2016 Processing Onion Weed Control Trial

Transcription

1 Intermountain Research & Extension Center RESEARCH REPORT Number 179, Processing Onion Weed Control Trial Rob Wilson, Center Director/Farm Advisor; Steve Orloff, Siskiyou County Director/Farm Advisor; Darrin Culp, Superintendent of Agriculture; Kevin Nicholson, Staff Research Associate; Skyler Peterson Staff Research Associate.. University of California Intermountain Research & Extension Center, 2816 Havlina Rd. Tulelake, CA Phone: 530/ Fax: 530/ Objective: Evaluate weed control and crop safety for three unregistered herbicides, pyroxasulfone (Zidua), bicyclopyrone, and fomesafen (Reflex), in Tulelake, CA processing onions. The study compared herbicide rates, application timings, and herbicide combinations to determine the potential fit for each herbicide in an onion weed control program. IREC Trial Site and Herbicide Application Information Location: Tulelake, CA Irrigation: Solid-set sprinklers Plot Size: 9 ft (3 beds) X 19 ft long Bed Spacing: 36 inches; 4 seed-lines spaced 6 inches apart per bed Trt Replication: 4 replications in a RCB design Soil Type: Tulebasin mucky silty clay loam; 6.46% OM Fertilizer: 270 # N, 40 # P205, soil tests showed K, S, and micro-nutrients were adequate. Irrigation: inches applied water for the entire growing season Planting Date: May 19, 2016 Harvest Date: September 21, 2016 Herbicide Application Methods: CO2 backpack sprayer at 30 GPA. 75% radical treatments were applied on treatments were applied on treatments were applied on Weed Density Counts and % Control Rating: Weed density counts were taken from the center bed in the center 8 feet of the plot. % weed control was visually estimated in each plot comparing weeds in the untreated check. Onion Stand, Onion Injury, and Yield: Stand counts were taken by counting every onion in all seed lines from the center 8 feet in the center bed. Onion injury consisted of a visual estimate of chlorosis, necrosis, and stunting compared to the untreated check. Yield was calculated by topping the onions, digging all onions in the center bed, and weighing the bulbs. Results: Treatments 16 and 17 were included as grower standards. Treatment 16 consisted of Prowl H20 applied alone premergence in combination with a Goal + Buctril postemergence program. Treatment 17 consisted of Prowl H20 + Dacthal applied premergence and the same postemergence Goal + Buctril program. Tank-mixing Dacthal + Prowl H20 numerically improved total weed control compared to using Prowl H20 alone (Tables 1a &1b). Using pyroxasulfone with Prowl H20 preemergence improved early-season control of some weeds but the difference in total weed control compared to the grower 1

