-fumigated ( Fennimore et al., 2005 ). Both flumioxazin and oxyfluorfen herbicides are registered for strawberry production in California, and each product was used on over 2000 ha of strawberry in 2010 ( California Department of Pesticide Regulation, 2012 ; Daugovish
Jayesh B. Samtani, J. Ben Weber, and Steven A. Fennimore
R. Kasten Dumroese, Jasmine L. Williams, Jeremiah R. Pinto, and Peng Zhang
-effective ( South and Gjerstad, 1980a ). To maximize germination and early growth of desired seedlings, bareroot beds are often treated with pre- and postemergence herbicides immediately after sowing ( South and Gjerstad, 1980b ). One such herbicide is oxyfluorfen
Wayne C. Porter
Oxyfluorfen was evaluated for weed control in sweet potatoes. In 1989, applications were made overtop transplants immediately after transplanting. The 1990 applications were made just prior to transplanting. Oxyfluorfen applied post-transplant at 0.38 lb ai/A and greater rates caused a significant reduction in crop vigor. A 1.0 lb ai/A rate of oxyfluorfen reduced crop vigor when applied pretransplant. All rates of oxyfluorfen controlled Brachiaria platyphylla, Digitaria sanguinalis, Cyperus iria, and Sesbania exaltata. Oxyfluorfen rates of 0.5 lb ai/A and greater were needed to consistently control Sida spinosa and Echinochloa crus-galli. Mollugo verticillata was controlled at all rates in 1989 but not controlled at all in 1990. Yields of all grades of sweet potato roots from plots treated with oxyfluorfen were not different from yields from plots treated with currently labeled herbicides. However, in 1989 yields from all oxyfluorfen-treated plots were lower than yields from the hoed check. In 1990, plots treated with oxyfluorfen at 0.25 or 0.38 lb ai/A had lower yields of No. 1 grade roots than the hoed check.
Charles H. Gilliam, Donna C. Fare, and Gary J. Keever
Little information is available on herbicide movement in soilless container media and subsequent movement in container leachate and container bed runoff. The objective of this study was to evaluate oxyfluorfen movement in irrigation water following application to container grown nursery crops in a commercial nursery. Oxyfluorfen levels in the container bed runoff were 9 to 27 times higher than those in container leachate during the 3 irrigations following herbicide application. Maximum oxyfluorfen level in the container leachate was 8.3 ppb following the first irrigation but declined to 2.0 ppb by the 12th irrigation. The oxyfluorfen level was still about 2.0 ppb following the 75th irrigation. Oxyfluorfen in the container bed runoff peaked at 99 ppb following the 3rd irrigation before declining to 67 ppb following the 6th irrigation.
P.B. Goodwin and S. Beach
Ronstar® and Rout® are two of the most common and effective preemergent herbicides used by the nursery industry. However, there is some uncertainty as to what happens to the chemicals in nurseries that are recycling their runoff water. The fate of the chemicals has been studied in two nurseries that are completely dependent on recycled water. Negligible amounts were found in the recycled irrigation water. Most of each herbicide remained where it was applied, either close to the top in the substrate, or on the surface of the growing area, for periods of ≈4 months. Five months after application, <10% of oryzalin remained vs. ≈30% of the oxyfluorfen and oxadiazon. Less residue was produced if oxadiazon was applied when the pots were packed together after potting up, compared to application to spaced pots in the standing area. These herbicides are of low mammalian toxicity, and the main hazard is from contamination on the standing area after application, and from the top layer of substrate. To minimize any risk, we recommend that the herbicides be applied before the plants are spaced out on the growing area, and that staff handling the pots take suitable precautions, and in particular avoid inserting their unprotected hands into the top of the mix. Chemical names used: 2-tert-butyl-4-(2,4-dichloro-5-isopropoxyphenyl)-Δ2-1,3,4-oxadiazolin-5-one (oxadiazon); 4-(dipropylamino)-3,5,-dinitrobenzenesulfonamide (oryzalin); 2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trichloromethyl)benzene (oxyfluorfen); tritium-labelled [N-(4-chloro-2-fluoro-S-(propargyloxy)-phenyl]-3,4,5,6-tetrahydrophthalimide [3H]THP.
