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Rice Stink Bug Management :. Michael Stout, Bryce Blackman, Jason Hamm & Natalie Hummel. A program in transition. Signalgrass. Crabgrass. Sprangletop. Life Cycle and Biology. Adults begin overwintering in October and emerge from overwintering in March/April
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Rice Stink Bug Management: Michael Stout, Bryce Blackman, Jason Hamm & Natalie Hummel A program in transition
Signalgrass Crabgrass Sprangletop Life Cycle and Biology • Adults begin overwintering in October and emerge from overwintering in March/April • Populations in spring and early summer build up on alternate grass hosts Barnyard grass
Life Cycle and Biology • Females lay rows of 20-30 eggs • Laid over 900 in lab tests • Eggs turn black as they age
Life Cycle and Biology • Nymphs hatch in 4-11 days • Five instars before adulthood
Life Cycle and Biology • Adults and nymphs suck fluid from developing grains
Economic Importance • Potential for yield losses • Feeding introduces fungi that causes peck • Leads to discoloration and broken kernels • Reduces grade and overall value of grain
Components of a RSB management program • Scouting and population monitoring • Thresholds for insecticide applications • Insecticide applications • Alternative management tactics
For each component of the RSB management program… • What is the current practice? • What are the weaknesses of the current practice? • What are we doing about it? • What should we be doing about it?
Components of a RSB Management Program • Scouting: • Thresholds: • Insecticides: • Alternatives to insecticides:
Scouting / population monitoring • Begin at 50 – 75% heading • Sweep net -- 15 inch diameter • 180˚ every step, at least 10 sweeps at 10 locations
What are the weaknesses of this scouting method? • Standardization / consistency among samplers • Labor intensive • How efficient?
Number of RSB recaptured Number of RSB “seeded” in 20 ft plot
Odor Source Methyl Salicylate Control * 67 33 40 60 Caryophyllene Control 48 52 Linalool Control 56 44 Limonene Control 100 75 50 25 0 25 50 75 100 % Response * P < 0.05
Prospective Technology • Electronic nose • Handheld volatile analysis computer • Tested on stink bugs in cotton
Components of a RSB Management Program • Scouting:Extension efforts to standardize sampling methods; research on attractants • Thresholds: • Insecticides: • Alternatives to insecticides:
Components of a RSB Management Program • Scouting: Extension efforts to standardize sampling methods; research on attractants • Thresholds: • Insecticides: • Alternatives to insecticides:
Current Thresholds • First two weeks of heading: 3 bugs per 10 sweeps (30 per 100) • After first two weeks: 10 bugs per 10 sweeps (100 per 100)
Potential weaknesses of these thresholds • Origin of thresholds unknown; has not been updated for 25+ years to account for new varieties, etc • Thresholds in TX recently increased • Growers satisfied with thresholds, but are we spraying too much? • Thresholds for different varieties, ratoon?
RSB Cage Study • 2010- Four replications • Cages infested with RSB at 50-75% heading • Cages removed after 11 days • Plots sprayed biweekly thereafter until grain hardening
RSB Cage Study • Treatments: 0, 1, 2, 5, or 10 stink bugs per 6.67 sq ft cage • Corresponds (roughly) to 0.8, 1.6, 4, and 8 x threshold
RSB Cage Study • 2010-Cage Study Yield (grams)
Components of a RSB Management Program • Scouting: Extension efforts to standardize sampling methods; research on attractants • Thresholds: Revise thresholds • Insecticides: • Alternatives to insecticides:
Components of a RSB Management Program • Scouting: Extension efforts to standardize sampling methods; research on attractants • Thresholds: Revise thresholds • Insecticides: • Alternatives to insecticides:
Currently registered insecticides • Pyrethroids (Karate, Mustang Max, Declare, Prolex) • Organophosphates (malathion, methyl parathion) • Sevin (carbaryl) • Neonicotinoids (dinotefuran – Section 18 in Texas)
What are the shortcomings of our current arsenal of insecticides? • Some options ineffective • Short residual activities • Loss of methyl parathion • Concerns about resistance
EPA has received requests from the registrants to voluntarily cancel all product registrations containing methyl parathion, a restricted use organophosphate insecticide and acaricide used primarily on cotton, corn, and rice, as well as on other agricultural crops. These requests would terminate the last methyl parathion products registered for use in the U.S., effective December 31, 2012. End-use products will not be sold after August 31, 2013, and end-use products cannot legally be used after December 31, 2013.
New alternatives • Declare, generic pyrethroids • Tenchu (dinotefuran), Section 18 submitted for Louisiana 2011 • Other neonicotinoids and pyrethroid/neonic mixes • Some of these new products expected to have longer residual activities, but no evidence for this yet • Tank mixes with fungicides?
Components of a RSB Management Program • Scouting: Extension efforts to standardize sampling methods; research on attractants • Thresholds: Revise thresholds • Insecticides: Evaluate new insecticides and cooperate in registration efforts • Alternatives to insecticides:
Components of a RSB Management Program • Scouting: Extension efforts to standardize sampling methods; research on attractants • Thresholds: Revise thresholds • Insecticides: Evaluate new insecticides and cooperate in registration efforts • Alternatives to insecticides:
RSB Variety Tolerance Trials • 2010- four experiments planted at different times, each with 4 reps • 1CL 151, 2CL161, 3Cocodrie, 4CL 131 • Top 4 long grain varieties in 2009 • 5Neptune, 6Jupiter (replaced w/ Bengal) • Medium grain varieties • 7CLXL723 • Hybrid • 8Kaybonnet and 9Lagrue • Displayed tolerance in previous tests
Components of a RSB Management Program • Scouting: Extension efforts to standardize sampling methods; research on attractants • Thresholds: Revise thresholds • Insecticides: Evaluate new insecticides and cooperate in registration efforts • Alternatives to insecticides: Host-plant resistance and cultural practices
Questions and comments: What should we be doing? • Scouting video? New sampling approaches? • Revise thresholds? • Evaluation of insecticides? • Host-plant resistance research? Cultural practices?
Author • Michael Stout • mstout@agcenter.lsu.edu