scholarly journals Sensitivity of Digitaria insularis to herbicides in agricultural areas, in the Brazilian Cerrado biome

2020 ◽  
Vol 55 ◽  
Author(s):  
Núbia Maria Correia ◽  
Pedro Eduardo Rampazzo ◽  
Lucas da Silva Araújo ◽  
Caio Vitagliano Santi Rossi
Keyword(s):  
Mineral Oil ◽  
Cross Resistance ◽  
Multiple Resistance ◽  
Brazilian Cerrado ◽  
Herbicide Application ◽  
Plant Populations ◽  
Susceptible Population ◽  
Cerrado Biome ◽  
Different Populations ◽  
Agricultural Areas

Abstract: The objective of this work was to evaluate the sensitivity of different populations of Digitaria insularis to the glyphosate, clethodim, and haloxyfop-P-methyl herbicides, in agricultural areas, and to develop infestation maps based on the responses of these populations. One hundred sixty-one populations suspected of being resistant were evaluated and compared to a susceptible population. When plants displayed three to four tillers, the populations were sprayed with glyphosate (1,000 g ha-1 a.e.), clethodim (108 g ha-1 a.i. + 0.5% mineral oil), and haloxyfop-P-methyl (62.35 g ha-1 a.i. + 0.5% mineral oil); plants without herbicide application were used as the control. The plant populations were classified as susceptible, intermediately resistant (with susceptible and resistant plants), or resistant to the tested herbicides. All populations were susceptible to clethodim; 97.5% were susceptible and 2.5% were intermediately resistant to haloxyfop-P-methyl; and 9.9% were susceptible, 21.1% intermediately resistant, and 68.9% resistant to glyphosate. Glyphosate-resistant populations are homogeneously distributed throughout the evaluated regions. There are no cases of D. insularis multiple resistance in the sampled regions; however, cross-resistance to glyphosate and haloxyfop-P-methyl was detected.

scholarly journals First case of Conyza canadensis from Hungary with multiple resistance to glyphosate and flazasulfuron

2018 ◽  
Author(s):  
Candelario Palma-Bautista ◽  
Behroz Khalil Tahmasebi ◽  
Pablo Tomás Fernández-Moreno ◽  
Antonia María Rojano-Delgado ◽  
Ricardo Alcántara de la Cruz ◽  
...  
Keyword(s):  
Dose Response ◽  
Shikimic Acid ◽  
Multiple Resistance ◽  
Conyza Canadensis ◽  
Herbicide Application ◽  
Susceptible Population ◽  
First Case ◽  
Acid Accumulation ◽  
Agricultural Areas ◽  
Als Inhibitor

Conyza canadensis is a species invading large agricultural areas throughout the world, mainly to its ability to evolve herbicide resistance. Specifically, in Hungary, extensive areas have been infested by this species due to the difficulty in controlling it with glyphosate. To corroborate this fact as resistance and not as an incorrect herbicide application, eight suspicious glyphosate-resistant C. canadensis populations from different Hungarian regions were studied. In dose-response assays with glyphosate, the LD50 and GR50 values indicated that populations 1 to 5 were resistant to this herbicide (H-5 population the most resistant). Besides, the shikimic acid accumulation tests corroborated the results observed in the dose-response assays. 11 alternative herbicides from 6 different mode of action (MOA) were applied at field doses as control alternatives on populations H-5 and H-6 (both in the same regions). The H-5 population showed an unexpected resistance to flazasulfuron (ALS-inhibitor). The ALS enzyme activity studies indicated that the I50 for H-5 was 63.3 fold higher compared to its correspondent susceptible population (H-6). Therefore, the H-5 population exhibited multiple-resistance to flazasulfuron and glyphosate, being the first case reported in Europe for this two MOA. For that reason, the other herbicides with different MOA have to be tested here.

scholarly journals Acetolactate synthase activity in Euphorbia heterophylla resistant to ALS- and protox- inhibiting herbicides

