Russian Wheat Aphid
Russian Wheat Aphid (RWA) (Diuraphis noxia) is a major field pest of wheat and barley in many grain producing countries. Yield losses of up to 80% in wheat and 100% in barley have been reported overseas. RWA injects toxins into the plant during feeding which stunts plant growth. Heavy infestations may kill plants.
Russian wheat aphid was first detected in wheat growing regions in South Australia in May 2016, and has now been detected in the Wimmera, Mallee and Northern country districts of Victoria. At the time of writing there have been no confirmed detections of RWA in NSW however it is expected that aphids will spread to other regions.
Wheat and barley are the primary hosts to RWA meaning the pest can feed on these plants at any stage of its lifecycle and reproduction can occur in crop. Crops such as oats, triticale and rice are secondary hosts. These crops can only support RWA as an adult and the pest cannot complete its lifecycle on these crops. Unfortunately there are many grasses both cultivated and naturalised species which can host RWA. It is known that Brome grasses are particularly important to RWA survival and population build-up.
Initial detection of RWA is most likely to occur with the observation of symptomatic plants. Plant symptoms associated with the presence of RWA include:
- Leaves with white, yellowish and red streaks
- Leaf rolling along margins
- Awns trapped by rolled flag leaves
- Heads with a bleached appearance
A national management plan for Russian wheat aphid is being developed to manage the pest in Australia. The plan has identified that it is not technically feasible to eradicate RWA from Australia however will include a range of elements such as immediate control options, training to promote early detections and best practice management, as well as research and development to provide longer term control options.
However, initially crops should be monitored for both RWA and their symptoms. The aphids themselves are very small (less than 2 mm) and a 10X magnification hand lens should be used to inspect aphids It is advised not to spray in hope of preventing an incursion. Sprays are not preventative and will kill predators and other beneficials, which may exacerbate aphid infestations in spring. It is not known how RWA will behave in Australia, however it is very likely that activity will decline with cooler winter temperatures.
Agronomists and farmers across NSW are encouraged to look for symptoms and presence of aphids in host crops and grasses. If you think you have found Russian wheat aphid, or have observed symptoms associated with the aphid, please report it to NSW DPI by calling the Exotic Plant Pest Hotline 1800 084 881.
Photographs of symptoms can also be sent to: email@example.com
Submission of negative surveillance reports is also encouraged where people have looked but not seen RWA or symptoms as this information will help to understand the likely distribution of RWA should it be found in NSW this season.
For further information within the South East Local Land Services region please contact Fiona Leech, Yass Ph 61187701 or email: firstname.lastname@example.org.