Invasive growth of Trichoderma over B. cinerea in two dualculturing tests indicates and aggressiveness of Trichoderma against B. cinerea (Bélanger et al., 1995; Harman et al., 2004; Ram and Kendurkar, 2014). Two dual-cultural tests were conducted to screen Trichoderma isolates with high capability to invade the colonies of B. cinerea (Fig. 1). The first dual-culturing test was done at 20 C and all the 72 Trichoderma isolates were included in this test. An mycelial agar plug (5 mm diameter) removed from the two-day-old PDA culture of a Trichoderma isolate and another mycelial agar plug removed from a PDA culture of B. cinerea were placed on PDA at 7 cm apart in a Petri dish (9 cm diameter, with 20 mL PDA). There were nine dual-cultures (replicates) for each Trichoderma isolate-B. cinerea combination. The dual-cultures were incubated at 20 C for 10 days. The isolates that completely colonized the B. cinerea colonies in the dual cultures were selected and used in the second dual-culture test, as well as in the following two other assays.
In the second dual-culture test, the dual-cultures of Trichoderma and B. cinerea were established on PDA using the same procedures described above and incubated at 15 C for 30 days. Degree of invasive growth of Trichoderma on the B. cinerea colony in each dual culture was scored using the numerical rating scales 0, 1, 3 and 5