Opportunistic association between Pythium species and weed residues causing seedling emergence failure in cereals

1995 ◽  
Vol 46 (3) ◽  
pp. 655 ◽  
Author(s):  
PA Pittaway
Keyword(s):  
Seedling Emergence ◽  
Field Trials ◽  
Residue Management ◽  
Systemic Fungicide ◽  
Pythium Species ◽  
Herbicide Application ◽  
Seedling Vigour ◽  
Weed Growth ◽  
Herbicide Glyphosate

Field trials were conducted to establish the link between weed residue management, Pythium infectivity and cereal seedling emergence failure. The herbicide glyphosate was used to manage weed-free and weed residue treatments, and the systemic fungicide metalaxyl was used to protect seedlings from pythiaceous attack. Seedling vigour and emergence were enhanced by the application of metalaxyl, and by the total suppression of weed growth. Invasion of cereal seedlings by pythiaceous fungi was greatest when seed was sown into cloddy seedbeds within 1-3 days after herbicide application. Debilitated weeds enhanced the activity of pythiaceous pathogens, promoting the invasion of cereals sown into the residues. If sowing is delayed for 3 weeks after herbicide application, pythiaceous activity will be reduced by saprophytic competitors colonizing the residues, resulting in improved seedling vigour and establishment.

Early seedling growth and forage production of diploid and tetraploid crested wheatgrass and Russian wildrye cultivars

2008 ◽  
Vol 88 (4) ◽  
pp. 687-693 ◽  
Author(s):  
Paul G Jefferson ◽  
Bruce Coulman
Keyword(s):  
Seedling Growth ◽  
Field Trial ◽  
Seedling Emergence ◽  
Field Trials ◽  
Tiller Number ◽  
The Other ◽  
Forage Production ◽  
Seedling Vigour ◽  
Crested Wheatgrass ◽  
Russian Wildrye

Cultivars selected for improved seedling vigour may also differ in seedling growth and subsequent forage production. The objective of this project was to compare three cultivars of crested wheatgrass (CWG) and four cultivars of Russian wildrye (RWR) for seedling growth in a greenhouse (GH) trial and two field trials when seeded at 15, 30 and 45 mm depths. Cultivars were Goliath, Kirk and Parkway CWG and SCR39903, Swift, Tetracan, and Tom RWR. Seedling emergence, tiller number, and seedling biomass were determined at 28 d after seeding (DAS) in all three trials. In addition, forage dry matter (DM) yield was determined for 2 yr in the field trials. Small-seeded diploid Parkway crested wheatgrass had reduced emergence at 45 mm seeding depth compared with larger-seeded tetraploid Kirk and Goliath. Goliath had reduced tillering compared with the other two CWG cultivars. The emergence of Tetracan tetraploid RWR was greater at deeper seeding depth than diploid cultivars, SCR39902, Swift and Tom in Field Trial 2, but not in Field Trial 1 and the GH trial. Seedling tiller number of Tetracan RWR was less than that of the other three cultivars. Two-year total CWG forage DM yield in the field was best correlated to emergence. In contrast, 2-yr total RWR forage DM was best correlated to seedling tiller number in GH and Field Trial 2 despite the low tiller numbers at 28 d after seeding. Field emergence of Russian wildrye did not appear to be limiting to seedling establishment in contrast to previous reports. Selection in RWR should include seedling tiller number in combination with seedling emergence in order to improve both seedling vigour and forage productivity. Key words: Establishment, tiller, emergence, forage yields, seedling depth

Effects of Population and Inter-Row Spacing on Yields of Maize and Control of Weeds with Herbicides in the Irrigated Savanna

1981 ◽  
Vol 17 (4) ◽  
pp. 389-397 ◽  
Author(s):  
A. H. Choudhary
Keyword(s):  
Dry Matter ◽  
Field Trials ◽  
Weed Suppression ◽  
Row Spacing ◽  
Herbicide Application ◽  
Grain Yields ◽  
Weed Growth ◽  
Experimental Area ◽  
Maize Plants ◽  
And Control

SUMMARYIn field trials a population of 61,700 maize plants/ha produced higher total dry matter and grain yields than the conventional 36,000 plants/ha. There was no difference in yields with inter-row spacings of 45, 60 or 90 cm, regardless of population levels. Weed suppression was increased by the higher population even though the entire experimental area was treated with herbicides. In one of three years perennial sedge and annual weed growth started 4–5 weeks after herbicide application, under which conditions row spacing had a greater effect and weed growth was significantly less with 45 or 60 cm maize rows than at 90 cm.

