Influence of soil properties and soil moisture on the efficacy of indaziflam and flumioxazin on Kochia scoparia L.
BACKGROUND
Kochia (Kochia scoparia L.) is a highly competitive, non-native weed found throughout the western United States. Flumioxazin and indaziflam are two broad-spectrum pre-emergence herbicides that can control kochia in a variety of crop and non-crop situations; however, under dry conditions, these herbicides sometimes fail to control this important weed. There is very little information describing the effect of soil properties and soil moisture on the efficacy of these herbicides.


RESULTS
Soil organic matter (SOM) explained the highest proportion of variability in predicting the herbicide dose required for 80% kochia growth reduction (GR80) for flumioxazin and indaziflam (R2= 0.72 and 0.79 respectively). SOM had a greater impact on flumioxazin phytotoxicity compared to indaziflam. Flumioxazin and indaziflam kochia phytotoxicity was greatly reduced at soil water potentials below -200 kPa.


CONCLUSIONS
Kochia can germinate at soil moisture potentials below the moisture required for flumioxazin and indaziflam activation, which means that kochia control is greatly influenced by the complex interaction between soil physical properties and soil moisture. This research can be used to gain a better understanding of how and why some weeds, like kochia, are so difficult to manage even with herbicides that normally provide excellent control. © 2016 Society of Chemical Industry.
Bioagricultural Science and Pest Management Department, Colorado State University, Fort Collins, CO, USA.
Derek J
DJ
Sebastian
Bioagricultural Science and Pest Management Department, Colorado State University, Fort Collins, CO, USA.
Scott J
SJ
Nissen
Bioagricultural Science and Pest Management Department, Colorado State University, Fort Collins, CO, USA.
Phil
P
Westra
USDA-ARS, Fort Collins, CO, USA.
Dale L
DL
Shaner
Soil and Crop Science Department, Colorado State University, Fort Collins, CO, USA.
Greg
G
Butters
D027467:Bassia scoparia / Q000502:physiology*; D048588:Benzoxazines; D018525:Germination / Q000502:physiology; D006540:Herbicides; D007192:Indenes; D010797:Phthalimides; D012987:Soil / Q000737:chemistry*; D014227:Triazines; D014867:Water / Q000032:analysis*
D048588:Benzoxazines; D006540:Herbicides; D007192:Indenes; C571026:N-(2,3-dihydro-2,6-dimethyl-1H-inden-1-yl)-6-(1-fluoroethyl)-1,3,5-triazine-2,4-diamine; D010797:Phthalimides; D012987:Soil; D014227:Triazines; D014867:Water; C106487:flumioxazin
flumioxazin; herbicide activation; indaziflam; pre-emergence; soil matric potential