Phenology of Five Palmer amaranth (Amaranthus palmeri) Populations Grown in Northern Indiana and Arkansas

Weed Science ◽  
2018 ◽  
Vol 66 (4) ◽  
pp. 457-469 ◽  
Author(s):  
Douglas J. Spaunhorst ◽  
Pratap Devkota ◽  
William G. Johnson ◽  
Reid J. Smeda ◽  
Christopher J. Meyer ◽  
...  
Keyword(s):  
Planting Date ◽  
Palmer Amaranth ◽  
Maximum Height ◽  
Amaranthus Palmeri ◽  
Male And Female ◽  
Late Season ◽  
Extension Center ◽  
Male To Female ◽  
Latitudinal Range ◽  
Growth And Reproduction

AbstractPalmer amaranth (Amaranthus palmeriS. Watson) is a problematic weed encountered in U.S. cotton (Gossypium hirsutumL.) and soybean [Glycine max(L.) Merr.] production, with infestations spreading northward. This research investigated the influence of planting date (early, mid-, and late season) and population (AR, IN, MO, MS, NE, and TN) onA. palmerigrowth and reproduction at two locations. All populations planted early or midseason at Throckmorton Purdue Agricultural Center (TPAC) and Arkansas Agriculture Research and Extension Center (AAREC) measured 196 and 141 cm or more, respectively. Amaranthus palmeriheight did not exceed 168 and 134 cm when planted late season at TPAC and AAREC, respectively. Early season plantedA. palmerifrom NE grew to 50% of maximum height 8 to 13 d earlier than all other populations under TPAC conditions. In addition, the NE population planted early, mid-, and late season achieved 50% inflorescence emergence 5, 4, and 6 d earlier than all other populations, respectively. All populations established at TPAC produced fewer than 100,000 seeds plant−1. No population planted at TPAC and AAREC produced more than 740 and 1,520 g plant−1of biomass at 17 and 19 wk after planting, respectively. Planting date influenced the distribution of male and female plants at TPAC, but not at AAREC. Amaranthus palmerifrom IN and MS planted late season had male-to-female plant ratios of 1.3:1 and 1.7:1, respectively. Amaranthus palmeriintroduced to TPAC from NE can produce up to 7,500 seeds plant−1if emergence occurs in mid-July. An NEA. palmeripopulation exhibited biological characteristics allowing it to be highly competitive if introduced to TPAC due to a similar latitudinal range, but was least competitive when introduced to AAREC. AlthoughA. palmerioriginating from different locations can vary biologically, plants exhibited environmental plasticity and could complete their life cycle and contribute to spreading populations.

Evaluating Effect of Degree of Water Stress on Growth and Fecundity of Palmer amaranth (Amaranthus palmeri) Using Soil Moisture Sensors

Weed Science ◽  
2018 ◽  
Vol 66 (6) ◽  
pp. 738-745 ◽  
Author(s):  
Parminder S. Chahal ◽  
Suat Irmak ◽  
Mithila Jugulam ◽  
Amit J. Jhala
Keyword(s):  
Soil Moisture ◽  
Water Stress ◽  
Seed Germination ◽  
Crop Production ◽  
Growth Index ◽  
The United States ◽  
Palmer Amaranth ◽  
Maximum Height ◽  
Amaranthus Palmeri ◽  
Soil Moisture Sensors

