Natural salicylaldehyde for fungal and pre- and post-emergent weed control

Authors: Kim, Jong Heon; Chan, Kathleen - Kathy

Submitted to: Applied Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/7/2022
Publication Date: 4/8/2022
Citation: Kim, J., Chan, K.L. 2022. Natural salicylaldehyde for fungal and pre- and post-emergent weed control. Applied Sciences. 12(8). Article 3749. https://doi.org/10.3390/app12083749.
DOI: https://doi.org/10.3390/app12083749

Interpretive Summary: The timely control of weeds in crop fields is an important task for agricultural industry. Uncontrolled weed growth engenders a diverse flora in crop fields, which not only competes with crops for water and nutrients but also hosts pests, such as fungi, bacteria, insects, nematodes, etc., damaging/contaminating crops. Transmission from such a field reservoir can trigger pest spillover, leading to the release of various pests into the environment. For example, recent study in wheat fields performed by a French group described that termination of herbicide usage during cultivation triggered unexpected increase in mycotoxin (Fusarium nivalenol) contamination in the grains near maximum thresholds. Therefore, rapid elimination of weeds via safe, cost-effective methods will positively impact the safety, quality and competitiveness of the agricultural commodities. In this investigation, we: (1) repurposed the natural salicylaldehyde (SA) as a pre- and post-emergent weed control agent, (2) developed tree nutshell particles as SA delivery vehicles for use in orchards, thus contributing to the growers’ sustainable by-product recycling program, and (3) examined soil covering/pasteurization as one of the optimum practices to effectively deliver SA to the soil.

Technical Abstract: We describe a sustainable, alternative weed control system which uses natural salicylaldehyde (SA; 2-hydroxybenzaldehyde) as an active ingredient. SA is a natural, redox-active small molecule listed as Generally Recognized As Safe agent by the United States Food and Drug Administration (FDA). SA has been used as an intermediate for pharmaceuticals or a food-flavoring agent. Repurposing FDA-classified food additives led us to the identification of SA, which possesses both pre- and post-emergent herbicidal, fumigant activity. Environmental degradation data available in the public database indicate that, once released to the environment, SA will be broken down in the air by sunlight or microorganisms, thus is not built up in aquatic organisms. Notably, SA also possesses an intrinsic antifungal activity, for which SA exerted a synergism with mild heat (42 oC) for the enhancement of antifungal efficacy. We also developed agricultural by-products (tree nutshell particles) as SA delivery vehicles to the soil, thus helping the growers’ sustainable by-products recycling program (carbon sequestration). Altogether, SA can serve as a safe, potent pesticide (herbicidal, fungicidal) ingredient, which contributes to sustainable crop production by lowering pesticide burden in the fields.