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PestFacts WA

Aphid and turnip yellows virus update

  • Walkaway
  • Nilgen
  • Dalwallinu
  • Toodyay
  • Narrogin
  • Cranbrook
  • Manjimup
  • Kendenup
  • South of Stirling Ranges
  • Scaddan west
Winged and non-winged green peach aphids on turnip yellows virus infected canola.
Winged and non-winged green peach aphids on turnip yellows virus infected canola. Photo courtesy of: Benjamin Congdon (DPIRD).

Large numbers of winged turnip yellows virus (TuYV) carrying aphids (including green peach aphids) were captured last week in sticky traps at Kendenup and at sites south of the Stirling Ranges.

Green peach aphids have been caught on traps around Toodyay and Cranbrook. Other aphid species have been caught on traps at Walkaway, Nilgen, Dalwallinu, Narrogin, Manjimup and West Scaddan.

The map below summarises aphid and TuYV trapping data collected by DPIRD as part of the Boosting Grains Science Partnership project.

Map of aphid and turnip yellow virus (TuYV) presence or absence findings by DPIRD yellow sticky traps this season to date across the WA grainbelt.
Map of aphid and turnip yellow virus (TuYV) presence or absence findings by DPIRD yellow sticky traps this season to date across the WA grainbelt. Map courtesy of: DPIRD.

Growers are reminded to monitor their canola crops for aphids or plants displaying TuYV symptoms.

If you see aphids colonising canola crops, or plants that look symptomatic that you are concerned about, they can be tested for the presence of TuYV through the Department’s Diagnostic Laboratory Services – Pathology Services.

For insecticide recommendations, refer to DPIRD’s 2021 autumn winter insecticide guide.

For previous aphid and TuYV findings and management information, refer to DPIRD’s:

For further information, contact Benjamin Congdon, Research Scientist, South Perth on +61 (0)8 9368 3499.

 

 

Article authors: Cindy Webster (DPIRD Narrogin) and Benjamin Congdon (DPIRD South Perth).

Locusts are still on the move

  • Eneabba
  • Mukinbudin
  • Wialki
  • Beacon
  • Moora
  • Merredin
  • Southern Cross
  • Yerecoin
  • Koorda
  • Cadoux
  • Beverley
  • Jerramungup
  • Scaddan
Adult Australian Plague Locust
An adult Australian Plague Locust. Photo courtesy of: DPIRD.

Due to the continuing warm weather in some parts of the State, Australian plague locust (APL) adults are still active.

APL activity has been reported over a wide area of the grainbelt, from as north as Eneabba and south to Scaddan (see reported locations above).

Growers from Mukinbudin and Eneabba have reported APL causing damage to crops, with some crops in Mukinbudin needing to be re-sown.

Even though APL activity is expected to decrease with cooler weather, insecticide control needs to occur if crops are being damaged. The best time to apply insecticide is early in the morning when APL are not actively moving. For more insecticide information, visit DPIRD’s Australian plague locust control: registered insecticides page.

The PestFax team would appreciate growers and consultants continuing to report APL activity this season by using the PestFax Reporter app.

To read about previous APL activity reported this season, refer to the 2021 PestFax Issue 1 article, Locusts can damage emerging crops.

Further APL information can be found at DPIRD’s Australian plague locust overview page.

For more information, contact Research Scientist Svetlana Micic, Albany on +61 (0)8 9892 8591.

 

 

Article authors: Svetlana Micic (DPIRD Albany) and Cindy Webster (DPIRD Narrogin).

Russian wheat aphids are now winged

  • Munglinup
  • Needilup
A Russian wheat aphid
A Russian wheat aphid. Photo courtesy of: DPIRD.

Russian wheat aphids (RWA) have been found on volunteer barley at Munglinup.

Entomologist Svetlana Micic (DPIRD) reports that Russian wheat aphids at Needilup, previously discussed in the 2021 PestFax Issue 2 article, are now winged and expected to move further into the WA grainbelt.

