scholarly journals Evaluation of Chemical Seed Treatment to Reduce Injury Caused by Preemergent Herbicides on Direct-seeded Turnips and Collard Greens

HortScience ◽  
2021 ◽  
pp. 1-5
Author(s):  
Giovanni Antoniaci Caputo ◽  
Sandra Branham ◽  
Matthew Cutulle

Poor competitive ability and limited herbicide options make weed management of Brassica crops difficult. Growers often adopt the use of transplants, which is less efficient in terms of time, material, and labor when compared with direct seeding, resulting in higher prices per unit. Seed treatment with protective compounds could decrease crop injury from preemergent (PRE) herbicides making it profitable to direct-seed Brassica plants for production. Research was conducted to evaluate the ability of three candidate safeners [24-epibrassinolide, melatonin, and ascorbic acid (AsA)] to reduce injury caused by four herbicides (S-metolachlor, pyroxasulfone, halosulfuron, and mesotrione) applied PRE on the collard green cultivar Top Bunch and turnip cultivar Purple Top White Globe. Two independent greenhouse trials were conducted at the Clemson University Coastal Research and Education Center in Charleston, SC. Visual injury of the treated plants was evaluated weekly and dry mass was collected 21 days after treatment. Seed treatment did not reduce injury efficiently caused by pyroxasulfone, halosulfuron, and mesotrione; all doses were lethal for both crops. However, collard seeds treated using melatonin and AsA had 66% and 54% less injury caused by S-metolachlor at 514 g⋅ha–1 a.i., respectively. On turnips, melatonin was the only treatment that reduced the S-metolachlor damage on seedlings, with 43% less injury than untreated seedlings. Plant injury and plant weight correlated significantly for both Brassica crops. The reduction in injury caused by S-metolachlor when seeds were treated with melatonin and AsA validated those compounds’ protective ability. Seed treatment with melatonin could be combined with PRE applications of S-metolachlor to overcome the low weed competitive ability of these species early in the season.

Weed Science ◽  
2011 ◽  
Vol 59 (3) ◽  
pp. 404-415 ◽  
Author(s):  
K. Neil Harker ◽  
John T. O'Donovan ◽  
Robert E. Blackshaw ◽  
Eric N. Johnson ◽  
Frederick A. Holm ◽  
...  

Growing crops that exhibit a high level of competition with weeds increases opportunities to practice integrated weed management and reduce herbicide inputs. The recent development and market dominance of hybrid canola cultivars provides an opportunity to reassess the relative competitive ability of canola cultivars with small-grain cereals. Direct-seeded (no-till) experiments were conducted at five western Canada locations from 2006 to 2008 to compare the competitive ability of canola cultivars vs. small-grain cereals. The relative competitive ability of the species and cultivars was determined by assessing monocot and dicot weed biomass at different times throughout the growing season as well as oat (simulated weed) seed production. Under most conditions, but especially under warm and relatively dry environments, barley cultivars had the greatest relative competitive ability. Rye and triticale were also highly competitive species under most environmental conditions. Canada Prairie Spring Red wheat and Canada Western Red Spring wheat cultivars usually were the least competitive cereal crops, but there were exceptions in some environments. Canola hybrids were more competitive than open-pollinated canola cultivars. More importantly, under cool, low growing degree day conditions, canola hybrids were as competitive as barley, especially with dicot weeds. Under most conditions, hybrid canola growers on the Canadian Prairies are well advised to avoid the additional selection pressure inherent with a second in-crop herbicide application. Combining competitive cultivars of any species with optimal agronomic practices that facilitate crop health will enhance cropping system sustainability and allow growers to extend the life of their valuable herbicide tools.


