
in population unaffected by insecticide
• Eventually can have super bugs that
are completely resistant, making
insecticide control ineffective
Just far-fetched hype?
Pest resistance to the Bt toxin
• 1985 - Indianmeal moth
• 1990 - Diamondback moth
• 1990s - Lab studies showed resistance in 11 species including ECB
and CO potato beetle  No resistance in field, but studies show
potential to develop resistance is very real!
• How insects resist Bt toxin is very complex and not well understood
• Unfortunately, resistance may be unavoidable
• IRM goal is not to stop resistance
entirely, but to slow its development and
extend insecticide’s useful lifespan
Making Sense of Bt Resistance
Management
Strategies
• Refugia - Maintaining a susceptible population for mating
w/ rare resistant insects
– Serves as source of susceptible insects in next generation
– Placed alongside treated areas and external to field
• Regardless whether one plants YieldGard®, Herculex®,
Agrisure®, or any other type, ALL Bt corn must be
planted with non-Bt refuge areas
• In non-cotton growing areas, 80%-20% Rule
– MAXIMUM 80% Bt corn acres
– Remaining 20% non-Bt corn hybrid
Disclaimer: Commercial products are named in this publication for informational purposes only. Virginia Cooperative
Extension does not endorse these products and does not intend discrimination against other products which also may be
suitable.
Acceptable Refuge Planting Schemes
• By maintaining refuge, we will help to reduce the
development of Bt-resistance in insect populations and
make sure this technology remains available
• Follow EPA refuge and spray guidelines on product label!
• Virginia Tech handout on refuge requirements and
spraying options
• Consult seed representative where you purchase Bt corn
• VCE/ Virginia Tech
Shifting gears…
My Program Direction
Local Food
Systems
Initiative
Agricultural
Awareness
Economic
Profitability
Viable,
Sustainable
Agriculture
Whole-farm
IPM
strategies
Marketing
Options
Alternative
Production
Systems
Pond
Management
Environmental
Stewardship
Water
Quality
Nutrient
Management
PesticideRelated
Issues
Bio-residuals
Utilization
Soil
Quality
Best Mgt
Practices
May I get your valuable input?
A simple survey
THANK YOU!!