Location: Application Technology ResearchTitle: Evaluation of anaerobic soil disinfestation to reduce soilborne diseases in soilless and soil-based substrates for specialty cut flower production
|GUTIERREZ YANEZ, DANIELA - The Ohio State University
|PEDUTO HAND, FRANCESCA - The Ohio State University
Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/7/2023
Publication Date: 10/9/2023
Citation: Gutierrez Yanez, D., Testen, A.L., Peduto Hand, F. 2023. Evaluation of anaerobic soil disinfestation to reduce soilborne diseases in soilless and soil-based substrates for specialty cut flower production. Plant Disease. https://doi.org/10.1094/PDIS-05-23-0857-RE.
Interpretive Summary: Farms that grow specialty cut flowers are increasing in the United States as cut flowers are highly valuable and relatively easy to grow. However, cut flowers are affected by soilborne diseases that can kill many cut flower species. In this project, anaerobic soil disinfestation, a pesticide-free method to manage soilborne diseases, was tested against a fungal pathogen (Rhizoctonia) of zinnia and a fungal-like pathogen (Phytophthora) on gerbera daisies. Cut flowers are produced in soilless, peat based substrates and soil-based substrates so anaerobic soil disinfestation was tested in both of these substrates. The disease management technique worked to reduce Rhizoctonia on zinnia in both substrates, but was ineffective against Phytophthora as this is a fast-growing, aggressive pathogen. Anaerobic soil disinfestation can be applied by cut flower growers to reduce some diseases, but further research is needed to improve its use against aggressive pathogens.
Technical Abstract: Anaerobic soil disinfestation (ASD) is a non-chemical soil treatment where an easily decomposable carbon source is incorporated into soil, which is then irrigated to saturation and tarped to create anaerobic conditions, prompting shifts in the soil microbiota from aerobes to anaerobes. ASD has been tested successfully for soilborne disease management in a variety of cropping systems but has not been sufficiently investigated in ornamentals. In this study, ASD was evaluated in soil-based and soilless substrates commonly used in specialty cut flower production, using two model pathosystems, Rhizoctonia solani - Zinnia elegans and Phytophthora drechsleri - Gerbera jamesonii. Each substrate was mixed with pathogen-infested vermiculite and amended with either wheat bran, tomato pomace, or soybean meal as the carbon source. Amended substrates were incubated at 25°C for 4 weeks and then used as growing substrates for the two crops, which were monitored weekly for disease development for up to five weeks post-transplant. Additional experiments tested the effect of plant age and inoculum concentration in the substrate on ASD efficacy. Results showed that ASD has the potential to be deployed successfully for the control of Rhizoctonia stem rot in both substrates. Conversely, ASD was not effective at controlling Phytophthora crown rot on gerbera daisy in any of the experiments conducted in this study. More research is needed to understand the influence of carbon amendments, inoculum thresholds, and environmental conditions on ASD efficacy.