2021 ◽  
Vol 53 (2) ◽  
pp. 135-141
Author(s):  
Sheela Barla ◽  
R.R. Upasani ◽  
Alfa Malika Beck

2010 ◽  
Vol 28 (3) ◽  
pp. 515-522 ◽  
Author(s):  
A.C.R. Dias ◽  
S.J.P. Carvalho ◽  
L.W. Marcolini ◽  
M.S.C. Melo ◽  
P.J. Christoffoleti

Weeds compete with field crops mainly for water, light and nutrients, and the degree of competition is affected by the weed density and the intrinsic competitive ability of each plant species in coexistence. The objective of this research was to compare the competitiveness of alexandergrass (Brachiaria plantaginea) or Bengal dayflower (Commelina benghalensis) in coexistence with soybean, cv. M-Soy 8045. A factorial experiment (2 x 5) with two weed species and five competition proportions was carried out in a completely randomized design with four replicates. Proportions were based on a replacement series competition design, always maintaining the total density of four plants per 10 L plastic pots, which corresponded to 60 plants m ². The weed-crop proportions were: 0:4; 1:3; 2:2; 3:1; 4:0; that corresponded to the proportion of 100, 75, 50, 25 and 0% of soybean plants and the opposite for weeds, B. plantaginea or C. benghalensis plants. Leaf area, shoot dry mass of the weeds and soybean and number of soybean trifoliate leaves were evaluated when the soybean reached the phenologic stage of full flowering. B. plantaginea was a better competitor than soybean plants. Otherwise, C. benghalensis revealed a similar competitive ability that of the soybean. In both cases, there were evidences that intraspecific competition was more important.


1999 ◽  
Vol 34 (6) ◽  
pp. 944-952 ◽  
Author(s):  
Moacyr Bernardino Dias-Filho

Ipomoea asarifolia (Desr.) Roem. & Schultz (Convolvulaceae) and Stachytarpheta cayennensis (Rich) Vahl. (Verbenaceae), two weeds found in pastures and crop areas in Brazilian Amazonia, were grown in controlled environment cabinets under high (800-1000 µmol m-² s-¹) and low (200-350 µmol m-² s-¹) light regimes during a 40-day period. For both species leaf dry mass and leaf area per total plant dry mass, and leaf area per leaf dry mass were higher for low-light plants, whereas root mass per total plant dry mass was higher for high-light plants. High-light S. cayennensis allocated significantly more biomass to reproductive tissue than low-light plants, suggesting a probably lower ability of this species to maintain itself under shaded conditions. Relative growth rate (RGR) in I. asarifolia was initially higher for high-light grown plants and after 20 days started decreasing, becoming similar to low-light plants at the last two harvests (at 30 and 40 days). In S. cayennensis, RGR was also higher for high-light plants; however, this trend was not significant at the first and last harvest dates (10 and 40 days). These results are discussed in relation to their ecological and weed management implications.


Author(s):  
Daisy Leticia Ramirez Monzon ◽  
Iara Maiqueli Stern Lemke ◽  
Lider Ayala ◽  
Maria Johana Gonzalez Vera ◽  
Geri Eduardo Menegelho

Aims: White oats are considered one of the most important cereals in the world. Currently, fertilizers based on phosphorus and silicon are being studied as inductors of resistance in the treatment of seeds, since they have as advantages such as low costs and excellent absorption by plants. The effects of seed treatment with phosphite resistance inducers are still unknown, being necessary the study in relation to interact with the seed at the time of twinning.  Study Design: The experimental design used was completely randomized, with four replications, two commercial products based on phosphite FullTec Mais and Ultra Plus and five doses.  Place and Duration of Study: The work was conducted at the Didactic Laboratory of Seed Analysis of the Faculty of Agronomy Eliseu Maciel of the Federal University of Pelotas (UFPel), Pelotas-RS, in 2019. Methodology: White oat seeds were used, produced in the 2018/2019 agricultural kharif and treated with commercial products based on FullTec Mais and Ultra Plus phosphites, in five doses: 0; 1.0; 2.0; 3.0; 4.5 mL for each 100 kg of seeds. The variables evaluated were first germination count (CP), germination (G), shoot length (CA), root length (CR), total length (CT), accelerated aging (EV) and total dry mass (MST). The data expressed as a percentage were subjected to analysis of variance to verify the effect of treatments. Then, the Duncan means test (P=0.5) was performed, for the discrimination between the treatment means. Statistical analyzes were performed using the R Core Team (2020). Results: The results showed that the FullTec Mais product stimulates the physiological performance of white oat seeds for the variables first germination count (CP), germination (G) and shoot length (CA), with a dose of 2 mL of the product per 100 kg of seeds that showed the highest expression. For the Ultra Plus product at a dose of 1 mL of the product per 100 kg of seeds it is more efficient in the accelerated aging test (EV), for the other variables it did not show significant differences. Conclusion: It is possible to use phosphite-based micronutrients in seed treatment, without causing physiological damage to the seed during the twinning process.


