Efficacy of some Trichoderma Species on Management of Sunflower Head-Rot

Abstract

The efficacy of different Trichoderma species were evaluated in vitro and under field conditions against five pathogenic of sunflower head-rot fungi (HRF). Bioagents were applied by three application methods during 2015and2016 growing seasons. In vitro, six species of Trichoderma harzinum, T.virid T.hamatum, T.koningii, T.reesei and T.polysporum were selected for field studies.Both of T. harzianum and T. viride recordid the highest antagonistic potential against almost of the pathogenic fungi followed by T.reesei. In field experiments, the tested bioagents were studied in series of experiments using different three application methods, i.e. foliar spray [F.S.], soil drench[S.D.] and foliar spray with soil drench[F.S.+ S.D.].These bioagents were applied at three stages i.e. 30, 45 and 60 days after sowing. Head diameter, stem diameter, leaf area, seed number per head, 1000 seed weight , seed yield per plant, yield per plot and yield per feddan were determined as crop parameters. Results indicated that the three application methods gave the lowest values of disease incidence and increased crop parameters compared with untreated plants. The highest antagonistic activity was achieved with T.harzinum when applied as foliar spray which gave the highest percentage of disease reduction and increased crop parameters during both seasons, followed by strain of T.viride when applied as soil drench and T. reesei when applied as (soil drench and foliar spray), respectively.