2009 Weed Cont trol trol Evaluations We conducted 5 trials i 2009

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1 Research Updates Weed Control Evaluations on Specialty Crops: Spinach, Beets, Leeks, Peppers Richard Smith, Vegetab ble Crop and Weed Science Farm Advisor, Monterey County

2 Spinach Weed Control Trials RoNeet is no longer being manufactured Dual Magnum was registered in California in 2008, however it has limitations: it ti 12 month plant back restriction to lettuce 50 day preharvest interval

3 2009 Weed Control Evaluations We conducted 5 trials in 2009 focusing on light soil types evaluating the safety and efficacy of Lorox and Dual Magnum

4 2009 Spinach Evaluations Treatment Material/A Lbs a.i./a RoNeet 6E Dual Magnum 7.63 Lorox 50 Lorox 50 Lorox 50 Untreated 125pt pt lb lb lb

5 Yield of Spina ach Trial No. 2 Soil type = C hualar Loam Ton ns/a

6 Soil Characte ristics of Five Spinach hti Trials Soil Type OM Sand Silt Clay Arnold Loamy Sand 1 Greenfield FSL* 0 Chualar Loam 0 Metz FSL 0 Chualar loam * Yield reduction was obser rved on soil types highlighted in red

7 Yield of Spinach Nine trials Average Ton ns/a

8 Lorox on Spinac ch Weed Control Summ mary Spinach is sensitiv ve to Lorox at rates at and above 0.4 lbs of material/a On key soil types looks to be safe, but on the coarse sandy soils of the organic matter soi ils, it is too injurious in the valley it eastside and low

9 Dual Magnum on Spinach In order to try to accommodate the 50 day PHI for spinach in the summer we conducted a trial in which Dual Magnum was applied 21 days prior to planting and watered into the soil (beds were lightly worked at planting)

10 Weed Counts Dual Magnu um Applied 21 Days Prio r to Planting Weed ds/150 ft 2

11 Dual Magnum on Spinach It is unclear when Summ mary interval for Dual Magnum will be reduced (20 days) the preharvest In the mean time, applying the Dual Magnum prior to planting can work around the curren t 50 day PHI

12 Beet Weed Control Trials Table Beets are in the same situation as spinach. They are dependent on RoNeet Ti Trials were conducted d to evaluate the efficacy and safety of Dual Magnum on this crop cop

13 Number of Weeds 6 ft 2 No. Weeds/6

14 Untreated RoNeet 4 pts Dual Magnum 0.7 pt Dual Magnum 1.3 pt

15 Weedin ng Time Hou urs/a

16 Yield of Beets Octob ber 9 Ton ns/a

17 Leek Weed Control Trials We explored other preemergence as well as Goal Tender post emergence on leeks

18 2009 Leek Weed Control Evaluations Treatment t Materia l/a Application Timing Untreated ---- Dacthal 6F 1.33 gal Prefar 6E 6.0 qt Prowl H2O 33.7 oz Goal Tender 4F 8.0 oz Goal Tender 4F 16.0 oz Goal Tender 4F 24.0 oz Goal Tender 4F 4.0 oz Goal Tender 4F 6.0 oz Goal Tender 4F 8.0 oz ---- Pre Pre Pre Pre Pre Pre Post Post Post

19 2009 Leek Weed Control Evaluations Treatment t Material/A Application Total Timing Weeds Untreated Dacthal 6F 1.33 gal Pre 7.0 Prefar 6E 6.0 qt Pre 6.3 Prowl H2O 33.7 oz Pre 8.3 Goal Tender 4F 8.0 oz Goal Tender 4F 16.0 oz Goal Tender 4F 24.0 oz Goal Tender 4F 4.0 oz Goal Tender 4F 6.0 oz Goal Tender 4F 8.0 oz Pre Pre Pre Post Post Post

20 2009 Leek Weed Control Evaluations Treatment t Material/A Application Weed Timing Time Untreated Dacthal 6F 1.33 gal Pre 4.0 Prefar 6E 6.0 qt Pre 3.8 Prowl H2O 33.7 oz Pre 4.2 Goal Tender 4F 8.0 oz Goal Tender 4F 16.0 oz Goal Tender 4F 24.0 oz Goal Tender 4F 4.0 oz Goal Tender 4F 6.0 oz Goal Tender 4F 8.0 oz Pre Pre Pre Post Post Post

21 2009 Leek Weed Control Evaluations Treatment t Material/A Application Grams Timing per plant Untreated Dacthal 6F 1.33 gal Pre 166 Prefar 6E 6.0 qt Pre 158 Prowl H2O 33.7 oz Pre 164 Goal Tender 4F 8.0 oz Goal Tender 4F 16.0 oz Goal Tender 4F 24.0 oz Goal Tender 4F 4.0 oz Goal Tender 4F 6.0 oz Goal Tender 4F 8.0 oz Pre Pre Pre Post Post Post

22 Pepper Weed Control Studies Peppers have a wide spectrum of materials for use pre and post plant The biggest issue with this crop is that it is a long-season crop that can be expensive to weed later in the growth cycle

23 Evaluated Contro ol of Late Season Wee eds Malva infestation prior to harvest Can be expensive e to control Can reduce quality of peppers

24 Treatment Application Material/A Malva Total weeds Untreated --- Dual Magnum Directed Prowl H2O Directed Dual Magnum Directed + Prowl H2O Outlook 6.0 Directed pints pints pints pints 14.0 oz

25 Treatment Application Material/A Malva Total weeds Untreated --- Dual Magnum Directed + Prowl H2O Chateau Directed Chateau Directed Chateau Shielded Chateau Shielded Chateau Directed +DC Chateau 51WG Directed +DC Broadstar 0.25G Broadcast pints 2.0 pints 3.0 oz oz oz oz oz oz lbs

26 Treatment Untreated --- Application Material/A Total Weed Time Dual Magnum + Prowl H2O Chateau Chateau Chateau Chateau Chateau +DC Chateau 51WG +DC Broadstar 0.25G Directed Directed Directed Shielded Shielded Directed Directed Broadcast 1.5 pints pints 3.0 oz oz oz oz oz oz lbs 7

27 Chateau Used Layby

28 Untreated 3 & 6 oz

29 Untreated Broadstar 37 lbs/a

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31 2010 Eva aluations Broadstar is register red for ornamentals and its price structur re will probably make it too expensive for use in vegetable crops However, on the Cha ateau label there is a provision for impreg gnating fertilizer with Chateau for use on mint, we would like to try that idea on pepp pers We are exploring the idea of obtaining a research authorizatio on to be able to treat 100 acres of peppers with Chateau on fertilizer

32 Significant Weed ed Issue in 2009

33 Branched Broomrape (Orobanche ramosa) An outbreak occurred in a tomato field in the Hollister area It is a parasitic plant that has a wide host range including lettuce CDFA delimited and is quarantining the infested part of the ranch

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36 Branched Broomrape This plant can be a serious threat to yield and productivity Ideally the plant should be eradicated Methyl Bromide is th he most effective control The economics of eradication are difficult to accommodate in some areas

37 Branched Broomrape Extreme care needs to be taken to avoid spread of seed of this plant on soil and equipment from affected fields

38 Weed Research Reports Online

39 ey.ucdavis.edu/

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41 Acknowle dgements All the many growers & PCA s, as well as the California Leafy Greens Research Board and chemical companies that cooperated and assis sted in carrying out these trials