2 standard was minimal. Substituting pyroxasulfone (trt 10) for Prowl H20 in a preemergence combination with Dacthal provided similar total weed control compared to Prowl + Dacthal (trt 17) suggesting pyroxasulfone may be a viable alternative for Prowl H20 in Federal lease lands where Prowl H20 cannot be used due to environmental concerns. Reflex herbicide applied preemergence (trt 18) gave excellent control of redroot pigweed, but it did not improve total weed control compared to Prowl + Dacthal. Bicyclopyrone gave excellent weed control, but it caused unacceptable crop injury (Tables 1 and 2). Both bicyclopyrone treatments (trts 20 & 21) caused lasting crop injury and they ranked lowest in onion yield (Table 2). Other herbicide treatments with lower onion yield compared to the top yielding treatment were those where the first application of Goal was delayed until the 2-. Delaying the first Goal application until the 2- resulted in early season weed competition and lower onion yield. Soil moisture trends for the test site using different soil moisture monitors are presented in figures on page 6 and 7. 2

3 Table 1a. % Weed Control and Weed Density for Processing Onion Herbicide Treatments test at IREC in Trt # Treatment name kochia 1-20 Bicyclopyrone at 75% radical emerg. & Goal 1- program 92.5 a 98.5 a 98.8 a 95.8 a a 98.3 a a 99.3 ab a 99.8 abcd a 2 Hand-weeded control 27.5 c 6.3 g 30.0 b 46.3 c 51.3 fg 62.5 de 87.5 a a a a a 10 Zidua 60g ai/a + Dacthal 3 pt/a at 75% radical emerg. & Goal 1- program 85.0 a 90.0 ab 93.8 a 75.0 b 92.3 abc 94.8 ab a 86.3 abc a 97.3 abcd a 17 Prowl H pt + Dacthal 3 pt at 75% radical emerg. & Goal 1- program 78.8 ab 68.8 cdef 80.0 a 85.0 ab 73.8 de 87.5 abcd a 87.5 abc 98.8 a 90.0 abcd a 15 Prowl H pt/a at 75% radical emerg. & Zidua 90 g ai/a at 1- & Goal 1- program 67.5 abc 62.5 f 75.0 a 75.0 b 82.5 abcde 90.0 abc a 77.5 cd a 97.5 abcd 97.5 ab 13 Prowl H pt/a at 75% radical emerg. & Zidua 45 g ai/a at 1- & Goal 1- program 75.0 ab 65.0 def 80.0 a 77.5 ab 78.8 bcde 90.8 abc a 80.0 cd 98.8 a 95.0 abcd a 18 Reflex 0.5 pt at 75% radical emerg. & Goal 1- program 71.3 abc 92.5 ab 81.3 a 70.0 b 97.0 ab 89.8 abc a 75.0 cd 99.8 a 86.3 bcde a 9 Zidua 60g ai/a + Prowl H pt/a at 75% radical emerg. & Goal 1- program 55.0 abc 88.8 abc 93.8 a 77.5 ab 92.5 abc 97.3 a a 81.3 bcd a 95.0 abcd a 14 Prowl H pt/a at 75% radical emerg. & Zidua 60 g ai/a at 1- & Goal 1- program 68.8 abc 63.8 ef 82.5 a 71.3 b 85.0 abcd 91.0 abc a 78.8 cd a 92.5 abcd a 12 Prowl H pt/a at 75% radical emerg. & Zidua 30 g ai/a at 