Effect of Moisture Stress on Wild Oat (Avena fatua) Response to Diclofop

Weed Science ◽  
1983 ◽  
Vol 31 (2) ◽  
pp. 247-253 ◽  
Author(s):  
William C. Akey ◽  
Ian N. Morrison

The effect of moderate moisture stress on the activity of the methyl ester of diclofop {2-[4-(2,4-dichlorophenoxy)phenoxy] propanoic acid} applied to wild oat (Avena fatuaL.) and the influence of morphological and physiological factors on the activity of the herbicide on stressed plants were investigated in growth-room experiments. Wild oat was grown in very fine sandy loam brought to a gravimetric soil moisture content (SMC) of 20% (water potential of -0.3 bars) or 10% (-6.5 bars) prior to herbicide treatment. The activity of diclofop on wild oat was slightly, but significantly, reduced when the SMC was increased from 10 to 20% immediately after spraying. Maintaining the SMC at 10% after spraying further reduced the activity of the herbicide. Wild oat plants grown at 20% SMC had 22% greater leaf area and retained 23% more herbicide than plants grown at 10% SMC. Penetration of the methyl ester of14C-diclofop into wild oat grown at 20 or 10% SMC did not differ significantly 12, 24, or 48 h after application. Stressed and unstressed plants did not differ significantly in the metabolism of the methyl ester of14C-diclofop. However, growth at a low SMC prior to treatment decreased the proportion of the radiolabeled herbicide recovered in the apex, third leaf, and tillers of wild oat. This may partially account for the reduced activity of this herbicide on wild oat subjected to moisture stress.

Weed Science ◽  
1976 ◽  
Vol 24 (1) ◽  
pp. 134-136 ◽  
Author(s):  
Stephen D. Miller ◽  
John D. Nalewaja

Wild oat (Avena fatuaL.) seedlings were exposed to vapors arising from soil treated with triallate [S-(2,3,3-trichloroallyl)diisopropylthiocarbamate]. Vapor from the liquid triallate formulation inhibited seedling growth more than vapor from the granular formulation, and the degree of inhibition was least in Fargo clay, intermediate in Hecla sandy loam and greatest in washed sand. Growth inhibition from vapors of soil-applied liquid or granular triallate increased as soil moisture content and soil temperature increased. The site of effective vapor action on wild oat seedlings was below the soil surface.


Weed Science ◽  
1984 ◽  
Vol 32 (3) ◽  
pp. 353-359 ◽  
Author(s):  
Carol N. Somody ◽  
John D. Nalewaja ◽  
Stephen D. Miller

Wild oat (Avena fatuaL. ♯3AVEFA) andAvena sterilisL. ♯ AVEST accessions from the United States were screened for tolerance to diallate [S-(2,3-dichloroallyl) diisopropylthiocarbamate], triallate [S-(2,3,3-trichloroallyl) diisopropylthiocarbamate], barban (4-chloro-2-butynylm-chlorocarbanilate), diclofop {2-[4-(2,4-dichlorophenoxy) phenoxy] propanoic acid}, difenzoquat (1,2-dimethyl-3,5-diphenyl-1H-pyrazolium), flamprop [N-benzoyl-N-(3-chloro-4-fluorophenyl)-DL-alanine], and MSMA (monosodium methanearsonate). Some accessions were tolerant to more than one herbicide but none were tolerant to all herbicides. Tolerance to a herbicide was not restricted to certain areas of origin of the accessions, and tolerant accessions occurred even in locations that had not been treated previously with the herbicide. In general, accessions from Southern California and Arizona were shorter, produced more tillers, and required the least number of days to panicle emergence. However, accessions from within individual areas were nearly as variable in these characteristics as the entire 1200 accessions. Tolerance of accessions to flamprop, difenzoquat, MSMA, and diclofop was not due to low leaf surface area, since the tolerant accessions usually had the most leaf surface area. All the accessions tolerant to difenzoquat, MSMA, and flamprop, and three of the four accessions tolerant to diclofop, tillered less than the susceptible accessions.


Weed Science ◽  
1992 ◽  
Vol 40 (4) ◽  
pp. 599-605 ◽  
Author(s):  
Ali M. Mansooji ◽  
Joseph A. Holtum ◽  
Peter Boutsalis ◽  
John M. Matthews ◽  
Stephen B. Powles

Resistance to the methyl ester of diclofop, an aryloxyphenoxypropionate graminicide, was shown for a wild oat (Avena fatua) population from Western Australia, and marked resistance to a range of aryloxyphenoxypropionate and cyclohexanedione graminicides was detected in a winter wild oat (Avena sterilisssp.ludoviciana) population from South Australia. TheA. sterilisbiotype exhibited high levels of resistance to the aryloxyphenoxypropionate herbicides diclofop, fluazifop, haloxyfop, fenoxaprop, quizalofop, propaquizafop, and quinfurop and low levels of resistance to the cyclohexanedione herbicides sethoxydim, tralkoxydim, and cycloxydim. Ratios of LD50values for responses of resistant and susceptibleA. sterilisto the aryloxyphenoxypropionate herbicides were between 20 for propaquizafop and > 1,000 for fluazifop, and were between 2.5 and 3 for the cyclohexanedione herbicides. The LD50value for diclofop for theA. fatuabiotype was 442 g ai ha-1which was 2.7-fold that of a susceptible control. Thirty-three percent of the plants survived at the registered rate of application.


