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Organic suckercides: Screening various compounds for efficacy and injury potential
David H Suchoff, Matthew C. Vann, Maggie M. Short
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Introduction-Growth and success of organic tobacco production
due to organic fatty alcohol suckercide.
-Fatty alcohols (O-TAC Plant Contact Agent ®; C8C10)
derived from palm oil / palm kernel oil.
2009: Certifiers allowed certain fatty alcohols (FA).
2009-15: OMRI classified fatty alcohols as synthetic.
2015: Petition to NOSB to add FA as synthetic.
2017: NOSB classified FA as synthetic but did not
recommend its use.
2018: Certifiers still allowed FA use, revised petition
submitted.
2019: NOSB meets October 25… FA future uncertain.
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Introduction
Objective:
Compare four OMRI-approved
compounds for sucker control and crop
injury potential in flue-cured tobacco.
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Materials and Methods
Upper Coastal Plain Research Station
Rocky Mount, NC
Oxford Tobacco Research Station
Oxford, NC
2018
Transplant: April
Harvest: September-October
‘NC 196’
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Materials and Methods
Compounds tested:
Pelargonic acid (680 g∙L-1 ai, Belchim Crop Protection)
Vegetable oil (Natur’l Oil, 93% ai, Stoller® USA)
Canola oil (100% ai, Catania Spagna Corporation)
Peppermint + Spearmint oil (SuckerZap™, 10% ai, ExcelAg Corp.)
Fatty Alcohol (O-TAC, 85% ai, Fair Products)
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Materials and Methods
Application methods:
Standard foliar application
3-nozzle boom
50.8 cm with TG3-TG5-TG3 nozzle arrangement
(TeeJet Spraying Systems Co.)
Calibrated to 467.7 L∙ha-1
Dropline application
CO2-pressurized backpack
Single nozzle calibrated to 29.57 mL/plant (439.6
L∙ha-1)
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Materials and Methods
5 (compounds) x 2 (application method)
Pelargonic acid
Vegetable oil
Canola oil
Peppermint + Spearmint oil
Fatty Alcohol
Standard foliar (3-nozzle boom)
Dropline
Applied every 5 d after 50% initiation of elongated button stage (6 total applications).
Peppermint + Spearmint applied at 3%, 4%, 4%, 4%, 4%, 4% v/v.
All other treatments applied at 4%, 5%, 5%, 5%, 5%, 5% v/v.
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Materials and Methods
RCBD with three (Oxford) and four (Rocky Mount) blocks.
Single-row plot size of 15.24m x 1.22m (0.46m spacing between plants).
Data taken from entire plot-row.
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Materials and MethodsData collected:
Yield
Quality
Crop value (combination of leaf yield and quality
with reported price indices – Fisher et al. 2018).
Visual chemical injury prior to each application.
Percent sucker control from 10 plants based on
non-suckered control.
Data analysis:
Analyzed by location
PROC GLIMMIX, SAS v 9.4
Tukey’s HSD used when appropriate.
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0 3 8
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Materials and MethodsData collected:
Yield
Quality
Crop value (combination of leaf yield and quality
with reported price indices – Fisher et al. 2018).
Visual chemical injury prior to each application.
Percent sucker control from 10 plants based on
non-suckered control.
control sucker weight – trt sucker weight x 100
control sucker weight
Data analysis:
Analyzed by location
PROC GLIMMIX, SAS v 9.4
Tukey’s HSD used when appropriate.
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Results
Oxford Rocky Mount
Percent
Sucker
Control Injury Yield Quality Value
Percent
Sucker
Control Injury Yield Quality Value
Compound *** *** *** *** *** *** *** *** NS ***
Application
methodNS *** * ** ** NS *** * * *
Compound
x
Application
NS *** * NS ** NS *** NS NS NS
NS denotes not significant at α = 0.05. *,**,*** denote significant at P < 0.05, 0.01, and 0.001, respectively.
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Results
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Results
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Results
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Results
Oxford
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Results
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Results
Rocky Mount
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Results
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Results
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Conclusions
Pelargonic acid did control sucker production.
BUT
Unacceptable levels of injury = reduced quality + reduced yield =
extreme loss in crop value.
All other compounds ineffective at controlling suckers.
Low yields due to preferential sucker development.
What about lower Pelargonic acid concentrations?
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Conclusions
Pelargonic acid concentrations (%) Pelargonic acid concentrations (%)
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