Selection and orchard testing of antagonists suppressing conidial production by the apple scab pathogen <Emphasis Type="Italic">Venturia inaequalis</Emphasis>

Apple scab caused by Venturia inaequalis is a major disease in apple production. Epidemics in spring are initiated by ascospores produced on overwintering leaves whereas epidemics during summer are driven by conidia produced on apple leaves by biotrophic mycelium. Fungal colonisers of sporulating colonies of V. inaequalis were isolated and their potential to reduce the production of conidia of V. inaequalis was evaluated on apple seedlings under controlled conditions. The four most effective isolates of the 63 screened isolates were tested subsequently under Dutch orchard conditions in 2006. Repeated applications of conidial suspensions of Cladosporium cladosporioides H39 resulted in an average reduction of conidial production by V. inaequalis of approximately 40%. In 2007, applications of conidial suspensions of C. cladosporioides H39 reduced conidial production by V. inaequalis by 69% on August 6 and by 51% on August 16, but no effect was found on August 20. However, viability of available conidia of C. cladosporioides H39 was low at the end of the experiment. Epiphytic and endophytic colonisation by Cladosporium spp. of leaves treated during the experiment with C. cladosporioides H39 was significantly higher than on control leaves sampled 6 weeks after the last application. It is concluded that C. cladosporioides H39 has promising potential as a biological control agent for apple scab control. More information is needed on the effect of C. cladosporioides H39 on apple scab epidemics as well as on mass production, formulation and shelf life of conidia of the antagonist.     

Haematological and serum biochemical reference values for apparently healthy working horses in Pakistan

This study aimed to establish comprehensive reference values for horses working in developing countries, and to compare them against accepted values for horses in developed countries, supporting diagnosis and clinical decision-making. Horses in developing countries usually perform strenuous work in hot, resource-limited conditions, so their ‘normal’ blood parameters may differ from other horses. Blood was analysed from 203 working horses in Pakistan, meeting defined clinical criteria. Age, sex, body condition and work-type showed small significant effects, but none were clinically relevant. Of the 32 reference intervals, 28 overlapped those of UK horses. However, the entire reference interval for creatine kinase was higher than for UK horses, while those for erythrocytes, albumin and albumin:globulin ratio were lower. Haematocrit and haemoglobin concentrations were also low. Therefore, apparently healthy working horses may have chronic muscle damage from overwork, and may have sub-clinical anaemia. Interventions combating these conditions could improve animal welfare, although it is unclear whether differences between UK and Pakistan reference values reflect chronic abnormalities, or are in fact physiological adaptations enabling horses to cope with the challenging conditions.     

Evapotranspiration of container ornamental shrubs: modelling crop-specific factors for a diverse range of crops

Crop coefficients, which define the relationship between estimated evapotranspiration from a standard reference crop and actual evapotranspiration of a specified crop, are generally not known for hardy ornamental nursery stock (HONS) crops. This severely limits the application of a sensor, known as the ‘Evaposensor’, which generates an electrical signal proportional to potential evapotranspiration, for irrigation scheduling of HONS. We therefore attempted to develop a method for the rapid estimation on the nursery of appropriate crop-specific calibration factors for use with the Evaposensor. Calibration factors were calculated for a range of HONS crops through the growing season, in a series of experiments under plastic tunnels or outdoors. Across all crops and over a growing season, 76% of the variation in calibration factors under a plastic tunnel could be explained by a combination of plant height, leaf area and stomatal conductance. For the same crops grown outdoors, 77% of the variation could be explained by these variables along with percentage cover. Plant height and percentage cover, which can both be easily and rapidly measured on commercial nurseries, alone explained 64 and 57% of the variation under plastic and outdoors, respectively.     

The decline of the sand lizard, Lacerta agilis L. Population on the sand dunes of the Merseyside coast,England

The population of the sand lizard Lacerta agilis in northwest England has declined sharply since 1930. The reasons for this decline are considered.Between Southport and the River Alt, approximately 50% of the sand dune habitat has been destroyed and a further 12% modified since 1801. Habitat losses resulting from building developments help to explain the sand lizard decline. The species has also disappeared from areas still supporting dune habitat. Here a combination of factors appear responsible, the effects of which are not uniform throughout the dune system.It is concluded that, in conjunction with a trend of less favourable climate over the last 15 years, habitat destruction, fragmentation and change of quality have brought about a catastrophic decline in the sand lizard population within the last 20 years. It is predicted that this population will become extinct before 2000 unless present trends are halted and adequate conservation measures taken.     

