Biology and Insecticide Management for Western Flower Thrips · 2014-01-23 · Western Flower...
Transcript of Biology and Insecticide Management for Western Flower Thrips · 2014-01-23 · Western Flower...
Biology and Insecticide Management for
Western Flower Thrips James A. Bethke
University of California Cooperative Extension
Western Flower Thrips • Probably the most serious pest of ornamentals in
greenhouses - Parrella 1995
• IR-4 considers this pest number one most years for research in ornamentals
• Efficient vector for many Tospviruses, TSWV, INSV
• Direct damage to buds and flowers, usually damaged much earlier
Impact on the Greenhouse Industry
TSWV - Tomato spotted wilt virus
Leaf, Flower/Petal Damage
INSV
Impatiens necrotic spot virus
The Most Common Causes of Pesticide Failure
Failure to implement IPM program Failure to monitor Misidentification of pest Wrong choice of pesticide Incorrect rates/off label use/old pesticide Water quality/pH/adjuvants/tank mixes Misuse of or poor calibration of equipment Inadequate coverage or placement of pesticide Great numbers or resistant populations
Effective sprays • Scouting
• Early detection
• Proper identification of the pest
• Minimize frequency of application
• Avoid tank mixes
• Rotate the mode of action
• Use a more integrated approach
Sticky Cards
- white, yellow or blue stick cards are attractive to thrips adults - trap above crop height - 1 trap/10,000 square ft. in doors; 1 trap/4 acres outdoors - place near sensitive plants, vents, doors - count/record trap data weekly - plot catches vs treatments to evaluate
Weed Control
Chickweed is also an indicator plant but also a harbor for pests and disease
Econet T Econet L
No Thrip Antivirus Screen
Conserve (Spinosad) • Arguably one of the best products for thrips control • 6ppm can cause 100% mortality to susceptible thrips • Some formulations are registered as ‘organic’ • Provides a unique mode of action
Dow & Conserve Resistance
• Great concern • Monitoring program using coated vial method (IOBC) • Thrips on roses in CA, 2002 • Survey of growers from San Diego to Watsonville • Most populations were very sensitive
Recent Assays
Recent Assays
Western Flower Thrips • Frankliniella occidentalis • Very small - Thigmotactic • Damage resembles mites, fecal flecks, terminal or leaf distortion, Tospoviruses • Monitor with sticky cards • Female WFT lay 130–230 eggs • Multiple genes for resistance • IR4 has been concentrating on thrips products for many years
Thrips Biology
Thrips Biology: Disease Transmission
Susceptible stages
Consider the Risk Save the most effective product(s) for the
time of year or cropping cycle with the most risk
• When no. of pest are most prevalent
• When the crop is the most susceptible
Use rotations with softer products or chemicals that are suppressive during the least risk
Example - Thrips The most effective products are Conserve
Pylon and Avid, so do not use these at any time during the year or cropping cycle when there is low risk
This ensures the products effectiveness as a cleanup product or preventive during high risk
Use soft products or suppressive products during the cooler times of the year when thrips are less likely to be present
Consider Other Pests Thrips and leafminers then never use Conserve for
leafminers
Thrips and mites then never use Avid for thrips
Low risk – Soap or Oil or IGR>BotaniGard>pyrethroid>OP
High risk - Conserve>Pylon>Avid>Overture>pyrethroid+OP
These rotations are appropriate as products with different modes of action are being used every two weeks.
IRAC Recommendation for Rotational Scheme
MoA = Mode of Action
w, x, y, and z are modes of action from the IRAC MoA chart
http://mrec.ifas.ufl.edu/lso/DOCUMENTS/ThripsManagementProgram-February%202011-FINAL.pdf
http://mrec.ifas.ufl.edu/lso/DOCUMENTS/ThripsManagementProgram-February%202011-FINAL.pdf
James A. Bethke UCCE San Diego
9225 Hazard Way, Suite 201 San Diego, CA 92123
[email protected] Cell: 951-775-7172