People

Research Interests

Prior to undertaking a PhD, I worked as an extension agronomist with NSW Department of Agriculture in Wagga Wagga and then the Hunter Valley, and worked for a private agronomic company in the United Kingdom. From April 2010 until August 2011, I worked in plant biosecurity for Plant Health Australia, a not-for-profit company funded by industry and government based in Canberra.

Current research areas include:

• Agronomy and nutrition of aerobic rice
• Herbicide residues in soils and implications for crop growth
• Phosphorus efficiency of crop plants, focussing on loading of phosphate into grains
• Enhanced efficiency fertilisers in the subtropics
• Cover cropping and intercropping in field crops and horticulture
• Coffee varietal performance in the Australian subtropics and the Pacific
• Organic agricultural systems (see details at Organic Research Centre website)
• Recycled organics: impacts of amendments on soils and crops
• Nitrogen efficiency in subtropical sugarcane systems
• Subtropical grazing systems
• New high value crops for coastal cropping systems in the subtropics

Recent grants, awards and publications

Research Interests

My research interest is integrated disease management of tropical and subtropical horticultural crops using techniques such as plant breeding and plant selection for resistance, optimised plant nutrition, use of defence activators and biological control organisms, and better understanding infection processes of pathogens to better target control and reduce losses due to disease.

Over the last 20 years my research has included; biological control of root knot nematode of sugarcane, breeding passionfruit for disease resistance, integrated management of pineapple diseases, control of avocado fruit and root diseases, and study of the infection process in Fusarium wilt of banana. 

I am based at NSW Department of Primary Industries at Wollongbar and I enjoy working closely with farmers, industry and my colleagues on the development of practical solutions for disease problems.

I have shared my knowledge through soil health masterclasses for sugarcane growers, participation in field days and roadshows for growers, publication of scientific papers and through teaching plant pathology and molecular diagnostics in plant protection at the University of Queensland.

Background

SCU PhD candidate Anders Claassens' work investigates fungal symbiosis in cropping systems. After his undergraduate studies in environmental science, Anders undertook a research MSc. to lay the foundations necessary for his PhD work under the supervision of scientists at SCU and the NSW Department of Primary Industries. His PhD is supported by Sugar Research Australia and is examining arbuscular mycorrhizal (AM) fungi in Australian sugarcane.

AM fungi are a key component of the sugarcane microbiome. In colonised hosts, AM fungi augment the capacity of root systems to assimilate mineral nutrients from soil in exchange for photosynthetically fixed carbon. AM fungi may confer additional benefits to hosts through enhanced biotic and abiotic stress resistance in some agronomic contexts. Presently, the factors driving AM symbioses in sugarcane are poorly understood and new knowledge will be critical to leveraging AM fungi in a management context. Specifically, these developments will allow the broader sugarcane research community to optimise experimental procedures, link AM fungal growth traits with molecular quantification of AM taxa and assess AM-mediated impacts on crop production.

Anders’ research employs microscopic assessments and molecular diagnostic techniques including PCR and DNA sequencing to address the following aims:

• Identify an optimal method for preservation of AM fungal DNA from sugarcane root tissue.
• Discriminate AM fungi forming active symbioses from latent AM taxa present in soils.
• Determine whether edaphic factors induce taxon-specific selection effects in AM symbiosis.
• Evaluate how host preference for native AM taxa shifts in response to increasing rates of soil-applied commercial mycorrhizal inoculum.

Background

Consumers are becoming more aware of insecticides in crops, and organic food is increasingly popular worldwide. Macadamia is the only native Australian food crop to be commercialised internationally, with an Australian farm-gate value of $286.5 million. In the Northern Rivers of NSW, one of macadamia’s native pests, the macadamia lace bug (Hemiptera: Tingidae), is a widespread seasonal pest of flowers. The two species identified impacting macadamias, Cercotingis decoris and Proteatingis howardi feed on flowers resulting in flower abscission that causes reduced nut set. Crop losses from lace bug have been as high as 100%, and is regarded as a new significant pest of macadamia in the region.

In 2004, Australia signed the Stockholm Convention on Persistent Organic Pollutants (POPs), many of which are insecticides, and dichlorodiphenyltrichloroethane (DDT) was phased out of use. In 2010, further insecticides were phased out, including endosulfan previously used in macadamias and likely to have controlled macadamia lace bugs. Further expected removal of chemicals is likely to limit the available options for treating macadamia lace bugs.

Biological control using predatory insects has successfully controlled pests in many crops. In macadamias, commercially produced Trichogramma crytophlebia (wasps) are mass released and have mostly removed the need for insecticides to control the macadamia nut-borer Cryptophlebia ombrodelta.

My research aims to understand the biology and ecology of lace bugs infecting macadamias in the Northern Rivers of NSW, by studying temperature effects on lifecycle, and identifying distribution and movement. It also aims to test the effectiveness of generalist predators against macadamia lace bugs to identify potential biological control options.

Background

Rice (Oryza sativa L.) is the staple food crop for half of the world’s population contributing to more than 20% of the total daily calorie intake (1). Most of the rice is consumed as a white rice in which, various bioactive compounds such as anthocyanins and gamma-oryzanol are removed by polishing. Hence, whole grain rice has more nutritional value and nutraceutical properties in comparison to white rice (2). In recent years, pigmented whole grain rice has received much attention due to its probable health benefits. Therefore, investigating a method to manipulate these bioactive compounds in pigmented rice could be advantageous for the rice industry.

During rice cultivation, the macro-nutrient (N, P and K) fertilizers are usually applied in significant amounts to achieve higher grain yield (3). But in this process, any possible effect of these fertilizers on bioactive compounds are not often considered. This PhD project will investigate the effect of these N, P and K nutrients on bioactive compounds of rice with the aim of optimizing both yield and nutrition in rice in relation to differential use of N, P and K fertilizers.

References

(1) Marco, C., Maria de La Luz, C.-G., & Antonio, S.-C. (2018). Extraction and Analysis of Phenolic Compounds in Rice: A Review. Molecules, 23(11), 2890. doi:10.3390/molecules23112890

(2) Rao, S., Schwarz, L. J., Santhakumar, A. B., Chinkwo, K. A., & Blanchard, C. L. (2018). Cereal phenolic contents as affected by variety and environment. Cereal Chemistry, 95:589-602

(3) Kyi, M., Aung Zaw, H., Thieu Thi Phong, T., Yoshinori, K., & Takeo, Y. (2019). Effects on NPK Status, Growth, Dry Matter and Yield of Rice (Oryza sativa) by Organic Fertilizers Applied in Field Condition. Agriculture (Basel), 9(5), 109. doi:10.3390/agriculture9050109

Background

Meta analyses from Europe indicate organic vegetables contain more beneficial secondary metabolites than conventionally grown vegetables. Currently there is no Australian research investigating the nutritional differences between organic and conventionally grown vegetables. This project is focussed on glucosinolates in broccoli which have proven nutritional and health benefits. The aim is to investigate differences in secondary metabolite production with different fertiliser regimes and also to identify other factors that may lead to improved broccoli nutrition

Reference

Higher antioxidant and lower cadmium concentrations and lower incidence of pesticide residues in organically grown crops: a systematic literature review and meta-analyses. Barański et al., 2014. DOI: doi.org/10.1017/S0007114514001366