Multifunctional Surface, Subsurface, and Systemic Therapeutic (MS3T) Formulation for the Control of Citrus Canker

A multifunctional surface, subsurface and systemic therapeutic (MS3T) formulation comprised of two bactericides, both didecyldimethylammonium chloride (DDAC) and a zinc (Zn)-chelate, was developed as an alternative to copper pesticides for crop protection. Agricultural grade chemicals were used to prepare MS3T formulations. Minimal inhibitory concentration (MIC) was determined to be tested in vitro against Xanthomonas alfalfae subsp. citrumelonis (herein called Xa), Escherichia coli (E. coli), and Pseudomonas syringae (Ps). Assessment of the phytotoxic potential was carried out on tomato under greenhouse conditions. Moreover, field trials were conducted during three consecutive years on grapefruit (Chrysopelea paradise) groves to evaluate efficacy against citrus canker (Xanthomonas citri subsp. citri), scab (Elsinoe fawcetti), and melanose (Diaporthe citri). In addition to disease control, improvements to both fruit yield and quality were observed likely due to the nutritional activity of MS3T via the sustained release of plant nutrients (Zn and nitrogen). Zn residues of leaf tissues were analyzed via atomic absorption spectroscopy (AAS) at various time points before and after MS3T foliar applications throughout the duration of the 2018 field trial. Field trial results demonstrated MS3T to be an effective alternative to copper (Cu)-based formulations for the control of citrus canker.

Control of Citrus Canker in Greenhouse and Field with a Zinc, Urea, and Peroxide Ternary Solution

Accumulation of toxic copper in soil and development of copper-resistant pests are emerging challenges currently faced by the agricultural community worldwide. As an alternative, we have developed a ternary zinc chelate solution (TSOL) pesticide where zinc ions are the primary active ingredient. The material is composed of zinc, urea, and hydrogen peroxide. Urea was chosen as it is widely used as a plant fertilizer and can also bind to both zinc and hydrogen peroxide. No phytotoxicity was observed with TSOL on Meyer lemon (Citrus × meyeri) seedlings at a field spray rate of 800 μg/mL Zn metal concentration. Antimicrobial studies showed that TSOL exhibited improved killing efficacy against Escherichia coli and Xanthomonas alfalfae compared to Zn ions alone. Citrus canker field trials in a grapefruit (Chrysopelea paradisi) grove over three years showed that TSOL provided comparable disease protection to copper products at an equivalent or lower metal content.

Fixed-Quat: An Attractive Nonmetal Alternative to Copper Biocides against Plant Pathogens

In this paper, we report a nonphytotoxic bactericide and fungicide formulation containing a composite of silica and quaternary ammonium compound (quat). The composite material was prepared using an acid-catalyzed sol-gel method. Positively charged quat was associated with a negatively charged silica-gel matrix, producing a stable suspension of fixed-quat gel (FQ-G). The morphology of FQ-G and the interaction of quat with silica were characterized using SEM and FTIR, respectively. Silica gel significantly reduced quat phytotoxicity when tested at 500 and 1000 μg/mL foliar-application rates. The in vitro antimicrobial efficacy of FQ-G was evaluated against Xanthomonas alfalfae, Pseudomonas syringae, and Clavibacter michiganensis, showing comparable efficacies to that of quat itself. In field conditions, its efficacy in controlling the bacterial and fungal diseases citrus canker, scab, and melanose on 'Ray Ruby' red grapefruit was evaluated. Foliar application rates at 100 and 200 μg/mL provided comparable disease control to those of several copper standards, demonstrating the potential for use as an alternative agricultural biocide.

Multimodal Generally Recognized as Safe ZnO/Nanocopper Composite: A Novel Antimicrobial Material for the Management of Citrus Phytopathogens

Copper (Cu) bactericides/fungicides are used extensively for crop protection in agriculture. Concerns for Cu accumulation in soil, Cu leaching into the surrounding ecosystem, and development of Cu resistance in phytopathogenic bacteria are evident. While there is no suitable alternative to Cu available to date for agricultural uses, it is possible to reduce Cu per application by supplementing with Zn and improving Cu bioavailability using nanotechnology. We have prepared a non-phytotoxic composite material consisting of generally recognized as safe ZnO 800 particles and nanocopper-loaded silica gel (ZnO-nCuSi). The morphology of the ZnO-nCuSi material was characterized using scanning electron microscopy, showing ZnO particles dispersed in the silica gel matrix. ZnO-nCuSi demonstrated strong in vitro antimicrobial properties against several model plant bacterial species. Two consecutive year field efficacy results showed that agri-grade ZnO-nCuSi was effective in controlling citrus canker disease at less than half the metallic rate of the commercial cuprous oxide/zinc oxide pesticide.

Potential of Nano-Formulated Zinc Oxide for Control of Citrus Canker on Grapefruit Trees

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.

