Powdery mildew found in canola
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Cascade
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Munglinup
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Ravensthorpe
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Borden
Plant Pathologist Andrea Hills (DPIRD) has reported that powdery mildew is present in canola crops around Esperance and Ravensthorpe.
Additionally, Technical Officer Daniel Malecki-Lee (DPIRD) recently found powdery mildew in a canola crop at Borden.
Powdery mildew can infect leaves, stems and pods of canola. Commonly seen from mid to late pod-filling, mildew can affect any part of the plant. Patches often appear on stems and pods and resemble talcum powder. These patches enlarge and coalesce to cover the entire stem. There may also be purpling of the stem under areas affected by powdery mildew. If pods are infected early, they may remain smaller and produce fewer seeds, and the seeds generally are shrivelled and of poor quality. Presence of the disease may not be noticed until swathing or harvest, when white clouds of spores are generated as machines move through the crop.
The disease development is generally favoured by dry conditions with moderate to high humidity (50 to 95%) and moderate temperatures (15 to 25°C). The disease is also favoured by dense canopy, and by high nitrogen fertilisation in canola.
Canola varieties vary only slightly in susceptibility, and variety resistance to this minor disease is not routinely assessed.
Powdery mildew is not considered a serious problem in Australia since the disease tends to occur too late in the season to cause significant yield loss. In northern NSW, this disease occurs regularly in canola and is thought to reduce yield in some seasons, particularly if the infection progresses to pods. The loss of photosynthetic area appears to be the main cause of yield loss but there is limited data available. The pathogen may survive between seasons on volunteer host plants or brassica/lupin weeds as well as old canola/lupin stubble.
Currently no fungicides are registered for the control of powdery mildew in canola or lupin in Australia, but applications to control sclerotinia or blackleg upper canopy infection (UCI) often reduce its incidence and severity.
Growers and consultants are urged to keep reporting with the PestFacts WA Reporter app if they see powdery mildew, as this will help in determining its distribution and formulating control tactics in the future.
For more information contact Plant Pathologists Ciara Beard in Geraldton on +61 8 9956 8504 or Andrea Hills in Esperance on +61 8 9083 1144.
Article authors: Ciara Beard (DPIRD Geraldton) and Andrea Hills (DPIRD Esperance).
Native budworm caterpillar numbers still rising in central and southern agricultural regions
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Bolgart
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Northam
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South Stirling
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Gnowellen
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Gibson
Growers on the south coast of the WA grainbelt should remain vigilant of potentially high numbers of native budworm appearing in later sown crops that have not been sprayed recently and remain susceptible to damage.
This week, above threshold numbers of caterpillars have been reported in the southern agricultural region following the large native budworm moth migration in late September and early October. This follows reports during late September and early October of high budworm caterpillars in lupin, pulse, canola, and even wheat crops in the north and central agricultural regions. For more information, including maps of these moth flights and caterpillar numbers in DPIRD’s canola focus crops, refer to last week’s 2024 PestFacts WA Issue 19 article Native budworm caterpillar numbers have increased in canola, pulse and wheat crops.
Research Officer Zia Hoque (DPIRD) has found native budworm caterpillars causing up to 30% damage to ripening lupin crops at Bolgart and Northam. The caterpillars, measuring 20 to 30 mm in size, were chewing on lupins pods that had begun to lose their green colouration.
DPIRD staff have reported native budworm caterpillars above threshold levels in canola crops at Gnowellen and Gibson, while Agworld users have reported similar levels in canola crops at Gnowellen and South Stirling.
Any late maturing pulse, oilseed and pasture seed crops should be checked for native budworm caterpillars, especially in areas where high moth numbers were recorded 2-3 weeks ago. Caterpillars hatching from eggs laid during that time will now be large enough (>5 mm) to be detected using sweep nets.
Swathed crops can still be damaged by native budworm caterpillars as long as the pods and seeds can be chewed into. Growers should be mindful of harvest, including swathing, withholding periods for insecticide applications. For more information of withholding periods refer to the 2024 PestFacts WA Issue 18 article Mind chemical withholding periods for native budworm sprays.
Further information
Detailed information on this pest can be found at the department’s Management and economic thresholds for native budworm.
For more information contact Alan Lord, Technical Officer in Perth on +61 409 689 468.
Article author: Bec Severtson (DPIRD Northam).
Do you use the PestFacts WA map?
The PestFacts WA map is a portal to extensive insect and disease data from the WA grainbelt. Growers and consultants may be surprised by the tool’s usefulness, if they are not already regularly generating maps.
What is the PestFacts WA map?
The PestFacts WA map provides a visual display of all pest and disease occurrences reported by the WA grains industry to the PestFacts WA (formerly PestFax) service since 1996.
How do I check what has been reported?
Viewers can select a host, disorder and time period in the PestFacts WA map, see screenshot below.
Reported occurrences are displayed as colour coded squares. Viewers can click on any square to see more detail, see screenshot below.
Viewers can compare report numbers and patterns between seasons and see how pests and diseases spread within a season.
Maps can be produced showing individual disorders, totals for disorder categories, or overall disorder totals.
I have found an insect or disease in my crop or pasture – how do I report it?
Reports can be made to the PestFacts WA team by either:
- downloading and using the PestFacts WA Reporter app
- emailing the PestFacts WA team via pestfactswa@dpird.wa.gov.au or
- phoning PestFacts WA newsletter editor Cindy Webster on +61 404 819 534.
The more reports received and mapped, the better growers and consultants are forewarned about emerging pest issues in their areas. Reporting both the presence and absence of common diseases or pests multiple times is encouraged to build a more detailed ‘picture’ of their distribution and severity.
How do I share a generated map with someone else?
Select 'share' and copy the map link. The link can be inserted in a document or sent in a message, allowing readers to click and view the same map.
PestFacts WA map project history
The former PestFax map service was developed through two successive projects jointly funded by the Grains Research and Development Corporation (GRDC) and DPIRD from 2010 to 2016. These projects were in partnership with Cesar Australia, the South Australian Research and Development Institute (SARDI) and the Australian Cereal Rust Control Program (ACRCP) at the University of Sydney.
Further information
For more information, or to generate a map, visit DPIRD’s PestFacts WA map.
For more information contact Cindy Webster, Research Scientist in Narrogin on +61 8 9881 0201.
Article author: Cindy Webster (DPIRD Narrogin).