1/7/19. Strawberry weeds: What does the future hold? Season-long weed management in strawberries: What does the future hold?

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1 Strawberry weeds: What does the future hold? Season-long weed management in strawberries: What does the future hold? Anything new on the way? Minnesota vs. Wisconsin herbicide registrations What s the risk of resistant weeds in strawberry? Putting it together: an integrated weed management program f strawberries Jed Colquhoun Profess and Extension Specialist University of Wisconsin-Madison There are no new strawberry herbicides on the way! MN vs. WI: Spartan 4F WI only: Special Local Needs (24c) label Herbicide-resistant weeds are on the increase Pre-emergent Mode of action herbicides Chateau SW PPO inhibit 1/7/19 University of Wisconsin Madison MN: Spartan 4F is included on full label, but use directions don t wk Cases resistant Weed species resistant to this herbicide to this mode of action 1 ** 1 Prowl H2 Microtubule inhibit 1 12 Microtubule inhibit 12 Devrinol LCFA inhibit Sinbar WDG PSII inhibit 18 **Source: Heap, I. The International Survey of Herbicide Resistant Weeds. Jan 7, 219. Available 1

2 Wisconsin waterhemp as an example of rapid invasion and resistance Post-emergent herbicides Aim EC Mode of action Ultra Blazer PPO inhibit Cases resistant to this herbicide ** Weed species resistant to this mode of action 1 PPO inhibit 9 1 Gramoxone SL 2. PS I inhibit 69 2 Spur Synthetic auxin 8 2,4-D amine Synthetic auxin 9 8 Roundup EPSP synthase inhibit 4 Poast ACCase inhibit Select Max ACCase inhibit Glyphosate resistance confirmed in 12 counties as of 21 **Source: Heap, I. The International Survey of Herbicide Resistant Weeds. Jan 7, 219. Available Wisconsin waterhemp as an example of rapid invasion and resistance Slide courtesy D. Stoltenberg Wisconsin waterhemp as an example of rapid invasion and resistance Glyphosate resistance has been confirmed in waterhemp from 2 counties as of 217 Glyphosate resistance has been confirmed in waterhemp from 28 counties as of 28 Multiple resistance to glyphosate and PPO inhibits confirmed in four counties Multiple resistance to glyphosate and PPO inhibits confirmed in 1 counties Resistance confirmed at UW-Madison the University of Illinois Plant Clinic; slide courtesy D. Stoltenberg Source: Zimbric, Stoltenberg, Renz and Werle, UW-Madison Agronomy Source: Pratt et al., Iowa State University,

3 How do we reduce weed resistance risk? Monit f weeds that escape control Rotate herbicide sites of action, not only within a growing season but also across years Guard against contaminated crop inputs that can spread resistant weeds Eliminate survivs and prevent seed production An overview of integrated weed management in strawberries Start clean: control weeds pri to planting Cultivation, particularly in establishment year Mulch Prevent weed seed production, in the field and beyond Renovation: weed control and crop competitiveness Source: Start clean: pri to planting Prevention: the best control Managing the weed seedbank Weed control options are limited in strawberry, therefe: Manage weeds in years pri to strawberries: Consider crop rotation and available weed management tools Prevent weed seed production in previous crops Manage soil f productive and competitive strawberry growth Germination (%) Green foxtail Lambsquarters Velvetleaf Pigweed 1 yr yr 9 yr 17 yr Prevention: consider ALL inputs! Start clean: pri to planting Weeds found in sand f cranberry marshes: Sand spread on cranberry marshes f weed control and bed management 74 weed species found in piles 2 plant families 79% considered weeds in cranberries Analogous to winter mulch on strawberries: make sure it s weed-free Stale seedbed depletes the weed seedbank: 1. Wk the soil well befe planting 2. Allow weeds to germinate. Eradicate emerged weeds 1. Herbicide 2. Very shallow tillage 4. Plant crop into exhausted soil

4 Pre-emergent herbicides Special notes Post-emergent herbicides Special notes Aim EC Hooded sprayer only no crop contact Chateau SW Ultra Blazer Prowl H2 Gramoxone SL 2. Devrinol Spur 2,4-D amine Sinbar WDG Roundup Weathermax Shielded sprayer no crop contact Wiper directed spray only Poast Select Max Current herbicides Highlight some of the newer strawberry herbicides Answer a few FAQs about older herbicides Put it together into season-long program options Chateau herbicide Similar mode of action as Spartan, Ultra Blazer Fairly broad spectrum of weed control Primarily pre-emergent weed control, but with some post-emergent activity when used with crop oil concentrate non-ionic surfactant Good soil residual Chateau on established strawberry Chateau use timings Pre-transplant: a minimum of days befe transplanting AND befe laying plastic, likely tank-mixed with glyphosate f me burndown Dmant plants (newly planted established), pri to any new growth, but not on frozen ground Shielded hooded application to row middles 4

5 application timings: Active ingredient: pendimethalin Controls most annual grasses and some annual broadleaves Applied pri to weed emergence, with moderate soil residual Pre- post-transplant, with no new strawberry growth present Banded spray to row middles, up to days befe harvest At the end of renovation, pri to weed emergence new strawberry growth At dmancy, pri to new seasonal crop growth on new plantings use notes: day PHI Use rate varies by soil type, from 1. to. pt/a Do not apply me than 6. pt/a/per season on new plantings Treatment Rate Timing fl oz/a -- Strawberry runners % runners/ plants 14. Handweeded 4 Pre-trans Pre-trans 1. LSD (p=.) -- Strawberry injury 6/6 6/1 2 pt/a 2.6 pt/a on new plantings Treatment Rate fl oz/a Shepherds Ladysthumb Giant Common -purse smartweed foxtail lambsquarters % Hand-weeded

6 FAQs: What s the difference among Devrinol fmulations? Devrinol DF: older fmulation Devrinol 2-XT and DF-XT: newer fmulations Slower and less photodegradation Perfmance and crop safety similar to past FAQs: Do I have to irrigate after Sinbar? Actively growing strawberries are susceptible to Sinbar injury F most plant species: Sinbar uptake is primarily by roots F strawberry: foliar uptake can cause severe injury Irrigation can safely remove Sinbar from foliage pri to damage Sinbar: crop injury after transplanting Sinbar: crop injury on low ganic matter, coarse-textured soils Label has precautions related to soil type and ganic matter Source: Polter et. al. 2 % ganic matter 1.4% ganic matter Source: Polter et. al. 2 IWM in new plantings: options IWM in bearing plantings: options Pre-plant At planting Mid-summer Late fall Early spring Late spring Midsummer Late fall Control perennials Prevent seed production Cover crops Manage weeds around fields Sinbar* Prowl H2 (sandy soils) Cultivation Prevent seed production Grass control: Poast Select Max Chateau Sinbar* Devrinol* Mulch (weedfree) Devrinol* Poast 2,4-D Chateau Select Max Renovation Sinbar* Sinbar* Spur** Devrinol* Spur** early fall f Canada thistle, pri to bud stage * See labels re: multiple Devrinol and/ Sinbar applications per season. * See labels re: multiple Devrinol and/ Sinbar applications per season. ** Only one Spur application allowed per crop per year 6

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