L. Buchwaldt et al., WINDBORNE DISPERSAL OF COLLETOTRICHUM-TRUNCATUM AND SURVIVAL IN INFESTED LENTIL DEBRIS, Phytopathology, 86(11), 1996, pp. 1193-1198
Different windborne materials were examined as potential sources of in
oculum of Colletotrichum truncatum, the cause of anthracnose of lentil
. Dust generated during harvest of anthracnose-infested lentil crops w
as shown to be a source of inoculum that could be dispersed by wind at
least 240 m from a combine. Plant debris and soil dispersed by high w
inds in the fall from fields with infested lentil stubble also were so
urces of inoculum. Infectivity of dust, debris, and soil samples was d
etermined by inoculating lentil assay plants. Samples that had overwin
tered outside also caused anthracnose on inoculated assay plants. Micr
osclerotia were on windborne lentil debris, but it was not possible to
identify C. truncatum microscopically in the collected dust and soil
samples. It appears that diseased lentil crops can be a source of inoc
ulum for subsequent lentil crops planted at a distance. Dispersal of C
. truncatum by wind has likely contributed to the spread of lentil ant
hracnose in western Canada. C. truncatum forms microsclerotia on infec
ted lentil plants. A 4-year survival study of the pathogen showed that
infectivity of infested debris placed on the soil surface declined du
ring the first 12 months of exposure, whereas infectivity of buried de
bris remained high, until a rapid decline occurred at 48 months. The l
ong-term survival of C. truncatum in buried lentil debris may explain
the high level of infestation found in many fields in the province of
Manitoba, although windborne inoculum may also be a source of infectio
n.