Browsing by Author "Powell, K"

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Giving it our best shot in the war against soldier flies - future research directions : ASSCT peer-reviewed paper
(ASSCT, 2021) Lenancker, P; Powell, K
Soldier flies are economically damaging pests of sugarcane, particularly in central and southern Queensland. Despite decades of research on soldier fly control, the search for an effective management approach, except for cultural control, remains elusive. Trials were conducted from 2015 to 2017 to identify potential management solutions for soldier flies by assessing insecticide efficacy and varietal tolerance in field conditions. Five field trials were established to determine whether applying insecticide at plant cane would reduce the build-up in soldier fly larvae in subsequent ratoons. Ten products, comprising seven active ingredients, were field tested at high application rates. Overall, as in most previous studies, none of the insecticides tested reduced the number of larvae in field-trial conditions. The inefficacy of insecticide treatments could be due to products failing to come into contact with soldier fly larvae or simply lack of an effective active. In addition, three field trials, using up to 14 varieties, were conducted, to assess varietal tolerance. Some varieties tended to host fewer larvae than others, suggesting some resistance, in two trials established in southern Queensland. Any future insecticide and varietal screening trials will need to be conducted in both controlled laboratory and field conditions. However, before such trials can be undertaken, a standardised laboratory rearing method and improved field sampling strategy for soldier flies needs to be developed. Soldier fly outbreaks are also unpredictable and developing methods to forecast them (e.g. using climatic data or identifying preferential soil properties) will also be highly beneficial to inform growers of the potential risk of soldier fly establishment in their paddocks and for selecting field-trial sites. Additionally, recent DNA barcoding and morphological studies have revealed that at least six species of soldier flies are found in sugarcane, not two as previously identified. That finding highlights that the distribution of soldier fly species in Australia and the relative damage to sugarcane varieties needs to be resolved to enable the development of targeted species-specific management approaches.
Soldier fly management; insecticide efficacy and varietal tolerance in field trials : ASSCT poster paper
(ASSCT, 2020) Lenancker, P; Lindsay, K; Khudhir, M; Jennings, J; Ward, A; Powell, K
Soldier flies (Inopus flavus and I. rubriceps) are an economically damaging pest of sugarcane that can periodically cause major yield losses for some growers in central and southern Queensland. Larvae alter plant growth by feeding on roots. There is currently no insecticide registered for soldier flies.
Solving YCS : final report 2014/049
(ASSCT, 2021) Scalia, G; Joyce, P; Powell, K
Yellow canopy syndrome (YCS) is a sporadic condition presenting as golden-yellowing of the mid canopy in sugarcane during the peak growing period of December to March. The key driver of YCS is growth rate and symptoms usually exhibit after rainfall. YCS can be induced or mitigated by altering sink strength and sugarcane can recover from a YCS event. Abiotic or biotic stress has a serious effect on the photosystems and the physiological fitness of the crop. There is a strong correlation between YCS expression, leaf sucrose and sink strength, independent of crop age. YCS symptomatic leaves always have high leaf sucrose and ?-glucan content. Under experimental conditions the pyrethroid bifenthrin supresses insect stress, promotes increased sink growth and maintains low leaf sucrose and ?-glucan levels. Induced senescence causes YCS plants to have a lower number of attached leaves. Yield loss precedes YCS expression and there is no correlation between YCS severity and cane yield or CCS. Lamina starch staining is a useful tool to assist in YCS identification. There is no strong evidence of genetic predisposition for YCS susceptibility. Industry-wide incidence and severity of YCS is too difficult to accurately assess due to its episodic nature, no single causal agent and the link to climate change and severe weather events. The data does not support the cause of YCS being a pathogen, specific insect or mite, soil borne agent, poor root health, nutrient deficiency, or heavy metal toxicity. YCS is a physiological disorder visualised as the terminal expression of metabolic perturbances caused by growth disruption.