1- & Goal 1- program 76.3 ab 66.3 def 77.5 a 72.5 b 76.3 cde 90.0 abc a 76.3 cd a 94.8 abcd a 19 Reflex 0.5 pt + Prowl 2.0 pt at 75% radical emerg. & Goal 1- program 86.3 a 92.5 ab 82.3 a 76.3 b 95.0 ab 92.0 abc a 78.8 cd 95.0 ab 85.0 cde a 7 Zidua 30g ai/a + Prowl H pt/a at 75% radical emerg. & Goal 2- program 80.0 ab 85.0 abcd 87.5 a 78.8 ab 76.3 cde 81.3 abcd 96.3 a 75.0 cd 92.5 abc 85.0 cde a 8 Zidua 60g ai/a + Prowl H pt/a at 75% radical emerg. & Goal 2- program 82.5 ab 91.3 ab 91.3 a 75.0 b 82.5 abcde 87.5 abcd 97.5 a 75.0 cd 93.8 ab 86.3 bcde a 21 Prowl H pt at 75% radical emerg. & Bicyclopyrone at 2- & Goal 1- program 68.8 abc 63.8 ef 72.5 a 70.0 b 67.5 def 78.8 abcd a 71.3 cde 95.0 ab 83.8 de 97.5 ab 16 Prowl H pt at 75% radical emerg. & Goal 1- program 67.5 abc 66.3 def 87.5 a 72.5 b 72.5 de 85.0 abcd a 73.8 cd 96.3 ab 86.3 bcde a 6 Zidua 90g ai/a at 75% radical emerg. & Goal 2- program 81.3 ab 90.0 abcd 92.5 a 46.3 c 72.5 de 77.5 abcd 58.8 b 66.3 de 93.8 ab 86.3 bcde a 5 Zidua 60g ai/a at 75% radical emerg. & Goal 2- program 72.5 abc 88.8 abcd 86.3 a 48.8 c 72.5 de 70.0 bcd 58.8 b 66.3 de 95.0 ab 83.8 de a 11 Zidua 60g ai/a at 75% radical emerg. & high rate of Goal and Buctril starting abc 83.8 abcde 90.0 a 50.0 c 66.3 ef 70.0 bcd 60.0 b 47.5 f 77.5 d 75.0 ef 93.8 b 4 Zidua 45g ai/a at 75% radical emerg. & Goal 2- program 61.3 abc 85.0 abcd 88.8 a 45.0 c 66.3 ef 67.5 cd 58.8 b 55.0 ef 86.3 bcd 75.0 ef a 22 Prowl H pt at 75% radical emerg. & high rate of Goal + Buctril starting at ab 62.5 f 80.0 a 73.8 b 36.3 g 63.8 d 85.0 a 55.0 ef 82.5 cd 75.0 ef a 3 Zidua 30g ai/a at 75% radical emerg. & Goal 2- program 61.3 abc 77.5 bcdef 76.3 a 37.5 c 50.0 fg 37.5 e 47.5 b 45.0 f 81.3 d 70.0 f 97.5 ab 1 Untreated control 37.5 bc 17.5 g 35.0 b 0.0 d 0.0 h 0.0 f 0.0 c 0.0 g 0.0 e 0.0 g 0.0 c Mean comparisons were performed using Tukey's-Kramer HSD; means with the same letter are not statistically different redroot pigweed 1- hairy nightshade kochia 2-1- % Weed Control Ratings redroot pigweed 2- hairy nightshade 2- purslane 2- kochia 3- redroot hairy pigweed 3- nightshade 3- purslane 3-3

4 Table 1b. Weed Density for Processing Onion Herbicide Treatments test at IREC in Trt # Treatment name kochia 4-20 Bicyclopyrone at 75% radical emerg. & Goal 1- program 1.3 g 0.3 c 0.0 a 0.0 b 0.0 a 1.5 e 2 Hand-weeded control 1.8 g 3.0 c 0.0 a 0.0 b 0.0 a 4.8 e 10 Zidua 60g ai/a + Dacthal 3 pt/a at 75% radical emerg. & Goal 1- program 13.3 fg 0.0 c 0.3 a 0.0 b 0.3 a 13.8 e 17 Prowl H pt + Dacthal 3 pt at 75% radical emerg. & Goal 1- program 17.5 efg 1.0 c 7.8 a 0.0 b 0.3 a 26.5 e 15 Prowl H pt/a at 75% radical