A review of the ecology and control of thistles in Australia

Studies on the ecology and control of thistles in Australia, particularly those related to pasture improvement, are reviewed, and the results used to interpret increases and changes in thistle dominance. Several hypotheses, based on ecological differences in the thistles, their life cycles and changes in the soil/seed environment may explain the changing species incidence in the field, and it is postulated that, within a restricted group of competing thistle species, it may be more meaningful to interpret these ecological differences in terms of ‘tolerance of unfavourable conditions’ than in terms of ‘optimal requirements’. Alternative strategies for the control of thistles, including pasture competition, grazing management, the utilization of high soil fertility, and chemicals, are also assessed. It is re-emphasized that the aim of any long-term programme to control thistles, with or without the release of biological agents, should be the establishment and/or maintenance of a vigorous perennial pasture. The relative importance of different thistle species in Australian pastures and the ecology and dynamics of soil seed banks are identified as important areas for future thistle research.     

Intestinal parasites: a study of human appendices

Histological sections of 414 appendices were examined parasitologically. Enterobius vermicularis was found in 8.7%, eggs of Ascaris lumbricoides in 0.5%, trophozites of Dientamoeba fragilis in 4.8%, Endolimax nana in 2.2%, Entamoeba coli in 1% and cysts of Giardia intestinalis in 1.9% of cases. Appendicopathies associated with Enterobius were most frequent in the age group from 6 to 10 years (24.3%) and from 21 to 25 years (12.2%). Patients older than 15 years were practically women only. Dientamoeba was most frequent in the age group from 11 to 15 years (11.3%). In women D. fragilis was three times more frequent than in men. The coincidence of D. fragilis and E. vermicularis infections was 50%. No interactions were seen between the protozoans in the contents of the appendix and its mucous membrane. Statistical evaluation indicates possible etiologic role of E. vermicularis in the occurrence of acute appendicities. D. fragilis appears to be the most common intestinal protozoan parasite in Bohemia.     

Problems of detecting phytopathogenic bacteria by ELISA1

Xanthomonas ampelina can be detected with the same sensitivity by ELISA double-antibody sandwich (ELISA-DAS) or indirect ELISA (ELISA-I) but the latter is preferred for its greater simplicity. The two methods also gave similar sensitivity results for soft-rot erwinias, but their application is complicated by the large number of erwinia serotypes. ELISA-I was unable to distinguish strains of Agrobacterium tumefaciens from A. radiobacter. The cross reactions with other bacteria of antisera against X. fragariae were tested by ELISA-I. The problems of applying these methods are discussed.