EFFECTS OF GROWTH STAGE ON TRANSLOCATION OF GLYPHOSATE IN QUACK GRASS

1974 ◽  
Vol 54 (2) ◽  
pp. 397-401 ◽  
Author(s):  
R. RIOUX ◽  
J. D. BANDEEN ◽  
G. W. ANDERSON

Visual symptoms of toxicity (inhibition of leaf growth and bud germination) were used to study the influence of growth stage of quack grass (Agropyron repens (L.) Beauv.) on glyphosate (N-phosphonomethyl glycine) transport and efficiency. Glyphosate (or a toxic metabolite) moved in sufficient quantity from the point of application on the leaf within 1 day to significantly affect the regrowth and within 2 days to affect the regenerative potential of rhizomes. As quack grass plants developed to the four-leaf stage the effect of glyphosate treatment increased. When only one shoot was sprayed on a rhizome supporting two shoots at the same leaf stage, glyphosate inhibited leaf growth on the untreated shoot at the two-leaf stage but not at the four-leaf stage. Similarly, glyphosate inhibited leaf growth on tillers when only the main shoot was sprayed. However, when only the tiller was sprayed, leaf production was not affected on the main shoot suggesting that glyphosate is phloem mobile.

Agriculture ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 70 ◽  
Author(s):  
Ralph Hale ◽  
Taghi Bararpour ◽  
Gurpreet Kaur ◽  
John Seale ◽  
Bhupinder Singh ◽  
...  

A field experiment was conducted in 2017 and 2018 to evaluate the sensitivity and recovery of grain sorghum to the simulated drift of glufosinate, glyphosate, and paraquat at two application timings (V6 and flag leaf growth stage). Paraquat drift caused maximum injury to sorghum plants in both years, whereas the lowest injury was caused by glyphosate in 2017. Averaged over all herbicide treatments, injury to grain sorghum from the simulated herbicide drift was 5% greater when herbicides were applied at flag leaf stage, as compared to herbicide applications at the six-leaf stage in 2017. In 2018, injury from glyphosate drift was higher when applied at the six-leaf stage than at the flag leaf stage. Paraquat and glufosinate drift caused more injury when applied at flag leaf stage than at six-leaf stage at 14 days after application in 2018. About 21% to 29% of injury from the simulated drift of paraquat led to a 31% reduction in grain sorghum yield, as compared to a nontreated check in 2017. The simulated drift of glyphosate and glufosinate did not result in any significant yield reduction compared to the nontreated check in 2017, possibly due to the recovery of sorghum plants after herbicides’ drift application.


1996 ◽  
Vol 121 (1) ◽  
pp. 6-12
Author(s):  
R. Bruce Carle ◽  
J. Brent Loy

The morphology, growth rate and anatomy of the fused vein trait were characterized in Cucurbita pepo using the inbreds NH2405 (fused vein), NH7210 (moderately fused vein), and NH614 (normal). Morphological analysis showed that the trait is characterized by a partial fusion of the five primary leaf veins. Fusion begins at the distal point of the petiole and extends along the central vein. Branching of the veins is delayed and there is a reduction of the interveinal leaf blade. Consequently, the upper leaf surface appears puckered or wrinkled. Depending on genetic background, the onset of fused vein leaf production starts at the fourth to tenth leaf stage and continues throughout vegetative growth. The extent of fusion increases with leaf number but stabilizes by the twentieth leaf stage maximum extent of vein fusion also varies with genetic background (5-20 cm). Though fused vein and normal inbreds differed in the rate and pattern of leaf growth, examination of F2 and BC populations revealed no significant effect of the fused vein trait on leaf number, leaf size, and rate of leaf initiation. Anatomical examination revealed different vascular patterns in the transition zone between petiole and leaf blade for normal and fused vein leaves. In normal leaves, the vascular bundles of the petiole enlarge and coalesce to form a vascular crescent. The crescent reorganizes and diverges as large vascular columns and pairs of smaller flanking vascular bundles into each vein. In contrast, two cycles of enlargement, coalescence, and dispersal occur in fused vein leaves.


1998 ◽  
Vol 12 (2) ◽  
pp. 254-257 ◽  
Author(s):  
David L. Jordan ◽  
Dearl E. Sanders ◽  
Steven D. Linscombe ◽  
Bill J. Williams

Experiments were conducted from 1994 through 1996 to determine the response of the rice cultivars ‘Bengal,’ ‘Cypress,’ ‘Jodon,’ and ‘Kaybonnet’ to triclopyr at 0.42 (standard rate) and 0.84 kg ai/ha applied postemergence at the four-leaf and panicle initiation stages of growth. Applications at the four-leaf stage were made in close association with fertilization and flood establishment, which often increases the potential for triclopyr to injure rice. Visible injury from triclopyr was slightly higher for the cultivar Jodon than for the cultivars Bengal, Cypress, or Kaybonnet. Injury was 3% or less when triclopyr at 0.42 kg/ha was applied at panicle initiation regardless of the cultivar. Triclopyr at 0.42 and 0.84 kg/ha applied at the four-leaf growth stage injured rice 7% and 22%, respectively. Triclopyr at 0.84 kg/ha applied at the four-leaf stage of growth delayed days from seedling emergence to seed head emergence and rice grain yield, irrespective of cultivar.


