Insect Control in Onions Tim Waters, PhD Regional Vegetable Specialist WSU Extension Franklin & Benton Co Farm Fair Dec 6 10:30 30 min
Seedcorn Maggot Wireworm Leafminer Lepidoptera Spider Mites Bulb Mites Grass hoppers Thrips Potential Culprits
Seedcorn Maggot Delia platura Broad host range Attack germinating seeds/seedlings Spring Destroys plant stand Found throughout N. America
The first-generation adult flies emerge in early spring. These flies are grayish-brown to slightly greenish in color and about 1/5 inch long. The flies deposit their eggs in the soil where there is an abundance of decaying organic matter.
Seedcorn maggots are pests of various seeds at germination. Stand loss and damage is greatest during the cool, (and wet) springs period. Decaying plant material attracts the adult flies where the females lay eggs. **
Seedcorn Maggot Recipe Seed corn maggot can infest the germinating seeds and roots of over 47 plant species. Double cropping Beans after peas or sweet corn after peas High residue Slow germination conditions Sometimes, it doesn t matter
Monitoring Sticky traps Yellow water pan Cut fruit or vegetable Open Pickup cab Exterior of non-red pickups
Control Monitor for Seedcorn maggot prior to planting If present consider in furrow, topical or seed treatment Reduce organic matter Timing of planting Planting Depth Avoid double cropping with susceptible crops
Chemical Control Lorsban (chemigation or in furrow granule) Pyrethroids post plant Seed treatments Lorsban Farmore FI 500 Sepresto
Wireworms (Coleoptera: Elateridae) Many species can be involved including the Pacific Northwest or sugar beet wireworm Pest of numerous crops including cereals, grasses, potato and others Most serious problems coming out of pasture or crops where they were not treated Have resurged as a problem with the discontinued use of organochlorine insecticides
Long life stages Life cycle In soil and move extensively in soil profile making control difficult Larvae move up in soil profile in spring, down in summer and back up in fall. Onion problem in spring
Wireworm Damage
Dammage? How many?
Monitoring Methods (larvae) Absolute Soil cores Labor intensive Populations are spotty Relative Method Various baits, usually include some source of CO2 which serves as an attractant. Less time and labor intensive Tends to overestimate population
Control Chemical Telone, pre-plant Cultural Crop Rotation Planting timing
Leaf Miner Liriomyza spp (pea leafminer) Adults lay eggs on leaf tissue Eggs hatch and larvae mine between upper and lower leaf tissue
Leaf Miner Mines start small and get larger as the maggot grows Damage results in reduced green leaf area Differentiating from thrips Association with pea crops???
Control Early season insecticide program likely impacts level of damage Readily develop insecticide resistance If you have this pest, you could modify your thrips management programs to address this Insecticides Radiant (spirotetremat) Agri-mek (abamectin)
Thrips/Plant Thrips UTC Plots 100 90 80 70 60 50 40 2009 O 2010 O 30 2011 P 20 10 0 2012 P 2013 P Date
Sequential Applications What combination, and in what sequence do currently registered thrips control products work with one another?
A B C D E F G H Net over Check $/A Week 1 2 3 4 5 6 7 8 Cost/A $ yield tons/a Thrips/Week Untreated Check 0 46.16 0.00 6.68a Delay Radiant + Movento Movento Radiant Agrimek Lannate 275 57.1 2350.60 4.83b AzaDirect AzaDirect WA Program Movento Movento + Radiant + Radiant Lannate Lannate 303 57.27 2363.40 5.3b NY Res. Man. Movento Movento Agrimek Agrimek Lannate Lannate Radiant Radiant 356 65.6 4309.60 4.2b Program AzaDirect + Radiant Movento Radiant Agrimek Lannate Lannate 293 50.4 724.60 4.6b Harsh Lannate Movento Lannate Agrimek Radiant Lannate 239 52.3 1233.40 4.5b Soft to Harsh Movento Movento Radiant Radiant Agrimek Lannate Lannate 305 54.2 1624.60 4.2b Radiant + Soft Early Movento Movento Radiant Agrimek Lannate 275 55.7 2014.60 4.6b Based on average retail product prices and onions selling at $240 per ton. ((Treatment yield-utc Yield)*240)-Product cost/a.
Weekly applications Which products are most effective at controlling thrips?
Weekly basis high rate
Resistance Management Rotate Chemistries w/different modes of Action. We have 5 soon to be 7 of these Know IRAC Codes Insecticide Resistance Action Committee Many Factors make thrips likely to develop resistance Identification of Knockdown Resistance Mutations in Onion Thrips M. Wu, H. Gotoh, T. Waters, D. Walsh, L Corley Lavine submitted
Things to consider Use good surfactants Scout fields often, begin applications before thrips populations spike Buffer spray solution when recommended by label Factors affecting thrips pressure Temperature Irrigation system Onion vigor Leaf color Plant structure Variety Nearby crops
Take Home Effective insecticides can increase bulb size and yield Radiant (5)- Good early and late season choice Lannate (1A)- Best used later in season. Overhead or drip Chem. Movento (23)-Good early season choice, slow acting, chem? AgriMek (6)-Good early or late season choice Pyrethroids (3A)-not effective in most areas Soon to be- Torac(tolfenpyrad) (21A) -good activity, late season choice, overhead chem Benivia/Exirel (cyazypyr)(28)-good activity, late season, overhead or drip chem.
Funding Carr Farms Cascade Specialties Easterday Farms Grigg Farms Mercer Canyons McCain Foods USA River Point Farms Roloff Farms Sunheaven Farms Syngenta Brandt Monterey DuPont Nichino Dow Agrosciences WSCPR Acknowledgments Technical assistance Don Kinion, WSU Extension Greg Jackson, Two Rivers Travis Whitney, Nunhems USA Bob Middlestat, Clearwater Supply C. Comstock, D. Vermul, J. Scozylas, R. Haun
Disclaimer Not all compounds tested are currently registered for use on Onions in Washington State. Do not use unregistered compounds Consult your local Extension office and read and follow label directions. Oregon and Washington labels (PICOL): http://cru66.cahe.wsu.edu/labeltolerance.html