2013 ◽  
Vol 31 (4) ◽  
pp. 867-874 ◽  
Author(s):  
E. Xavier ◽  
M.C. Oliveira ◽  
M.M. Trezzi ◽  
R.A. Vidal ◽  
F. Diesel ◽  
...  
Keyword(s):  
Acetolactate Synthase ◽  
Inhibitory Effect ◽  
Cross Resistance ◽  
Multiple Resistance ◽  
Vitro Assay ◽  
Susceptible Population ◽  
Resistance Factors ◽  
Als Inhibitors ◽  
High Inhibitory Effect

The objective of this study was to determine the activity of the enzyme acetolactate synthase in biotypes of wild poinsettia (Euphorbia heterophylla) with multiple resistance to ALS- and Protox- inhibitors in the presence and absence of imazapyr, imazethapyr and nicosulfuron. We conducted in vitro assay of ALS enzyme extracted from plants of Vitorino, Bom Sucesso do Sul and Medianeira biotypes (with multiple resistance) and a susceptible population in the absence and presence of imazapyr, imazethapyr and nicosulfuron. In the absence of herbicides, biotypes with multiple resistance showed higher affinity for the substrate of the enzyme compared with the susceptible population. The herbicides imazapyr, imazethapyr and nicosulfuron had little effect on the enzyme activity of ALS-resistant biotypes and, conversely, high inhibitory effect on ALS of the susceptible population. Resistance factors were very high, greater than 438, 963 and 474 for Vitorino, Bom Sucesso do Sul and Medianeira biotypes, respectively. The resistance to ALS inhibitors is due to the insensitivity of ALS to herbicides of both imidazolinone and sulfonylurea groups, characterizing a cross-resistance.

High throughput screening to investigate Brazilian Cerrado biome plant extract bank chemical diversity

Planta Medica ◽  
2016 ◽  
Vol 81 (S 01) ◽  
pp. S1-S381
Author(s):  
LS Espindola ◽  
RG Dusi ◽  
KR Gustafson ◽  
J McMahon ◽  
JA Beutler
Keyword(s):  
High Throughput ◽  
Plant Extract ◽  
High Throughput Screening ◽  
Chemical Diversity ◽  
Brazilian Cerrado ◽  
Cerrado Biome

scholarly journals Globe fringerush (Fimbristylis miliacea) cross resistance to als-inhibitor herbicides under field conditions in irrigated rice in the south of Brazil

2013 ◽  
Vol 31 (4) ◽  
pp. 893-902 ◽  
Author(s):  
C.E. Schaedler ◽  
J.A. Noldin ◽  
D.S. Eberhardt ◽  
D. Agostinetto ◽  
N.R. Burgos
Keyword(s):  
Grain Yield ◽  
Weed Control ◽  
Rice Fields ◽  
Field Conditions ◽  
Cross Resistance ◽  
Herbicide Application ◽  
The South ◽  
Santa Catarina ◽  
Irrigated Rice ◽  
South Of Brazil

ALS-inhibiting herbicides usually provide adequate weed control in irrigated rice fields. After consecutive years of use, the Cyperaceae species, globe fringerush (Fimbristylis miliacea) began to show resistance to ALS (acetolactate synthase) inhibitors. Globe fringerush is one of the most problematic herbicide-resistant weeds in irrigated rice in the state of Santa Catarina in the South of Brazil. The objective of this research was to examine cross resistance of globe fringerush to ALS inhibitors, under field conditions. Two experiments were conducted in a rice field naturally infested with ALS-resistant globe fringerush in Santa Catarina, in the 2008/09 and 2009/10 cropping seasons. The experimental units were arranged in randomized complete block design, with five replicates, consisting of two factors (herbicide and dose) in a 4 x 5 factorial arrangement. ALS herbicides included bispyribac-sodium, ethoxysulfuron, pyrazosulfuron-ethyl and penoxsulam. Six-leaf globe fringerush was sprayed with herbicide doses of 0, 0.5, 1, 2 and 4X the recommended doses in a spray volume of 200 L ha-1. The number of rice culm, filled and sterile grains, plant height, dry shoot biomass and grain yield were recorded. Globe fringerush control was evaluated 28 and 70 days after herbicide application (DAA); shoots were harvested at 13 weeks after herbicide application and dry weight recorded. Competition with globe fringerush reduced the number of culm and rice grain yield. The globe fringerush biotype in this field was resistant to all ALS herbicides tested. Penoxsulam had the highest level of activity among treatments at 28 and 70 DAA, but the control level was only 50% and 42%, respectively, in the second year of assessment. This was not enough to prevent rice yield loss. Alternative herbicides and weed control strategies are necessary to avoid yield losses in rice fields infested with ALS-resistant biotypes of globe fringerush.