AbstractPalmer amaranth (Amaranthus palmeriS. Watson) is the most problematic weed in agronomic crop production fields in the United States. The objective of this study was to determine the effect of degree of water stress on the growth and fecundity ofA. palmeriusing soil moisture sensors under greenhouse conditions. TwoA. palmeribiotypes collected from Nebraska were grown in loam soil maintained at 100%, 75%, 50%, 25%, and 12.5% soil field capacity (FC) corresponding to no, light, moderate, high, and severe water stress levels, respectively. Water was regularly added to pots based on soil moisture levels detected by Watermark or Decagon 5TM sensors to maintain the desired water stress level.Amaranthus palmeriplants maintained at ≤25% FC did not survive more than 35 d after transplanting.Amaranthus palmeriat 100%, 75%, and 50% FC produced similar numbers of leaves (588 to 670 plant−1) based on model estimates; however, plants at 100% FC achieved a maximum height of 178 cm compared with 124 and 88 cm at 75% and 50% FC, respectively. The growth index (1.1×105to 1.4×105cm3plant−1) and total leaf area (571 to 693 cm2plant−1) were also similar at 100%, 75%, and 50% FC.Amaranthus palmeriproduced similar root biomass (2.3 to 3 g plant−1) at 100%, 75%, and 50% FC compared with 0.6 to 0.7 g plant−1at 25% and 12.5% FC, respectively. Seed production was greatest (42,000 seeds plant−1) at 100% FC compared with 75% and 50% FC (14,000 to 19,000 seeds plant−1); however, the cumulative seed germination was similar (38% to 46%) when mother plants were exposed to ≥50% FC. The results of this study show thatA. palmerican survive ≥50% FC continuous water stress conditions and can produce a significant number of seeds with no effect of on seed germination.

scholarly journals Late-season surveys to document seed rain potential of Palmer amaranth (Amaranthus palmeri) and waterhemp (Amaranthus tuberculatus) in Texas cotton

PLoS ONE ◽  
2020 ◽  
Vol 15 (6) ◽  
pp. e0226054
Author(s):  
Kaisa Werner ◽  
Debalin Sarangi ◽  
Scott Nolte ◽  
Peter Dotray ◽  
Muthukumar Bagavathiannan
Keyword(s):  
Seed Rain ◽  
Palmer Amaranth ◽  
Amaranthus Palmeri ◽  
Late Season ◽  
Amaranthus Tuberculatus

scholarly journals Late-season surveys to document seed rain potential of Palmer amaranth (Amaranthus palmeri) and waterhemp (Amaranthus tuberculatus) in Texas cotton

2019 ◽  
Author(s):  
Kaisa M. Werner ◽  
Debalin Sarangi ◽  
Scott A. Nolte ◽  
Peter A. Dotray ◽  
Muthukumar V. Bagavathiannan
Keyword(s):  
Seed Rain ◽  
Palmer Amaranth ◽  
High Plains ◽  
Amaranthus Palmeri ◽  
Weed Species ◽  
Species Persistence ◽  
High Fecundity ◽  
Late Season ◽  
Central Texas ◽  
Cotton Fields

AbstractDespite the best weed control efforts, weed escapes are often present in large production fields prior to harvest, contributing to seed rain and species persistence. Late-season surveys were conducted in cotton (Gossypium hirsutum L.) fields in Texas in 2016 and 2017 to identify common weed species present as escapes and estimate seed rain potential of Palmer amaranth (Amaranthus palmeri S. Watson) and waterhemp [A. tuberculatus (Moq.) J.D. Sauer], two troublesome weed species with high fecundity. A total of 400 cotton fields across four major cotton-producing regions in Texas [High Plains (HP), Gulf Coast (GC), Central Texas, and Blacklands] were surveyed. Results have revealed that A. palmeri, Texas millet [Urochloa texana (Buckley) R. Webster], A. tuberculatus, ragweed parthenium (Parthenium hysterophorus L.), and barnyardgrass [Echinochloa crus-galli (L.) P. Beauv.] were the top five weed escapes present in cotton fields. Amaranthus palmeri was the most prevalent weed in the HP and Lower GC regions, whereas A. tuberculatus escapes were predominantly observed in the Upper GC and Blacklands regions. On average, 9.4% of an individual field was infested with A. palmeri escapes in the Lower GC region; however, it ranged between 5.1 and 8.1% in the HP region. Average A. palmeri density ranged from 405 (Central Texas) to 3,543 plants ha−1 (Lower GC). The greatest seed rain potential by A. palmeri escapes was observed in the upper HP region (13.9 million seeds ha−1), whereas the seed rain potential of A. tuberculatus escapes was the greatest in the Blacklands (12.9 million seeds ha−1) and the upper GC regions (9.8 million seeds ha−1). Results indicated that seed rain from late-season A. palmeri and A. tuberculatus escapes are significant in Texas cotton, and effective management of these escapes is imperative for minimizing seedbank inputs and impacting species persistence.