Soil Application of SAR Inducers Imidacloprid, Thiamethoxam, and Acibenzolar-S-Methyl for Citrus Canker Control in Young Grapefruit Trees

Soil applications of inducers of systemic acquired resistance (SAR) imidacloprid, thiamethoxam, or acibenzolar-S-methyl, at various rates and application frequencies, were evaluated for control of citrus canker caused by Xanthomonas citri subsp. citri in a field trial of 3- and 4-year-old 'Ray Ruby' grapefruit trees in southeastern Florida. Reduction of foliar incidence of canker produced by one, two, or four soil applications of imidacloprid, thiamethoxam, and acibenzolar-S-methyl was compared with 11 foliar sprays of copper hydroxide and streptomycin applied at 21-day intervals. In the 2008 and 2009 crop seasons, canker incidence on each set of vegetative flushes was assessed as the percentage of the total leaves with lesions. By the end of the 2008 season, despite above-average rainfall and a tropical storm event, all treatments significantly reduced foliar incidence of citrus canker on the combined spring-summer-fall flushes. Sprays of copper hydroxide and streptomycin were effective for reducing canker incidence on shoot flushes produced throughout the season compared with the untreated control, whereas soil-applied SAR inducers reduced foliar disease depending on rate, frequency, and timing of application. Except for the treatment of four applications of acibenzolar-S-methyl at 0.2 g a.i. per tree or two applications of imidacloprid, SAR inducers were ineffective for reducing foliar disease on the flushes that were present during the tropical storm. In 2009, all treatments significantly reduced the incidence of foliar canker on the combined spring-summer-fall flushes but not all treatments of spring-summer flushes with SAR inducers were effective compared with the untreated control. Hence, depending on rate, frequency, and timing of application, soil-applied SAR inducers reduced incidence of canker on foliar flushes of young grapefruit trees under epidemic conditions.

Selective cervical nerve root blockade: prospective study of immediate and longer term complications

BACKGROUND AND PURPOSE

Selective cervical nerve root blockade (SCNRB) is a useful procedure for evaluating and treating patients with cervical radiculopathy. Reports of complications related to injections within the cervical nerve root foramen have raised serious doubts regarding the safety of this procedure. This study was performed to prospectively evaluate the safety of fluoroscopically guided outpatient diagnostic and therapeutic SCNRB.

MATERIALS AND METHODS

Eight hundred two consecutive fluoroscopically guided diagnostic and/or therapeutic SCNRBs in 659 patients were performed during a 14-month period (November 2006-December 2007) at affiliated outpatient imaging centers. Each examination was performed by 1 of 8 experienced procedural radiologists by using an anterior oblique approach, with the needle position confirmed with radiographic contrast before injection of an admixture of local anesthetic and steroid. All patients were assessed immediately and at 30 minutes following the procedure. Additionally, 460 patients were called by telephone 30 days following the procedure. All complications were recorded.

RESULTS

Of the 802 attempted procedures, 799 were successfully completed. Three procedures were aborted due to anxiety, challenging body habitus, or persistent venous opacification observed during contrast injection and despite needle repositioning. There were no serious complications, such as stroke, spinal cord insult, permanent nerve root deficit, infection, or significant hematoma. There were 33 minor complications occurring within 30 minutes of the procedure; the most common was vasovagal symptoms. Three hundred forty-five patients were successfully contacted by telephone at 30 days postinjection, 9 of whom reported increased or new pain symptoms.

CONCLUSIONS

With our technique, fluoroscopically guided SCNRB is a safe outpatient procedure with a low immediate and delayed complication rate.

The radiographic diagnosis and treatment of paraneoplastic central nervous system disease

Paraneoplastic nervous system syndromes are being identified with increasing frequency because of greater physician awareness and the availability of serodiagnostic tests for some syndromes. Frequently, paraneoplastic syndromes develop in the setting of an indolent, limited stage, or otherwise occult malignancy. As a result, the paraneoplastic disorder often becomes the most disabling part of a patient's disease. Effective treatment appears to require early identification. For these reasons, the ability to diagnose a paraneoplastic syndrome, follow its course, and treat it successfully are important. The authors describe four patients with neurologic paraneoplastic syndromes and identical magnetic resonance imaging abnormalities. Three patients responded to immunosuppressive or immunomodulatory therapy, and in one, corresponding radiographic improvement was documented. Strategies for early diagnosis and options for treatment of paraneoplastic nervous system disorders are discussed.

Delegation of clinical dietetic tasks in military and civilian hospitals: implications for practice

The purposes of our research were two-fold: to determine perceptions of the quality of task performance and to identify dietetic personnel currently performing clinical dietetic tasks in military and civilian hospitals. Questionnaires were returned from 309 dietitians and 208 dietetic support personnel at 151 military and civilian hospitals (73% response overall). For tasks completed by support personnel, no task was rated as having optimum quality, 1 was rated as highly acceptable, 6 as acceptable, 19 as somewhat unacceptable, and 4 as unacceptable. Current performance ratings indicated that 1 task was performed solely by dietitians, 21 were completed by dietitians with assistance, 6 were completed jointly by dietitians and support personnel, 2 were completed by support personnel with supervision by dietitians, and no task was completed independently by support personnel. Tasks were grouped into four categories: basic clinical dietetics (11 tasks), intermediate and in-depth clinical dietetics (12 tasks), outpatient nutrition clinic (5 tasks), and nutrition education (community) (4 tasks). Quality scores for the US Air Force (USAF) hospitals were higher for all task categories except intermediate and in-depth clinical dietetic tasks. The quality scores of support personnel were higher than those of dietitians for all task categories. The USAF performance scores indicated significantly more involvement of support personnel. Generally, the performance scores of dietitians increased with experience; the scores of support personnel decreased with experience. Correlations between quality and performance ratings for individual tasks revealed low to moderate relationships. Our results suggest that additional delegation of tasks to dietetic support personnel may be possible without negatively affecting perceptions of the quality of task outcome.(ABSTRACT TRUNCATED AT 250 WORDS)