Resistance Evaluation of Some Chinese Leading Rice Maintainer, Restorer lines and Their Hybrids to Magnaporthe grisea

Six isolates of Magnaporthe grisea were selected to inoculate on 10 Chinese leading maintainer lines (B-lines), 14 restorer lines (R-lines) and their F1 hybrid plants. In the tested rice materials, R-lines were proved to be more resistant to blast than B-lines.The resistance frequency of about 25% F1 hybrid plants was less than their parents. In addition, 26 isolates of M. grisea collected from different rice growing areas of China were inoculated on 13 new improved hybrid rice combinations. The resistance frequencies of 5 improved hybrids were better than those of the controls and leading varieties in rice production of China.     

Alternate crop and weed host plant oviposition preferences by the Mexican rice borer (Lepidoptera: Crambidae)

The Mexican rice borer, Eoreuma loftini (Dyar), is the key pest of sugarcane, Saccharum hybrids, in south Texas, having largely displaced the sugarcane borer, Diatraea saccharalis (F.), and it is moving into rice- and sugarcane-growing areas of east Texas and Louisiana. While a number of alternative weed and crop hosts have been reported, the extent to which they might support Mexican rice borer populations is unknown. This study involved choice assays that compared oviposition preference for and larval infestations of five mature graminaceous weed species. Levels of infestation between sugarcane and corn, Zea mays L., crop hosts and between corn and sorghum, Sorghum bicolor (L.) Moench, were also assessed. We determined that the average number of larval entry holes in sudangrass stems was ≥2.5-fold more than for any of the other four weed host plants, that corn had ≥5.9-fold more larval entry holes than sorghum and ≥8.2-fold more than sugarcane. Greater oviposition and infestation of one non-crop host over another was not related to numbers of stems per plant, but was associated with the greater stem diameter and abundance of dry leaf tissue found in Sudangrass, Sorghum bicolor (L.) Moench ssp. drummondi (Nees ex Steud.) de Wet & Harlan, johnsongrass, S. halepense (L.) and barnyardgrass, Echinochloa crus-galli (L.) P. Beauv.; relative to the other weed species in this study. In terms of the crop plants, stalk diameter and quantity of dry leaf tissue were not associated with numbers of eggs or larval entry holes in the choice assays between corn and sorghum, and between sugarcane and corn. While corn has been known as a host of the Mexican rice borer for at least 84 yr, its role in area-wide population dynamics and control efforts has likely been greatly underestimated.     

Plant biology and other issues that relate to the management of water hyacinth: a global perspective with focus on Europe1

Water hyacinth reproduces vegetatively and sexually and seeds are numerous and long‐lived. Rates of vegetative growth are high (weight and numbers can double in less than 1 week in optimal conditions) and governed by temperature and available nutrients. The period from germination to setting seed can be less than 12 weeks. Dispersal of propagules is by flow, man and machines. Biomass of living material is high 90 to > 800 tonnes/ha and comprises around 95% water, and the weed often grows in inaccessible areas. Consequently, social, economic and environmental impacts of water hyacinth are often large and management of the problem becomes very important. However, management of water hyacinth is difficult, and utilization of this weed should not be mistaken as a control measure. Containment and eradication from a catchment may only be accomplished if the invasion is very young, small, isolated and accessible, and if the short‐term resource commitment is high. Most infestations are non‐eradicable because once noticed reaction time is too long. However, in Europe, as the weed invades new areas on the edges of its ecological range, eradication of new infestations could (should) be attempted as this is the most cost effective way to deal with the weed. In addition, pathway shut‐down and awareness campaigns should seek to reduce further new introductions, which, for spread to new regions, are mostly anthropogenic. For established populations the removal of accessible floating biomass can be accomplished using herbicides (if permitted) and by mechanical means. Both are expensive because re‐growth ensures repeated action is necessary. Biological control is a useful tool in warmer climates, less so in cooler climates. It may be more useful in cooler areas if integrated with other management techniques. Additional biological control agents are being studied to improve and broaden the value of biological control. The lack of policies to permit the use of biological control for weeds in Europe limits the ability to manage this weed.     

The native South American crayfishes (Crustacea,Parastacidae): state of knowledge and conservation status

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Modelling bovine babesiosis: a tool to simulate scenarios for pathogen spread and to test control measures for the disease

Tick-borne diseases are of increasing concern in many countries, particularly as a consequence of changes in land use and climate. Ticks are vectors of numerous pathogens (viruses, bacteria, protozoa) that can be harmful to humans and animals. In the context of animal health, bovine babesiosis poses a recurrent threat to cattle herds. In this study, we use a modeling approach to investigate the spread of babesiosis and evaluate control measures. A previously developed tick population dynamics model (here, Ixodes ricinus) is coupled with a pathogen spread model (here, the protozoan Babesia divergens), which describes pathogen spread in a dairy herd through the following processes: transmission, acquisition, transovarial transmission, transstadial persistence, and clearance of the pathogen. An assessment of the simulated B. divergens prevalence levels in ticks and cattle in the context of existing knowledge and data suggested that the model provides a realistic representation of pathogen spread. The model was then used to evaluate the influence of host density and the effect of acaricides on B. divergens prevalence in cattle. Increasing deer density results in an increase in prevalence in cattle whereas increasing cattle stocking rate results in a slight decrease. A potential increase in deer density would thus have an amplification effect on disease spread due to the increase in the number of infected ticks. Regular use of acaricides produces a reduction in pathogen prevalence in cattle. This model could be adapted to other tick-borne diseases.     