scholarly journals Recurrent Selection with Glufosinate at Low Rates Reduces the Susceptibility of a Lolium perenne ssp. multiflorum Population to Glufosinate

Agronomy ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1288 ◽  
Author(s):  
Maor Matzrafi ◽  
Sarah Morran ◽  
Marie Jasieniuk
Keyword(s):  
Lolium Perenne ◽  
Recurrent Selection ◽  
Cross Resistance ◽  
Susceptible Population ◽  
Selection Cycle ◽  
Herbicide Resistant ◽  
Repeated Applications ◽  
Resistance To Herbicides ◽  
Rate Selection ◽  
Low Rate

Repeated applications of herbicides at the labelled rates have often resulted in the selection and evolution of herbicide-resistant weeds capable of surviving the labelled and higher rates in subsequent generations. However, the evolutionary outcomes of recurrent herbicide selection at low rates are far less understood. In this study of a herbicide-susceptible population of Lolium perenne ssp. multiflorum, we assessed the potential for low glufosinate rates to select for reduced susceptibility to the herbicide, and cross-resistance to herbicides with other modes of action. Reduced susceptibility to glufosinate was detected in progeny in comparison with the parental population following three rounds of selection at low glufosinate rates. Differences were mainly observed at the 0.5X, 0.75X, and 1X rates. Comparing the parental susceptible population and progeny from the second and third selection cycle, the percentage of surviving plants increased to values of LD50 (1.31 and 1.16, respectively) and LD90 (1.36 and 1.26, respectively). When treated with three alternative herbicides (glyphosate, paraquat, and sethoxydim), no plants of either the parental or successive progeny populations survived treatment with 0.75X or higher rates of these herbicides. The results of this study provide clear evidence that reduced susceptibility to glufosinate can evolve in weed populations following repeated applications of glufosinate at low herbicide rates. However, the magnitude of increases in resistance levels over three generations of recurrent low-rate glufosinate selection observed is relatively low compared with higher levels of resistance observed in response to low-rate selection with other herbicides (three fold and more).

scholarly journals Recurrent selection with glufosinate at low rates reduces the susceptibility of a Lolium perenne ssp. multiflorum population to glufosinate

2020 ◽  
Author(s):  
Maor Matzrafi ◽  
Sarah Morran ◽  
Marie Jasieniuk
Keyword(s):  
Lolium Perenne ◽  
Recurrent Selection ◽  
Cross Resistance ◽  
Susceptible Population ◽  
Selection Cycle ◽  
Herbicide Resistant ◽  
Repeated Applications ◽  
Resistance To Herbicides ◽  
Rate Selection ◽  
Low Rate

