(Photo: GRDC) (Photo: GRDC) THE steadyl spread of the Russian Wheat Aphid (RWA) from southern regions into the northern farming zone has prompted researchers to intensify their surveillance of the damaging crop … The recommended threshold to apply insecticide is 50% of cereal tillers have 15 or more aphids and crops are expected to yield three tonnes/ha or more. The GRDC investment UOA1805-018RTX ‘Russian wheat aphid risk assessment and regional thresholds’, investigated regional risk and management tactics for Russian wheat aphid (RWA). Russian wheat aphid uses grasses, barley grass in particular, as its non-host plant and prefers temperature ranges of nine to 21 degrees Celsius. “The action threshold developed for RWA is ‘dynamic’. It was first noted as a pest in the Crimea in 1901, hence the common name. Sep Russian wheat aphid Russian wheat aphid (RWA) (Diuraphis noxia), is a newly arrived pest of wheat, barley and other cereal grains. Corn leaf aphids and bird cherry oat aphids are very common in the fall while English grain aphids are most abundant in the spring. Russian wheat aphid. The Grains Research and Development Corporation has developed the FITE strategy against Russian wheat aphids. At least 120 scientists from 20 countries participated in the program, which imported more than 12 million benefi-cial insects of at least 24 species. Photo: GRDC . Symptoms include rolled leaves, chlorotic spots, prominent leaf streaking, trapped awns giving a hooked appearance, and a stunted crop. What to look for. September 2016, Primefact 1489, first edition . RWA is an aphid that can cause significant damage and yield losses, particularly in infected wheat and barley crops but also in triticale and oats. Although experts stress that the outbreak is not yet a crisis, farmers in the Free State and Western Cape are urged to be vigilant and conduct necessary inspections. Through a Grains Research and Development Corporation (GRDC) investment, a RWA action threshold calculator has been developed to underpin grower and adviser decision […] Australian scientists have developed a new tool to reduce the guesswork by grain growers in assessing the need to take action against Russian wheat aphid (RWA) to prevent yield and financial loss. This aphid is pale green and up to 2 mm long. The GRDC investment, ‘Russian wheat aphid risk assessment and regional thresholds’, was established to investigate regional risk and management options for RWA. Key identifying features of Russian wheat aphid (Photo: A. Nicholas, Oklahoma 2011). 20 days at 10oC, and 9 days at 20oC. During this time, a suggested monitoring approach is to fortnightly mark out some locations, then (1) Count tillers over 50cm row, (2) Count tillers with symptoms (3) Take 20-30 tillers with symptoms and check for aphid presence , (4)Calculate % infested tillers. It was first detected in South Australia in 2016 and is now present in Victoria, New South Wales and Tasmania. SARDI-PIRSA CommunicationsPIRSA.Media@sa.gov.au, Sharon Watt, GRDC Communications Manager – South0409 675 100sharon.watt@grdc.com.au, To protect your privacy, please do not include contact information in your feedback. Researchers from SARDI and Cesar Australia have developed a calculator to help crop advisors and growers decide if spraying for Russian wheat aphid (RWA, Diuraphis noxia) is economically justified. It is a major pest of cereal crops that injects toxins into the plant during feeding which retards growth and, with heavy infestations, kills the plant. Any feedback on the calculator can be sent to jlye@cesaraustralia.com. Through a GRDC investment, a RWA action threshold calculator has been developed to underpin grower and adviser decision-making. Currently the Russian wheat aphid and yellow sugarcane aphid are not present in Kentucky. If establishment occurs after GS30 there is low aphid growth potential. In most areas of California, it appears that Russian wheat aphid builds to damaging levels sporadically, much like the population cycles of bird cherry-oat aphid. Among the guest speakers will be entomologist Maarten van Helden from SARDI, who will provide an update on the management of Russian wheat aphid, particularly the performance capability of the new RWA threshold calculator in determining cost-effective treatment. Russian Wheat Aphids (RWA) have recently been reported in Vic and SA recently, providing the perfect time to consider your pest management strategies and RWA control options. Russian wheat aphid can generally survive winter in the Great Plains, with the possible exception of North Dakota. The aphid injects toxins into the plant during feeding which retards growth and with heavy infestations, kills the plant. (Ed.) Russian wheat aphid is able to survive under a wide range of temperatures and may perform better at lower temperatures than other cereal aphid pests. The species was introduced to the United States in 1986 and is considered an invasive species there. “Unlike most action threshold rules in the grains industry which have been set based on field observations and estimation, our research into RWA has used an experimental approach to collect data on the relationships between damage, pest numbers and impact.” SARDI and cesar researchers have observed that in low green bridge risk years (dry, hot summer and autumn), natural infestations are very low and populations reaching economically damaging levels are unlikely. It is difficult to determine if an individual aphid will be winged or wingless until it is near maturity. Researchers from SARDI and Cesar Australia have developed a calculator to help crop advisors and growers decide if spraying for Russian wheat aphid (RWA, Diuraphis noxia) is economically justified. Russian wheat aphid is a major production pest of wheat, barley and oat crops. 