In vitro evaluation of culture filtrates
Each concentration of culture filtrates were bio-assayed
for their fungitoxicant activity on conidial germination
of Phyllactinia corylea by employing detached leaf
method of Sukumar and Ramalingam (1981) with some
modifications. The leaves on fourth position (in
descending order from the top) of a susceptible mulberry
variety (Goshoerami) were detached and washed
thoroughly with tap water and then with sterilized
distilled water. The leaves were then dipped for five
seconds in test concentrations of biocontrol agents
(6.25%, 12.50%, 25.00% and 50.00%) and 0.05%
carbendazim 50 wp and then air dried in shade to
remove excess water droplets. The water treated leaves
served as check. The leaves of each treatment were
placed on moist blotting paper in 15mm diameter
petridishes, keeping abaxial surface exposed. .The
freshly developed conidia were obtained by shaking
off the mature conidia from the highly infected leaves
in the field, one day prior to their collection. These
were evenly dusted over the abaxial surface of the
treatment leaves. The inoculated leaves in the
petridishes were incubated at ambient temperature (28
± 2oC) for 24 hours under continuous fluorescence
light of 400 lux. The conidia from incubated leaves
were picked on sticky side of cellophane tape to
observe the conidial germination. Cellophane tapes
were placed on glass slides having a drop of cotton
blue in lactophenol and were examined under
microscope (Nayar and Wilson, 1973). Twenty random
microscopic fields were scored for each of the three
replications. Percent conidial germinations and percent
conidial germination inhibition were calculated.