In vivo evaluation of culture filtrates
The test concentrations of culture filtrate of
biocontrol agents which inhibited the conidial germination
of P. corylea by more than 50.0% were evaluated
in vivo, along with check (water spray) and carbendazim
50 wp at recommended concentration of 0.05%, for their
efficacy in controlling powdery mildew intensity. The
experiment was conducted on two year old plants at
mulberry plants. The experiment was laid down in a
randomized block design with three replications, each
comprising of three plants of a susceptible variety
(Goshoerami). The treatments were applied three times
at an interval of 15 days starting from the first appearance
of the disease. A guard row was kept in between the
treatments to prevent the drift while spraying.
Observations were recorded 15 days after third spray to
estimate disease intensity. All the leaves of three
randomly selected plants, per replication, were examined
and were grouped in to the following five grades (0, 1,
2, 3 and 4 grades for no infection, 0.1 - 25.0, 25.1 to 50.0,
50. 1 to 75.0 and > 75.0% infection respectively) for
calculation of disease intensity (James, 1974). Percent
disease intensity (PDI) and percent disease control
(PDC) were calculated using standard method of plant
disease assessment (FAO, 1967).