2.4. Tolerance assessment to imidacloprid
Assessment of tolerance to imidacloprid was employed following
a technique described by Tang et al. (2009) with a slight
modification. A 5 mm mycelial plug of each transformant was
transferred to a potato dextrose agar (PDA) plate with 200 lgmL1
imidacloprid. A single plug of parent strain T23 on a PDA plate with
the same imidacloprid concentration was employed as a control
treatment. After incubation at 28 C for 4 d, average diameters of
T. atroviride colonies were measured in triplicates. The transformants
with larger diameter than parent strain T23 were selected
for further screening. The experiment was repeated in triplicates.