Glyphosate-Resistant Russian-thistle (Salsola tragus) Identified in Montana and Washington

2017 ◽  
Vol 31 (2) ◽  
pp. 238-251 ◽  
Author(s):  
Vipan Kumar ◽  
John F. Spring ◽  
Prashant Jha ◽  
Drew J. Lyon ◽  
Ian C. Burke
Keyword(s):  
Best Management Practices ◽  
Management Practices ◽  
Field Experiments ◽  
Dry Weight ◽  
Effective Control ◽  
Best Management ◽  
Shoot Dry Weight ◽  
Greenhouse Study ◽  
Whole Plant ◽  
Site Field

Two putative glyphosate-resistant (GR) Russian-thistle accessions were collected from fallow fields (wheat-fallow rotation): one from Choteau County, MT (MT-R), and a second from Columbia County, WA (WA-R) in summer/fall of 2015. Greenhouse and outdoor/field whole-plant dose-response studies were conducted to confirm and characterize the levels of glyphosate resistance in these GR accessions relative to known glyphosate-susceptible accessions (MT-S and WA-S from MT and WA, respectively). Based on GR50values of the progeny plants, the MT-R accession exhibited 4.5-fold and 5.9-fold resistance to glyphosate relative to the MT-S accession under greenhouse and outdoor conditions, respectively. The WA-R accession showed 3.0- to 5.0-fold resistance relative to the WA-S accession in greenhouse experiments, and 1.9- to 7.5-fold resistance in multi-site field experiments. In a separate greenhouse study on alternative POST herbicides to control GR Russian-thistle, bicyclopyrone plus bromoxynil, bromoxynil plus fluroxypyr, bromoxynil plus pyrasulfotole, bromoxynil plus MCPA, paraquat alone, paraquat plus metribuzin, saflufenacil alone, saflufenacil plus 2,4-D, and 2,4-D plus bromoxynil plus fluroxypyr provided effective control (≥95%) and shoot dry weight reduction (up to 98%) of GR accessions. This research confirms the first global case of field-evolved GR Russian-thistle. Best management practices (BMPs); including alternative, effective herbicide programs (based on multiple mechanisms of action highlighted in this study) need immediate implementation to prevent further spread of GR or evolution of multiple HR Russian-thistle populations in this region.

Confirmation of Glyphosate-Resistant Horseweed (Conyza canadensis) in Montana Cereal Production and Response to POST Herbicides

2017 ◽  
Vol 31 (6) ◽  
pp. 799-810 ◽  
Author(s):  
Vipan Kumar ◽  
Prashant Jha ◽  
Amit J. Jhala
Keyword(s):  
Great Plains ◽  
Dose Response ◽  
Best Management Practices ◽  
Management Practices ◽  
Dry Weight ◽  
Shoot Dry Weight ◽  
Greenhouse Study ◽  
Whole Plant ◽  
Cereal Production ◽  
Sites Of Action

In recent years, horseweed has become an increasing problem in Montana. To confirm and characterize the level of glyphosate resistance, seeds were collected from putative glyphosate-resistant (GR) horseweed (GR-MT) plants in a wheat–fallow field in McCone County, MT. Known GR (GR-NE) and glyphosate-susceptible (GS-NE) horseweed accessions from Lincoln, NE, were included for comparison in dose–response and shikimate accumulation studies. Whole-plant glyphosate dose–response experiments conducted at the early- (5- to 8-cm diameter) and late- (12- to 15-cm diameter) rosette stages of horseweed indicated that GR-MT accessions had a 2.5- to 4.0-fold level of resistance to glyphosate relative to the GS-NE accession, on the basis of shoot dry weight (GR50values). The level of resistance was 3.1- to 7.9-fold on the basis of visually assessed injury estimates (I50values). At the whole-plant level, about 2.1- to 4.5-fold higher shikimate accumulation was observed in the GS-NE accession compared with the GR-MT and GR-NE accessions over a 10-d period after glyphosate was applied at 1,260 g ae ha−1. In a separate greenhouse study, all three horseweed accessions were also screened with alternate POST herbicides registered for use in wheat–fallow rotations. The majority of the tested herbicides provided ≥90% injury at the field-use rates for all three horseweed accessions 3 wk after treatment. This is the first published report on the occurrence of GR horseweed in Montana cereal production. Increased awareness and adoption of best management practices, including the use of diversified (based on multiple sites of action) herbicide programs highlighted in this study, would aid in mitigating the further spread of GR horseweed in the cereal production fields of the U.S. Great Plains.

scholarly journals Effect of Soil Amendments on Growth of Pentas in a Simulated Landscape

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 790B-790
Author(s):  
Sudeep Vyapari* ◽  
S.M. Scheiber ◽  
Richard C. Beeson
Keyword(s):  
Best Management Practices ◽  
Soil Type ◽  
Management Practices ◽  
Soil Amendments ◽  
Dry Weight ◽  
Initial Growth ◽  
Growth Indices ◽  
Root Dry Weight ◽  
Shoot Dry Weight ◽  
Top Soil

