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RESULTS
Two hundred and twelve Tric.hndem~u isolates were obtarned from the groundnut rhr~osphere
soil samples collected from four d~stncts of Andhra pradesh (Ananthapur. Ch~ttoc~r. Cuddapnti
and Kurnool) and Karnataka (Kolar and Tumkur) (Tablc I).
Of the 386 soil samples analyzed. 156 (40.46) yrelded liichoddpmu. Maxrmum of 64.1%.
Trichoderma isolates were obtained from the soil samples of Anantapur nnd minimum of
I I. 1%) from the samples of Kolar (Fig 3). Trichodtmra population density was nlaxlnium in
Chittoor soil samples (Table 2).
All the ~solates of Trirhod~rma were tested for antagonism or ~iiycoparasit~sm in vrtro against
A. flavus (Af 11-4). Mycoparasitic interaction was assessed following Bell's ranking (Bell er
01, 1982) (Fig 2).
From a prel~minary screening of the total 212 Trichodernlu isolates, 150 antagonist~c isolates
were selected. Among the 150 isolatcs antagonlstlc to A. j7~vu.t (Af I I-4), 38 were just in
contact with A. j7avus colony, 48-showed ~nhibitron zone agarnst .4. flavu.~, and 64 paras~tized
A, j7avu.r. For further screening 117 isolates that showed ~nhibrt~on zone and parasiti7td A.
fIavus were selected and of these only 48 isolates showed clear inhibition zone against Af 11-
4. These were further valuated for mechan~sms of antagon~sm involving production of
volat~le and non-volatile productron of antibiotics.
Among 48 isolates, T. viridt (T 16 and T 188) and 7: har:~unum (T 109) showed clear hyphal
coiling with ,4f 11-4 mycelia (Fig JJ.