Orville C. Baldos, Joseph DeFrank, and Glenn Sakamoto
salt were assessed. The pre-emergence herbicides that were evaluated in the study were oxadiazon, oxyfluorfen, dithiopyr, and a commercial formulation consisting of trifluralin + isoxaben. Oxadiazon is an oxadiazole herbicide that has been labeled for
Yushan Duan, Thomas W. Walters, and Timothy W. Miller
, 1973 , 1980 ; Sheets, 1973 ). Since that time, the herbicides carfentrazone and oxyfluorfen have replaced dinoseb for this use in the PNW, ‘Meeker’ has replaced ‘Willamette’ as the most widely grown raspberry cultivar in the PNW, and more efficient
Jason C. Fausey
The liverwort, marchantia (Marchantia polymorpha), and silver thread moss (Bryum argenteum) are two highly invasive and difficult to control pests in containerized ornamentals. Container trials were conducted evaluating marchantia and silve r thread moss control with preemergence and postemergence applications of chlorothalonil, captan, ammonium chlorides, hydrogen dioxide, flumioxazin, oxyfluorfen, pelargonic acid, acetic acid (vinegar), copper sulfate, cinnamaldehyde, prodiamine, and oxadiazon. Flumioxazin, oxyfluorfen, pelargonic acid, acetic acid, and oxadiazon provided acceptable preemergence and/or postemergence marchantia and silver thread moss control; however, no product provided acceptable control of these weeds at all evaluations. Under controlled environmental conditions marchantia and silver thread moss were controlled with flumioxazin, oxyfluorfen, pelargonic acid, acetic acid, and oxadiazon. In addition to providing postemergence control of these weeds, flumioxazin, oxyfluorfen, and oxidiazon also had residual activity when applied to potting media. However, the length and effectiveness of the preemergence control with flumioxazin, oxyfluorfen, and oxadiazon was dependant upon formulation. In a separate study comparing granular and sprayable formulations of flumioxazin, oxyfluorfen, and oxidiazon, results indicated control of established marchantia and silver thread moss was greater with sprayable formulations when compared with granular formulations. Similarly, sprayable formulations of these active ingredients enhanced residual marchantia and silver thread moss control. The granular and sprayable formulations of flumioxazin provided greater preemergence and postemergence control of marchantia and silver thread moss when compared with granular or sprayable formulations of oxyfluorfen and oxadiazon, and of the products evaluated, displayed the greatest level of activity against these weeds.
Kassim Al-Khatib, Carl Libbey, and Sorkel Kadir
Broadleaf weed control with trifluralin, oxyfluorfen, pendimethalin, clopyralid, pyridate, and metolachlor in cabbage (Brassica oleracea L.) grown for seed was evaluated. No single herbicide controlled broadleaf weeds adequately, with the exception of pendimethalin at 1.92 and 3.84 kg a.i./ha. However, combinations of trifluralin + oxyfluorfen, pendimethalin + clopyralid, and oxyfluorfen + pyridate effectively controlled weeds and did not reduce seed yields. Herbicides caused slight to moderate injury symptoms to cabbage plants, with the greatest injury caused by pendimethalin and the least by trifluralin and metolachlor. However, plants recovered from these symptoms and appeared normal at the bud stage. None of the herbicides applied alone or in combinations adversely affected cabbage population, height, or flowering date. Chemical names used: 3,6-dichloro-2-pyridinecarboxylic acid (clopyralid); 2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide (metolachlor); 2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl) benzene (oxyfluorfen); N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine (pendimethalin); O-(6-chloro-3-phenyl-4-pyridazin-yl)S-octylcarbonothioate (pyridate); 2,6-dinitro-N,N-dipropyl-4-(trifluoromethyl)benzenamine (trifluralin).
Joseph DeFrank and Charles R. Clement
Pejibaye (Bactris gasipaes Kunth, Palmae) is being evaluated for production of fresh heart of palm in Hawaii. Precocity, yields, and weed control were evaluated in response to woven black polypropylene mat (control), oryzalin, oxyfluorfen, and paraquat. Control plots attained 100% of plants harvested by 26 months, followed by oxyfluorfen (97.5%), oryzalin (77.5%), and paraquat (60%). Estimated heart of palm yields (3731 plants/ha) were similar with oxyfluorfen 1.2 kg a.i./ha (707 kg·ha–1), polypropylene mat (612 kg·ha–1), oxyfluorfen 0.6 kg a.i./ha (600 kg·ha–1), and oryzalin 4.5 kg a.i./ha (478 kg·ha–1). Based on precocity, yields, and weed control efficiency, the performance rating of these weed control treatments was mat ≈ oxyfluorfen > oryzalin > paraquat. Chemical names used: 4-(dipropylamino)-3,5-dinitrobenzenesulfonamide (oryzalin); 2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl)benzene (oxyfluorfen); 1,1′-dimethyl-4-4′-bibyridinium ion (paraquat).