TY - JOUR
T1 - Conidial germination and germ tube elongation of Phomopsis amaranthicola and Microsphaeropsis amaranthi on leaf surfaces of seven Amaranthus species
T2 - Implications for biological control
AU - Ortiz-Ribbing, Loretta
AU - Williams, Martin M.
PY - 2006/9/1
Y1 - 2006/9/1
N2 - Microsphaeropsis amaranthi and Phomopsis amaranthicola are potential biological control agents for several Amaranthus species. In an effort to understand the initial infection processes with these pathogens, a study was conducted of the conidial germination and germ tube length (μm) on the weed leaf surfaces at 21 °C and 28 °C. Weeds included Amaranthus rudis, A. palmeri, A. powellii, A. retroflexus, A. spinosus, A. hybridus, and A. albus. For P. amaranthicola, conidial germination and germ tube length varied among the seven weed species at both temperatures, while for M. amaranthi the differences in germ tube lengths were significant among weed species only at 21 °C. While the conidia of M. amaranthi and P. amaranthicola germinated on the leaf surfaces of all seven weed species, temperature appeared to impact the number and length of germ tubes on the leaf surfaces. The percentage of germinated conidia and the length of germ tubes at both temperatures were often greater for M. amaranthi than for P. amaranthicola. In order for the fungal pathogen to successfully infect and kill a weedy host, conidia must germinate and form a germ tube, two processes that vary with host species and temperature for M. amaranthi and P. amaranthicola. The extent to which successive infection processes, e.g., penetration, invasion and colonization, contribute to host specificity warrants study.
AB - Microsphaeropsis amaranthi and Phomopsis amaranthicola are potential biological control agents for several Amaranthus species. In an effort to understand the initial infection processes with these pathogens, a study was conducted of the conidial germination and germ tube length (μm) on the weed leaf surfaces at 21 °C and 28 °C. Weeds included Amaranthus rudis, A. palmeri, A. powellii, A. retroflexus, A. spinosus, A. hybridus, and A. albus. For P. amaranthicola, conidial germination and germ tube length varied among the seven weed species at both temperatures, while for M. amaranthi the differences in germ tube lengths were significant among weed species only at 21 °C. While the conidia of M. amaranthi and P. amaranthicola germinated on the leaf surfaces of all seven weed species, temperature appeared to impact the number and length of germ tubes on the leaf surfaces. The percentage of germinated conidia and the length of germ tubes at both temperatures were often greater for M. amaranthi than for P. amaranthicola. In order for the fungal pathogen to successfully infect and kill a weedy host, conidia must germinate and form a germ tube, two processes that vary with host species and temperature for M. amaranthi and P. amaranthicola. The extent to which successive infection processes, e.g., penetration, invasion and colonization, contribute to host specificity warrants study.
KW - A. albus
KW - A. hybridus
KW - A. palmeri
KW - A. powellii
KW - A. retroflexus
KW - A. spinosus
KW - Amaranthus rudis
KW - Bioherbicide
KW - Biological control
KW - Microsphaeropsis amaranthi
KW - Mycoherbicide
KW - Phomopsis amaranthicola
KW - Spore germination
UR - http://www.scopus.com/inward/record.url?scp=33746886998&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33746886998&partnerID=8YFLogxK
U2 - 10.1016/j.biocontrol.2006.04.002
DO - 10.1016/j.biocontrol.2006.04.002
M3 - Article
AN - SCOPUS:33746886998
SN - 1049-9644
VL - 38
SP - 356
EP - 362
JO - Biological Control
JF - Biological Control
IS - 3
ER -