Evaluating the Compatibility of Trichoderma harzianum with Three Commercial Systemic Fungicides Against Some Phytopathogenic Fungi

Background: The compatibility of Trichoderma harzianum with some recent commercial fungicides by combining them to promote an efficacious IDM for controlling plant pathogens and prohibiting chemical resistance evolution in pathogens. Materials and Methods: laboratory experiments were conducted to study the compatibility of Trichoderma harzianum with three commercial systemic fungicides: Al-Sary (Carbendazim 50%WP), Top Topsin (Thiophanate-methyl 70%), and Tachichem (Hymexazol 30%WP) at recommended doses (2500 ppm for Al-Sary fungicide, 500 ppm for Top topsin, and 1.5 ppm for Tachichem) by the food poisoning technique against six pathogenic fungi: Alternaria sp., Aspergillus flavus, Aspergillus niger, Aspergillu wentii, Penicillium sp., and Rhizopus sp . Results:T. harzianum displays various degrees of antagonism against the tested pathogenic fungi in dual culture. Asp. wentii was most sensitive to the T. harzianum antagonistic activity, with an inhibition percent of 67.91%, while Rhizopus sp. displayed complete resistance to the antagonistic activity. The results showed Asp. niger, Asp. wentii, and Penicillium sp. were completely inhibited by Al-Sary fungicide. Asp. wentii and Penicillium sp. were totally inhibited by Top Topsin fungicide, Rhizops sp. was not affected by the two fungicides. Asp. niger displays high sensitivity to Tachichem fungicide (87.23%), whereas Penicillium sp. was resistant to the fungicide (0.0%). Tachichem fungicide showed complete compatibility with T. harzianum,but Al Sary and Top-Topsin fungicides were remarkably toxic to T. harzianum. The effect of fungicides on T. harzianum antagonistic activity was estimated in PDA medium. Conclusion The compatible fungicide Tachichem can be applied with T. harzianum in a comprehensive way to disease control techniques.