Using Pseudomonas spp. for Integrated Biological Control

ABSTRACT Pseudomonas spp. have been studied for decades as model organisms for biological control of plant disease. Currently, there are three commercial formulations of pseudomonads registered with the U.S. Environmental Protection Agency for plant disease suppression, Bio-Save 10 LP, Bio-Save 11 LP, and BlightBan A506. Bio-Save 10 LP and Bio-Save 11 LP, products of Jet Harvest Solutions, Longwood, FL, contain Pseudomonas syringae strains ESC-10 and ESC-11, respectively. These products are applied in packinghouses to prevent postharvest fungal diseases during storage of citrus, pome, stone fruits, and potatoes. BlightBan A506, produced by NuFarm Americas, Burr Ridge, IL, contains P. fluorescens strain A506. BlightBan A506 is applied primarily to pear and apple trees during bloom to suppress the bacterial disease fire blight. Combining BlightBan A506 with the antibiotic streptomycin improves control of fire blight, even in areas with streptomycin-resistant populations of the pathogen. BlightBan A506 also may reduce fruit russet and mild frost injury. These biocontrol products consisting of Pseudomonas spp. provide moderate to excellent efficacy against multiple production constraints, are relatively easy to apply, and they can be integrated with conventional products for disease control. These characteristics will contribute to the adoption of these products by growers and packinghouses.     

Chemical composition of shallot (Allium ascalonicum Hort.)

An extensive phytochemical analysis of the polar extracts from bulbs of shallot, Allium ascalonicum Hort., led to the isolation of two new furostanol saponins, named ascalonicoside A1/A2 (1a/1b) and ascalonicoside B (4), respectively, along with compounds 2a and 2b, most likely extraction artifacts. On the basis of 2D NMR and mass spectrometry data, the structures of the novel compounds were elucidated as furost-5(6)-en-3beta,22alpha-diol 1beta-O-beta-D-galactopyranosyl 26-O-[alpha-L-rhamnopyranosyl-(1-->2)-O-beta-D-glucopyranoside] (1a), its epimer at position 22 (1b), and furost-5(6),20(22)-dien-3beta-ol 1beta-O-beta-D-galactopyranosyl 26-O-[alpha-L-rhamnopyranosyl-(1-->2)-O-beta-D-glucopyranoside] (4). This is the first report of furostanol saponins in A. ascalonicum. High concentrations of quercetin, isorhamnetin, and their glycosides were also isolated and described.     

Soil quality indicators under continuous cropping systems in the Argentinean Pampas

Over the last two decades, soil cultivation practices in the southern Argentinean Pampas have been changing from a 7 year cash-crop production system alternated with 2–3 years under pasture, to a continuous cropping system. A better understanding of the impact of the period of time a field has been under continuous cropping on a broad spectrum of soil properties related to soil quality is needed to target for sustainable cropping systems. The objectives of this study were to: (i) assess the relationship between physical and chemical soil parameters related to soil quality and (ii) identify soil quality indicators sensitive to soil changes under continuous cropping systems in the Argentinean Pampas.

Correlation analysis of the 29 soil attributes representing soil physical and chemical properties (independent variables) and years of continuous cropping (dependent variable) resulted in a significant correlation (p < 0.05) in 78 of the 420 soil attribute pairs. We detected a clear relationship between hydraulic conductivity at tension h (K_h) and structural porosity (ρ_e); ρ_e being a simple tool for monitoring soil hydraulic conditions.

Soil tillage practice (till or no-till) affected most of the soil parameters measured in our study. It was not possible to find only one indicator related to the years under continuous cropping regardless of the cultivation practice. We observed a significant relationship between years under continuous cropping and K_h under no-till (NT) and wheat fallow (p < 0.001, R² = 0.70). Under these conditions, K₋₄₀ diminished as the number of years under continuous cropping increased.

The change in mean weight diameter (CMWD) was the only physical parameter related to the number of years under continuous cropping, explaining 36% of the variability in the number of years under continuous cropping (p < 0.001) The combination of three soil quality indicators (CMWD, partial R² = 0.38; slope of the soil water retention curve at its inflexion point (S), partial R² = 0.14 and cation exchange capacity (CEC), partial R² = 0.13) was able to explain, in part, the years under continuous cropping (R² = 0.65; p value > 0.001), a measure related to soil quality.     

Organochlorine pesticide residues in strawberries from integrated pest management and organic farming

A rapid, specific, and sensitive method based on the Quick Easy Cheap Effective Rugged and Safe (QuEChERS) method and a cleanup using dispersive solid-phase extraction with MgSO(4), PSA, and C18 sorbents has been developed for the routine analysis of 14 pesticides in strawberries. The analyses were performed by three different analytical methodologies: gas chromatography (GC) with electron capture detection (ECD), mass spectrometry (MS), and tandem mass spectrometry (MS/MS). The recoveries for all the pesticides studied were from 46 to 128%, with relative standard deviation of <15% in the concentration range of 0.005-0.250 mg/kg. The limit of detection (LOD) for all compounds met maximum residue limits (MRL) accepted in Portugal for organochlorine pesticides (OCP). A survey study of strawberries produced in Portugal in the years 2009-2010 obtained from organic farming (OF) and integrated pest management (IPM) was developed. Lindane and β-endosulfan were detected above the MRL in OF and IPM. Other OCP (aldrin, o,p'-DDT and their metabolites, and methoxychlor) were found below the MRL. The OCP residues detected decreased from 2009 to 2010. The QuEChERS method was successfully applied to the analysis of strawberry samples.     

Effect of general anesthesia on plasma cardiac troponin I concentrations in healthy horses

Objective

To evaluate the effect of general anesthesia on plasma cTnI concentrations in horses.

Animals, materials and methods

Thirty-two horses undergoing general anesthesia and either elective surgery or MRI without surgery were prospectively studied. Twenty-nine horses (22 surgical, 7 imaging) completed the study. Plasma cTnI concentrations were determined prior to anesthesia and at 6, 12 and 24 h following discontinuation of the inhalant anesthetic.

Results

All horses had cTnI values within the reference range at all time points. Six horses (21%) developed detectable cTnI 6 or 12 h following anesthesia. Risk factors for detectable cTnI include increasing age and dorsal recumbency. Horses with detectable cTnI had significantly lower mean and diastolic arterial blood pressures than those without detectable cTnI.

Conclusion

Uncomplicated general anesthesia with or without surgery does not result in cardiac troponin I elevations above the reference range in the first 24 h postoperatively.     

Effect of gastrointestinal nematodes on serum copper and phosphorus of growing beef calves in northwestern Argentina

Tropical Animal Health and Production - The aim of this work was to study the effect of gastrointestinal nematodes (GINs) on copper (Cu) and phosphorus (P) in blood of beef cattle in two ranches...