Effect of planting time and row spacing on growth and seed production of junglerice (<i>Echinochloa colona</i>) and feather fingergrass (<i>Chloris virgata</i>) in sorghum

Squires, Caleb C.; Mahajan, Gulshan; Walsh, Michael; Chauhan, Bhagirath Singh

doi:10.1017/wet.2021.60

Cited by 14 publications

(14 citation statements)

References 20 publications

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“…This weed harms Australian crop production, as it competes with crops for water and soil nutrients (Mahajan et al 2019;Mutti et al 2019). Junglerice can produce a considerable number of seeds (12,380 to 20,280 seeds per plant), especially when grown under fallow conditions (Squires et al 2021). Furthermore, its emergence in multiple cohorts is a great challenge for season-long weed control (Wu et al 2004).…”

Section: Introductionmentioning

confidence: 99%

Glyphosate resistance in junglerice (Echinochloa colona) and alternative herbicide options for its effective control

2022

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Control of glyphosate-resistant (GR) junglerice is quite a challenging task in eastern Australia. There is limited information on the efficacy and reliability of alternate herbicides for GR populations of junglerice, especially when targeting large plants and when temperatures are high. A series of experiments were conducted to confirm the level of glyphosate resistance in three populations of junglerice and to evaluate the efficacy of alternate herbicides for the control of GR-junglerice populations. The lethal dose (LD50) of glyphosate required to kill 50% plants of B17/7, B17/34, and B17/35 populations was found to be 298, 2260, and 1715 g ae ha−1, respectively, suggesting populations B17/34 and B17/35 were highly resistant to glyphosate. Glyphosate efficacy was reduced at high-temperature (35/25 C day/night) compared with low-temperature conditions (25/15 C day/night), suggesting that control of susceptible populations may also be reduced if glyphosate is sprayed under hot conditions. PRE herbicides dimethenamid (1000 g ai ha−1) and pendimethalin (1500 g ai ha−1) provided 100% control of GR populations (B17/34 and 17/35). POST herbicides, such as clethodim (60 or 90 g ai ha−1), glufosinate (750 g ai ha−1), haloxyfop (52 or 78 g ai ha−1), and paraquat (400 or 600 g ai ha−1), applied at the 4-leaf stage provided 100% control of GR populations. For larger junglerice plants (8-leaf stage), POST applications of paraquat (400 or 600 g ai ha−1) provided greater weed control than clethodim, glufosinate, and haloxyfop. A mixture of either glufosinate or haloxyfop with glyphosate provided poor control of GR-junglerice populations compared with application of glufosinate or haloxyfop applied alone. Efficacy of glufosinate and haloxyfop for the control of GR populations reduced when applied in the sequential spray after glyphosate application. This study identified alternative herbicide options for GR-junglerice populations that can be used in herbicide rotation programs for sustainable weed management.

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Section: Introductionmentioning

confidence: 99%

Glyphosate resistance in junglerice (Echinochloa colona) and alternative herbicide options for its effective control

2022

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“…A recent field study, conducted in Queensland and New South Wales, reported that the seed production of E. colona was greater for the November planting (16,300 seeds plant −1 ) compared with the January planting (12,400 seeds plant −1 ) (Squires et al 2021). In the United States, April and May plantings of E. crus-galli produced a greater number of seeds compared with June, July, or August plantings (Keeley and Thullen 1989).…”

Section: Biomass and Seed Productionmentioning

confidence: 97%

“…Results are similar to those of a recent field study conducted at Gatton (QLD) and Narrabri (NSW), in which E. colona produced greater biomass for the November planting in comparison with the January planting. However, the previous study had only those two common planting times (Squires et al 2021). For A. retroflexus and A. viridis (summer broadleaf weeds), shoot biomass was reduced by 70% to 80% as a result of a delay in planting from October to January (Khan et al 2021), suggesting that Amaranthus species could be more sensitive to planting time in Queensland compared with E. colona.…”

Section: Biomass and Seed Productionmentioning

confidence: 99%

“…Therefore, Australian grain growers spend about AU $500 million yr −1 to control weeds during the fallow phase. In fallow conditions in the eastern grain region of Australia, E. colona can produce more than 20,000 seeds plant −1 (Squires et al 2021). This weed can also produce a significant number of seeds when in competition with a crop.…”

