Aggressiveness of green mould on cultivated mushroom (Agaricusbisporus) in Turkey

Agaricus bisporus, called as button mushroom, constitutes majority of the cultivated mushrooms in the world. Green mould, caused by Trichoderma species, is a destructive fungal disease causing epidemics in A. bisporus cultivation. In 2015, 2016 and 2017, a total of 71 samples including compost, casing soil and mushroom tissues were collected from mushroom farms in Antalya Province, Turkey. Of 24 Trichoderma isolates obtained, 13 were identified as Trichoderma aggressivum f. aggressivum (Th4). To date, Th4 is known to occur in North America, but it was also reported in Hungary in 2017. In addition, to our knowledge, this is the first record of occurrence of Th4 on button mushroom in Turkey. In the present study, in vitro and in vivo experiments were also conducted to examine aggressiveness of the Trichoderma isolates on A. bisporus. In vitro experiments, based on confrontation tests, it was found that mycelial growth of A. bisporus was inhibited up to 71.99% and 58.71% in the presence of Th4 and Th1 isolates, respectively. In vivo experiments, biomass and morphological features (cap weight, stipe weight and so on) of the mushrooms in the treatments were compared with controls. Th4 isolates caused 95.06% mean reduction in biomass. Th4 and Th1 isolates significantly affected all the examined morphological features. The study revealed that Th4 and Th1 isolates had significant (P < 0.01) inhibitory influence on A. bisporus growth in vitro and in vivo. But, aggressiveness of the Th4 isolates was significantly much higher than that of the Th1 isolates.