Preparation of Antagonist Suspension of S. griseus for
resuspended in sterile distilled water. microconidial
suspension of F. oxysporum f. sp. lycopersici, final
density of 10 microconidia/5 ml was inoculated in to sand
maize medium and it was incubated at room temperature
for 14 days. For green house experiment, the substrate at
5 percent (w/w) was mixed with sterilized soil and infested
into the pot ten days prior to transplanting the 60-day-old
seedling transplantation. The population of F. oxysporum
f. sp. lycopersici in the substrate was estimated as
number of colony forming units (CFU) per gram of
substrate, as previously described [6]. Approximately 2 x
108 cfu/g of innoculum of F. oxysporum f. sp. lycopersici
was used for pot experiments.
Preparation of Talk Based Formulation of Biocontrol
Agent: A loop full of S. griseus was inoculated in to the
nutrient broth medium and incubated for seven days
at 30°C and at 125 shakes/min. (Remi - C 24). After
incubation the broth containing 9 x 108 cfu/ml was used
for the preparation of talc based formulation. To 400 ml of
mycelial or spore suspension 1 kg of talc powder, calcium
carbonate 15 g (to adjust the pH to neutral and carboxy
methyl cellulose 10 g (as additive) were mixed under
sterile condition following the method described by
Vidhyasekaran and Muthamilan [7]. The product was
shade dried to reduce the moisture content to 20% and
then packed in polypropylene bags and sealed [8].
Chitin Amendment with Talc-based Formulations:
Colloidal chitin was prepared by the procedure stated in
3.2.1.1. Colloidal chitin was incorporated into and nutrient
8
Preparation of Seeds Using Talk Based Formulation:
Root Application: The isolated S. griseus was grown on
MS with 1 g colloidal chitin. 1ml of the bacterial spore
suspension was inoculated into flasks containing the
production medium and incubated for seven days at 30°C
and at 125 shakes/min. (Remi - C24) At the end of
incubation the culture was the culture was harvested,
filtered and it was centrifuged at 10,000 rpm for 10 min at
4°C and used as crude enzyme. The cell suspension of
S. griseus were re suspended in sterile distilled water at
the rate of 9 x 108 cfu/ml was used to control the fusarium
wilts of tomato [11, 12].