Integrating the herbicide imazapic and the fungal pathogen P yrenophora semeniperda to control B romus tectorum

• Published in: Weed research Vol. 54; no. 4; pp. 418 - 424
• Main Authors: Ehlert, K A, Mangold, J M, Engel, R E
• Format: Journal Article
• Language: English
• Published: 01-08-2014
• ISSN: 0043-1737; 1365-3180
• DOI: 10.1111/wre.12089

Bromus tectorum
is a winter annual grass that affects rangeland in western North America. A glasshouse pot experiment was conducted that integrated imazapic application and inoculation of the soil‐borne fungal pathogen,
P
yrenophora semeniperda,
for the purpose of providing greater control of
B
. tectorum
. We hypothesised that
P
. semeniperda
inoculation would reduce
B
. tectorum
emergence and integration of imazapic and
P
. semeniperda
would result in a greater reduction in
B
. tectorum
biomass and density compared with either treatment applied alone. This study revealed that
P
. semeniperda
significantly reduced
B
. tectorum
emergence and density and the responses were greatest for seed placed below the soil surface. Further,
B
. tectorum
biomass was similar between imazapic and
P
. semeniperda
treatments. This indicates that
P
. semeniperda
could be applied in advance of
B
. tectorum
germination and emergence. After emergence, imazapic application could reduce
B
. tectorum
biomass and kill seedlings. A two‐pronged approach to controlling
B
. tectorum
that combines
P
. semeniperda
inoculation and post‐emergent imazapic application may provide a greater opportunity to limit invasion of this weed in rangeland of western North America. Future work should be directed towards the pathogen–plant relationship and how it relates to integrating biological control with traditional methods, towards the effect of varying
P
. semeniperda
inoculum and imazapic rates and lastly, to how environmental conditions in the field may affect implementation and efficacy of this two‐pronged approach.