Cranberry Weed Management in Wisconsin: Recent tools and future needs

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1 Cranberry Weed Management in Wisconsin: Recent tools and future needs Jed Colquhoun and Jack Perry University of Wisconsin-Madison Department of Horticulture

2 Cranberry weed management The big picture of minor crop herbicides: threats and opportunities Observations from the marsh: recent herbicides in commercial use Research results: strengthening weed control with new wiper combinations What does the weed management future hold in cranberries?

3 The big picture of minor crop herbicides New registrations fairly rare GMO herbicide-tolerant crops Registration costs Liability associated with high value minor crops Few new active ingredients or modes of action in development New uses for already-registered products more common this is where we get cranberry herbicides

4 Herbicide use on at least 10% of acreage in US Source: Duke and Powles AgBioForum 12:

5 Current status of weed resistance

6 Battling weed resistance HPPD inhibitors (Callisto) Tall waterhemp and Palmer amaranth in 6 cases In some cases, resistant to 4 modes of action Rapid selection pressure at lower use rates 5 applications over 6 to 8 years cropsci.illinois.edu

7 Observations from the marsh: Callisto When does Callisto injury occur? Drought or over-watered vines Harvest damage/winter damage Fluctuating temperatures Inadequate nutrients Poor vine storage and health prior to planting High soil ph and high irrigation water ph? Not based on our research results

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10 Observations from the marsh: Making it work: QuinStar 4L Early post-emergent applications critical Control of difficult species drops RAPIDLY on larger weeds Control is persistent, even observed the year after application, so be patient! A surfactant is needed for good postemergent control Still have that MRL issue

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13 We have good tools, but weeds are accomodating

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15 2014 wick wiper studies Collect new data to justify a new wiper label request, particularly tankmixed with qlyphosate Investigate other potential tank-mix partners that meet our modern weed control spectrum Looked at 5 other active ingredients and surfactant systems Four studies in 2014 Repeated in 2015

16 Maple control: nonionic silicone surfactants Herbicide* 14 DAT 30 DAT 2015 Control 2015 Regrowth glyphosate glyphosate + 2,4-D glyphosate + synthetic auxin glyphosate + synthetic auxin glyphosate + synthetic auxin glyphosate + synthetic auxin glyphosate + contact/non-selective glyphosate + QuinStar glyphosate + Callisto ,4-D Non-treated check * 1% v/v nonionic silicone surfactant; 1 part herbicide/2 parts water As always, read and follow the label prior to herbicide use! Labels change and vary regionally.

17 Maple control: adjuvant comparisons Herbicide* Adjuvant 14 DAT 30 DAT 2015 Control 2015 Regrowth glyphosate none glyphosate silicone glyphosate NIS glyphosate COC ,4-D none glyphosate + 2,4-D silicone glyphosate + 2,4-D NIS glyphosate + 2,4-D COC glyphosate + 2,4-D none Non-treated check none * Adjuvants added at 0.5% v/v; 1 part herbicide/2 parts water As always, read and follow the label prior to herbicide use! Labels change and vary regionally.

18 Maple control: Dilution rate vs silicone surfactant Glyphosate at 1:2 ratio compared to 1:10 ratio, with and without nonionic silicone surfactant Maple control better with glyphosate at 1:10 ratio with nonionic silicone surfactant than 1:2 ratio without surfactant As always, read and follow the label prior to herbicide use! Labels change and vary regionally.

19 2014 wick wiper studies

20 2014 wick wiper studies

21 2014 wick wiper studies

22 In the longer term Protect current tools New uses for older tools New application technologies to make herbicides work better: electrostatic, etc. Site specific: UAVs for detection and spray Big data, little weeds: what are growers doing that have no weeds? (i.e. how do we make cranberries more invasive?)

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