ABSTRACTRepeated applications of herbicides at the labelled rates have often resulted in the selection and evolution of herbicide-resistant weeds capable of surviving the labelled and higher rates in subsequent generations. However, the evolutionary outcomes of recurrent herbicide selection at low rates are far less understood. In this study of an herbicide-susceptible population of Lolium perenne ssp. multiflorum, we assessed the potential for low glufosinate rates to select for reduced susceptibility to the herbicide, and cross-resistance to herbicides with other modes of action. Reduced susceptibility to glufosinate was detected in progeny in comparison with the parental population following three rounds of selection at low glufosinate rates. Differences were mainly observed at the 0.5X, 0.75X, and 1X rates. Comparing the parental susceptible population and progeny from the second and third selection cycle, the percentage of surviving plants increased to values of LD50 (1.31 and 1.16, respectively) and LD90 (1.36 and 1.26, respectively). When treated with three alternative herbicides (glyphosate, paraquat, and sethoxydim), no plants of either the parental or successive progeny populations survived treatment with 0.75X or higher rates of these herbicides. The results of this study provide clear evidence that reduced susceptibility to glufosinate can evolve in weed populations following repeated applications of glufosinate at low herbicide rates. However, the magnitude of increases in resistance levels over three generations of recurrent low-rate glufosinate selection observed is relatively low compared with higher levels of resistance observed in response to low-rate selection with other herbicides (three fold and more).

Two new wild cassava species (Manihot, Euphorbiaceae) from the Brazilian Cerrado

Phytotaxa ◽  
2015 ◽  
Vol 213 (2) ◽  
pp. 131 ◽  
Author(s):  
Marcos José Silva
Keyword(s):  
Conservation Status ◽  
Taxonomic Study ◽  
Brazilian Cerrado ◽  
Habitat Distribution ◽  
Cerrado Biome

Manihot luxurians and M. confertiflora are herein described and illustrated. Both species were collected in the Chapada dos Veadeiros region during a taxonomic study of the genus Manihot in the Cerrado Biome. The morphological affinities, habitat, distribution, conservation status of both species are also provided.

Predicting runoff series in ungauged basins of the Brazilian Cerrado biome

2022 ◽  
pp. 105315
Author(s):  
Daniel Althoff ◽  
Lineu Neiva Rodrigues ◽  
Demetrius David da Silva
Keyword(s):  
Ungauged Basins ◽  
Brazilian Cerrado ◽  
Cerrado Biome ◽  
Runoff Series

Resistance to Aryloxyphenoxypropionate and Cyclohexanedione Herbicides in Wild Oat (Avena fatua)

Weed Science ◽  
1993 ◽  
Vol 41 (2) ◽  
pp. 232-238 ◽  
Author(s):  
Ian M. Heap ◽  
Bruce G. Murray ◽  
Heather A. Loeppky ◽  
Ian N. Morrison
Keyword(s):  
Dry Matter ◽  
Cross Resistance ◽  
Western Canada ◽  
Wild Oat ◽  
Recommended Dosage ◽  
Susceptible Population ◽  
South Central ◽  
Repeated Applications ◽  
High Level ◽  
Very High

Resistance to aryloxyphenoxypropionate and cyclohexanedione herbicides was identified in four wild oat populations from western Canada. Populations UM1, UM2, and UM3 originated from northwestern Manitoba and UM33 from south-central Saskatchewan. Field histories indicated that these populations were exposed to repeated applications of diclofop-methyl and sethoxydim over the previous 10 yr. The populations differed in their levels and patterns of cross-resistance to these and five other acetyl-CoA carboxylase inhibitors (ACCase inhibitors). UM1, UM2, and UM3 were resistant to diclofop-methyl, fenoxaprop-p-ethyl, and sethoxydim. In contrast, UM33 was resistant to the aryloxyphenoxy propionate herbicides but not to sethoxydim. The dose of sethoxydim required to reduce growth of UM1 by 50% was 150 times greater than for a susceptible population (UM5) or UM33 based on shoot dry matter reductions 21 d after treatment. This population differed from UM2 and UM3 that had R/S ratios of less than 10. In the field UM1 also exhibited a very high level of resistance to sethoxydim. In contrast to susceptible plants that were killed at the recommended dosage, shoot dry matter of resistant plants treated at eight times the recommended dosage was reduced by only 27%. In growth chamber experiments none of the four populations was cross-resistant to herbicides from five different chemical families.

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