Abstract

Enriching organic fertilizers with biological control agents to combine biocontrol of pests and plant growth promotion is gaining popularity as a means to support environmentally friendly agricultural practices and develop successful and efficient pest management programs.

However, the success of microbiological inoculation may be significantly affected by the characteristics of the organic matter used in combination. Although wool-based organic fertilizers have been studied recently, there has been no experimental data on the antagonistic colonization of wool pellets or on plant-antagonist-pest interactions. Wool pellets are made of raw, unwashed wool that is dried under sunlight and chopped into 4-6 mm pieces. These pieces are then pelletized under 110°C temperature and high pressure. The present study investigates wool pellets combined with Trichoderma asperellum against Macrophomina phaseolina, Rhizoctonia solani, and Sclerotinia sclerotiorum in vitro. Potato Dextrose Agar (PDA) medium was used, and three treatments were established by incorporating wool into the PDA at concentrations of 0.5%, 1%, and 2% (w/v). The medium was then autoclaved three times consecutively at 121°C for 20 minutes. Although wool alone suppressed the growth of the three pathogens, combining it with T. asperellum in a dual culture test enhanced the inhibitory effect and significantly improved the growth and sporulation of T. asperellum at higher wool concentrations. Furthermore, a serial dilution of the wool pellets was performed, and six bacterial isolates were obtained from the non-sterilized wool pellets.

These isolates were screened for antifungal activity against T. asperellum, M. phaseolina, and S. sclerotiorum using a similar dual culture assay. Among the six isolates, three (B1, B3, B5) showed strong antifungal activity against T. asperellum and M. phaseolina, while four isolates (B1, B3, B5, B7) inhibited the growth of S. sclerotiorum. This research highlights the potential of wool pellets as a sustainable tool for integrated pest management and plant growth promotion.