Your browser doesn't support javascript.
loading
Combined Use of PGPRs and Reduced Rates of Azoxystrobin to Improve Management of Sheath Blight of Rice.
Zhou, Xin-Gen; Kumar, K Vijay Krishna; Zhou, Linda W; Reddy, M S; Kloepper, Joseph W.
Afiliação
  • Zhou XG; Texas A&M AgriLife Research Center, Beaumont, TX 77713, U.S.A.
  • Kumar KVK; Regional Agricultural Research Station, Maruteru, Acharya N. G. Ranga Agricultural University, Andhra Pradesh 534 122, India.
  • Zhou LW; Texas A&M AgriLife Research Center, Beaumont, TX 77713, U.S.A.
  • Reddy MS; Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, U.S.A.
  • Kloepper JW; Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, U.S.A.
Plant Dis ; 105(4): 1034-1041, 2021 Apr.
Article em En | MEDLINE | ID: mdl-32931392
ABSTRACT
Farmers rely heavily on the use of strobilurin fungicides to manage sheath blight (ShB) caused by Rhizoctonia solani AG1-IA, the most important disease in rice in the southern United States. Greenhouse and field studies were conducted to evaluate the potential use of plant growth-promoting rhizobacteria (PGPRs) in combination with a reduced rate of azoxystrobin application as a strategy to improve the current fungicide-reliant management. Of the nine antagonistic PGPR strains screened in the greenhouse, Bacillus subtilis strain MBI600 provided the most significant and consistent suppression of ShB. Efficacy of strain MBI600 was further evaluated at the concentrations of 0, 103, 106, 109, and 1011 CFU/ml alone or in combinations with 0, 17, 33, 50, 67, 83, and 100% of the recommended application rate (0.16 kg a.i./ha) of azoxystrobin. Strain MBI600 applied at 106,109, and 1011 CFU/ml alone was effective in reducing ShB severity. Combinations of this strain at these rates with ≥33% of the recommended application rate of azoxystrobin further reduced ShB severity. A dose-response model defining the relationships between strain MBI600, azoxystrobin, and ShB severity was established. Estimates of the effective concentrations (EC50 and EC90) of strain MBI600 when applied in combination with 50% of the recommended application rate of azoxystrobin were 104 and 109 CFU/ml, respectively. A field trial was conducted over 4 years to verify the efficacy of their combinations. Strain MBI600 alone, when applied at 109 CFU/ml at the boot stage, reduced ShB severity but did not significantly increase grain yields each year. Combination of strain MBI600 with azoxystrobin at half of the recommended application rate improved efficacy of strain MBI600, reducing ShB severity to a level comparable to that of azoxystrobin applied at the full rate in all 4 years. The combined treatment also increased grain yield by 14 to 19%, comparable to the fungicide applied at the full rate in 3 of 4 years. Combined use of PGPR strain MBI600 with a reduced rate of azoxystrobin application can be a viable management option for control of ShB while allowing producers to use less fungicide on rice.
Assuntos
Palavras-chave

Texto completo: 1 Bases de dados: MEDLINE Assunto principal: Oryza País/Região como assunto: America do norte Idioma: En Revista: Plant Dis Ano de publicação: 2021 Tipo de documento: Article País de afiliação: Estados Unidos

Texto completo: 1 Bases de dados: MEDLINE Assunto principal: Oryza País/Região como assunto: America do norte Idioma: En Revista: Plant Dis Ano de publicação: 2021 Tipo de documento: Article País de afiliação: Estados Unidos