Growers are urged not to panic as this aphid is readily managed. Even though low levels of Russian wheat aphid can cause striping symptoms on plants, if you find Russian wheat aphids in your cereal crops it does not necessarily mean there will be yield loss. Trials conducted by SARDI have found the most significant correlation is the number of tillers with Russian wheat aphids and yield loss. For more information, refer to GRDC’s Russian wheat aphid page.

Growers should consider applying sprays only when threshold levels are reached. A Russian wheat aphids threshold calculator is available on GRDC’s Russian wheat aphid page

For a list of insecticides registered for use on aphids (including Russian wheat aphids), see DPIRD’s 2021 autumn winter Insecticide Guide or refer to the Australian Pesticides and Veterinary Medicines Authority (APVMA) products database for all chemical control options available for Russian wheat aphids in grains crops.

Please report any suspect detections of Russian wheat aphids, or Russian wheat aphids damage, by using DPIRD’s PestFax Reporter app.

To read about previous Russian wheat aphids activity reported this season, refer to the 2021 PestFax Issue 2 article Russian wheat aphid found in barley regrowth down south.

For more information on Russian wheat aphids, refer to the:

For more information on Russian wheat aphids, or other aphids, contact Research Scientist Svetlana Micic, Albany on +61 (0)8 9892 8591.

 

 

Article authors: Svetlana Micic (DPIRD Albany) and Cindy Webster (DPIRD Narrogin).

Blackleg - spores are present and forecasts have begun for 2021

  • Albany region

A spore trap
A spore trap and trap plants. Photo courtesy of: Kithsiri Jayasena (DPIRD).

Plant pathologist Kithsiri Jayasena (DPIRD) has reported finding blackleg spores in spore traps in the Albany region.

Kithsiri also reports that very early sown canola crops in the South Stirlings area are already coming into the flowering stage. As these crops will be flowering during a period when blackleg spores are being released, they are at increased risk of developing blackleg upper canopy infections (UCI).

With the increase in canola prices, many WA growers are taking the opportunity to sow canola now, which is quite late in the canola sowing window for some areas of WA. There are concerns that untreated canola seed, such as ATR Bonito (rated moderately susceptible or MS as a bare seed), is being sown. Late sowing of canola with untreated seed is a concern because it puts crops at risk of emerging and being at their most susceptible growth stage (4-6 leaf) during the high risk blackleg spore release period. The use of flutriafol,  as either a liquid in-furrow or treated fertiliser, at seeding will help reduce blackleg infections but, ideally, seed should be treated with a seed dressing prior to sowing. If untreated seed is sown, growers will need to make decisions regarding applying foliar fungicides during this early vegetative stage to control blackleg stem canker infection.

What is blackleg?

Blackleg in canola
Blackleg on a canola leaf. Photo courtesy of: DPIRD.

Blackleg, caused by the fungus Leptosphaeria maculans, is one of the most serious diseases of canola in Western Australia. Blackleg can cause significant damage by infecting the cotyledons, or first leaves, early in the season, leading ultimately to crown lesions or cankers later in the season.

Blackleg is spread primarily by wind, with the heaviest spore fall out normally occurring within 500 metres of any canola residue. Each year, canola residue continues to produce blackleg spores at a diminishing rate until the stubble has completely broken down.

The overall risk of blackleg infection on a property will be determined by factors such as choice of variety resistance group (and frequency of variety use), paddock rotation, fungicide usage, distance from previous year’s canola residues, and stubble reduction.

To minimise the risk of blackleg infection, growers should consider:

  • Sowing into paddocks that are out of canola rotation for more than three years.
  • Avoiding sowing within 500m of last year’s canola residues.
  • Applying seed dressing and fertiliser applied fungicide. Reduced sensitivity to Jockey® and flutriafol has been reported in some WA blackleg populations. Please report any unexpected failures to your agronomist or DPIRD.
  • Applying a foliar seedling fungicide in case of high disease pressure. You can assess your risk level by referring to GRDC’s Blackleg Management Guide 2021 Autumn Fact Sheet, and DPIRD’s BlacklegCM  decision support tool.

