Michele Dale

James Cook University | JCU

The Australian and increasingly international landcare movement reflects renewed recognition of the concept of personal and local self-reliance within national, provincial and local governance systems. While the word ‘subsidiarity’ is seldom used to describe landcare, the concept deeply espouses and reflects a key governance system principle. Subsi...

With community concerns about environmental issues such as global warming receiving scientific and political priority, there is a corresponding demand for mainstream environmental education initiatives. The plethora of information available regarding broad environmental issues can be intimidating to educators keen to foster an informed sense of ste...

Shoot blight of spotted gums (Eucalyptus maculata Hook E. citriodora Hook and E. henryi S.T. Blake) caused by Ramularia pitereka Unger has recently emerged as the major disease problem of spotted gum plantations in Queensland and Northern New South Wales. A difference in disease susceptibility was demonstrated between provenances of spotted gums in...

This study aims to determine if iron chelators, namely Citric Acid, 2,3-dihydroxybenzoic acid (DHBA) and 8-hydroxy-7-iodo-5-quinoline sulfonic acid (IQSA) are capable of reducing the dew period requirement of Drechslera avenacea (Curtis and Cooke) Shoem (telomorph: Pyrenophora chaetomioides).

Shake-flask liquid fermentation was investigated to mass-produce spores of the fungal pathogen, Phloeospora mimosae-pigrae, a potential biological control agent for the giant sensitive plant, Mimosa pigra. Twenty percent Campbell's V-8 juice in large shake flasks with a pH of 6.5 yielded 9.7 x 10 conidia mL in vitro after ten days fermentation, pro...

In Australia, fungi associated with larvae of the biological control agent Cactoblastis cactorum may contribute to the control of the exotic weed pricklypear (Opuntia inermis). C. cactorum larvae were assessed for their ability to vector pathogenic fungi into O. inermis by the infestation of larvae with fungal suspensions. Six fungal isolates cause...

During the 1995-96 growing season, the effects of fertiliser application and growth of different crops on the population of Fusarium oxysporum f. sp. vasinfectum (Fov) in field soils were examined. In soil samples collected 35 days after fertiliser application, densities of Fov were significantly lower in soils receiving 180 units of anhydrous ammo...

Mimosa pigra L.(Mimosaceae), or giant sensitive plant, is a tropical, woody perennial shrub originating from tropical America. In its country of origin M. pigra seldom reaches a height of 2m but in its introduced range it grows up to 6m tall forming dense, impenetrable, thorny thickets. In the northern part of Australia M. pigra covers approximatel...

Fusarium wilt, caused by Fusarium oxysporum f. sp. vasinfectum, is a new and important disease of cotton in Australia. Some factors affecting either the infection process or the subsequent development of symptoms under glasshouse conditions were examined in this study. The pathogenicity of inocula was significantly affected by the media in which th...

The incidence and severity of fusarium wilt of cotton in glasshouse trials increased when levels of plant residue in the soil were increased by the incorporation of whole cotton plants (6-week-old seedlings dried out for a further 6 weeks) into the soil. In non-residue-supplemented potting mix, disease incidence was <50%, but ranged from 74 to >90%...

In undisturbed natural ecosystems, relationships between pathogens and their hosts tend to attain a level of stability and plant populations are rarely severely damaged by diseases. However, in artificial or disturbed systems that exist in agriculture, horticulture and silviculture, the development of disease epidemics often seriously limits produc...

The term cultural control describes the activities of humans aimed at controlling disease through the cultural manipulation of plants. At present, cultural control practices find their greatest value in large area and low unit value crops such as temperate cereals and forests. For some crops, such control practices may be the only economically viab...

It might not be immediately obvious, but fungi are a very important group of organisms. Anthony Wheeler (ASTJ 41 (2)) outlines the confusion for science teachers caused by his Year 8 science textbook classifying the fungi as plants. Whilst this does simplify matters, it is does the fungi an injustice. Fungi form a distinct Kingdom, quite apart from...

Spoilage of fruits and vegetables due to postharvest diseases is a serious economic problem world-wide, causing 10-30% losses in most crops, and up to 50% in more perishable produce such as tomatoes. Some postharvest diseases are simply an extension of diseases occurring in the field, but many are a result of infection of the fruit or other produce...

For humans. one of the most beneficial characteristics of the fungi is their ability to use a wide range of substrates to produce useful chemicals. Fungi can use a variety of biochemical pathways to metabolise carbohydrates in order to release energy. One of the most useful processes for commercial application is that of fermentation. Fermentation...

The multimedia computer package DIAGNOSIS provides a training aid to students of crop protection for pest and disease diagnosis. The program simulates field and laboratory scenarios, in which students must actively seek clues and interpret observations on the cause of plant problems. Output may consist of text, graphics and video. The software allo...

Stomata located beneath the cotyledons of 7-day-old chickpea seedlings were the preferential infection court for zoospores of Phytophthora megasperma f. sp. medicaginis. Zoospores also accumulated preferentially in the root-hair zone. Penetration usually was intercellular between anticlinal epidermal cell walls, but intracellular penetration did oc...

The resistance expressed by a range of chickpea cultivars to phytophthora root rot in glasshouse and field trials was examined. Van der Plank's compound interest equation was the most suitable transformation for providing parameters to describe epidemic development for most of the cultivars when compared to the simple interest equation by plotting...

Thesis (Ph. D.)--University of Queensland, 1991. Includes bibliographical references.

A survey of chickpea (Cicer arietirium) fields in south-eastern Queensland revealed that Phytophthom megasperma f. sp. medicaginis (Pmm) was the major cause of root rot in 1988. Eleven sites were each sampled 3 times during the growing season and the levels of infective units of Pmm present in the soil samples collected from each site were determin...

Australian collections of the Colletotrichum gloeosporioides group and closely related species were studied to assess the suitability of existing taxonomic criteria and to examine the possibility of using alternative characters in the delimitation of taxa within the group. Conidia produced on free hyphae in slide cultures were consistently more var...