Potential Of Nano-Formulated Zinc Oxide For Control Of Citrus Canker On Grapefruit Trees

Abstract

Antimicrobial activity of experimental formulations of two structurally different nano-zinc oxide materials, plate-like Zinkicide SG4 and particulate Zinkicide SG6, was evaluated against Xanthomonas citri subsp. citri, the cause of citrus canker. In vitro assay demonstrated Zinkicide SG4 had a twofold lower minimum inhibitory concentration (MIC) against Escherichia coli and X. alfalfae subsp. citrumelonis (62.5 to 250 mg/ml) compared with copper sulfate (250 mg/ml), copper hydroxide (250 to 500 mg/ml), or cuprous oxide/zinc oxide (125 to 250 mg/ml). Zinkicide SG6 had a sevenfold to eightfold lower MIC against Escherichia coli and X. alfalfae subsp. citrumelonis (31 to 250 mg/ml). Leaves of sweet orange (Citrus sinensis) and fruit of ‘Ruby Red’ grapefruit (C. paradisi) were evaluated for citrus canker disease control. A greenhouse assay with foliage demonstrated that spray treatment with Zinkicide reduced citrus canker lesion development after injection-infiltration of X. citri subsp. citri into the leaf intercellular space. In field trials conducted in Southeast Florida in 2014 and 2015, Zinkicide SG4 and SG6 reduction of grapefruit canker incidence exceeded that of cuprous oxide and cuprous oxide/zinc oxide bactericides. Zinkicide formulations were also effective against the fungal diseases, citrus scab (Elsinoe fawcetti) and melanose (Diaporthe citri), on grapefruit. No sign of phytotoxicity to the fruit rind was observed during either season. Antimicrobial activity of Zinkicide for protection of leaves and fruit against X. citri subsp. citri was comparable or exceeded that for commercial copper and zinc oxide formulations which may be attributed to translaminar movement of Zinkicide.

Publication Date

12-1-2016

Publication Title

Plant Disease

Volume

100

Issue

12

Number of Pages

2442-2447

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1094/PDIS-05-16-0598-RE

Socpus ID

85017563449 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/85017563449

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