Oxytetracycline Dynamics on Peach Leaves in Relation to Temperature, Sunlight, and Simulated Rain

Abstract

Oxytetracycline (OTC), a member of the tetracycline antibiotics, is used as a foliar spray to control Xanthomonas arboricola pv. pruni on stone fruits and Erwinia amylovora on pome fruits. We studied the dynamics of OTC residues on attached peach (Prunus persica) leaves treated with 300 ppm active ingredient of an agricultural OTC in relation to temperature, natural sunlight, and simulated rain. We further evaluated the potential of three ultraviolet (UV) protectants (lignin, titanium dioxide, and oxybenzone) and one sticker-extender (Nu Film-17) to prolong OTC longevity on the leaf surface. OTC residue was determined by high-pressure liquid chromatography (HPLC)-UV (C18 reversed-phase column). In controlled conditions in darkness, constant temperatures up to 40°C did not affect OTC degradation on leaves. In contrast, OTC residue decreased rapidly in natural sunlight in the absence of rain, declining, on average, by 43.8, 77.8, and 92.1% within 1, 2, and 4 days after application, respectively; 7 days after application, OTC levels were near the detection limit. Use of shade fabric with 10 and 40% sunlight transmittance, simulating overcast sky, reduced OTC degradation significantly but did not extend OTC persistence beyond 7 days. Areas under the OTC residue curve, summarizing OTC dynamics during the 7-day exposure period, were negatively and significantly correlated with solar radiation and UV radiation variables, but not with temperature. UV protectants and Nu Film-17 were ineffective in improving OTC persistence in outdoor conditions. Simulated rain at 44 mm h–1 drastically (by 67.2%) lowered OTC residue after 2 min, and levels were near the detection limit after 60 min of continuous rain, regardless of whether plants were exposed to rainfall 1 or 24 h after OTC application. In artificial inoculation experiments with X. arboricola pv. pruni on attached peach leaves, OTC concentrations ≥50 ppm active ingredient (corresponding to ≥0.06 μg OTC cm–2 leaf surface) were sufficient to suppress bacterial spot development. By extrapolation from our outdoor exposure experiments, similar OTC residues following application of labeled OTC rates would be reached after less than 2 days under full sunlight, after 4 days under overcast sky, or after 2 min of a heavy rainstorm.

Antibiotics- A Miracle Drug as Crop Protectants: A Review

“…Antibiotics inhibit the growth of antibiotic-sensitive bacteria on flower and leaf surfaces for less than five days over its application (Stockwell et al 2008). The degradation of antibiotics resulted due to its exposure to sunlight and rainfall do reduce its concentrations over the plant tissues (Christiano et al 2010). Soil particles do absorb and inactivate the tetracyclines antibiotics (Subbiah et al 2011).…”

“…In fact bacterial disease management in most cropping systems is based on the integration of genetic resistance of the host, sanitation and cultural practices that create an unfavorable environment for multiplication of pathogens. Indeed the application of copper compounds found to be effective in population reduction of some bacterial plant pathogens, although several species have become resistant to copper (Christiano et al 2010) where the most of tree-fruit crops are sensitive to copper injury.…”

Metabolomics-Based Chemotaxonomic Classification of Streptomyces spp. and Its Correlation with Antibacterial Activity

“…Various biological activities of oxytetracycline have previously been reported, including antibacterial [45], anti-acne, and anti-inflammatory effects [15]. In particular, oxytetracycline was mainly used for fire blight management of fruit in America [11]. In this study, eight Streptomyces species (14 strains) were classified based on secondary metabolite profiling analyzed by UPLC-Q-TOF-MS.…”

“…As shown in Table 2, 2-hydroxystaurosporinone (5), staurosporine (9), and three unidentified metabolites (1,8,17) were found in S. rubrolavendulae, whereas oxytetracycline (3), altamycin (4), rimocidin (13), and four unidentified metabolites (2,15,16,19) were detected in S. rimosus. Furthermore, three unidentified metabolites (10,11,12) were S. scabiei-specific metabolites, and strevertene A (14) and unidentified metabolites (21) were from S. virginiae.…”

Агроекологічні Аспекти Контролю За Поширенням Антибіотикорезистентності Мікроорганізмів

“…pruni [6,18], у Мек-сиці та Центральній Америці -для контролю E. amylovora на яблуні та хвороб деяких овоче-вих культур, спричинених Pectobacterium spp., Pseudomonas spp. і Xanthomonas spp.…”