Influence of Planting Date on Growth of Palmer Amaranth (Amaranthus palmeri)

Weed Science ◽  
1987 ◽  
Vol 35 (2) ◽  
pp. 199-204 ◽  
Author(s):  
Paul E. Keeley ◽  
Charles H. Carter ◽  
Robert J. Thullen
Keyword(s):  
Seed Production ◽  
Dry Matter ◽  
Planting Date ◽  
Palmer Amaranth ◽  
Amaranthus Palmeri ◽  
Seed Plant ◽  
Viable Seed ◽  
Soil Temperatures ◽  
Total Seed

Palmer amaranth (Amaranthus palmeriS. Wats. # AMAPA) planted in a field at monthly intervals from March through October at Shafter, CA, began to emerge in March when soil temperatures at a depth of 5 cm reached 18 C. With the exception of March and April plantings, at least 50% of the seed of later plantings produced seedlings within 2 weeks after planting. Although growth of plants was initially slower for early plantings, plantings from March to July reached 2 m or greater in height by fall. Due to longer growing times, plantings from March to June eventually produced more dry matter and a greater number of inflorescences than later plantings. Plants began flowering 5 to 9 weeks after planting in March through June and 3 to 4 weeks after planting in July through October. Some viable seed was produced as early as 2 to 3 weeks after flowering began. Total seed production in the fall ranged from 200 000 to 600 000 seed/plant for the March through June plantings, and 115 to 80 000 seed/plant for the July through September plantings. Killing frosts in November prevented Palmer amaranth planted in October from producing seed.

Palmer Amaranth (Amaranthus palmeri) Control in Soybean with Glyphosate and Conventional Herbicide Systems

2010 ◽  
Vol 24 (4) ◽  
pp. 403-410 ◽  
Author(s):  
Jared R. Whitaker ◽  
Alan C. York ◽  
David L. Jordan ◽  
A. Stanley Culpepper
Keyword(s):  
North Carolina ◽  
Field Experiments ◽  
Management Strategies ◽  
Palmer Amaranth ◽  
Amaranthus Palmeri ◽  
Soybean Yield ◽  
Late Season ◽  
Southern States ◽  
Narrow Row ◽  
Conventional Systems

Glyphosate typically controls Palmer amaranth very well. However, glyphosate-resistant (GR) biotypes of this weed are present in several southern states, requiring the development of effective alternatives to glyphosate-only management strategies. Field experiments were conducted in seven North Carolina environments to evaluate control of glyphosate-susceptible (GS) and GR Palmer amaranth in narrow-row soybean by glyphosate and conventional herbicide systems. Conventional systems included either pendimethalin orS-metolachlor applied PRE alone or mixed with flumioxazin, fomesafen, or metribuzin plus chlorimuron followed by fomesafen or no herbicide POST.S-metolachlor was more effective at controlling GR and GS Palmer amaranth than pendimethalin; flumioxazin and fomesafen were generally more effective than metribuzin plus chlorimuron. Fomesafen applied POST following PRE herbicides increased Palmer amaranth control and soybean yield compared with PRE-only herbicide systems. Glyphosate alone applied once POST controlled GS Palmer amaranth 97% late in the season. Glyphosate was more effective than fomesafen plus clethodim applied POST. Control of GS Palmer amaranth when treated with pendimethalin orS-metolachlor plus flumioxazin, fomesafen, or metribuzin plus chlorimuron applied PRE followed by fomesafen POST was equivalent to control achieved by glyphosate applied once POST. In fields with GR Palmer amaranth, greater than 80% late-season control was obtained only with systems of pendimethalin orS-metolachlor plus flumioxazin, fomesafen, or metribuzin plus chlorimuron applied PRE followed by fomesafen POST. Systems of pendimethalin orS-metolachlor plus flumioxazin, fomesafen, or metribuzin plus chlorimuron applied PRE without fomesafen POST controlled GR Palmer amaranth less than 30% late in the season. Systems of pendimethalin orS-metolachlor PRE followed by fomesafen POST controlled GR Palmer amaranth less than 60% late in the season.