emerg. & Zidua 90 g ai/a at 1- & Goal 1- program 40.8 defg 0.3 c 0.5 a 0.0 b 0.0 a 41.5 de 13 Prowl H pt/a at 75% radical emerg. & Zidua 45 g ai/a at 1- & Goal 1- program 43.5 defg 0.0 c 1.3 a 0.0 b 0.0 a 44.8 cde 18 Reflex 0.5 pt at 75% radical emerg. & Goal 1- program 38.3 defg 0.0 c 7.5 a 0.0 b 0.0 a 45.8 cde 9 Zidua 60g ai/a + Prowl H pt/a at 75% radical emerg. & Goal 1- program 46.0 defg 0.3 c 0.0 a 0.0 b 0.0 a 46.3 cde 14 Prowl H pt/a at 75% radical emerg. & Zidua 60 g ai/a at 1- & Goal 1- program 56.5 cdefg 0.0 c 0.0 a 0.0 b 0.0 a 56.5 cde 12 Prowl H pt/a at 75% radical emerg. & Zidua 30 g ai/a at 1- & Goal 1- program 63.5 cdefg 0.3 c 1.8 a 0.0 b 0.0 a 65.5 cde 19 Reflex 0.5 pt + Prowl 2.0 pt at 75% radical emerg. & Goal 1- program 35.5 defg 0.3 c 30.0 a 0.0 b 0.5 a 66.3 cde 7 Zidua 30g ai/a + Prowl H pt/a at 75% radical emerg. & Goal 2- program 58.8 cdefg 1.5 c 9.3 a 0.0 b 0.0 a 69.5 cde 8 Zidua 60g ai/a + Prowl H pt/a at 75% radical emerg. & Goal 2- program 71.5 cdefg 0.5 c 5.0 a 0.0 b 0.0 a 77.0 cde 21 Prowl H pt at 75% radical emerg. & Bicyclopyrone at 2- & Goal 1- program 70.5 cdefg 0.0 c 20.3 a 0.0 b 0.0 a 90.8 cde 16 Prowl H pt at 75% radical emerg. & Goal 1- program 85.3 bcdefg 0.3 c 6.0 a 0.0 b 0.0 a 91.5 cde 6 Zidua 90g ai/a at 75% radical emerg. & Goal 2- program bcde 0.0 c 4.5 a 0.0 b 0.5 a cde 5 Zidua 60g ai/a at 75% radical emerg. & Goal 2- program bcd 0.3 c 8.0 a 0.0 b 0.3 a cde 11 Zidua 60g ai/a at 75% radical emerg. & high rate of Goal and Buctril starting bcdef 33.0 bc 20.5 a 0.0 b 0.0 a cd 4 Zidua 45g ai/a at 75% radical emerg. & Goal 2- program bc 3.3 c 10.5 a 0.0 b 0.3 a cd 22 Prowl H pt at 75% radical emerg. & high rate of Goal + Buctril starting at cdefg 69.0 b 23.0 a 0.0 b 0.0 a bc 3 Zidua 30g ai/a at 75% radical emerg. & Goal 2- program b 40.5 bc 75.0 a 0.0 b 0.5 a b 1 Untreated control a a 68.3 a 5.0 a 0.8 a a Mean comparisons were performed using Tukey's-Kramer HSD; means with the same letter are not statistically different Weed Density (weeds per 24ft 2 ) redroot pigweed 4- hairy nightshade 4- purslane 4- lambsquarter 4- total weed 4-4

5 Table 2. Processing Onion Injury Ratings and Onion Yield for 2016 Herbicide Treatments at IREC Trt # Treatment name 12 Prowl H pt/a at 75% radical emerg. & Zidua 30 g ai/a at 1- & Goal 1- program 5.0 bc 12.5 b 7.5 bc 6.3 bcdef 13.0 bcd 6.8 bcd 0.0 e 0.0 c a 15 Prowl H pt/a at 75% radical emerg. & Zidua 90 g ai/a at 1- & Goal 1- program 3.8 c 7.5 b 10.0 b 8.8 bcde 13.5 bcd 8.5 b 0.0 e 0.0 c a 17 Prowl H pt + Dacthal 3 pt at 75% radical emerg. & Goal 1- program 3.8 c 10.0 b 5.0 bcd 10.0 bcd 14.8 bc 7.0 bc 0.0 e 0.0 c ab 13 Prowl