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Irdation of Trichoderma isolates
MATERIALS AND METHODS
Groundnut rhuosphere soil samples collected from various groundnut-growing areas in
Andhra pradah and Karnataka under a National Agricultural Technology Project
(NATP) on "Atlatoxin Contamination in Groundnut Mapping and Management in
Gujarat, Andhra Pradesh, and Adjoining Areas are used for isolating 7irchudenna
isolates"
Five hundred pl of each soil samplc at 10' and 10' aqueous dilutions was spread on
plates containing Trichodenna specific medium (TSM glucose 3 g, NH.NO3 1 g,
Na2HIP04 0 9 g, MgS04 7H20 0 2 g, KC1 0 15 g. FeS04 7H20 20 mg. ZnS04 71320 20
mg. MnS04 .H20 20 mg, Rose Bengal 30 p& agar log. and distilled water 1000 rnl)
After autoclaving at 121 C for 20 min the medium was cooled to 50 C and added with
streptomycin sulfate 50 mg, chloram~henicol 50 mg, metalaxyl 10 mg, and PCNB
(pentachloronitro benzene) 10 mg) Two plates were maintained for each dilution The
plates were incubated for 4 days in dwk at 28 C and typical Trichcdenna colonies (white
or whitish-green ro green, conidiophores long and thick, with or without sterile branches,
side branches mostly thick beanng short and plump phialides, phialospores are globose or
ellipsoidal rough or sr 300th walled) were isolated (Srilakshmi el a/., 2001)
In vim antagonistic studies
The biocontrol ability of 212 isolates of Tr~choderma spp was studied against the
pathogen A fravus, using dual culture technique (Dennis and Webster 1971~) The
.
mycelial discs (5 mm dia) of Trrch&-nna spy and A. jlams from a four-day-old culture
on 2% agar were placed on PDA plates on one side, 1 cm away from the edge of the