scholarly journals Sex Lability and Dimorphism in Dioecious Palmer Amaranth (Amaranthus palmeri)

2019 ◽  
Author(s):  
Mohsen B. Mesgaran ◽  
Maor Matzrafi ◽  
Sara Ohadi
Keyword(s):  
Water Stress ◽  
Sex Ratio ◽  
Sex Expression ◽  
Palmer Amaranth ◽  
Amaranthus Palmeri ◽  
Dioecious Species ◽  
Relative Growth ◽  
Male And Female ◽  
Secondary Sex Characters

AbstractDioecious weeds (separate sexes) may benefit from a maximized outcrossing and optimal sex-specific resource allocation but there are costs associated with the evolution of this breeding system which can be exploited for long-term management of dioecious weeds. That is, seed production in dioecious species is contingent upon the co-occurrence and co-flowering of the two genders and can be further complicated by biases in sex ratio. We therefore explored the sex ratio and dimorphism in secondary sex characters in three populations of Palmer amaranth (Amaranthus palmeri) from California, Kansas and Texas and tested if water stress can change the sex expression and/or the synchrony of flowering (anthesis) between male and female plants. Sex ratio (proportion of males) was balanced and did not deviate from 1:1 in all experiments and populations (California, Kansas, Texas) when plants received normal watering. Male and female plants of A. palmeri did not differ in timing of emergence, plant height and relative growth rate. While the initiation of flowering (emergence of inflorescence) occurred earlier in males than females, females preceded males in timing of anthesis. Water stress delayed anthesis in males to a larger extent than females giving rise to an anthesis mismatch as large as seven days between the two sexes. Water stress induced a female sex expression in Kansas population giving rise to a female to male ratio of 1.78 which significantly differed from the equal 1:1 sex ratio. Our data provide the first evidence of sex lability and environment sex determination (ESD) in A. palmeri, suggesting manipulation of sex expression and phenological asynchrony as novel tools for ecological management of dioecious weeds.

Safety and efficacy of linuron with or without an adjuvant or S-metolachlor for POST control of Palmer amaranth (Amaranthus palmeri) in sweetpotato

2021 ◽  
pp. 1-18
Author(s):  
Levi D. Moore ◽  
Katherine M. Jennings ◽  
David W. Monks ◽  
Ramon G. Leon ◽  
David L. Jordan ◽  
...  
Keyword(s):  
Nonionic Surfactant ◽  
Weed Control ◽  
Critical Period ◽  
Total Yield ◽  
Field Studies ◽  
Palmer Amaranth ◽  
Amaranthus Palmeri ◽  
Foliar Injury ◽  
Protoporphyrinogen Oxidase ◽  
Safety And Efficacy