Student training in large-animal handling at the School of Veterinary and Biomedical Sciences, Murdoch University, Australia

The ability to handle animals safely, competently, and with confidence is an essential skill for veterinarians. Poor animal-handling skills are likely to compromise credibility, occupational health and safety, and animal welfare. In the five-year veterinary science degree at Murdoch University, animal handling is taught in a prerequisite unit in the second semester of the second year. From 2008, however, this unit will be taught in the first year of the five-year course. Students are taught to handle sheep, cattle, pigs, and horses safely and competently. Each student receives 30 hours of formal practical instruction. Animal-to-student ratios are 2:1, and staff-to-student ratios vary from 1:8 (sheep, cattle, horses) to 1:17 (pigs). Students must pass the practical exam to proceed into third year. Additional experience with animals is gained during third year (14 hours of practical instruction with sheep, goats, pigs, and cattle) and during the 5 weeks and 2 days of vacation farm experience during the second and third years. In the fourth and fifth years, students consolidate their handling experience with sheep (including rams), goats, pigs, cattle (including bulls), horses (including stallions), and alpacas. As a result, students are able to handle and restrain client animals with confidence. There is no formal course in small-animal handling at Murdoch University. Factors that have enhanced the success of the large-animal handling program include purpose-built on-campus facilities. Inadequate resources (time, facilities, and animals) remain the main impediment to effective learning, further compounded by the increasing tendency of university administrators to make decisions based on economic expediency rather than educational benefit.     

Assessing the resistance to gangrene of progenies of potato (Solanum tuberosum L.) from parents differing in susceptibility

Summary The resistance to gangrene (caused byPhoma exigua var.foveata) of progenies from two hybridisation schedules involving cultivars resistant, susceptible, or of intermediate reaction to gangrene was assessed. Two methods of sampling tubers from field-grown single-plant plots of 18 clones representing each progeny were used: one tuber was taken from each plant, and a bulk sample of 18 tubers was selected at random from the whole progeny. Gangrene resistance was assessed after incubating tubers which had been rolled in cornmeal-sand inoculum ofP. exigua var.foveata, and was expressed as a percentage of tubers infected. Results from the two methods of sampling correlated closely, and agreed well with tests in a subsequent year on 10-tuber samples of each individual clone. It is concluded that an 18-clone sample adequately represented each progeny, and that the mid-parent gangrene score satisfactorily predicted the resistance of the resulting progeny. There are indications that susceptibility tended to be dominant. The implication of these findings to breeding for resistance to gangrene is discussed.     

Multigenerational effects of 17β-estradiol and nonylphenol on euryhaline cladoceran <Emphasis Type="Italic">Diaphanosoma celebensis</Emphasis>

ABSTRACT:     The effects of parental exposure to 17β-estradiol (E2) and 4-nonylphenol (4-NP) on life history parameters of three successive generations of the euryhaline cladoceran Diaphanosoma celebensis were assessed under laboratory conditions. Less than 24-h-old neonates (P) were exposed to five sublethal concentrations of E2 (0.1, 1, 10, 100 and 1000 μg/L) and 4-NP (0.01, 0.1, 1, 10 and 50 μg/L) at 25°C. Age at first reproduction, reproductive period, fecundity and lifespan were investigated. Successive generations (F₁–F₃) were monitored further in the absence of toxicants. Results showed that cladocerans exposed to 10–1000 μg/L E2 produced more neonates at a younger age compared to the control. The same effects were also observed in the F₁ and F₂ but ceased in F₃. Cladocerans exposed to 1 μg/L 4-NP also produced significantly more neonates compared to the control, but this effect was not found in successive generations. The results suggest that vertebrate hormone can modify the reproduction of D. celebensis , and the effects are multigenerational.     

Abnormal sebaceous gland differentiation in 10 kittens ('sebaceous gland dysplasia') associated with generalized hypotrichosis and scaling

A rare congenital dermatosis, characterized by progressive hypotrichosis with variable scaling and crusting, occurred in 10 short-haired kittens in North America and Europe. Lesions appeared at between 4 and 12 weeks of age, commencing on the head and becoming generalized. The tail was spared in two kittens. Generalized scaling was mild to moderate, often with prominent follicular casts. Periocular, perioral, pinnal and ear canal crusting was occasionally severe. The skin was thick and wrinkled in two kittens. Histologically, the main lesion was abnormal sebaceous gland morphology. Instead of regular differentiation from basal cells to mature sebocytes, the glands were composed of a haphazard collection of undifferentiated basaloid cells, some partly vacuolated and a few containing eosinophilic globules. Mitotic figures and apoptotic cells were present in an irregularly thickened follicular isthmus. Lymphocytic mural folliculitis and mild sebaceous adenitis were rare. Orthokeratotic hyperkeratosis and follicular casts were present. Hair follicles were of normal density and were mostly in anagen, but some contained malacic hair shafts. Perforating folliculitis, leading to dermal trichogranuloma formation, occurred occasionally. Further biopsy samples taken at 2 years and at 3 and 4 years, respectively, from two kittens revealed similar but often more severe sebaceous gland lesions. Hair follicles were smaller, with many in telogen. The young age of onset suggests a genetic defect interfering with sebaceous and, possibly, follicular development. These lesions are discussed with reference to studies of mouse mutants in which genetic defects in sebaceous differentiation cause a similar phenotype of hyperkeratosis and progressive alopecia.