Western Australia - New resource for advice about aphids
Western Australia
September 29, 2017
A new GRDC video featuring DPIRD development officer Dustin Severtson is a practical guide for dealing with aphids. - Photo: GRDC
Western Australian grain growers have access to a new tool to help with diagnosis and management of aphids this season.
The Grains Research and Development Corporation (GRDC) ‘Know More’ video ‘Strategies to control aphids’ is a practical guide to dealing with this insect in parts of the western region where it is likely to strike this spring. It can be viewed at: https://youtu.be/3R-CrOi6bD0
The video features Department of Primary Industries and Regional Development (DPIRD) development officer Dustin Severtson, who outlines tips for identifying and controlling aphids; threshold guidelines for economic control; and how new technologies are being trialled for better surveillance of this pest.
Dr Severtson says that as temperatures rise, aphids become more active and crops are colonised.
His key message for the management of aphids this spring is to apply registered insecticides (at label rates) only when economic losses are likely to occur.
“Products can be expensive and insecticide resistance is a major industry issue,” Dr Severtson said.
“Growers are reminded to adhere to chemical registration thresholds and to avoid unnecessary or prophylactic sprays.
“If a protective insecticide has been applied earlier in the season to avoid aphid virus transmission, another treatment may be needed in spring.”
Trials in WA, with GRDC investments, have found yield loss in canola is typically most likely when 20 per cent or more of plants are infested with aphids at bud formation and flowering stages.
Dr Severtson said insecticide applications on paddock borders may be warranted and economic at this threshold level, particularly for cabbage aphid (Brevicoryne brassicae).
“But in higher rainfall areas, canola can often recover from aphid infestations at flowering and yield loss does not typically occur when aphids are found in crops at podding stage,” he said.
“For cereals, research and experience in WA indicates applying insecticides to curb aphid feeding damage is typically worthwhile when crops are expected to yield more than three tonnes per hectare and in which 50 per cent of tillers have 15 or more aphids.”
Dr Severtson said parasitic wasps, ladybeetles, lacewings and hoverflies provided useful biological control of aphids, mainly by preventing secondary outbreaks.
“This reiterates the importance of using ‘soft’ insecticides that only control aphids, such as pirimicarb,” he said.
Dr Severtson said growers could use a hand-held lens or mobile phone clip-on lens to inspect crops and he recommended regular monitoring for the insect in susceptible areas of the State where numbers had built up and/or crops were at higher risk due to being moisture-stressed.
He encouraged growers to continue monitoring canola and cereal crops closely, report aphid activity and check maps of aphid incidence through PestFax using phone, email or the PestFax Reporter mobile telephone app at: https://www.agric.wa.gov.au/diseases/pestfax-reporter
Dr Severtson said paddock observations were a key part of grains industry surveillance for the Russian wheat aphid (RWA, Diuraphis noxia) and would also assist WA researchers to produce forecasts and alerts for a the most common species of this pest in particular areas.
“RWA has not been detected in WA, but has caused some damage to crops in South Australia and the eastern states since it was discovered in 2016,” he said.
“If in doubt, growers and advisers are encouraged to send any suspect aphid samples to agriculture and food offices at DPIRD for identification.”
This year, innovative technologies for faster and more accurate aphid (and other insect) surveillance are being trialled in WA by DPIRD researchers, funded by Royalties for Regions. These include DNA techniques, mobile device apps and ‘smart’ traps.
DPIRD has released an app for iPhones and android devices called ‘CropScout’, which Dr Severtson said stemmed from his recent GRDC-supported PhD research into spatial distribution of aphids in canola crops during spring and how it effects sampling accuracy.
MyCrop online diagnostic tools, available at https://www.agric.wa.gov.au/mycrop, can assist growers and advisers in identifying and managing aphids.
The Resistance Management Strategy for the Green Peach Aphid in Australia, available at www.grdc.com.au/GPAResistanceStrategy, provides information which can help minimise selection pressure for resistance in green peach aphid (GPA).
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