Trichodermaand placed in a Petri dish opposite to
a fusarium mycelial disc. After 4 days, inhibition of
fusarium growth was measured in terms of inhibition
zone (from the edge of the fusarium mycelium to the
edge of antagonist growth) and growth of fusarium
mycelium (cm). Three replicates of 10 plates each
were made perTrichodermaisolate.
Five organic substrates: farm yard manure, rice
chaffy grains, dried banana leaf, banana pseudostem
and rice bran were evaluated for their ability to support the growth of different isolates ofTrichoderma
spp. Of each substrate 500 g was mixed with 100 ml
of 30% molasses solution (v/v), filled in polypropylene bags and sterilized twice at 121
◦
C for 2 h. After
sterilization, the substrates were inoculated under
aseptic conditions with an 8 mm mycelial disc ofT.
harzianumTh-10 obtained from a 5-days-old culture.
Bags were incubated at 28±2
◦
C for 20 days. The
population ofT. harzianumon the organic substrates
was assessed 20 days after incubation by serial dilution technique using Trichodermaspecial medium
(Elad and Chet, 1983).
Dried banana leaves only were selected for further studies. To find out whether jaggery increased T.
harzianumgrowth, 1 kg of dried banana leaves was
immersed in 1, 5 and 10% (w/v) jaggery solution for
30 min. The excess jaggery solution was drained. One
set of leaf material was boiled for 10 min and dried under shade for 10 min in a tray. An 8-mm mycelial disc
ofT. harzianumTh-10 was added to it, mixed in a tray
covered with polythene bags and incubated at 28±
2
◦
C. Another set of banana leaves (1 kg) was packed
in polythene bags and sterilized twice at 121
◦
C for 2 h.
The sterilized leaves were emptied onto plastic trays
and an 8-mm mycelial disc ofT. harzianumTh-10
was added before trays were covered with polythene
bags and incubated at 28±2
◦
C. Dried banana leaves
treated with water served as control. The population
ofT.harzianumTh-10 on the dried banana leaves was
estimated 4 days after incubation as described earlier.
Dried banana leaf (1 kg) was added 1% (w/v) jaggery solution boiled for 10 min and dried in the shade
for 15 min. The material was spread in a tray and an
8 mm mycelial disc was added. The trays were covered with polythene sheets and incubated at 28±2
◦
C.
Samples were drawn at monthly interval and the population ofT. harzianumTh-10 assessed as described
earlier.