Biological control of Thielaviopsis paradoxa on pineapple by an isolate of Trichoderma asperellum C.J. Wijesinghe a, * , R.S. Wilson Wijeratnam a , J.K.R.R. Samarasekara b , R.L.C. Wijesundera c a Post Harvest Technology Laboratory, Industrial Technology Institute, 363, Bauddhaloka Mawatha, Colombo 07, Sri Lanka b Herbal Technology Laboratory, Industrial Technology Institute, 363, Bauddhaloka Mawatha, Colombo 07, Sri Lanka c Department of Plant Sciences, University of Colombo, Colombo 03, Sri Lanka article info Article history: Received 31 July 2009 Accepted 12 February 2010 Available online 19 February 2010 Keywords: Trichoderma asperellum Biocontrol formulations Pineapple (Ananas comosus) black rot disease abstract An isolate of Trichoderma asperellum was tested for its antagonistic activity against Thielaviopsis paradoxa, the causal agent of black rot of pineapple, Anansas comosus. Results of our investigation clearly demon- strated antagonistic activity of T. asperellum against Th. paradoxa. The antagonistic activity was mainly due to coil formation around the pathogen hyphae by T. asperellum. The activity was found to be fungi- cidal. Pineapple fruits inoculated with 10 5 conidia/mL of Th. paradoxa, followed by an application of a for- mulation containing spores of T. asperellum within 10 and 30 min after inoculation, were free of disease when stored at 28 °C for 7 days. Fruits treated with the blank formulation (formulation without conidia) and the control fruits showed characteristic symptoms of black rot disease. Black rot symptoms also were observed on fruits that were inoculated with Th. paradoxa and held as inoculated controls under similar storage conditions. Chemical parameters namely; pH and titratable acidity among treated, untreated (controls) and fruits treated with a blank formulation showed no significant difference. The data suggest that a formulation of T. asperellum might be an alternate and ecofriendly method for the control of black rot disease of Pineapple. Ó 2010 Elsevier Inc. All rights reserved. 1. Introduction Fruits are a very important part of the human diet as they pro- vide essential micronutrients such as vitamins, minerals and other compounds such as antioxidants (Spadaro and Gullino, 2004). Postharvest losses in fruit caused by fungal decay are rather high and fungicides still provide the primary means of control. The development of fungicide resistant pathogens and the public de- mand to reduce pesticide use have increased the need for alterna- tive control strategies (Sholberg et al., 2008; Leverentz et al., 2000; Tian and Fan, 2001). Black rot, caused by Thielaviopsis paradoxa (De Seyen.) is the most common and well-known postharvest disease of the pineap- ple ( Ananas comosus (L.) Merr) fruit. Th. paradoxa is a soil borne plant pathogen (Sanchez et al., 2007). Infections usually take place through wounds at the base of the fruit during harvest. In Sri Lan- ka, infection occurs at the cut end of the peduncle after harvest either in the field or during packing house operations (Wilson Wijeratnam et al., 2005). The infection initiates from the cut end of the peduncle in the form of small, circular, water-soaked spots, which are very soft. The spots enlarge and coalesce forming a large black patch extending throughout the fruit. The internal tissues be- come soft, black, and watery and emit a foul smell (Verma, 1999; Broadley, 1993). Black rot of pineapple is controlled by the applica- tion of the fungicide Benomyl Ò . Biological control through the use of antagonistic microorgan- isms has recently emerged as a viable disease management strat- egy (Alvindia and Natsuaki, 2008; Wisniewski et al., 1989). The main modes of action of the biocontrol agent include competition for nutrients (Ugur and Altintas, 2008) and space (Ruano Rosa and Herrera, 2009; Djonovic et al., 2007), production of cell wall degrading enzymes (Tahia et al., 2004), production of antifungal diffusible and volatile metabolites (Tahia et al., 2004) and myco- parasitism (Viterbo et al., 2002). Trichoderma spp. are considered to be antagonistic to many plant pathogenic fungi including Botrytis cinerea (Pers.:Fr), Botryodiploidea theobromae (Pat.), Colletotrichum gloeosporioides (Penz.) Sacc., (Sivakumar et al., 2000; Mortuza and Ilag, 1999) and soil borne fungi including Rhizoctonia, Sclerotina, Pythium and Fusarium (Knudsen and Bac, 2007; Santamarina and Rosello, 2006; Suleman et al., 2008; Prasad et al., 2002). Trichoderma species are ubiquitous, rela- tively easy to isolate, grow quickly on many substrates and produce metabolites with demonstratable antibiotic activity. The objective of this study was to investigate the effect of Trichoderma asperellum (Samuels, Liechfeldt & Nirenberg) on Th. paradoxa and to test the efficacy of an emulsion formulation of conidia of T. asperellum to control black rot disease of pineapple. 1049-9644/$ - see front matter Ó 2010 Elsevier Inc. All rights reserved. doi:10.1016/j.biocontrol.2010.02.009 * Corresponding author. E-mail address: chamilawije@iti.lk (C.J. Wijesinghe). Biological Control 53 (2010) 285–290 Contents lists available at ScienceDirect Biological Control journal homepage: www.elsevier.com/locate/ybcon