1988 ◽  
Vol 2 (3) ◽  
pp. 310-316 ◽  
Author(s):  
Joel K. Ransom ◽  
Ervin A. Oelke

Field experiments were conducted to evaluate the effect of application time on common waterplantain control in wild rice with MCPA and 2,4-D. Common waterplantain control was greatest when MCPA or 2,4-D were applied at 1.1 or 1.7 kg ai/ha at the two-aerial leaf stage. The best late-season control was MCPA applied at the scape elongation growth stage. Common waterplantain was controlled adequately when 0.6 to 0.8 kg/ha of MCPA were applied at the scape elongation or early flowering stage. However, because of common water plantain interference and sensitivity of wild rice to late herbicide applications, the best treatment stage for wild rice yield was when MCPA was applied at 0.6 kg/ha to common waterplantain at the two-aerial leaf stage. Wild rice at this time is at the more tolerant one-aerial leaf growth stage.


HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 471E-472
Author(s):  
George H. Clough

Field trials were conducted at Hermiston, Ore., from 1995 through 1998 to determine the impact of stand loss and plant damage at different growth stages on yield of onions grown for dehydration. The experiment was a complete factorial with four replications. Stand reduction (0%, 20%, 40%, 60%, 80%) and foliage damage (0%, 25%, 50%, 75%, or 100%) treatments were applied at 3-, 6-, 9-, and 12-leaf onion growth stages. All average onion production characteristics decreased linearly as stand reduction increased (plant population decreased) at all plant growth stages except average bulb weight which increased as stand was reduced. Bulb weight was not changed by up to 100% foliage removal at the three-leaf stage of growth. At the 6- and 12-leaf stages, bulb weight was reduced when >50% of the foliage was removed. The most severe response occurred at the nine-leaf stage when bulb weights were reduced the most. At the three-leaf stage, yield was not affected by foliage damage. At the six-leaf growth stage, yield was reduced by 75% or more foliage loss, but at the 9- and 12-leaf stages, >50% foliage removal reduced expected yields. As with bulb weight, the impact of foliage removal on yield was most severe at the nine-leaf growth stage.


Weed Science ◽  
2006 ◽  
Vol 54 (4) ◽  
pp. 793-799 ◽  
Author(s):  
Jeanne S. Falk ◽  
Douglas E. Shoup ◽  
Kassim Al-Khatib ◽  
Dallas E. Peterson

Greenhouse and field studies were conducted with a population of common waterhemp resistant to POST protoporphyrinogen oxidase (protox)-inhibiting herbicides to compare its response to PRE and POST applications of selected herbicides. In the greenhouse, a dose–response study of PRE applications of acifluorfen, fomesafen, or lactofen was conducted on protox-susceptible and -resistant common waterhemp. The protox-resistant biotype was approximately 6.3, 2.5, and 2.6 times more resistant than the susceptible biotype to acifluorfen, fomesafen, and lactofen, respectively. In a separate study under field conditions, protox-resistant common waterhemp were treated with PRE and POST applications of acifluorfen, azafenidin, flumioxazin, fomesafen, lactofen, oxyfluorfen, or sulfentrazone. At 14 and 28 d after POST treatment (DAPT) in 2002 and 2004, all PRE applications of herbicides gave greater control than did POST applications. At 14 DAPT, oxyfluorfen had the greatest difference in PRE and POST control, with 85 and 10% control in 2002, respectively. An additional field study was conducted to determine the stage of growth at which resistance to protox-inhibiting herbicides becomes most prevalent. Protox-resistant common waterhemp were treated with herbicides at the 2-leaf, 4- to 6-leaf, and 8- to 10-leaf growth stage. Acifluorfen and fomesafen at 420 g ha−1gave greater than 90% control at the 2-leaf stage and 4- to 6-leaf stage, except in 2003 when control was 85% with acifluorfen. In 2003 and 2004, common waterhemp control at the 8- to 10-leaf stage ranged between 54 and 75% with acifluorfen or fomesafen. Results indicate that common waterhemp resistance to customary rates of POST protox-inhibiting herbicides becomes prevalent after the 4- to 6-leaf growth stage.


