Timing of infection of macadamia fruit by Pseudocercospora macadamiae and climatic effects on growth and spore germination.

Pseudocercospora macadamiae causes husk spot of macadamia. Husk spot control would be improved by verifying the stages in fruit development susceptible to infection, and determine some of the climatic conditions likely to lead to high disease pressure periods in the field. Our results showed that the percent conidia germination and growth of germ tubes and mycelia of P. macadamiae were greatest at 26 degrees C, with better conidia germination associated with high relative humidity and free water. The exposure of match-head-sized and pea-sized fruit stages to natural P. macadamiae inoculum in the field led to 2 5-fold increases in husk spot incidence, and up to 8.5-fold increases in premature abscission, compared with unexposed fruit. Exposure of fruit stages later than match-head-sized and pea-sized fruit generally caused no further increases in disease incidence or premature abscission. Climatic conditions were found to have a strong influence on the behaviour of P. macadamiae, the host, oil accumulation, and the subsequent impact of husk spot on premature abscission. Our findings suggest that fungicide application should target fruit at the match-head-sized stage of development in order to best reduce yield losses, particularly in seasons where oil accumulation in fruit is prolonged and climatic conditions are optimal for P. macadamiae.

Culture Condition Dependent Changes Of 4-Thiouridine In The Transfer-Rna Of Azotobacter-Vinelandii

4..T~iouridine, a thionucleoside present in the transfer RNA of the free living, nitrogen-fixing ?actenu~ Azotobacter »inelandii shows a culture condition dependent change. When thebacterium IS grown Intheabsen~e ofanyfixed nit~ogen thetRNA contains 4-thiouridine to theextent of 45% of the total sulphur Incorporated. This gets reduced to 5%when the bacterium is grown in the presen~e of.e~ces~ ofamm~nium salt.Instead, a new thionucleoside which appears to be a derivative of 4-thloundlne IS found In the tRNA to the extent of 28%of the total sulphur incorporated.

The use of heat-sums to predict harvest dates following potassium chlorate (KClO3) application in longan.

The ability to initiate and manipulate flowering with KClO3 allows flowering of longan, to be triggered outside of the normal flowering season (July-September) in Australia. Fruit maturity following normal flowering will occur approximately six-eight months (180-220 days) from flowering, depending on variety. Out of season flowering will result in differing times to maturity due to different temperature regimes during the maturity period. Knowing how long fruit will take to mature from different KClO3 application dates is potentially a valuable tool for growers to use as it would allow them to time their applications with market opportunities, e.g. Chinese New Year, periods of low volumes or periods of high prices. A simple heat-sum calculation was shown to reliably quantify fruit maturity periods, 2902 and 3432 growing degree days for Kohala and Biew Kiew respectively. Growers can use heat-sum as a predictive tool to allow for efficient planning of harvesting, packaging and freight requirements.

Integrated pond culture for improved production and environmental performance

This presentation given at the World Aquaculture conference in 2008 describes research undertaken at the Bribie Island Research Centre involving zero water exchange co-culture of whiting and banana prawns.

Modulation of arginine decarboxylase activity in cucumber (Cucumis sativus) cotyledons in short-term organ culture

Among the various amines administered to excisedCucumis sativus cotyledons in short-term organ culture, agmatine (AGM) inhibited arginine decarboxylase (ADC) activity to around 50%, and putrescine was the most potent entity in this regard. Homoarginine (HARG) dramatically stimulated (3- to 4-fold) the enzyme activity. Both AGM inhibition and HARG stimulation of ADC were transient, the maximum response being elicited at 12 h of culture. Mixing experiments ruled out involvement of a macromolecular effector in the observed modulation of ADC. HARG-stimulated ADC activity was completely abolished by cycloheximide, whereas AGM-mediated inhibition was unaffected. Half-life of the enzyme did not alter on treatment with either HARG or AGM. The observed alterations in ADC activity are accompanied by change in Km of the enzyme. HARG-stimulated ADC activity is additive to that induced by benzyladenine (BA) whereas in presence of KCl, HARG failed to enhance ADC activity, thus demonstrating the overriding influence of K+ on amine metabolism.

Passionfruit growing guide - Second edition

This edition of 'The passionfruit growing guide' is a substantial update of the first edition, which was published in 2006. Each chapter deals with a specific aspect of the development and management of a passionfruit plantation. This guide is intended for use by prospective, new and established growers and addresses all aspects of passionfruit growing, from site selection and planning through to harvesting and marketing the fruit. It provides practical advice and propogation, fertilising, irrigation, and pest disease and control. Also, it includes information on varieties of passionfruit, financial budgets, chemicals registered for use on passionfruit and useful contacts.

Climate Change - Risks and Opportunities for the Custard Apple Industry

Climate affects the custard apple industry in a range of ways through impacts on growth, disease risk, fruit set and industry location. Climates in Australia are influenced by surrounding oceans, and are very variable from year to year. However, amidst this variability there are significant trends, with Australian annual mean temperatures increasing since 1910, and particularly since 1950, with night-time temperatures increasing faster (0.11oC/decade) than daytime temperatures (0.06oC/decade). These temperature increases and other climate changes are expected to continue as a result of greenhouse gas emissions, with ongoing impacts on the custard apple industry. Five sites were chosen to assess possible future climate changes : Mareeba, Yeppoon, Bundaberg, Nambour and Lismore, these sites representing the extent of the majority of custard apple production in eastern Australia. A fifth site (Coffs Harbour) was selected as it is south of the current production regions. A mean warming of 0.8 to 1.2oC is anticipated over most of these sites by the year 2030, relative to 1990. This paper assesses the potential effects of climate change on custard apple production, and suggests strategies for adaptation.

In vitro culture of buffalo fly and infections with Wolbachia

"Develop and optimise reliable in vitro culture methods for buffalo fly "Use the in vitro system to determine whether experimental Wolbachia infection can be established in buffalo fly. "Prepare further applications for related work towards better control of buffalo fly, exploiting the in vitro culture system.

Integrated pest management and supply chain improvement for mangoes in the Philippines and Australia

This project will incorporate two strategies for improving industry sustainability in the Philippines and Australia: (a) developing improved field management and quarantine monitoring and detection of mango pests and diseases; and (b) working with selected mango supply chains to identify and test areas for improvement.

Evaluation of APFIP (apple) varieties

Evaluation of APFIP (apple) varieties.

Honey Gold Mango

To improve the yield of Honey Gold mango through nutrition, pruning and growth regulators.

Strategic banana tissue culture industry development and biosecurity act

Application and development of activities based on in vitro technologies delivering research, industry development and biosecurity activities to sustain and improve the Australian banana industry.

Vapour heat treatment of honey gold mango

Vapour heat treatment of honey gold mango for access to the Japanese market.

Developing Queensland 3D Tropical Fruits and Nuts modelling capabilities

Development of 3D functional structural plant models for macadamias and other tropical fruit and nuts.