Delivery System for Enhanced Efficacy of Trichoderma harzianum against Fusarium Wilt of Lakatan Banana

Abstract

Biological control is a potential approach in the management of Fusarium wilt (Foc) of banana. To be effective, however, biological disease control depends not only on suitable biocontrol organisms but also on methods and strategies of introducing and maintaining these organisms in association with plants. This paper presents the influence of delivery systems on the efficacy of Trichoderma harzianum for Fusarium wilt control in ‘Lakatan’ banana. T. harzianum was applied prior to transplanting and during transplanting in 30 cm X 30 cm polypropylene bags with follow-up application of T. harzianum in the forms of conidial suspension every two weeks or in substrate at monthly intervals. Negative and positive controls were provided. Among the delivery systems, disease incidence and severity and Foc colony-forming units (CFU) per gram of substrate were significantly (p <0.001) low in meriplants grown in T. harzianum-inoculated planting medium with basal and monthly follow-up application of T. harzianum in substrate or composted coco coir dust (67% incidence; disease severity index (DSI)=2.0; cfu/g medium=2,050). The effects were comparable to incorporation of T. harzianum in the potting medium of three-week-old plants with basal application of T. harzianum in substrate at transplanting and follow-up application of T. harzianum suspension every two weeks (60% incidence; DSI=2.1; cfu/g medium=5,790). Likewise, comparable results were obtained with pre-treated three-week-old potted plants with basal application of T. harzianum in substrate at transplanting but no follow-up application of T. harzianum (67% incidence; DSI=2.1; cfu/g medium=6,240). Costs incurred per plant in the application of T. harzianum were P2.41, P3.03, and P1.28, respectively.