Efficacy of Clonostachys rosea strain ACM941 and fungicide seed treatments for controlling the root rot complex of field pea

2003 ◽  
Vol 83 (3) ◽  
pp. 519-524 ◽  
Author(s):  
A. G. Xue
Keyword(s):  
Root Rot ◽  
Untreated Control ◽  
Seedling Emergence ◽  
Field Trials ◽  
Field Pea ◽  
Seed Treatments ◽  
Clonostachys Rosea ◽  
Pea Root ◽  
Pea Root Rot ◽  
Better Than

The efficacy of seed treatments with bioagent ACM941 (a strain of Clonostachys rosea), its formulated products GB116 and ACM941-Pro, and common fungicides for the control of pea root rot complex were examined in six field trials in western Canada from 1996 to 2000. The effects on seedling emergence, root rot severity, and yield varied among years. In trials 1 and 2 (1996–1997), none of the treatments significantly reduced root rot severity or increased yield. ACM941 + Thiram 75WP was the most effective treatment, increasing emergence by 17.4% and was significantly better than that of the untreated controls. In trials 3 and 4 (1997–1998), Apron FL alone and ACM941 + Apron FL were significantly better than the untreated control, increasing emergence by 6.2 and 7.7%, and yield by 10.8 and 11.5%, respectively. In trials 5 and 6 (1999–2000), AC M 941 and GB116 were equally the most effective treatments, increasing emergence by 11.5 and 12.2%, and yield by 8.2 and 6.3%, respectively. These effects were significantly greater than that of the untreated control, but not significantly different from those of Apron FL or Vitaflo-280. ACM941-Pro was developed and tested in 2000 only, and it increased emergence by 17.1% and reduced root rot severity by 29.6%. Key words: Bioagent, Clonostachys rosea, field pea, Pisum sativum, pea root rot complex (PRRC), seed treatment, fungicide

scholarly journals Seed Treatment With Systemic Fungicides: Time for Review

2021 ◽  
Vol 12 ◽  
Author(s):  
Mulla S. Ayesha ◽  
Trichur S. Suryanarayanan ◽  
Karaba N. Nataraja ◽  
Siddegowda Rajendra Prasad ◽  
Ramanan Uma Shaanker
Keyword(s):  
Plant Growth ◽  
Seedling Growth ◽  
Growth And Development ◽  
Seed Treatment ◽  
Plant Diseases ◽  
Systemic Fungicide ◽  
Plant Growth And Development ◽  
Seedling Vigour ◽  
Systemic Fungicides ◽  
Seed Endophytes

Pre-sowing seed treatment with systemic fungicides is a firmly entrenched practice for most agricultural crops worldwide. The treatment is intended to protect the crop against seed- and soil-borne diseases. In recent years, there is increasing evidence that fungicidal applications to manage diseases might inadvertently also affect non-target organisms, such as endophytes. Endophytes are ubiquitously present in plants and contribute to plant growth and development besides offering resistance to biotic and abiotic stresses. In seeds, endophytes may play a role in seed development, seed germination, seedling establishment and crop performance. In this paper, we review the recent literature on non-target effects of fungicidal applications on endophytic fungal community and discuss the possible consequences of indiscriminate seed treatment with systemic fungicide on seed endophytes. It is now well recognized that endophytes are ubiquitously present in all parts of the plant, including the seeds. They may be transmitted vertically from seed to seed as in many grasses and/or acquired horizontally from the soil and the environment. Though the origins and evolution of these organisms in plants are a matter of conjecture, numerous studies have shown that they symbiotically aid in plant growth and development, in nutrient acquisition as well in protecting the plants from abiotic and biotic stresses. Against this background, it is reasonable to assume that the use of systemic fungicides in seed treatment may not only affect the seed endophytes but also their attendant benefits to seedling growth and establishment. While there is evidence to indicate that fungicidal applications to manage plant diseases also affect foliar endophytes, there are only few studies that have documented the effect of seed treatment on seed-borne endophytes. Some of the convincing examples of the latter come from studies on the effect of fungicide application on rye grass seed endophyte AR37. More recently, experiments have shown that removal of seed endophytes by treatment with systemic fungicides leads to significant loss of seedling vigour and that such losses could be partially restored by enriching the seedlings with the lost endophytes. Put together, these studies reinforce the importance of seed endophytes to seedling growth and establishment and draw attention on how to trade the balance between the benefits of seed treatments and the direct and indirect costs incurred due to loss of endophytes. Among several approaches, use of reduced-risk fungicides and identifying fungicide-resistant endophytes are suggested to sustain the endophyte contribution to early seedling growth.