CLINICAL SIGNIFICANCE AND PROGNOSIS OF DEEP DIGITAL FLEXOR TENDINOPATHY ASSESSED OVER TIME USING MRI

Deep digital flexor (DDF) tendinopathy is one of the most frequent causes of foot lameness and the prognosis is guarded. The progress of lesion healing may be followed by magnetic resonance (MR) imaging to formulate a prognosis and to adapt the rehabilitation program. We assessed the correlation of outcome with total tendon damage and temporal resolution of MR abnormalities. Images from 34 horses with DDF tendinopathy that had undergone at least two low‐field standing MR examinations of the foot (mean 2.5 ± 1.3 times) were reviewed. No horse having a T1‐GRE hyperintense lesion over 30 mm in length or over 10% tendon cross‐sectional area returned to its previous activity level. Horses with concomitant lesions had worse outcome than horses with DDF tendinopathy only (P = 0.005). In all horses including those with excellent outcome, the lesion persisted, even mildly, in T1‐GRE and PD images. Horses with tendon lesion resolution on STIR‐FSE and T2‐FSE images on recheck examination had a better outcome (P = 0.0004 and P = 0.002, respectively), and all horses that returned to their previous level of performance had complete resolution of signal hyperintensity on the STIR‐FSE sequence. Although rehabilitation remains multifactorial, characteristics of DDF tendinopathy and concomitant lesions on first and recheck MR examinations allow refining the prognosis.     

Age-related thoracic radiographic changes in golden and labrador retriever muscular dystrophy

Golden retriever and Labrador retriever muscular dystrophy are inherited progressive degenerative myopathies that are used as models of Duchenne muscular dystrophy in man. Thoracic lesions were reported to be the most consistent radiographic finding in golden retriever dogs in a study where radiographs were performed at a single-time point. Muscular dystrophy worsens clinically over time and longitudinal studies in dogs are lacking. Thus our goal was to describe the thoracic abnormalities of golden retriever and Labrador retriever dogs, to determine the timing of first expression and their evolution with time. To this purpose, we retrospectively reviewed 390 monthly radiographic studies of 38 golden retrievers and six Labrador retrievers with muscular dystrophy. The same thoracic lesions were found in both golden and Labrador retrievers. They included, in decreasing frequency, flattened and/or scalloped diaphragmatic shape (43/44), pulmonary hyperinflation (34/44), hiatal hernia (34/44), cranial pectus excavatum (23/44), bronchopneumonia (22/44), and megaesophagus (14/44). The last three lesions were not reported in a previous radiographic study in golden retriever dogs. In all but two dogs the thoracic changes were detected between 4 and 10 months and were persistent or worsened over time. Clinically, muscular dystrophy should be included in the differential diagnosis of dogs with a combination of these thoracic radiographic findings.     

Effect of breed, age, weight and gender on radiographic renal size in the dog

In the adult dog, kidney length has been reported as 2.98 ± 0.44 times the length of L2 on ventrodorsal views and 2.79 ± 0.46 times the length of L2 on lateral radiographs. Our aim was to test the hypothesis that the suggested maximum normal left kidney size is too high, and to evaluate the effect of breed type, gender, weight and age of the dog on kidney size. Abdominal radiographs of 200 dogs with no evidence of concurrent disease that might have an effect on renal size were included in the study. The mean ratio of kidney length to the second lumbar vertebra length was similar to previous reports. For the right lateral view it measured 2.98 ± 0.60 and for the ventrodorsal view 3.02 ± 0.66. Significant differences of this ratio between skull type were present, especially between brachycephalic and dolichocephalic dogs. On the right lateral view brachycephalic dogs had the highest median LK/L2 ratio of 3.1 (3.20 ± 0.40), whereas for dolichocephalic dogs it was 2.8 (2.82 ± 0.50), and for mesaticephalic dogs it was 2.97 (3.01 ± 0.6). A ratio >3.5 was found only in mesaticephalic dogs on the ventrodorsal view. There was a significant difference in the LK/L2 ratio between small (≤10kg) and large breed dogs (>30kg) where small dogs had a significantly higher LK/L2 ratio. There was no statistically significant relation between this ratio and age or gender. The previously reported ratios for kidney size seem valid, but because skull type has an impact on the LK/L2 ratio, a single normal ratio should not be used for all dogs.