2.1.2. Isolation of Fusarium pathogenic fungi
Pathogenic fungi were isolated from bean plants collected from
a bean production field in Yaoundé, Cameroon on September 10,
2014, and that exhibited typical symptoms (wilting, chlorosis,
unthrifty growth, premature defoliation, poor emergence, stand
establishment, and plant death) of root rot or damping-off. The
plants were carefully uprooted and taken directly to the laboratory
where they were rinsed under running tap water for 10 min to
remove soil and debris. Symptomatology of the disease was studied
under natural and in vitro conditions. Isolation of the pathogen
was done from each of the distinct soft rots type of symptoms
observed on plant. Infected roots were cut into small pieces (1 to
2 mm) using sterilized blade, then surface sterilized as described
above. Root pieces were placed on Petri dishes (90-mm diameter)
containing 20 mL PDA medium and incubated at 25 C until mycelia
emerge. Fragments of emerging mycelium from plant tissues
into the agar were transferred to fresh PDA plates.
Twenty isolates of Fusarium species (FS1–FS20) were identified
based on cultural and morphological characteristics. Briefly, each
Fusarium isolate was transferred to carnation leaf agar (CLA) and
antibiotic-amended PDA (39 g Difco PDA per liter), and cultures
were incubated for 7–20 days at room temperature under fluorescent
light. Each isolate was examined microscopically and
R.M.K. Toghueo et al. / Biological Control 96 (2016) 8–20 9
identified to species according to the system of Leslie a