H pt/a at 75% radical emerg. & Zidua 45 g ai/a at 1- & Goal 1- program 3.8 c 12.5 b 8.8 bc 6.9 bcdef 11.8 bcd 7.3 bc 0.0 e 0.0 c ab 19 Reflex 0.5 pt + Prowl 2.0 pt at 75% radical emerg. & Goal 1- program 7.5 bc 10.0 b 10.0 b 8.8 bcde 16.5 b 8.5 b 0.0 e 0.0 c ab 18 Reflex 0.5 pt at 75% radical emerg. & Goal 1- program 6.3 bc 10.0 b 8.8 bc 8.0 bcdef 15.8 bc 7.8 bc 0.0 e 0.0 c abc 7 Zidua 30g ai/a + Prowl H pt/a at 75% radical emerg. & Goal 2- program 3.8 c 12.5 b 5.0 bcd 2.5 def 12.3 bcd 7.8 bc 0.0 e 0.0 c abc 9 Zidua 60g ai/a + Prowl H pt/a at 75% radical emerg. & Goal 1- program 10.0 ab 13.8 b 10.0 b 12.5 b 14.3 bcd 8.5 b 0.0 e 0.0 c abcd 10 Zidua 60g ai/a + Dacthal 3 pt/a at 75% radical emerg. & Goal 1- program 7.5 bc 11.3 b 6.3 bcd 11.3 bc 13.0 bcd 8.5 b 0.0 e 0.0 c abcd 16 Prowl H pt at 75% radical emerg. & Goal 1- program 5.0 bc 11.3 b 6.3 bcd 7.5 bcdef 14.8 bc 7.8 bc 0.0 e 0.0 c abcd 14 Prowl H pt/a at 75% radical emerg. & Zidua 60 g ai/a at 1- & Goal 1- program 3.8 c 12.5 b 10.0 b 10.0 bcd 9.8 bcde 6.8 bcd 0.0 e 0.0 c abcd 8 Zidua 60g ai/a + Prowl H pt/a at 75% radical emerg. & Goal 2- program 6.3 bc 11.3 b 7.5 bc 1.3 ef 13.5 bcd 7.3 bc 0.0 e 0.0 c abcd 2 Hand-weeded control 3.8 c 7.5 b 5.0 bcd 5.0 bcdef 8.6 cde 1.3 cd 0.0 e 0.0 c abcde 22 Prowl H pt at 75% radical emerg. & high rate of Goal + Buctril starting at bc 11.3 b 3.8 bcd 1.3 ef 11.0 bcde 11.8 b 17.5 b 2.5 c bcdef 5 Zidua 60g ai/a at 75% radical emerg. & Goal 2- program 7.5 bc 10.0 b 3.8 bcd 0.0 f 8.5 cde 7.0 bc 5.0 d 0.0 c bcdef 4 Zidua 45g ai/a at 75% radical emerg. & Goal 2- program 5.0 bc 11.3 b 2.5 cd 0.0 f 9.3 bcde 6.5 bcd 5.0 d 0.0 c bcdef 6 Zidua 90g ai/a at 75% radical emerg. & Goal 2- program 6.3 bc 13.8 b 8.8 bc 1.3 ef 9.8 bcde 7.8 bc 5.0 d 0.0 c cdef 11 Zidua 60g ai/a at 75% radical emerg. & high rate of Goal and Buctril starting bc 10.0 b 3.8 bcd 0.0 f 7.0 de 11.3 b 16.3 b 1.3 c def 3 Zidua 30g ai/a at 75% radical emerg. & Goal 2- program 5.0 bc 10.0 b 0.0 d 0.0 f 8.5 cde 8.5 b 5.0 d 0.0 c ef 21 Prowl H pt at 75% radical emerg. & Bicyclopyrone at 2- & Goal 1- program 5.0 bc 7.5 b 6.3 bcd 3.8 cdef 12.8 bcd 6.5 bcd 11.3 c 16.3 b f 1 Untreated control 5.0 bc 6.3 b 0.0 d 0.0 f 3.8 e 0.0 d 0.0 e 0.0 c 9.45 g 20 Bicyclopyrone at 75% radical emerg. & Goal 1- program 15.0 a 37.5 a 65.0 a 76.3 a 78.8 a 83.8 a 78.8 a 76.3 a 9.41 g loop Mean comparisons were performed using Tukey's-Kramer HSD; means with the same letter are not statistically different Onion % Injury (0% = no injury; 100% = crop death) Visual level of nercrosis, chlorosis, & stunting Onion Yield ton/acre 5

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