Abstract Field studies were conducted to evaluate linuron for POST control of Palmer amaranth in sweetpotato to minimize reliance on protoporphyrinogen oxidase (PPO)-inhibiting herbicides. Treatments were arranged in a two by four factorial where the first factor consisted of two rates of linuron (420 and 700 g ai ha−1), and the second factor consisted of linuron applied alone or in combinations of linuron plus a nonionic surfactant (NIS) (0.5% v/v), linuron plus S-metolachlor (800 g ai ha−1), or linuron plus NIS plus S-metolachlor. In addition, S-metolachlor alone and nontreated weedy and weed-free checks were included for comparison. Treatments were applied to ‘Covington’ sweetpotato 8 d after transplanting (DAP). S-metolachlor alone provided poor Palmer amaranth control because emergence had occurred at applications. All treatments that included linuron resulted in at least 98 and 91% Palmer amaranth control 1 and 2 wk after treatment (WAT), respectively. Including NIS with linuron did not increase Palmer amaranth control compared to linuron alone, but increased sweetpotato injury and subsequently decreased total sweetpotato yield by 25%. Including S-metolachlor with linuron resulted in the greatest Palmer amaranth control 4 WAT, but increased crop foliar injury to 36% 1 WAT compared to 17% foliar injury from linuron alone. Marketable and total sweetpotato yield was similar between linuron alone and linuron plus S-metolachlor or S-metolachlor plus NIS treatments, though all treatments resulted in at least 39% less total yield than the weed-free check resulting from herbicide injury and/or Palmer amaranth competition. Because of the excellent POST Palmer amaranth control from linuron 1 WAT, a system including linuron applied 7 DAP followed by S-metolachlor applied 14 DAP could help to extend residual Palmer amaranth control further into the critical period of weed control while minimizing sweetpotato injury.

scholarly journals Response of Palmer amaranth (Amaranthus palmeri S. Watson) and sugarbeet to desmedipham and phenmedipham

2021 ◽  
pp. 1-9
Author(s):  
Clint W. Beiermann ◽  
Cody F. Creech ◽  
Stevan Z. Knezevic ◽  
Amit J. Jhala ◽  
Robert Harveson ◽  
...  
Keyword(s):  
Mortality Rates ◽  
Selectivity Index ◽  
Palmer Amaranth ◽  
Greenhouse Experiment ◽  
Amaranthus Palmeri ◽  
True Leaf ◽  
Cotyledon Stage ◽  
Equivalent Rate ◽  
Herbicide Treatments ◽  
High Level

Abstract A prepackaged mixture of desmedipham + phenmedipham was previously labeled for control of Amaranthus spp. in sugarbeet. Currently, there are no effective POST herbicide options to control glyphosate-resistant Palmer amaranth in sugarbeet. Sugarbeet growers are interested in using desmedipham + phenmedipham to control escaped Palmer amaranth. In 2019, a greenhouse experiment was initiated near Scottsbluff, NE, to determine the selectivity of desmedipham and phenmedipham between Palmer amaranth and sugarbeet. Three populations of Palmer amaranth and four sugarbeet hybrids were evaluated. Herbicide treatments consisted of desmedipham and phenmedipham applied singly or as mixtures at an equivalent rate. Herbicides were applied when Palmer amaranth and sugarbeet were at the cotyledon stage, or two true-leaf sugarbeet stage and when Palmer amaranth was 7 cm tall. The selectivity indices for desmedipham, phenmedipham, and desmedipham + phenmedipham were 1.61, 2.47, and 3.05, respectively, at the cotyledon stage. At the two true-leaf application stage, the highest rates of desmedipham and phenmedipham were associated with low mortality rates in sugarbeet, resulting in a failed response of death. The highest rates of desmedipham + phenmedipham caused a death response of sugarbeet; the selectivity index was 2.15. Desmedipham treatments resulted in lower LD50 estimates for Palmer amaranth compared to phenmedipham, indicating that desmedipham can provide greater levels of control for Palmer amaranth. However, desmedipham also caused greater injury in sugarbeet, producing lower LD50 estimates compared to phenmedipham. Desmedipham + phenmedipham provided 90% or greater control of cotyledon-size Palmer amaranth at a labeled rate but also caused high levels of sugarbeet injury. Neither desmedipham, phenmedipham, nor desmedipham + phenmedipham was able to control 7-cm tall Palmer amaranth at previously labeled rates. Results indicate that desmedipham + phenmedipham can only control Palmer amaranth if applied at the cotyledon stage and a high level of sugarbeet injury is acceptable.

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