For more information, refer to DPIRD’s Diagnosing blackleg in canola page.

Managing blackleg infection

For both blackleg stem canker and blackleg UCI, growers need to consider their varietal resistance levels before they spray as it may not be economical to spray varieties with high resistance levels (look at the bare seed rating as an indication of UCI susceptibility).

Fungicides applied during the bloom stage (before 50% bloom) may reduce UCI, and there are now some products, like Aviator Xpro®, registered for use. These products should be applied at similar times to the fungicides used for Sclerotinia control. These fungicide applications for UCI are likely to be more economical in higher yielding crops.

For more information regarding canola variety resistance ratings and blackleg management, refer to GRDC’s Blackleg Management Guide 2021 Autumn Fact Sheet, and DPIRD’s Registered foliar fungicides for canola in WA page.

Deciding on your best course of action

DPIRD’s BlacklegCM is a useful decision support tool for assessing the value of spraying to manage blackleg stem canker during the 4-6 leaf stage. Growers can manually enter the blackleg risk levels (low, moderate and high) that relate to your sowing date and location into the tool. These risks can be found online at DPIRD’s blackleg spore maturity forecasts for Western Australia. BlacklegCM cannot be used to determine the value of flowering sprays for management of upper canopy infection. For more information on this decision support tool, refer to DPIRD's BlacklegCM page. This tool can be used on both Apple and Android tablet devices and can be downloaded for free from the App stores. 

Canola blackleg risk forecasts

DPIRD's blackleg spore maturity forecasts for Western Australia for the 2021 growing season have begun, and forecasts are available online. The latest forecast is current to 19 May 2021.

The forecasts show the expected risk during the 4-6 leaf stage, relative to the date of sowing. For crops sown in late April and early May, the risk of blackleg spore showers coinciding with the seedling susceptible stage are already at high or moderate risk.

For more information, refer to DPIRD’s Canola blackleg spore maturity forecast for Western Australia page to check the blackleg model forecast for your district.

For more information about blackleg in canola, contact Andrea Hills, Senior Research Scientist, Esperance on +61 (0)8 9083 1144 or Ravjit Khangura, Senior Research Scientist, South Perth on +61 (0)8 9368 3374. 

For more information about the blackleg risk forecast, or the BlacklegCM decision support tool, contact Jean Galloway, Senior Research Scientist, Northam on +61 (0)8 9690  2172 or Art Diggle, Principal Research Scientist, Nash Street on +61 (0)8 9368 3563.

 

 

Article authors: Jean Galloway (DPIRD Northam) and Cindy Webster (DPIRD Narrogin).

Article input: Andrea Hills (DPIRD Esperance).

Slime mould found on canola

  • Wittenoom
  • Pingrup
  • Quairading
  • Hyden
Slime mould on a canola plant.
Slime mould on a canola plant. Photo courtesy of: Luke Marquis (South East Agronomy Services).

Luke Marquis (SEAS) recently found slime mould on canola at Wittenoom.

Logan Smith (Elders) also tweeted this week that he is seeing slime mould everywhere from Pingrup to Quairading and out to Hyden.

Slime mould found on living canola plants is a little unusual as slime moulds generally appear on decaying plant material when warm wet weather, combined with high nitrogen levels, is experienced.

Plant pathologist Ravjit Khangura (DPIRD) advises that slime mould on living plants should be harmless and not require any control measures. It is expected to disappear if a couple of dry, warm days are experienced.

To read about previous slime mould activity this season, refer to DPIRD’s 2021 PestFax Issue 4 Slime mould article.

For more information on slime moulds, visit DPIRD’s Slime moulds page.

For more information, contact Ravjit Khangura, Senior Research Scientist, South Perth on +61 (0)8 9368 3374.

 

 

Article authors: Cindy Webster (DPIRD Narrogin) and Ravjit Khangura (DPIRD South Perth).