Almond processing residues as a source of organic acid biopesticides during biosolarization. (1st January 2020)

• Record Type: Journal Article
• Authors: Fernandez-Bayo, Jesus D.; Shea, Emily A.; Parr, Amy E.; Achmon, Yigal; Stapleton, James J.; VanderGheynst, Jean S.; Hodson, Amanda K.; Simmons, Christopher W.
• Is Part Of: Waste management. Volume 101(2020)
• Page Start: 74
• Page End: 82
• Publication Date: 2020-01-01
• Subjects: Fumigation alternative -- Integrated pest management -- Sustainable agriculture -- Anaerobic soil disinfestation (ASD) -- Almond hulls and shells -- Pratylenchus vulnus; Hazardous wastes -- Periodicals; Refuse and refuse disposal -- Periodicals; 363.728
• DOI: 10.1016/j.wasman.2019.09.028
• Languages: English
• ISSNs: 0956-053X

Abstract

Highlights: Feasibility of almond by-products was demonstrated for use in biosolarization. Treated soils experienced pH depression and organic acid accumulation. Residue application to soil resulted in 84–100% nematode inactivation. Both endogenous and fermentative organic acids likely contribute to efficacy. Abstract: Biosolarization utilizes organic amendments to produce biopesticide compounds in soil that can work in tandem with other stresses to inactivate agricultural pests. The prospect of using by-products from industrial almond processing as amendments for biosolarization was assessed. Soil mesocosms were used to simulate biosolarization using various almond by-products, application rates, and incubation times. Several potentially biopesticidal organic acids were identified and quantified in the soil, and the toxicity of soil extracts was evaluated for the root lesion nematode ( Pratylenchus vulnus ). It was determined that both almond hulls and a mixture of hulls and shells harbored several acids, the concentration of which was enhanced 1–7 fold via fermentation by native soil microbes. Organic acid concentration in the soil showed a significant linear relationship with the quantity of waste biomass amended. Extracts from soils containing at least 2.5% incorporated biomass by dry weight showed a 84–100% mortality of nematodes, which corresponded to acid concentrations 0.75 mg/g (2.0 g/L) or greater. This study showed that almond processing by-products – hulls and a hull and shell mixture – were suitable amendments for control of P. vulnus and potentially other soil agricultural pests in the context of biosolarization.