Regional Corn Meeting

Transcription

1 Regional Corn Meeting extension.missouri.edu plantsci.missouri.edu agriculture.com extension.missouri.edu nebraskacorn.org extension.missouri.edu southeastfarmpress.com cafnrnews.com plantsci.missouri.edu ipm.missouri.edu bakerimplement.com weedscience.missouri.edu paael.unl.edu

2 Regional Corn Meeting Fall Herbicide Application Impacts and Resistance Management Jim Heiser University of Missouri Fisher Delta Research Center

3 Introduction Focus on Fall Applications Pesky Pigweeds, Annoying Amaranths and Other Worrisome Weeds

4 Fall Herbicide Applications Weather Uncertainty Impact on Soil Pest Interactions Weed Control cornandsoybeandigest.com

5 Spring Uncertainty What kind of spring will we have this year?

6 Suitable Work Days in Missouri (30 Year Average)

7 Soil Conditions Effects of vegetation on soil Benefits of winter vegetation removal Erosion

8 Influence of Winter Annual Weed Removal with a Residual Fall Herbicide Application on Soil Temperature Prior to Corn Planting

9 Influence of Winter Annual Weed Removal with a Residual Fall Herbicide Application on Soil Temperature Prior to Soybean Planting

10

11 Soil Conditions Higher soil temperatures Removal resulted in a 5-8 increase Lower moisture content Corn 13-14% Soybean 6%

12 Pest Interactions Alternate hosts Soybean cyst nematode (SCN) Black cutworm Corn flea beetle

13 Alternate SCN Hosts Strong Purple Deadnettle Henbit Moderate Field Pennycress Weak Shepard s purse Smallflowered bittercress Common chickweed

14 Weed Control Benefits SCN reduction > 50 reproduction in infested fields 24 day life cycle, cooler soil = longer Location extension.missouri.edu

15 Other Pest Interactions Black Cutworm Attracted to early flowering plants Moths lay eggs Larvae feed on young corn Purdue Agriculture/John Obermeyer ppp.extension,missouri.edu

16 Other Pest Interactions Corn flea beetle Overwinters on winter annuals Moves to young plants after natural senescence Increased population-increased injury extension.entm.purdue.edu

17

18 Fall Herbicide Applications Non-residual Controls weeds present Warm winter Plan ahead Residual Existing Later emerging Less flexible Summer Annuals? aganytime.com

19 Influence of a Fall Residual vs. Spring Preplant Herbicide Application on Cumulative Annual Weed Emergence

20 Resistance Management Do Fall residual applications count as an additional mode of action? Species dependent Horseweed YES Ragweed Maybe Palmer/Waterhemp - NO

21 Horseweed Fall/winter emergence Size at planting/burndown failure Chlorimuron No good POST options in soybean

22 Ragweeds and Amaranths Little control from fall residual Later emerging Fall dissipation

23 Pesky Pigweeds

24 Why So Problematic? Seed Production Tumble -50K+ Palmer 250K+ Waterhemp 300K+ Germination Pattern Generally May-frost Seed to seed rapidly

25 Why So Problematic? Efficient, Competitive

26 Palmer Amarantha and Waterhemp Growth (Mokane, Mo 2009)

27 Why So Problematic? Dioecious plants Pollen Transfer Longevity Distance Among and between species

28 Why So Problematic? Hybridization Looks can be deceiving Palmer transfer Gly resistance Spiny 0.4% Waterhemp 0.2% Smooth 0.01

29 Adaptive

30 Weaknesses We must identify and exploit the weaknesses of herbicide resistant weeds!

31 Amaranths Seed do not survive long in soil Reduce seedbank ANY means necessary Will not emerge if deeper than a couple inches Deep tillage Leave on surface

32 Giant Ragweed Emergence Early Simultaneous Take advantage of this!

33 Horseweed Wide emergence window Short controllable window Ideal size for easy control Biology and Management of Horseweed

34 More on Fall Applications How well are we really controlling amaranth species in corn? Postharvest to tillage Before wheat planting Post Harvest vs. Fall applied DO SOMETHING! Gramoxone 3-4wks Tillage

35 Post Harvest Options Plan Ahead Wheat Valor (30d) or Sharpen (PRE), Metribuzin (sensitivity) Soybean Dual Magnum, Sharpen, Metribuzin, Valor Corn Dual Magnum, Sharpen, Simizine, Valor Cotton Dual Magnum, Sharpen

36 Awknowlegements University of Missouri Extension Anthony Ohmes and David Reinbott Dr. Kevin Bradley University of Missouri, Extension Weed Scientist

37 Contact Information Jim Heiser Fisher Delta Research Center PO Box State Hwy T Portageville, MO (573) (O) (573) (C)