Compost-borneTrichodermaspp and attributes useful for the control of plantpathogens

Abstract

Hand-crafted compost may be a useful source of Trichodermaspp. The present study sought to isolate Trichoderma from compost aged one week, compost aged one and two years, and from nearby forest soil. Isolates were tested for characteristics useful in the control of plant pathogens. Eight isolates; three from year-old compost (N1, N2, N3), three from two-year old compost (M1, M2, M3), and two from nearby forest soil were obtained by directly plating compost and soil fragments onto selective growth media of Trichodermaspp. The isolates M1 and M2 were identified as Trichoderma asperellum and Hypocrea lixii (the teleomorph of Trichoderma harzianum). The seisolates were compared to a commercial formulation of T. asperellum, for mycelial growth and sporulation on potato-dextrose agar. These isolates were then confronted with Sclerotinia sclerotium. One of the isolates (M2), from two year-old compost, was compared to the commercial strain (TC), in confrontations with S. sclerotiorum, Rhizoctonia sp. and Fusarium solani. Mycelial growth of compost isolates was similar. Isolates from one year-old showed the highest rate of sporulation. Isolates from two year-old compost competed best against pathogens, competing for space and nutrients, one of the possible mechanisms for the suppressive nature of compost.