Investigation of a suitable formulation for Trichoderma harzianum in different compositions of solid carrier materials at two temperatures

Abstract

In sustainable agriculture, the application of Trichoderma spp. is a widely accepted, eco-friendly method. But, in the commercialization process, the effectiveness of Trichoderma spp. as a biological control agent, plant growth promoter, and as a decomposing agent affectsthe selection of the carrier material and the formulationprocedure. The present investigation was carried out in an attempt to develop an effectiveorganic carrier material using abundant natural solid materials in which the viability and the effectiveness of T. harzianum could be maintained for a sufficient duration at an optimum temperature for product stabilization. Previously isolated and identified T. harzianum (KT852821.1), which can enhance the growth of many crops (e.g.: Pisum sativum, Cucumis sativus, Solanum lycopersicum, and Tulipa gesneriana), was selected for the present investigation. Five carrier formulations were made using different compositions of compost, straw, clay, and cow urine. Inocula taken from pure cultures of T. harzianum grown on PDA media were introduced separately into sterilized polypropylene bags containing different proportionsof carrier materials. They were then incubated at 25°C for 7 days and then stored at room temperature (28°C) and in the refrigerator (4°C) for 12 months. Viability was determined at frequent intervals of 2, 6, 9, and 12 months for the formulations kept at 28℃ and 4℃ separately. Colony-forming units per gram of substrate were calculated following the dilution plate method in 10 replications for each formulation. Among the five different formulations used for formulating T. harzianum, the formulationconsisting of compost 50%, straw 25%, clay 12.5%, and cow urine 12.5% (V/W) stored at 4°C for a 12-month time period, proved to be significantly the most effective composition for the commercialization of T. harzianum, which gave a colony count of 6.99 log CFU/g whereas the other formulations provided the values of 6.36 log CFU/g, 6.26 log CFU/g, 6.91 log CFU/g, and 6.45 log CFU/g. The present investigation highlighted the significance of using the formulation consisting of compost 50%, straw 25%, clay 12.5%, and cow urine 12.5% (V/W) to develop T. harzianum as a commercialproduct.