The virulence by these three fungal species,
as displayed by the decreasing LT^ values,
demonstrated a common trend of generally
increasing potency (i.e. the rate and speed of
mortality) with increasing concentration (Table4). The most virulent isolate was P. fumosoroseus.
This is shown by the lower LTW for P. fumosoroseus,
which was almost half day lower than that of the
other two species.
Oil may have helped in
spreading the conidia on the surface of a
hydrophobic surface such as insect cuticle (Inglis
et al 1996). Ibrahim and Low (1993) reported
P. fumosoroseus to be highly efficacious in the
cabbage field against the diamondback moth
when applied at the rate of 108 conidia mL1 in
375 L water ha1, however, further effort is
necessary in order to develop management
strategies for CHC in the highlands.