Section: Introductionmentioning

confidence: 99%

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Phenology, growth, and seed production of junglerice (Echinochloa colona) in response to its emergence time and populations

Chauhan

2022

Weed Sci

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Junglerice [Echinochloa colona (L.) Link.] is the most important grass weed species in Australian summer cropping systems. Although it is mainly a spring- and summer-emerging weed species, field observations suggest that E. colona is expanding its seasonality. A common garden experiment was conducted at the farm of the University of Queensland to examine the effect of planting dates on phenology, growth, and fecundity of eight populations of E. colona. All populations were planted every second month from September to July in 2019-20 and 2020-21. Echinochloa colona took the shortest time (4-6 d) to emerge when planted in November or January. However, the November population took the longest number of growing-degree days to exhibit panicle emergence. In both years, populations differed in height and leaf, tiller, panicle, and seed production in response to planting times. Plants produced significantly greater biomass for the November planting (123-147 g plant-1) followed by the January and then the September planting. The lowest biomass was produced for the March planting. In the first year, the lowest number of seeds (3500 plant-1) was produced for the March planting; however, in the second year, similar numbers of seeds were produced for March and July plantings. In the first year, seed production (51,000 seeds plant-1) was greatest for the November planting; however, some populations produced a similar number of seeds for the January planting also. In the second year, significantly greater seed production (111,000 seeds plant-1) was observed for the January planting compared with other planting dates. The aboveground biomass and seed production of E. colona were positively correlated. This study reveals variations among E. colona populations and suggests that although a greater emphasis is needed to control spring- and summer-emerging plants, management practices need to be extended throughout the year to control E. colona in southeastern Australia.

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“…Chloris virgata possesses a C 4 photosynthetic pathway and can produce more than 140,000 seeds per plant in fallow conditions [ 4 ]. The seeds of this species are small and lightweight, which easily disperse via wind or overland water flow and sometimes via livestock.…”

Section: Introductionmentioning

confidence: 99%

Management options for large plants of glyphosate-resistant feather fingergrass (Chloris virgata) in Australian fallow conditions

2021

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Chloris virgata has become one of the most difficult glyphosate-resistant (GR) grass weeds in summer fallows in the eastern region of Australia. It germinates in several cohorts following rainfall events; therefore, growers are often tempted to wait for most of the weeds to emerge before herbicide application. However, by that time, some seedlings have reached an advanced stage and there is limited information on the efficacy and reliability of alternate herbicides when targeting large plants of GR C. virgata. A series of experiments were conducted to determine the efficacy of alternate herbicides for the control of GR C. virgata. Haloxyfop (80 g a.i. ha-1) on its own, in mixtures, or sequential applications of haloxyfop and paraquat or glufosinate provided 97 to 100% mortality of the 8–10 leaf stage plants. Glufosinate (1500 g a.i. ha-1) also provided complete control of plants at this growth stage. For larger plants at the 24–28 leaf stage, glufosinate, with or without additional tank-mixed adjuvants, generally did not provide full control, however did show very high levels of biomass reduction and panicle suppression at application rates of 750 or 1500 g a.i. ha-1. Haloxyfop (40 to 160 g a.i. ha-1) and clethodim (180 g a.i. ha-1) on their own achieved 96 to 100% mortality at this growth stage. When applied to large plants (40–50 leaf stage), a tank-mix of isoxaflutole plus paraquat demonstrated significantly higher levels of plant mortality and biomass reduction than either herbicide used alone, and this mixture appears to be synergistic when tested via the Colby equation for synergy or antagonism. Plant mortality was greater (83%) when isoxaflutole (75 g a.i. ha-1) plus paraquat (300 g a.i. ha-1) was taken up through the foliage and soil, compared with the foliage alone. This study identified alternative herbicide options for large plants of GR C. virgata.

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Effect of planting time and row spacing on growth and seed production of junglerice (Echinochloa colona) and feather fingergrass (Chloris virgata) in sorghum

Cited by 14 publications

References 20 publications

Glyphosate resistance in junglerice (Echinochloa colona) and alternative herbicide options for its effective control

Glyphosate resistance in junglerice (Echinochloa colona) and alternative herbicide options for its effective control

Phenology, growth, and seed production of junglerice (Echinochloa colona) in response to its emergence time and populations

Management options for large plants of glyphosate-resistant feather fingergrass (Chloris virgata) in Australian fallow conditions

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