61–68. Russian wheat aphid (Diuraphis noxia; RWA) was first identified in South Australia in 2016. Australia, Privacy policy & terms | Legal terms & conditions | ABN 26 123 867 587, Russian wheat aphid action threshold calculator, Russian wheat aphid action threshold calculator: instructions for use. AUSTRALIAN scientists have developed a new tool to reduce the guesswork by graingrowers in assessing the need to take action against Russian wheat aphid to prevent yield and financial loss. “This means a very high likelihood of resistance that renders this control method useless.” Only a limited selection of active ingredients are registered for RWA control in South Africa, says Jankielsohn. The project was led by the South Australian Research & Development Institute (SARDI) and undertaken in partnership with Cesar Australia over 2018-2020. In some aphids the cornicles are easily observed, while in others they are greatly reduced in size. Aphids--adults and nymphs--can damage plants anytime after emergence. Dr van Helden says that due to the delay between crop inspection and pest control, a predictive action threshold is preferred in integrated pest management, as it factors in the rate of change in aphid pressure during the intervening period. Growers and agronomists are urged to check cereal crops and grass weeds for aphids and damage symptoms. Russian wheat aphid, Diuraphis noxia, is a small green aphid whose feeding produces strong plant symptoms due to the injection of saliva into the plant. Russian Wheat Aphid. New tool cuts Russian wheat aphid action threshold guesswork. In general, fields with >10% infested tillers will benefit from an insecticide areas. ©Colorado State University Extension. The GRDC investment, ‘Russian wheat aphid risk assessment and regional thresholds’, was established to investigate regional risk and management options for RWA. Russian wheat aphid appears in the high desert (Antelope Valley), however, it is rarely a damaging pest because wheat heads are usually past the boot stage before damaging numbers can develop. Prolonged periods below 15°F (9°C), extended snow cover, and rapid freezing and thawing are detrimental to the aphid. “The economic injury level is reached when the cost of pest control equals the value of yield loss resulting from feeding damage. The economic threshold for Russian wheat aphid in winter wheat from regrowth to heading can be predicted (1% infested tillers = 0.5% yield loss). Heading into spring, rising temperatures are expected to cause an increase in populations of Russian wheat aphid (RWA), Diuraphis noxia, and natural enemies.The latest cereal aphid monitoring data have shown a recent decline in RW aphid populations in SARDI trial sites monitored fortnightly at Loxton, Bool Lagoon and Roseworthy (SAGIT Funded). The Russian wheat aphid (Diuraphis noxia Kurdju-mov, Hemiptera: Aphididae) is a severe global pest of small grains including wheat (Triticum aestivum L., 1 USDAÐARS, Wheat, Peanuts, and … They have been building a biological and ecological profile of the pest to provide Australian growers with scientifically robust management tactics for the future. 6/98. Parkville The GRDC investment, ‘Russian wheat aphid risk assessment and regional thresholds’, was established to investigate regional risk and management options for RWA. Du Toit, F. & Walters, M.C. Russian wheat aphids on a leaf, showing damage to the leaf, and different forms and multiple generations of the aphid. To send this article to your … Photo: Tom Heddle PIRSA-SARDI The more Australian researchers learn about Russian wheat aphid (RWA), the more confident they are that the pest does not pose a major threat to winter cereal crops in this country if growers and advisers understand how to manage it effectively. Predation and parasitism would also be expected to play a role in controlling the aphid population growth rate. The salivaof this aphid is toxic to the plant and causes whitish striping on cereal leaves. Monitoring and making threshold-based decisions are key to effective long-term management of Russian wheat aphid. Wetter and cooler summers or early breaks could increase the risk of early season infestation by RWA in mainland grain growing areas. Heading into spring, rising temperatures are expected to cause an increase in populations of Russian wheat aphid (RWA), Diuraphis noxia, and natural enemies.The latest cereal aphid monitoring data have shown a recent decline in RW aphid populations in SARDI trial sites monitored fortnightly at Loxton, Bool Lagoon and Roseworthy (SAGIT Funded). There is an appendage above the cauda giving the aphid the appearance of having two tails. Russian Wheat Aphid is the latest broadacre crop pest to challenge the grains industry and was detected on the Liverpool Plains in northern New South Wales late last year. SARDI researchers Thomas Heddle (left) and Maarten van Helden using Berlese funnels to extract Russian wheat aphids from grass samples. 