Abstract
A popular pre-harvest strategy to mitigate aflatoxin contamination of corn involves field application of non-aflatoxigenic strains of Aspergillus flavus. The basis of this biological control may involve multiple factors, but competitive displacement of aflatoxigenic strains by the biocontrol strains is a likely mechanism. Three biocontrol strains (NRRL 21882, 18543 and 30797) were applied annually, over a four-year period, to the same 3.2 ha commercial corn field in the Mississippi Delta, where we monitored their post-release establishment, spread and persistence. Within two months of the first biocontrol application, the percentage of soil-inhabiting aflatoxigenic A. flavus strains in some plots was reduced from 48% to 9% of the population. The frequency of aflatoxigenic A. flavus strains was also significantly reduced in the rest of field. After four years, neighboring plots that had never received a biocontrol treatment, and distanced from our treatment plots by at least 20 meters, had less than 20% aflatoxigenic isolates. This significant halo effect might be attributed to movement of soil through tillage operations, but the aflatoxigenicity shift could be detected in the untreated plots within two months of the initial applications, at a time when there was no tillage. The A. flavus populations that colonized the grain were also monitored and found to be less than 15% toxigenic in the fourth year for all treatments. Over all treatments and years, less than 2 ppb of aflatoxin was detected, which could be a consequence of the field-wide shift of the inherent A. flavus population to predominately non-aflatoxigenic strains. This study supports the efficacy of using non-aflatoxigenic A. flavus strains as pre-harvest biocontrol, and shows that most of its effectiveness occurs with the first application.
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Claims 6
Claim · model-written summary
Within two months of the first biocontrol application in a Mississippi Delta corn field, the percentage of soil-inhabiting aflatoxigenic A. flavus strains in some plots was reduced from 48% to 9% of the population.
- Taxon
- corn
Zea mays subsp. mayse0 - Treatment
- first biocontrol applicatione2
- Interactor
- aflatoxigenic A. flavus strainse1pathogen
- Second interactor
- biocontrol strainse3biocontrol_agent
- Outcome
- percentage of soil-inhabiting aflatoxigenic A. flavus strainse1
- Direction
- reducede1
- Value
- from 48% to 9%e1
- Setting
- Mississippi Deltae0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“3.2 ha commercial corn field in the Mississippi Delta”
e1“the percentage of soil-inhabiting aflatoxigenic A. flavus strains in some plots was reduced from 48% to 9% of the population”
e2“Within two months of the first biocontrol application”
e3“Three biocontrol strains (NRRL 21882, 18543 and 30797)”
Claim · model-written summary
The frequency of aflatoxigenic A. flavus strains was also significantly reduced in the rest of the field.
- Taxon
- cornZea mays subsp. mayse0
- Interactor
- aflatoxigenic A. flavus strainse1pathogen
- Outcome
- frequency of aflatoxigenic A. flavus strainse1
- Direction
- reducede1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“3.2 ha commercial corn field in the Mississippi Delta”
e1“The frequency of aflatoxigenic A. flavus strains was also significantly reduced in the rest of field”
Claim · model-written summary
After four years, neighboring plots that never received a biocontrol treatment, at least 20 meters from treatment plots, had less than 20% aflatoxigenic isolates, described as a significant halo effect.
- Taxon
- cornZea mays subsp. mayse0
- Interactor
- aflatoxigenic isolatese1pathogen
- Outcome
- aflatoxigenic isolatese1
- Value
- less than 20%e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“3.2 ha commercial corn field in the Mississippi Delta”
e1“After four years, neighboring plots that had never received a biocontrol treatment, and distanced from our treatment plots by at least 20 meters, had less than 20% aflatoxigenic isolates”
Claim · model-written summary
A. flavus populations that colonized the grain were less than 15% toxigenic in the fourth year for all treatments.
- Taxon
- cornZea mays subsp. mayse0
- Organ / stage
- graine1
- Interactor
- A. flavus
Aspergillus flavuse1pathogen - Outcome
- toxigenice1
- Value
- less than 15%e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“3.2 ha commercial corn field in the Mississippi Delta”
e1“The A. flavus populations that colonized the grain were also monitored and found to be less than 15% toxigenic in the fourth year for all treatments”
Claim · model-written summary
Over all treatments and years, less than 2 ppb of aflatoxin was detected.
- Taxon
- cornZea mays subsp. mayse0
- Outcome
- aflatoxine1
- Value
- less than 2 ppbe1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“3.2 ha commercial corn field in the Mississippi Delta”
e1“Over all treatments and years, less than 2 ppb of aflatoxin was detected”
Claim · model-written summary
The authors conclude that most of the effectiveness of non-aflatoxigenic A. flavus biocontrol occurs with the first application.
- Taxon
- cornZea mays subsp. mayse0
- Outcome
- most of its effectiveness occurs with the first applicatione1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“3.2 ha commercial corn field in the Mississippi Delta”
e1“most of its effectiveness occurs with the first application”
The same questions in other papers
biocontrol · organism · Zea mays (maize)Results agree
3 papers in the same direction as this paper
- positive
- positive
- positive
Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.