Preharvest glyphosate in alfalfa for seed production: Effect on alfalfa seed yield and quality

2003 ◽  
Vol 83 (1) ◽  
pp. 189-197 ◽  
Author(s):  
W. E. May ◽  
H. A. Loeppky ◽  
D. C. Murrell ◽  
C. D. Myhre ◽  
J. J. Soroka
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Seed Quality ◽  
Seedling Emergence ◽  
Canada Thistle ◽  
Seedling Vigour ◽  
Yield And Quality ◽  
Alfalfa Seed ◽  
Medicago Sativa L ◽  
Seed Yields

Preharvest applications of glyphosate have been shown to be effective in controlling Canada thistle in annual crops, but may reduce alfalfa seed yield depending on time and rate of application. The objective of this study was to determine the effect of preharvest applications of glyphosate on subsequent alfalfa seed yield and quality. The effects of timing, 1, 26, 51 and 76% alfalfa seed pod maturity, and rate, 0, 440, 880, 1320, and 1760 g a.i. ha-1, of a preharvest application of glyphosate on alfalfa seed yield and quality in the year of application, and regrowth and seed yield in the following year were determined. The rate of glyphosate applied did not affect seed yield in the application year; however, in the following year, growth and seed yield were reduced as rates increased. Delaying the application of glyphosate increased seed yields in the application year, but decreased alfalfa regrowth and flowering the following year. Germination and seedling emergence were not affected by the rate or timing of the glyphosate. A preharvest application of glyphosate at 1760 g a.i. ha-1 at 76% pod maturity is a viable option in the last year of seed production. Key words: Alfalfa (Medicago sativa L.), glyphosate, abnormal seeds, seed quality, and seedling vigour

EARLY SEEDLING VIGOUR AND SEED WEIGHT IN RELATION TO BREEDING IN SMOOTH BROMEGRASS, BROMUS INERMIS LEYSS.

1960 ◽  
Vol 40 (2) ◽  
pp. 268-280 ◽  
Author(s):  
W. E. Tossell
Keyword(s):  
Seed Weight ◽  
Field Trials ◽  
Bromus Inermis ◽  
Rapid Progress ◽  
Initial Screening ◽  
Agronomic Characters ◽  
Smooth Bromegrass ◽  
Seedling Vigour ◽  
Close Relationship ◽  
Early Seedling

Variability in early seedling vigour was studied in polycross progenies from highly selected plants rated as good in other agronomic characters and in open-pollinated progenies from previously unselected So plants. Differences were found in both groups in rate and per cent emergence, and in height and vigour at 28 days. Considering the variability observed in these characters and the favourable associations found, it appears that early seedling vigour in bromegrass can be improved by selection within the species.Seed weight was closely associated with early seedling vigour. Plants differed widely in seed weight, and in breeding for early seedling vigour it appears that most rapid progress can be made by screening breeding material for seed weight. Because seed weight did not account for all of the differences among progenies in seedling vigour, progenies from high seed weight plants or families should be subjected to a seedling vigour test to further select for this character. The close relationship found between greenhouse and field trials indicates that at least the initial screening can be done in the greenhouse.

Influence of Simulated Rainfall and Soil Moisture on Herbicidal Activity of Cinmethylin

Weed Science ◽  
1990 ◽  
Vol 38 (3) ◽  
pp. 267-272 ◽  
Author(s):  
Steven G. Russell ◽  
Thomas J. Monaco ◽  
Jerome B. Weber
Keyword(s):  
Weed Control ◽  
Sandy Loam ◽  
Field Trials ◽  
Herbicidal Activity ◽  
Herbicide Application ◽  
Weed Species ◽  
Green Foxtail ◽  
Loam Soil ◽  
Dry Soil ◽  
Prickly Sida

Field trials were conducted in 1986 and 1987 to determine the effects of moisture on herbicidal activity of cinmethylin applied preemergence at 0.0, 0.3, 0.6, and 0.9 kg ai ha to both dry and moist sandy loam soil. Herbicide application was followed by varying amounts of irrigation. Weed species included velvetleaf, prickly sida, green foxtail, and barnyardgrass. When cinmethylin was applied to a moist soil or when 2.5 cm of irrigation was applied 5 days after cinmethylin application to a dry soil, overall weed control was reduced. Optimum weed control resulted from cinmethylin application to dry soil followed either by a 2.5-cm irrigation within 8 h or a 7.6-cm irrigation within 36 h.

Weeds and yields of spring cereals as influenced by stubble-cultivation and reduced doses of herbicides in five long-term trials

2000 ◽  
Vol 134 (3) ◽  
pp. 237-244 ◽  
Author(s):  
U. BOSTRÖM ◽  
M. HANSSON ◽  
H. FOGELFORS
Keyword(s):  
Weed Management ◽  
Plant Density ◽  
Crop Yields ◽  
Field Trials ◽  
Herbicide Application ◽  
Weed Species ◽  
Full Dose ◽  
Spring Cereals ◽  
One Year