2020. Through a Grains Research and Development Corporation (GRDC) investment, a RWA action threshold calculator has been developed to underpin grower and adviser decision making. This action threshold calculator is the culmination of field trial data collection and analysis over two winter cropping seasons (2018-2019) in south eastern Australia. Russian Wheat Aphids (RWA) have recently been reported in Vic and SA recently, providing the perfect time to consider your pest management strategies and RWA control options. Cornicles are very short, rounded, and appear to be lacking. This cereal pest is now present in cropping areas of SA, Victoria, Tasmania, New South Wales and Western Australia. The aphid, which is up to 2mm long, is light green in colour and has a tiny spike at the rear above its tail, giving the impression of two tails. It is part of a collaborative investment, ‘Russian wheat aphid risk assessment and economic threshold’, led by SARDI in partnership with sustainable agriculture research organisation cesar. Russian wheat aphid (Diuraphis noxia) is found in all major cereal production regions around the world, but never in Australia before now. Prior to using the calculator it’s important that you read the following document – Russian wheat aphid action threshold calculator: instructions for use: We acknowledge Aboriginal and Torres Strait Islander peoples as the first inhabitants of Australia and the traditional custodians of the lands on which we work. For Russian wheat aphid: The main risk period is approximately GS 20–40. Russian wheat aphid damages plants by injecting salivary toxins and can severely reduce yields if not controlled. Experimental data was not sufficient to develop an action threshold for infestations detected before GS30. Monitoring and making threshold-based decisions are key to effective long-term management of Russian wheat aphid. The economic threshold for Russian wheat aphid in winter wheat from regrowth to heading can be predicted (1% infested tillers = 0.5% yield loss). If pest densities surpass this level, losses will be greater than the cost of control,” he says. Plant Biosecurity and Product Integrity, Orange . Russian wheat aphid population has exceeded the recommended economic threshold before making an insecticide application. Growers should implement the “FITE” strategy (Find, Identify, Threshold approach and Enact) and report any incursions. It can help growers determine whether a timely spray application is needed to prevent crop and profit losses, or whether insecticide application would be an unnecessary cost. Australian scientists have developed a new tool to reduce the guesswork by grain growers in assessing the need to take action against Russian wheat aphid (RWA) to prevent yield and financial loss. The Russian wheat aphid (RWA) is native to south-western Asia and was introduced into many European countries in the 20th century. While it won't reproduce below 4oC, it … Russian wheat aphid How to recognise it Russian wheat aphid (Diuraphis noxia) has been found in many grain growing regions of Australia since May 2016. SARDI entomologist Maarten van Helden says the data on infestation levels, symptoms and associated yields has helped to determine the regional production risk posed by RWA and a dynamic action threshold that will guide growers in effective management of RWA, taking into account infestation level, cost of control, market grain value and yield potential. a response, please, Grains Research & Development Corporation, Business development and commercialisation, RWA growth stage 30 action threshold calculator, New tool cuts Russian wheat aphid action threshold guesswork, The best metric for predicting yield loss is percentage of tillers with RWA, On average, for each percent of tillers with RWA there is 0.28% yield loss. Photo: Michael Nash, South Australian Research and Development Institute, a division of Primary Key findings that have been used to form the basis of the Australian intervention rule for RWA are: Dr van Helden says the maximum percentage of tillers with RWA is usually reached between GS40 (start of booting) to GS50. Photo: Tom Heddle PIRSA-SARDI Photo: Tom Heddle PIRSA-SARDI The more Australian researchers learn about Russian wheat aphid (RWA), the more confident they are that the pest does not pose a major threat to winter cereal crops in this country if growers and … Scientists, with GRDC investment, have been studying RWA under southern Australian conditions and within local farming systems since it was first detected in 2016. A control decision should be made based on RWA population densities between GS30 and GS50. The research has shown that the plant growth stage at which RWA establishes has a strong effect on yield loss potential. 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