2017 ◽  
pp. 45-142 ◽  
Author(s):  
Adusumilli N. Rao ◽  
Daniel C. Brainard ◽  
Virender Kumar ◽  
Jagdish K. Ladha ◽  
David E. Johnson

2018 ◽  
Vol 36 (0) ◽  
Author(s):  
R.R. ZANDONÁ ◽  
D. AGOSTINETTO ◽  
B.M. SILVA ◽  
Q. RUCHEL ◽  
D.S. FRAGA

ABSTRACT: Weeds emergence times modify competition with crops. Thus, the hypothesis was that the increase in weed emergence flow decreases the period prior to interference (PPI) in soybeans and increases the critical period of interference prevention (CPIP). The objective was to determine the PPI and the CPIP of weeds in soybean crops as affected by the preferred time of weeds emergence flow. Three experiments were conducted in the field in a randomized block design with four replications. The treatments were arranged in a factorial design with factor A consisting of coexistence or weed control in soybeans and factor B for eight periods (0, 7, 14, 21, 28, 35, 42 and 135 days after crop emergence (DAE)). The numbers of emerged plants and weed dry mass by genus and crop productivity were evaluated. The weed interference in culture during all the crop cycle reduces the soybean average yield 73, 94 and 89% in the first, second and third sowing times, respectively. Chemical control may be adopted at the end of PPI, which must be done at 14, 15 and 5 DAE crop, for the first, second, third times, respectively. The sowing in advance and intermediate time of recommendation increase the PPI in about 10 days, favoring the weed management in soybean crops.


Weed Science ◽  
1995 ◽  
Vol 43 (4) ◽  
pp. 627-633 ◽  
Author(s):  
David T. Patterson

When velvetleaf plants from Mississippi and Minnesota populations were maintained in growth chambers with day/night temperatures of 29/23 C and photoperiods of 11, 12, 13, 14, and 15 h, flower buds and open flowers appeared first in the 12 h photoperiod. Buds and flowers appeared 2 to 4 d later at photoperiods of 11, 13, or 14 h. Increasing the photoperiod beyond 14 h to 15 h delayed bud appearance an additional 7 d in the MN plants and 12 d in the MS plants. Open flowers appeared four to five nodes higher, 10 d later at 15 than at 14 h in the MN plants and 20 d later in the MS plants. Vegetative shoot weight and fruit weight 73 d after emergence were greater in 13 h or longer photoperiods than at 11 or 12 h. In shorter photoperiods, MN plants produced more vegetative growth than MS plants, but the reverse occurred at longer photoperiods where MS plants were taller than MN plants. These growth differences occurred because earlier shifts in allocation to reproductive growth in MN plants limited their vegetative growth, particularly in the longest photoperiods. Differences in rate of reproductive development between populations were not evident until photoperiod exceeded 13 h. Reciprocal transfer of plants of the MS population between short and long photoperiods revealed the durations of the juvenile (pre-inductive), inductive, and post-inductive phases to be 3 to 5, 7 to 8 (short day) or 30 (long day), and 10 to 11 d, respectively. Differences in competitive ability among latitudinal biotypes of photoperiodically-sensitive weeds may depend on time of emergence in the field and consequent photoperiod exposure. Weed growth simulation models to be used in development of expert systems for weed management should take photoperiodic sensitivity into account.


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