Small Grains Update, 2018

1. Small Grains Update, 2018

2. Protecting Your Pest Management Options for the Long Haul! David Kee Director of Research Minnesota Soybean

3. Recent Pest control failures • Round up Resistant weeds • Waterhemp, Ragweed (Common and Giant), Kochia, several others • Pyrethroid resistant Soybean Aphids • Cercospora Leaf spot resistance to strobilurin fungicides in sugar beets • Big problem in Louisiana soybeans too. • Soybean Cyst Nematode resistance to PI88788 SCN Resistance

4. How did this happen • YOU selected the monster!!!

5. How we got here? • If you always do what you always done, you’ll always get what you always got. • A statement that has been proven incorrect. • New Farming Philosophy • If you do the same thing over and over, nature will evolve around you. • How did we get here? • Guess

6. Resistance • Resistance is the genetically-based decrease in susceptibility to a pesticide or practice • Not the same as “tolerance” or “inherent susceptibility” • Baseline susceptibility before exposure to pesticide • Also happens with non pesticide options! • Certain populations of Soybean Cyst Nematodes now possess resistance to PI 88788 gene • Rhizomatous grasses possess resistance to “steel” • Corn rootworm resistance to Bt Corn

7. Insecticide resistance • Variability exists in population • Variability is heritable • Some variants survive & reproduce better • Same thing happens with weeds, fungus, bacteria, nematodes, etc. • All living species that reproduce adapt or face extinction

8. Resistance in pests is increasing

9. Multiple resistance • Cross resistance • Resistance to one pesticide confers resistance to other similar pesticides (one mechanism) • Sequential (multiple) resistance • Resistance to different pesticides acquired at different times (multiple mechanisms) al. 2014

10. Resistance in soybean aphid

11. Foliar insecticides for soybean aphid

12. Soybean aphid & resistance? • “Light resistance” to organophosphates in China (Quin et al. 2011) • No evidence of resistance in MI (Chandrasena et al. 2011) • First records of resistance in North America (Hanson et al. 2017) D. Ragsdale, bugwood.org

13. Counties with pyrethroid performance issues (2015) • University of Minnesota: • Koch, Potter, MacRae, Glogoza • Map by B. Potter

14. Counties with pyrethroid performance issues (2016) University of Minnesota: Koch, Potter, MacRae, Glogoza Iowa State University: Hodgson Map by B. Potter

15. Counties with pyrethroid performance issues (2017)

16. How did we get here? • Reliance on few insecticide groups for aphid management • Persistent infestations in/near MN • Treating more than needed • Treating fields below threshold • Adding insecticide when targeting weeds or pathogens (“…just in case”) • Using low rates of insecticide

17. Now what? • Don’t waste your bullets

18. 1. Don’t spray when not needed • i.e. Truly practice IPM • Goal is to minimize pesticide applications • Use cultural practices when possible • Provide clean fields • Watch for field side vectors • Manage for a healthy plant • Canopy closure • Seeding rate/date • Row width • nutrition • Manage the seed bank • Tillage (burial) • At harvest • Baling • Narrow windrow • Etc.

19. 1. Don’t spray when not needed • Practice IPM (minimize pesticide applications) • Anticipate conflicts • Steel in the field/ Soil erosion • Harvest seed management • Loss of OM, fire hazards, etc. • Enhance canopy closure/increased field humidity • White mold, here we come • Adequate Nitrogen • Fine line between just enough and too much • etc. • Make the best judgement possible

20. 1. Don’t spray when not needed • Rotate • Crops • Corn on corn, soybean on soybean has never been a great idea • Rotate genetic resistance • Peking instead of PI88788 • Applies to disease and insect resistance, also • Rotate Modes of Action • At the very least, Rotate chemicals • Don’t do Enlist soybeans following Enlist corn • Don’t follow Liberty Link soybeans with Liberty link corn, • Etc. • Know a lot more about your crop!

21. 1. Don’t spray when not needed Use Economic Thresholds!!! 250 aphids/ plant Graph by Losey & DiTomasso

22. Damage curve: pest population & yield

23. Decision making ~5,500 CAD Damage boundary 4,000-5,000 CAD 250 aphids/plant

24. 2. If you spray, do it right • Scout field • Before application • Do you have a problem? • Do you have the correct solution? • After application • Did it work? • Time depends on Pest • Insect/disease • 3-5 days after spraying to check effectiveness • Weeds • Read the label, product dependent

25. 2. If you spray, do it right • Do your part to attain success • Use correct rates • ½ rates cost less, in the short term • Nozzles, volume & pressure • Applying insecticide with glyphosate • Low volume, low pressure • Environmental conditions • Avoid spraying under conditions that promote droplet or vapor drift • Drift lowers applied rate • Windy, temperature inversion, etc.

26. 3. If you have a failure… • Rule out other causes • Incorrect pesticide or rate, poor coverage • Unfavorable conditions during application • Re-colonization by pest

27. 3. If you have a failure… • If follow up application required • If possible, use alternate Mode of action for next spray • Group numbers are on labels • Use Mixtures: • When appropriate! • Often one of the problems.

28. 3. If you have a failure… • Use of Mixtures: • Effectiveness is very pest dependent • Mostly reproduction dependent • Often ineffective on pests with multi-generations per season • Mixtures maybe the best option for single generation pests • Kill’em dead so they don’t reproduce! • Generally less effective for resistance management • Pest susceptibility may have been reduced • Registered rates are lower • Duration of residual activity • Cross-resistance develops

29. Rotating pesticides for Soybean aphids

30. Foliar insecticides for soybean aphid

31. Pyrethroids (3A): (e.g., Warrior, Tundra, Asana, Hero) • Potential issues: • Resistance is developing • Sensitive to application technology • Toxic to beneficials • Most have potential to flare spider mites • Potential benefits: • Rapid knockdown • Some residual activity • Inexpensive generics • Low mammalian toxicity • Broad spectrum

32. Example insecticide rotations

33. Example insecticide rotations

34. 3. If you have a failure… • Rule out other causes • Utilizer alternate pesticide mode of action for next spray • Report to U of MN Extension z.umn.edu/aphidinsecticidefailure

35. Conclusions • Realize, our tools are limited in number • 3 years of pyrethroid failures & confirmed resistance • Glyphosate tolerant weeds • PI88788 • We are loosing tools faster than we are creating them.

36. Conclusions • What to do? • PLAN!!! • Adjust cultural practices when possible • Seeding rate, row width, etc. • Rotate • Crops, chemicals, modes of action, genetic resistance • Scout! • Don’t spray when not needed • Let the good guys do their job • If you spray, do it right • If you have a failure, alternate pesticide groups and communicate to others.

37. Thank you Questions??? David Kee David@mnsoybean.com 507.388.1635