Confirmation ofS-metolachlor resistance in Palmer amaranth (Amaranthus palmeri)
| Autor: | Chad Brabham, Vijay K. Varanasi, Tom Barber, Michael M. Houston, Jason K. Norsworthy |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
0106 biological sciences
Acetolactate synthase Amaranth 04 agricultural and veterinary sciences Plant Science Biology biology.organism_classification 01 natural sciences Gossypium hirsutum Amaranthus palmeri chemistry.chemical_compound Horticulture chemistry Glyphosate 040103 agronomy & agriculture biology.protein 0401 agriculture forestry and fisheries Acetochlor Agronomy and Crop Science Metolachlor After treatment 010606 plant biology & botany |
| Zdroj: | Weed Technology. 33:720-726 |
| ISSN: | 1550-2740 0890-037X |
| Popis: | S-Metolachlor is commonly used by soybean and cotton growers, especially with POST treatments for overlapping residuals, to obtain season-long control of glyphosate- and acetolactate synthase (ALS)–resistant Palmer amaranth. In Crittenden County, AR, reports of Palmer amaranth escapes followingS-metolachlor treatment were first noted at field sites near Crawfordsville and Marion in 2016. Field and greenhouse experiments were conducted to confirmS-metolachlor resistance and to test for cross-resistance to other very-long-chain fatty acid (VLCFA)–inhibiting herbicides in Palmer amaranth accessions from Crawfordsville and Marion. Palmer amaranth control in the field (soil –1; emulsifiable concentrate formulation) and dimethenamid-P (631 g ai ha–1). However,S-metolachlor at 1,064 g ai ha–1provided only 76% control, which was not significantly different from the 1/2× and 1/4× rates of dimethenamid-P and acetochlor (66% to 85%). In the greenhouse, Palmer amaranth accessions from Marion and Crawfordsville were 9.8 and 8.3 times more resistant toS-metolachlor compared with two susceptible accessions based on LD50values obtained from dose–response experiments. Two-thirds and 1.5 timesS-metolachlor at 1,064 g ha–1were the estimated rates required to obtain 90% mortality of the Crawfordsville and Marion accessions, respectively. Data collected from the field and greenhouse confirm that these accessions have evolved a low level of resistance toS-metolachlor. In an agar-based assay, the level of resistance in the Marion accession was significantly reduced in the presence of a glutathione S-transferase (GST) inhibitor, suggesting that GSTs are the probable resistance mechanism. With respect to other VLCFA-inhibiting herbicides, Marion and Crawfordsville accessions were not cross-resistant to acetochlor, dimethenamid-P, or pyroxasulfone. However, both accessions, based on LD50values obtained from greenhouse dose–response experiments, exhibited reduced sensitivity (1.5- to 3.6-fold) to the tested VLCFA-inhibiting herbicides. |
| Databáze: | OpenAIRE |
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