The influence of herbicides at reduced rates and repeated stubble-cultivation on weeds and crop yields was estimated in five field trials with spring-sown cereals situated in the south of Sweden during the autumn of 1989 until the spring of 1997. Stubble-cultivation was accomplished during 1989–1996, while herbicides were applied at 0, 1/8, 1/4 or 1/2 of full dose during 1990–1996.In the spring of 1997, i.e. after 7 years without herbicide application, seedling densities 3 weeks after weed emergence were 68–340/m2 at three sites and 535–610/m2 at two sites when averaged over tillage treatments.Averaged over herbicide doses, stubble-cultivation reduced the plant density of annual broad- leaved weeds by 6–32% at three sites and increased the density by 25% at one site. At the remaining site, the density was not significantly influenced. Stubble-cultivation reduced the populations of two perennial and seven annual weed species, while one species was stimulated and nine species showed null, or inconsistent, responses. In the spring of 1997, i.e. one year after the last herbicide application, the densities of weed seedlings in 1/8, 1/4 and 1/2-doses were 34, 46 and 56% lower, respectively, than in the untreated controls.Stubble-cultivation increased crop yields at four sites by 200 kg/ha as a mean over herbicide doses. At these four sites, averaged over 1993–1995, herbicides increased yields in plots that were not stubble-cultivated by 7, 8 and 10% in the 1/8, 1/4 and 1/2 of a full dose, respectively, relative to the untreated control. In 1996, herbicides increased yields at only two sites.It is concluded that a fruitful way for weed management with a low input of agrochemicals is to combine the use of herbicides at reduced rates with repeated stubble-cultivation.

scholarly journals A linuron-free weed management strategy for carrots

2019 ◽  
Vol 33 (03) ◽  
pp. 464-474
Author(s):  
Tessa de Boer ◽  
Peter Smith ◽  
Kevin Chandler ◽  
Robert Nurse ◽  
Kristen Obeid ◽  
...  
Keyword(s):  
Effective Dose ◽  
Pest Management ◽  
Weed Management ◽  
Management Strategy ◽  
Seedling Emergence ◽  
Growing Season ◽  
Field Trials ◽  
Organic Soils ◽  
Biologically Effective Dose ◽  
And Control

AbstractThe development of a linuron-free weed management strategy for carrot production is essential as a result of the herbicide reevaluation programs launched by the Pest Management Regulatory Agency in Canada for herbicides registered before 1995 and the discovery of linuron-resistant pigweed species in Ontario. Field trials were conducted in one of Ontario’s main carrot-growing regions on high organic soils in 2016 and 2017. Pigweed species seedlings were effectively controlled with PRE treatments of prometryn, pendimethalin, S-metolachlor, or glufosinate. POST treatments of pyroxasulfone and metribuzin followed by predetermined biologically effective dose (≥90% control of pigweed seedlings) of acifluorfen, oxyfluorfen, fluthiacet-methyl, and fomesafen achieved excellent crop selectivity and commercially acceptable pigweed species seedling control under field conditions. Carfentrazone-ethyl or fomesafen applied PRE severely reduced seedling emergence and yield in the wet growing season of 2017. This study demonstrated clearly that an alternative linuron-free strategy can be developed for carrots. The strategy of exploring the potential to use the biologically effective dose of selected herbicides to achieve crop selectivity and control of pigweed species seedlings was verified.

Tropical Soda Apple (Solanum viarum) Control

1993 ◽  
Vol 7 (3) ◽  
pp. 723-727 ◽  
Author(s):  
J. Jeffrey Mullahey ◽  
John A. Cornell ◽  
Danny L. Colvin
Keyword(s):  
Seedling Emergence ◽  
Ground Cover ◽  
Diesel Oil ◽  
South Florida ◽  
Individual Plant ◽  
Herbicide Application ◽  
Application Method ◽  
Tropical Soda Apple ◽  
Solanum Viarum ◽  
Plant Treatment

Hexazinone (1.12 kg ai/ha), triclopyr (1.12 kg ai/ha), metsulfuron (0.008 kg ai/ha), dichlorprop + 2,4-D, glyphosate (2.8%), and triclopyr (2%) + diesel oil (98%), applied as a broadcast or spot (individual plant) treatment, were evaluated over two years in south Florida for tropical soda apple (TSA) control and their effects on grass ground cover. For broadcast treatments, triclopyr (98%) and hexazinone (93%), had significantly (P < 0.05) higher percent control of marked TSA plants 90 d after herbicide application. However, triclopyr (99%) had significantly higher grass ground cover than hexazinone (78%). Hexazinone severely damaged Pangola digitgrass, but had no effect on bahiagrass. For spot treatments, dichlorprop + 2,4-D (100%) had the highest percent total control of TSA and least effect on grass ground cover (96%) 90 d after herbicide application, followed by glyphosate (96% control) and triclopyr + diesel oil (95% control). Based on acceptable (>90%) TSA control and grass ground cover, triclopyr broadcast or dichlorprop + 2,4-D spot provided the greatest control. With either application method, repeated herbicide applications will be necessary to eliminate TSA because of rapid seedling emergence following control of existing plants.

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