Weed Science ◽  
1982 ◽  
Vol 30 (2) ◽  
pp. 147-152 ◽  
Author(s):  
Mahendra P. Sharma ◽  
Fayaz A. Qureshi ◽  
William H. Vanden Born

Absorption, translocation, and metabolism of the methyl ester of14C-flamprop [N-benzoyl-N-(3-chloro-4-fluorophenyl)-DL-alanine] (hereafter referred to as flamprop-methyl) and14C-barban (4-chloro-2-butynyl-m-chloro carbanilate) in wild oat (Avena fatuaL.) were investigated to determine the basis of the synergistic interaction between the two herbicides. The mutual effects of the two herbicides were studied when they were applied together to wild oat at the two- and four-leaf stage. The addition of the commercial formulation of barban, barban formulation additives, technical barban, or the nonionic surfactant polyoxyethylene-6-tridecylether resulted in varying degrees of increase in the absorption of14C-flamprop-methyl. Translocation of14C-flamprop-methyl following leaf application in wild oat was mainly acropetal. The addition of commercial barban to14C-flamprop-methyl did not influence the pattern of14C translocation. Metabolism of flamprop-methyl by wild oat at either leaf stage was not influenced by barban. Absorption of14C-barban was increased by the addition of the commercial formulation of flamprop-methyl and by polyoxyethylene-6-tridecylether. The addition of flamprop-methyl did not influence the pattern of translocation and metabolism of14C-barban in wild oat at either leaf stage. It is concluded that increased absorption of flamprop-methyl and barban by wild oat at the two- and four-leaf stages is the most important factor in the synergistic interaction between these herbicides. Translocation and metabolism of the herbicides do not seem to be important factors in the synergism observed.


Weed Science ◽  
1978 ◽  
Vol 26 (6) ◽  
pp. 566-570 ◽  
Author(s):  
C. E. G. Mulder ◽  
J. D. Nalewaja

Experiments were conducted in controlled environmental chambers to determine the influence of temperature on the phytotoxicity of seven soil-applied herbicides. Diclofop {2-[4-(2,4-dichlorophenoxy)phenoxy] propanoic acid} soil incorporated or surface applied, was more toxic to wild oat(Avena fatuaL.) shoots at 10 and 17 C than at 24 C. Efficacy of diclofop was enhanced with soil incorporation. Diclofop toxicity to wild oat roots was not influenced by a change in temperature. EPTC(S-ethyl dipropylthiocarbamate) stimulated sugarbeet(Beta vulgarisL. ‘American Crystal Hybrid B’) shoot dry weight production at 10 C and caused dry weight reduction at 24 C. Atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] toxicity to barley(Hordeum vulgareL. ‘Larker’) and alachlor [2-chloro-2′,6′-diethyl-N-(methoxymethyl)acetanilide] toxicity to oats(Avena sativaL. ‘Chief’) increased with increased temperature from 10 to 17 C. Temperatures within the range of 10 to 24 C did not affect trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) toxicity to barley or BAY-5653 [N-(2-benzothiazolyl)-N-methylurea] or chloamben (3-amino-2,5-dichlorobenzoic acid) toxicity to oats.


Weed Science ◽  
1981 ◽  
Vol 29 (5) ◽  
pp. 566-571 ◽  
Author(s):  
Wayne A. Olson ◽  
John D. Nalewaja

Experiments were conducted in the field, greenhouse, and controlled environment chambers to determine the extent to which MCPA {[(4-chloro-o-tolyl)oxy] acetic acid} antagonizes wild oat (Avena fatuaL.) control with diclofop {2-[4-(2,4-dichlorophenoxy)phenoxy] propanoic acid}. Wild oat control with diclofop at 1 kg/ha was reduced from 96% when used alone to 76, 48, 31, and 14% by tank mixture with IAA (3-indole acetic acid), MCPA, 2,4-D [(2,4-dichlorophenoxy)acetic acid], or dicamba (3,6-dichloro-o-anisic acid), respectively. Wild oat control with diclofop applied alone at 1.1 kg/ha was similar to that of diclofop at 2.2 kg/ha applied as a tank mixture with MCPA at 0.15 or 0.3 kg/ha. MCPA antagonism of wild oat control with diclofop increased as the post-treatment temperature increased from 10 to 30 C. MCPA antagonism of wild oat control with diclofop was the same whether the herbicides were applied to the foliage only or to the foliage and soil. Approximately 20% of the wild oat root inhibition with diclofop applied postemergence, however, was from diclofop uptake from the soil. MCPA at 0.6 kg/ha did not reduce wild oat control when applied as a sequential treatment 2 days before or 1 day after diclofop at 1.1 kg/ha.


