Banca de QUALIFICAÇÃO: TATIANE SEVERO SILVA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE : TATIANE SEVERO SILVA
DATA : 06/02/2023
HORA: 14:30
LOCAL: Google Meet
TÍTULO:

Preemergence Herbicide Premixes Reduce the Risk of Soil Residual Weed Control Failure in Corn

 

Evaluating cover crop tolerance to corn residual herbicides using field treated soil in greenhouse bioassay

PALAVRAS-CHAVES:

Primeiro trabalho: herbicide efficacy; herbicide mixture; residual herbicide; weed management

Segundo trabalho: preemergence herbicides; herbicide injury; carryover; biomass production

PÁGINAS: 74
RESUMO:

Primeiro trabalho: Widespread occurrence of herbicide-resistant weeds and more variable weather conditions across the United States are challenging weed control in corn. Preemergence (PRE) herbicides with soil residual activity resurge as foundation for early-season weed control in corn. Field experiments were conducted at Janesville and Lancaster, WI in 2021 and 2022 (4 site-years) to evaluate the weed control efficacy of solo (single site of action [SOA]) and premix (two or more SOAs) PRE herbicides in conventional tillage corn systems. Treatments consisted of 18 PRE herbicides plus a non-treated check. At Janesville-2021, S-metolachlor + bicyclopyrone + mesotrione, atrazine + S-metolachlor + bicyclopyrone + mesotrione, and clopyralid + acetochlor + mesotrione provided >72% giant ragweed (Ambrosia trifida L.) control and >60% biomass reduction. At Janesville-2022, none of the PRE herbicides evaluated provided >70% giant ragweed control due to the heavy giant ragweed density and the lack of timely rainfall for herbicide activation in the soil. At Lancaster-2021, atrazine, dicamba, and flumetsulam + clopyralid provided ≤70% waterhemp (Amaranthus tuberculatus [Moq.] J.D. Sauer) control, but the remaining treatments provided >90% control. At Lancaster-2022, the efficacy of some PRE herbicides was reduced due to the high pressure of waterhemp, but most of the herbicides provided >75% control. At Lancaster-2021 and 2022, only dicamba and S-metolachlor did not provide >75% common lambsquarters (Chenopodium album L.) control. PRE herbicides containing SOA group 15 provided >75% control of giant foxtail (Setaria faberi Herrm.). Across weed species, PRE herbicides with two (78%) and three (81%) SOAs provided higher weed control than PRE herbicides with a single SOA (68%), indicating at least two SOAs are needed in a premix to achieve better weed control. PRE herbicide efficacy varied according to the weed species, but the premixes appeared as a more reliable option to improve early-season weed control in conventional tillage corn systems.

 

Segundo trabalho: More growers across the US Midwest are considering interseeding and overseeding cover crops into corn for soil health purposes. One challenge of this practice is the potential injury from soil residual herbicides applied preemergence (PRE) for weed control in corn to the interseeded and/or overseeded cover crop species. Field treated soil was collected in 2021 and 2022 at Janesville and Lancaster, WI to investigate the impact of PRE residual herbicides on establishment of interseeded and overseeded cover crops via greenhouse bioassay. Soil samples (0-5 cm depth) were collected from field experiments at 0, 10, 20, 30, 40 and 50, 60, and 70 days after treatment (DAT). Treatments consisted of 14 single and multiple sites of action PRE herbicides plus a nontreated check (NTC). Four bioindicator cover crops species were used in the greenhouse bioassay: annual rye, cereal rye, radish, and red clover. Cover crop biomass was collected 28 days after bioassay seeding. Cover crop species responded differently across herbicide treatments. Annual rye and cereal rye were sensitive to treatments containing herbicide group 15 but not as impacted by herbicide groups 2, 4, 5, and 27 when field soil was collected at 30 DAT (interseeding scenario) and 70 DAT (overseeding scenario) compared to the NTC. Radish and red clover were sensitive to herbicide groups 2, 4, and 27 whereas groups 5, 14, and 15 had minimal impact on their establishment. Based on these greenhouse bioassay results; PRE herbicides should be carefully selected when multispecies cover crop mixes will be interseeded (~V3 corn growth stage) or overseeded into. Field studies will be conducted to validate these results and support recommendations for growers interested in this system.

MEMBROS DA BANCA:
Externo à Instituição - RODRIGO WERLE - PESQUISADOR
Externo à Instituição - LUIS ANTONIO DE AVILA - PESQUISADOR
Externo à Instituição - ALEXANDRE TONON ROSA - PESQUISADOR
Presidente - 2213033 - DANIEL VALADAO SILVA
Externo à Instituição - GUILHERME BRAGA PEREIRA BRAZ - UNIRV