Investigating the phytotoxicity of the graminicide fluazifop-P-butyl against native UK wildflower species

BACKGROUND: The selective graminicide fluazifop‐P‐butyl is used for the control of grass weeds in dicotyledonous crops, and commonly applied in amenity areas to reduce grass productivity and promote wildflower establishment. However, evidence suggests that fluazifop‐P‐butyl might also have phytotoxic effects on some non‐target plants. This study investigates the effects of fluazifop‐P‐butyl on the emergence, phytotoxicity and above‐ground biomass of nine perennial wildflower species and two grass species, following pre‐ and post‐emergent applications at half, full and double label rates in a series of glasshouse experiments. RESULTS: While pre‐ and post‐emergent applications of fluazifop‐P‐butyl caused reductions in seedling emergence and increased phytotoxicity on native wildflower and grass species, these effects were temporary for the majority of wildflower species tested, and generally only occurred at the double application rate. No differences in biomass were observed at any of the rates, suggesting good selectivity and no long‐term effects of fluazifop‐P‐butyl application on the wildflower species from either pre‐emergent or post‐emergent applications. CONCLUSION: These results have direct relevance to the management of amenity areas for biodiversity, as they confirm the suitability of these wildflower species for inclusion in seed mixtures where fluazifop‐P‐butyl is to be applied to control grass productivity. Copyright © 2011 Society of Chemical Industry     

Computed tomography-guided fine-needle aspiration and tissue-core biopsy of bone lesions in small animals

In humans, free-hand computed tomography (CT)-guided biopsy is an accurate method to obtain a tissue sample. There are only a few reports of this technique in veterinary medicine. In the present study, 21 dogs and two cats underwent a free-hand CT-guided tissue-core biopsy (17 animals) or fine-needle aspiration (six animals) of a bone lesion. Two out of 17 tissue-core samples were also cultured. All 17 tissue-core biopsy samples were diagnostic (accuracy of 100%). Five out of six aspirates were diagnostic (accuracy of 83.3%). The overall accuracy was 95.7%. In one aspirate, cytologic quality was insufficient containing only blood. No major complications were encountered. Fourteen neoplastic, two infectious and six benign lesions were diagnosed. CT examination after intravenous contrast medium added useful information to avoid large vessels and to biopsy-viable tissue. Free-hand CT-guided tissue-core biopsy and aspiration appears to be a safe and very accurate procedure for use in the diagnosis of bone-associated diseases in small animals.     

Severity and persistence of footrot in Merino sheep experimentally infected with a protease thermostable strain of Dichelobacter nodosus at five sites

Objective To test the hypothesis that ovine footrot associated with a thermostable protease strain of Dichelobacter nodosus undergoes self cure or is sustained as an annually recurring disease, depending on the environment.
Design and procedure Forty Merino sheep from a single blood line were infected with a protease thermostable strain of D nodosus a t each of five sites in Western Australia. Footrot lesions and microscopic evidence of D nodosus were recorded every fortnight for 2.5 years, supplemented by laboratory culture. Rainfall, soil and air temperature, pasture quantity and composition and soil types were also recorded. Flocks that apparently self cured were relocated to a more favourable site for footrot in the final spring season.
Results The maximum prevalence of feet with clinical footrot lesions was 80.6, 1.3, 14.4, 3.8 and 88.1% at the five sites. Severe footrot occurred for three consecutive spring seasons at one site that had clay loam soil and at least 3500 kg/ha total pasture dry matter annually. However, the infection was asymptomatic for up to 10 weeks between outbreaks. D nodosus was isolated from flocks for 2.5 years at only two sites, although there was microscopic evidence of the organism at other sites in the final year. A thermolabile variant (strain U6) of D nodosus was isolated from the two sites where footrot persisted.
Conclusion Depending on time and location, ovine footrot induced by a protease thermostable strain of D nodosus either self cured or persisted as annual outbreaks interspersed with periods of asymptomatic infection.     