Weed Science ◽  
1986 ◽  
Vol 34 (1) ◽  
pp. 62-65 ◽  
Author(s):  
James J. Kells ◽  
William F. Meggitt ◽  
Donald Penner

Several herbicides were toxic to barnyardgrass [Echinochloa crus-galli(L.) Beauv. # ECHCG] when applied as a soil treatment at 0.56 kg ai/ha to a sandy loam soil with 0.8% organic matter. At this application rate, haloxyfop {methyl ester of 2-[4-[[3-chloro-5-(trifluoromethyl)-2-pyridinyl] oxy] phenoxy] propanoic acid}, CGA-82725 {2-propynyl ester of 2-[4-[(3,5-dichloro-2-pyridinyl)oxy] phenoxy] propanoate}, and DPX-Y6202 {ethyl ester of 2-[4-[(6-chloro-2-quinoxalinyl)oxy]-phenoxy] propanoate} provided the greatest persistence of activity. At 31, 28, and 25 days after treatment with these herbicides, respectively, barnyardgrass growth was still inhibited by 50%. Soil activity and persistence of fluazifop {butyl ester of (±)-2-[4-[[5-trifluoromethyl)-2-pyridinyl] oxy] phenoxy] propanoic acid} increased following soil sterilization. Covering the soil surface with vermiculite prior to treatment intercepted the spray and significantly reduced control of 4- to 6-cm-tall barnyardgrass plants with fluazifop.


Weed Science ◽  
1981 ◽  
Vol 29 (1) ◽  
pp. 33-37 ◽  
Author(s):  
S. D. Miller ◽  
J. D. Nalewaja ◽  
E. Pacholak

Postemergence applications of MSMA (monosodium methanearsonate) for weed control in spring wheat (Triticum aestivumL.) were evaluated in the field, greenhouse, and controlled environmental chamber. MSMA controlled weeds better when applied to wheat at the four- to five-leaf stage than when applied at the two- to three-leaf stage. MSMA, tank mixed with barban (4-chloro-2-butynyl-m-chlorocarbanilate) or diclofop {2-[4-(2,4-dichlorophenoxy)phenoxy] propanoic acid}, controlled wild oat (Avena fatuaL.), green foxtail, [Setaria viridis(L.) Beauv.] and broadleaf weeds better than did MSMA applied alone. Wild oat control with tank-mix applications of MSMA and difenzoquat (1,2-dimethyl-3,5-diphenyl-1H-pyrazolium) was variable. Weed control with MSMA was enhanced by 30 C air temperatures, 90% relative humidity, and adequate soil moisture. A simulated rainfall of 0.5 mm within 0.5 h or 4 mm with 4 hr after application reduced wild oat control with MSMA.


Weed Science ◽  
1990 ◽  
Vol 38 (6) ◽  
pp. 475-479 ◽  
Author(s):  
Olufunmilayo O. Joseph ◽  
Shaun L.A. Hobbs ◽  
Sakti Jana

The differences in tolerance, morphology, and physiological response of diclofop-resistant and -susceptible wild oat biotypes collected from fields in Saskatchewan, Canada, were investigated under growth room and field conditions. Under herbicide-free conditions the resistant biotype had more upright leaves with about 12% less leaf area and 50% less leaf width than the susceptible biotype. A marked difference in the level of tolerance to diclofop was observed. Photosynthesis was initially significantly reduced in both biotypes after treatment with diclofop at the rate of 0.70 kg ai ha−1, but the resistant biotype was able to recover. Injury to the susceptible biotype was reduced by coating the seeds with 1,8-naphthalic anhydride. Differential foliar retention was not an important factor in selectivity of diclofop among the two biotypes.


Weed Science ◽  
1979 ◽  
Vol 27 (1) ◽  
pp. 83-87 ◽  
Author(s):  
Christiaan E. G. Mulder ◽  
John D. Nalewaja

The influence of soil moisture on wild oat control from soil-incorporated methyl ester of diclofop {2-[4-(2,4-dichlorophenoxy)-phenoxy] propanoic} was determined in the greenhouse. Wild oat control with soil-incorporated diclofop at 1.5 or 3 ppmw increased linearly when soil moisture in a Tiffany sandy loam increased from 18.5 to 23.5% (75% to 125% of field capacity). The efficacy of soil-incorporated diclofop was not reduced when soil moisture was allowed to decrease from 21 (field capacity) to 18.5, 16, 13.5, or 11% (wilting point) before rewatering to 21%. The soil moisture level at the time of herbicide application determined the degree of wild oat control with soil-incorporated diclofop. Wild oat control with diclofop increased when a Tiffany sandy loam with 16% moisture (50% of field capacity) at the time of herbicide application, was watered to field capacity after 8 or 12 days delay, and control did not change with watering to field capacity at the time of herbicide application or when delayed 4 or 16 days. The movement of14C-diclofop in soil columns was greater within coarse than fine textured soils and increased with water volumes applied, regardless of soil type. Further, the leachability of14C-diclofop was two and a half times greater than that of14C-trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine).


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