HortScience ◽  
2004 ◽  
Vol 39 (5) ◽  
pp. 1005-1007 ◽  
Author(s):  
George H. Clough

Field trials were conducted at Hermiston, Ore., from 1995 through 1998, to determine impact of stand loss and plant damage at different growth stages on yield of onions (Allium cepa) grown for dehydration. Stand reduction (0%, 20%, 40%, 60%, 80%) and foliage damage (0%, 25%, 50%, 75%, 100%) treatments were applied at three-, six-, nine-, and twelve-leaf onion growth stages. Although average bulb weight increased as stand was reduced, marketable, cull, and total yields decreased as stand reduction increased (plant population decreased) at all plant growth stages. Bulb weight was not changed by up to 100% foliage removal at the three-leaf stage. At the six- and twelve-leaf stages, weight was reduced when ≥50% of the foliage was removed. The most severe response occurred at the nine-leaf stage. At the three-leaf stage, yield was not affected by foliage damage. At the six-leaf growth stage, yield was reduced by 75% or more foliage loss, but at the nine- and twelve-leaf stages, ≥50% foliage removal reduced expected yields. As with bulb weight, the impact of foliage removal on yield was most severe at the nine-leaf growth stage.


2015 ◽  
Vol 33 (3) ◽  
pp. 509-519 ◽  
Author(s):  
C. A. DAMALAS ◽  
T. K. GITSOPOULOS ◽  
S.D. KOUTROUBAS ◽  
I. GEORGOULAS

ABSTRACTPanicoid grasses are major weeds of maize and sugarcane as well as of several other important grains, including sorghum, pearl millet, and foxtail millet. Pot trials were conducted to study the activity and potential interactions of topramezone in mixture with recommended rates of rimsulfuron or nicosulfuron on three annual panicoid grasses (i.e. Echinochloa oryzoides,E.phyllopogon, and Panicum miliaceum). Target weeds were treated at the four- to five-leaf growth stage. On the basis of fresh weight reduction, topramezone alone provided 78% control of E.oryzoides, 68% control of E.phyllopogon, and 99% control of P.miliaceum. Topramezone plus rimsulfuron or nicosulfuron provided decreased control of both Echinochloa spp. compared with topramezone alone. The decreased control of E.oryzoidesand E.phyllopogon was more pronounced with rimsulfuron as a companion herbicide in the mixtures. Slightly decreased control of P.milaceum was observed with topramezone plus rimsulfuron compared with topramezone alone, but this was not the case for topramezone plus nicosulfuron. Increased topramezone rates mixed with rimsulfuron or nicosulfuron did not improve control of E.oryzoides and E.phyllopogon compared with the lowest topramezone rate. Also, increased topramezone rates mixed with rimsulfuron or nicosulfuron showed decreased control of both Echinochloa spp. when compared with either rimsulfuron or nicosulfuron alone, suggesting a two-way interaction between topramezone and the ALS-inhibiting herbicides. The above-mentioned interaction was not observed in P.miliaceum, probably related with species sensitivity to the herbicides tested. Newly introduced or naturalized panicoid grasses in maize fields may complicate selection of companion herbicides and rates for effective weed control.


1991 ◽  
Vol 5 (2) ◽  
pp. 439-441
Author(s):  
Randy L. Anderson ◽  
David C. Nielsen

Paraquat was applied at 0.28 and 0.56 kg ai ha-1to winter wheat at five growth stages at 0800, 1300, and 1600 hr to determine whether growth stage or time of application influenced winter wheat response to paraquat. Paraquat bioactivity was affected by growth stage. Biomass reduction by paraquat was 84% when winter wheat was in the 1 to 3 leaf stage, but only 68% when application was delayed until tillering. Paraquat bioactivity continued to decrease at later growth stages. The time of day when paraquat was applied did not affect its bioactivity on winter wheat.


Weed Science ◽  
1987 ◽  
Vol 35 (6) ◽  
pp. 784-791 ◽  
Author(s):  
Peter H. Sikkema ◽  
Jack Dekker

Field experiments were conducted during 1981 and 1982 in Ontario, Canada, on the effects of quackgrass [Agropyron repens(L.) Beauv. # AGRRE] interference in soybean [Glycine max(L.) Merr.] and the usefulness of infrared thermometry in predicting critical periods of weed interference. Soybean seed yield, dry weight, number of leaves, height, and number of pods were substantially reduced due to quackgrass interference. High levels of P and K fertility did not overcome the quackgrass interference. Part of the competitive effects of quackgrass was alleviated by irrigation. Infrared thermometry successfully detected the first occurrence of quackgrass-induced stress during the early soybean flowering stage, when the quackgrass was in the four-leaf gtowth stage. This coincided with the onset of the first significant soybean yield loss. No additional soybean yield loss occurred after quackgrass reached the five-leaf growth stage. There was an inverse relation between accumulated stress degree days and soybean yield reductions due to quackgrass interference. The use of the stress degree day concept may be a valuable tool in predicting soybean yield losses due to quackgrass interference.


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