Orchard and Vineyard Weed Management in California

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1 Orchard and Vineyard Weed Management in California Weeds Class Fresno State May 3, 2017 Kurt Hembree Weed Management Farm Advisor, UCCE Fresno County

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3 Todays Message: What goes into making decisions regarding weed management in orchards and vineyards?

4 Some weed impacts Steals water and nutrients (in come cases sunlight) Impacts irrigation, nut drying, harvest, and other cultural operations Reservoir for pest and rodent problems Reduced returns (due to increased costs for control)

5 Weed management decisions are made with three crop stages in mind: 1. Before planting 2. After planting (next 2-3 years) 3. Productive (bearing) years

6 1. Before planting General goals: 1. Get rid of as many perennial weeds as possible. 2. Use pre-plant herbicides to control annual weeds to encourage crop growth and establishment.

7 2. After planting (2-3 years) General goals: 1. Eradicate weeds to reduce competitive effects. 2. Avoid mechanical or chemical damage.

8 Letting weeds grow >12 weeks after planting can reduce productivity

9 Weed-free Weeds removed after 12 weeks Weeds removed after 24 weeks

10 3. Productive (bearing) years General goals: 1. Keep weed population at a manageable level. 2. Be proactive to help avoid weed resistance and maintain herbicide effectiveness.

11 Weed growth and management decisions can be affected by many factors, including Crop age and spacing Irrigation and soil Management technique

12 Age and spacing Sunlight and shading on the soil surface: - weed type and pattern Water availability: - weed type and growth Weed control decisions: - herbicide and mechanical options change with crop age

13 Irrigation and soil Different wetting patterns from flood, drip, and microjet irrigation (and soil type): - repeated weed flushes - doughtier weeds on perimeter of wetted areas (purslane, junglerice) Changes in soil textures and patterns from field to field or within a field: - affects weed type, growth, and unevenness in emergence

14 Management technique Middles management: - mowing favors annual grasses like sprangeltop and can make fleabane difficult to burn down before harvest in nut crops Row management: - repeated postemergent sprays can favor tough weeds like fleabane, knotweed, and palmer amaranth if herbicides are applied to late

15 Managing weeds with herbicides - things to consider Select appropriate combinations Treat at the right time Preserve herbicide MOAs Application and applicator awareness Regulations (drift, ground water, etc.) Cost

16 1. Select appropriate combinations Horseweed Hairy fleabane Annual sowthistle Prickly lettuce Pigweed Rattail fescue

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18 Glyphosate-resistant weeds Horseweed Hairy fleabane Palmer amaranth Rigid ryegrass Junglerice

19 Other problem weeds Purslane Lambsquarters Annual sowthistle Sprangletop

20 Spurge Puncturevine Cheeseweed Nutsedge

21 Weeds controlled with some of the preemergents Chateau Trellis Matrix Pindar GT Alion Mission Broadworks (14) (21) (2) (2 + 14) (29) (2) (27) Filaree Hairy fleabane Horseweed Knotweed?? Malva Nettle Prickly lettuce Puncturevine Purslane Spurge Sprangletop Junglerice

22 Good soil contact is a must for preemergents to work effectively

23 Weeds controlled with some of the postemergents Rely 280 Shark Treevix Venue Mission Roundup (10) (14) (14) (14) (2) (9) Filaree Hairy fleabane Horseweed Knotweed? Malva Nettle Prickly lettuce Puncturevine Purslane?? Spurge Sprangletop Junglerice??

24 Rely and Lifeline Treevix)

25 Start clean stay clean POST Program PRE+POST Program Brad Hanson, UC Davis

26 Control 2. Treat at the right time Horseweed control across postemergence herbicides tested Parlier leaf Rosette 6-12" bolted Horseweed growth stage

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28 3. Preserve herbicide MOAs Control tactic Herbicide rotate different MOAs Herbicide mix different MOAs Herbicide timing of treatment Herbicide uniformity of coverage Herbicide rate Mechanical - tillage Cultural irrigation type Cultural cover crops, mulching Effectiveness Excellent Excellent Excellent Good to Excellent Good Fair to Good Fair to Good Poor to Fair

29 Rotate and/or tank-mix MOAs (almond herbicides)

30 UNT Broadworks (27) + Prowl H2O (3) + Rounup (9) + Rely 280 (10) Mustard Filaree Hairy fleabane Swinecress Spotted spurge Annual bluegrass Annual sowthistle Grower Roundup (9) Broadworks (27) GoalTender (14) + Rounup (9) + Rely 280 (10) Broadworks (27) + Alion (29) + Rounup (9) + Rely 280 (10)

31 RU (9)+ AMS RU (9) + Mission (2) z + MSO + AMS RU (9) + Chateau (14) z + Mission (2) z + MSO + AMS RU (9) + Alion (29) + Mission (2) z + MSO + AMS

32 *Look for MOA group number on the container and/or the label.

33 4. Application and applicator awareness Sprayer is functioning right? Target rate(s) achieved? Favorable weather conditions met? Spray nozzles, volume, and coverage adequate for the herbicide(s)? Spray additives used as required? Enough labor and equipment to meet proper timing demands? Applicator is skilled and pays close attention to the details?

34 Anyone doing the spraying should have these!

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36 Randall sprayer Boom sprayer Shielded sprayer for middles Enviromist low-volume sprayer

37 What do these have in common? Apricot - Shark Pistachio - Chateau Almond - Roundup Almond Pindar GT

38 Managing weeds mechanically - things to consider In-row (mainly grapes) and between-row uses Treat at the right time Avoid damaging the trunks (canker) Regulations (dust, burning) Cost

39 In-row disking In-row plowing In-row mowing In-row tilling

40 THANK YOU! (for staying awake)

41 cefresno.ucanr.edu Office: (559) ; Cell: (559)