Test antagonism of several Trichoderma species in suppressing the growth of Alternaria sp. in vitro

Abstract

Abstract Alternaria sp. is a pathogenic fungus that causes purple blotch disease in onion plants. Losses from this disease lead to a decrease in yield by more than 70% and seed damage to 100%. For this reason, a study was conducted to test the antagonistic ability of several Trichoderma species in suppressing the growth of Alternaria sp. in-vitro as an alternative to plant disease control that is safer and more environmentally friendly. Alternaria sp. isolate. derived from onion plants located in Bale Atu, Bukit District, Bener Meriah Regency, Aceh Province. The Trichoderma species used are T. asperellum, T. harzianum, T. virens, and Trichoderma sp. Antagonism testing was carried out using a dual culture method in a 9 cm diameter petri dish. The results showed that, T. asperellum, T. harzianum, T. virens, and Trichoderma sp. able to suppress the growth of Alternaria sp. on observation of 5 HSI. The antagonistic mechanism that occurs is competition against space, nutrition, antibiosis and mycoparasites. The best percentage of resistance occurred in the treatment of T. virens, which was 77.78%. next followed by the inhibitory power of Trichoderma sp. by 72.39%, T. harzianum by 64.80%, and T. asperellum by 60.77%.