PREVALENCE OF GALLBLADDER SLUDGE IN DOGS AS ASSESSED BY ULTRASONOGRAPHY

Ultrasonography of the gallbladder was performed in 3 groups of dogs: 30 clinically healthy dogs, 50 dogs with hepatobiliary disease, and 50 dogs with diseases other than hepatobiliary disease. The gallbladder was evaluated for the presence of sludge (echogenic material without acoustic shadowing). Maximal gallbladder length, width, height, and area were measured as well as the gallbladder wall thickness. The relative sludge area was calculated as the ratio of sludge area over gallbladder area on longitudinal images. No significant difference was found in the prevalence of gallbladder sludge among healthy dogs (53%), dogs with hepatobiliary diseases (62%), and dogs with other disease (48%). The mean age of dogs with sludge was higher than the mean age of dogs without sludge in dogs with hepatobiliary disease and dogs with other diseases (p ≤0.05). The mean relative sludge area did not differ significantly among the 3 groups. A trend to larger gallbladder dimensions in dogs with sludge compared to dogs without sludge was detected within the 3 groups. The gallbladder wall thickness was not different between dogs with and without sludge within the 3 groups. However, the gallbladder wall was more frequently isoechoic than hyperechoic to the liver in dogs with sludge than in dogs without sludge. The results of this study indicate that gallbladder sludge, in dogs, in not particularly associated with hepatobiliary disease and should be considered an incidental finding.     

Carbohydrate mobilization following shoot defoliation and decapitation in hybrid poplar

The effects of shoot defoliation, decapitation, and disbudding on carbon mobilization were investigated in rooted cuttings of Populus maximowiczii x nigra L. 'MN9'. Ten days after complete shoot defoliation or decapitation, the stem starch concentration of treated plants declined to one-half that of intact plants, and there were similar or greater reductions in the concentrations of glucose, fructose, sucrose, galactose, and shikimic acid. Partial shoot defoliation (50%) and complete disbudding had no effect on stem starch concentration, but stem sucrose concentration was reduced in all treatments. Sucrose depletion preceded and may have induced other changes in the carbon status of plants subjected to leaf or shoot removal. Four days after shoot decapitation, the sucrose concentration of roots of treated plants was reduced to 25% of that of intact plants. However, the concentrations of fructose and glucose increased in the roots of treated plants and was followed by the accumulation of shikimic acid, salicyl alcohol, unknown compound A and salicin. The possible role of increased concentrations of root organic solutes in the water relations and regrowth process of decapitated plants is discussed.     

"肉鸡球虫病及其综合防治措施"专栏(七)成功控制禽球虫病的挑战

艾美尔球虫以宿主特异性的方式感染家畜,是引起球虫病的病原体.艾美尔球虫的控制是必要的.目前主要的控制方法是化学疗法,而用由活野毒株或弱毒虫株制成的疫苗进行免疫预防则呈流行趋势.新一代的亚单位疫苗、活栽体疫苗和DNA疫苗正在研究之中,而合适抗原的鉴定是仍需要解决的难题.本文简述了过去和当前控制球虫病的方法,及一种鉴定作为候选疫苗免疫保护性抗原的新方法.     

Changes in soil chemistry accompanying acidification over more than 100 years under woodland and grass at Rothamsted Experimental Station, UK

We have examined the effect that acid deposition and other sources of acidity have had over the last 110–140 years on soil under woodland (Broadbalk and Geescroft Wildernesses) and grassland (Park Grass) comprising some of the Classical Experiments at Rothamsted Experimental Station. Changes in soil chemistry have been followed by analysing some of the unique archive of stored samples for pH, water-soluble and exchangeable base cations, aluminium, iron and manganese, exchangeable acidity, cation exchange capacity (CEC) and soluble anions. Proton balances and historical data show the importance of acid deposition to acidification and concomitant changes in the chemistry of the soil. The pH of the surface soil of Geescroft Wilderness has fallen from 6.2 to 3.8 since 1883. The decrease in the pH of the unlimed, unfertilized plot on Park Grass was less over a similar period (from pH 5.2 to 4.2), illustrating the significant effect of the woodland canopy on the interception of acidifying pollutants. The effect of increasing acidity on the soil chemistry of Geescroft Wilderness is seen in its decreasing base saturation and CEC, with base cations moving down the soil profile. Clay minerals are being irreversibly weathered, and Mn and Al progressively mobilized, so that today Al occupies 70% of the exchange complex in the surface soil. Even with present reductions in sulphur deposition critical loads for sulphur, nitrogen and acidity are still exceeded. Such semi-natural ecosystems are unsustainable under the current climate of pollution.