During Fall 2003, a study was conducted to determine the effect of soil amendments on growth and response of Pentas lanceolata `New Look Red' in the landscape. Pentas were grown in 250L drainage lysimeters in an open-sided clear polyethylene covered shelter filled with local top soil (Apopka fine sand). The treatments used were non-amended top soil (control) and soil amended with either compost (5% by volume) or clay (5% by volume) in the top 15 cm. Best Management Practices were followed. Irrigation frequency and rate were regulated using a tensiometer-controlled automatic irrigation system. When plant available water in each soil type had declined to 70% or less, the plants were irrigated back to field capacity. Data were recorded on initial and final growth indices, shoot dry weight, and root dry weight. Final growth indices between control and soil amended with compost were not different; however, growth in the clay-based soil was significantly less than the compost-based soil type. The mean shoot dry weight (77.2 g) produced from plants in compost amended soil type was significantly higher than either control (57.45 g) or clay amended (54.92 g) soil types. No significant differences were found for either initial growth indices or root dry weight among the three treatments.

scholarly journals (111) Establishment of Root-bound Plumbago auriculata Lam. in a Landscape

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1078D-1078
Author(s):  
Sudeep Vyapari ◽  
Edmund L. Thralls ◽  
Michele S. Scheiber
Keyword(s):  
Best Management Practices ◽  
Management Practices ◽  
Dry Weight ◽  
Growth Indices ◽  
Root Dry Weight ◽  
Shoot Dry Weight ◽  
Shoot Ratio ◽  
Root Shoot Ratio ◽  
Randomized Design ◽  
Harvest Dates

A study was conducted to evaluate establishment of root-bound vs. nonroot-bound container-grown Plumbago auriculata Lam. in a landscape. A total of 144 plants were transplanted from #1 containers in a rain-out shelter at Mid-Florida Research and Education Center, Apopka, Fla., in June 2004. The field soil type was amended with composted yard waste. The three treatment types used for the study were: 1) root-bound plants; 2) root-bound plants with a vertical slice made through the root ball at a 90° angle; and 3) nonroot-bound plants. To evaluate the effect of these three treatments during the course of establishment period, harvesting was done once every 2 weeks. Data on growth indices (height × width × width), shoot dry weight, root dry weight, and length of the longest root were recorded. The experimental design was a completely randomized design consisting of three treatments, 12 harvest dates (days after planting), and four replicates per harvest date. Plants were maintained according to the best management practices recommended by the UF/IFAS, and were irrigated once a day using microirrigation. Experimental data were analyzed for significance of correlation among variables using SAS version 9.1. Results of the correlation and regression analysis indicated that the increase in the shoot dry weights (g), root dry weights (g), growth indices (m3), and root: shoot ratio had significant relationship with the harvest dates. Correlation among harvest dates and shoot dry weight, root dry weight, or growth indices was found to be positive. However, results of the study indicated that as the number of days after planting increased, the root to shoot ratio decreased.

Shoot and Root Interference of Common Cocklebur (Xanthium strumarium) and Soybean (Glycine max)

Weed Science ◽  
1993 ◽  
Vol 41 (1) ◽  
pp. 34-37 ◽  
Author(s):  
Robert C. Bozsa ◽  
Lawrence R. Oliver
Keyword(s):  
Field Experiments ◽  
Plant Root ◽  
Soybean Seed ◽  
Growth Period ◽  
Dry Weight ◽  
Porous Membrane ◽  
Xanthium Strumarium ◽  
Shoot Dry Weight ◽  
Whole Plant ◽  
Plant Interference

Field experiments were conducted in 1986 and 1987 to determine the effects of shoot and root interference of common cocklebur and soybean. Plants were grown in porous membrane envelopes. Common cocklebur plants had a longer vegetative growth period than soybean and were twice as tall as soybean at maturity. Soybean root and shoot dry weight and seed yield were reduced by shoot and whole plant (root and shoot) interference of common cocklebur, with whole plant interference giving the greatest reduction. Common cocklebur growth was affected little by soybean interference. Common cocklebur shoot interference alone reduced total soybean seed weight by 48%, the amount caused by common cocklebur whole plant interference.

scholarly journals Evaluating cassava best management practices towards low fertility soil in West Java, Indonesia

2021 ◽  
Vol 911 (1) ◽  
pp. 012028
Author(s):  
Nuning A. Subekti ◽  
Oky Dwi Purwanto ◽  
Endang Y. Purwani ◽  
Abdullah Taufiq ◽  
Rizky P. Ramadhan ◽  
...  
Keyword(s):  
Best Management Practices ◽  
Management Practices ◽  
Management Practice ◽  
Dry Weight ◽  
Low Fertility ◽  
Chicken Manure ◽  
Growth And Yield ◽  
High Yield ◽  
Storage Roots ◽  
Best Management

Abstract Marginal land with low fertility is a major problem in cassava cultivation. The purpose of this study was to determine the best combination of fertilization to increase the growth and yield of cassava on an Inceptisols soil. Urea (46% N), SP-36 (36% P2O5), KCl (60% K2O), NPK Phonska (15% N:15% P2O5:15% K2O), Poly4 Sirius (14% K2O:17% CaO:6% MgO: 19% S), and chicken manure were used as a nutrient source into six treatment combinations. The results showed that fertilizer application significantly affected the plant height, stem diameter, leaf number, diameter of tubers, the total number of tubers, number and weight of marketable tubers, and the total weight of tubers per plant. The highest fresh and dry weight of storage roots was achieved in the best management practice involving application of 138 kg N + 36 kg P2O5 + 60 kg K2O + 37 kg Ca + 13 kg Mg + 41 kg S per hectare compared to other treatments where the weight of marketable tubers was also higher. The right combination of fertilizer rates was needed to achieve high yield targets of cassava and depends on the site- specific conditions of soil fertility and nutrient status.

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