Graham J H, Johnson E G, Myers M E, Young M, Rajasekaran P, Das S, Santra S
University of Florida, IFAS, Soil and Water Science and Plant Pathology Departments, Citrus Research and Education Center, Lake Alfred 33850.
NanoScience Technology Center, Department of Chemistry, Department of Materials Science and Engineering and Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL 32826.
Plant Dis. 2016 Dec;100(12):2442-2447. doi: 10.1094/PDIS-05-16-0598-RE. Epub 2016 Oct 4.
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 µg/ml) compared with copper sulfate (250 µg/ml), copper hydroxide (250 to 500 µg/ml), or cuprous oxide/zinc oxide (125 to 250 µg/ml). Zinkicide SG6 had a sevenfold to eightfold lower MIC against Escherichia coli and X. alfalfae subsp. citrumelonis (31 to 250 μg/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.
评估了两种结构不同的纳米氧化锌材料——片状的锌杀灭剂SG4和颗粒状的锌杀灭剂SG6的实验制剂对柑橘溃疡病菌（柑橘溃疡病的病原菌）的抗菌活性。体外试验表明，与硫酸铜（250μg/ml）、氢氧化铜（250至500μg/ml）或氧化亚铜/氧化锌（125至250μg/ml）相比，锌杀灭剂SG4对大肠杆菌和苜蓿黄单胞菌西瓜亚种的最低抑菌浓度（MIC）低两倍（62.5至250μg/ml）。锌杀灭剂SG6对大肠杆菌和苜蓿黄单胞菌西瓜亚种的MIC低七至八倍（31至250μg/ml）。对甜橙（Citrus sinensis）叶片和“红宝石红”葡萄柚（C. paradisi）果实进行了柑橘溃疡病防治评估。一项温室叶片试验表明，在用柑橘溃疡病菌注射浸润到叶片细胞间隙后，用锌杀灭剂进行喷雾处理可减少柑橘溃疡病病斑的发展。在2014年和2015年于佛罗里达州东南部进行的田间试验中，锌杀灭剂SG4和SG6对葡萄柚溃疡病发病率的降低超过了氧化亚铜和氧化亚铜/氧化锌杀菌剂。锌杀灭剂制剂对葡萄柚上的真菌病害——柑橘疮痂病（Elsinoe fawcetti）和黑星病（Diaporthe citri）也有效。在两个季节中均未观察到对果皮有任何植物毒性迹象。锌杀灭剂对叶片和果实抵御柑橘溃疡病菌的抗菌活性与商业铜和氧化锌制剂相当或超过它们，这可能归因于锌杀灭剂的跨层移动。
