Title: Extending the Use of Bioplastic Granules for the Application of Trichoderma Biocontrol Isolates in Flori/Horticulture and Turfgrass Authors
Submitted to: Acta Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 1, 2013
Publication Date: N/A
Interpretive Summary: Biocontrol isolates are commonly formulated as inoculated or spore-coated grain seeds. More recently, efforts to explore new approaches and technologies have resulted in the development of other practical solutions, including a bioplastic-based formulation. This formulation, originally developed in 2008, consists of bioplastic granules entrapping spores of two biocontrol Trichoderma isolates. Field studies have clearly shown that granules of the starch-based bioplastic Mater-Bi® are effective in delivering this biocontrol isolates and can controlling damping-off disease in horticultural and turfgrass species by up to 90%. Bioplastic granules inoculated with the T. harzianum isolate significantly reduced (~ 90%) the impact of damping-off caused by this pathogen. Results from this study indicated that the usage of this bioplastic-based formulation is extendable for the biocontrol of damping-off in flori/horticulture crops and turfgrass. This data will be useful for horticulture growers, industry, ARS scientists and university people that work in this area of research.
Technical Abstract: Bioplastic materials are gaining increasing interest in a variety of different industrial and domestic applications. Beside its usage as mulching films and plant clips in horticulture, no other agricultural applications have been proposed. In 2009 we demonstrated that granules made of the bioplastic Mater-Bi are an efficient and practical solution for field applications of biocontrol isolates of the fungus Aspergillus flavus. Here, we investigated the feasibility to extend this approach for delivering propagules of two biocontrol Trichoderma isolates with the final objective to control damping-off of selected bedding, horticultural and turfgrass species. Bioplastic granules entrapping conidia of Trichoderma virens Gv29-8 or T. harzianum ATCC 20847 were applied to a potting mix infested with the fungal pathogen Rhizoctonia solani. Both isolates showed a positive effect in reducing damping-off disease of impatiens and tomato seedlings. In the case of potting mix infested with the lowest level of pathogen propagules causing 30% of damping-off, application of 1% (w/w) of inoculated granules resulted in 5 and 3% of impatiens and tomato seedlings, respectively, affected by damping-off. With a more severe infestation (50% of damping-off), amending the potting mixture with 10% bioplastic granules produced an average of 91% suppression of damping-off in both species. Granules entrapping conidia of the biocontrol isolate ATCC 20847 were significantly more effective in protecting impatiens and tomato seedlings. The experiment was repeated with potting mix infested with Pythium ultimum and planted with annual bluegrass. Bioplastic granules inoculated with the T. harzianum isolate significantly reduced (~ 90%) the impact of damping-off caused by this pathogen. Results from this study indicated that the usage of this bioplastic-based formulation is extendable for the biocontrol of damping-off in flori/horticulture crops and turfgrass.