Crop disease surveillance activities

NVT sites surveillance 

A number of national variety trial (NVT) sites in high risk environments were surveyed across the WA cropping regions and assessed for disease incidence and severity, if measurable levels were detected. Disease severity in different varieties was assessed on a plot by plot basis with severity (0-9 rating scale) assessed for each plot. Data was reported to Western Australian NVT disease monitoring project. 

Number of NVT sites monitored for each crop:

• Wheat – Kwinana (1), Esperance (5), Albany (3) and Geraldton (6) port zones.
• Barley – Kwinana (12), Esperance (6) and Albany (8) and Geraldton (4) port zones.
• Oats – Esperance (1) port zone
• Canola – Esperance (2), and Geraldton (3) port zones.
• Lupin – Kwinana (1), Esperance (1), and Geraldton (2) port zones.
• Pulses - Lentil – Esperance (1) and Geraldton (1) port zones. Chickpea: Esperance (1) and Geraldton (1) port zones; Field pea: Kwinana (1) and Esperance port zones (1).

Plant sampling for diseases (including rusts), viruses and fungicide resistance testing

Plant samples were collected where foliar disease or viruses were observed or suspected if diagnosis confirmation was required or to contribute plant disease isolates to local, regional and national pathotype monitoring surveys and isolates added to the WA culture collection. Targeted sampling of crops and non-crop hosts of endemic plant viruses was done to determine what virus species are present across the WA grainbelt.

At least 240 leaf samples were taken during the growing season surveillance activities, this includes 80 samples collected specifically for ramularia testing which were collected for the Ramularia surveillance project (DAW1909-003RTX). 23 rust samples (20 from the Esperance port zone and three from the Kwinana port zone) were submitted to the Australian cereal rust survey in 2020. These were primarily crown rust of wild oats, one oat stem rust on wild oats, one brome leaf rust, five crown rust on oats (some oats were not commercial paddocks but were weeds at sides of paddock), and one oat stem rust on oats. 12 samples of wheat or barley powdery mildew were submitted to CCDM for fungicide resistance testing. 29 samples were collected for virus specific sampling in high risk areas or where symptoms were virus-like. By crop type, samples were: 11 wheat, one barley, one oat, nine lentil, two lupin, one faba bean, one chickpea, and three canola. 2020 was generally a low virus year particularly in cereals, despite some suspicious leaf symptoms being submitted to DDLS for diagnosis they came back as clear of viruses. Due to high aphid numbers late in the season there was likely a lot of late but inconsequential spread of TuYV in Canola, and late BYMV infection in lupins causing some black pod syndrome.

Spore trapping in the Lower Great Southern

Nine passive wind vane traps were set up near nine commercial paddocks in the Lower Great Southern district of the Albany port zone to monitor the airborne spores in the region during the 2020 cropping season. In addition, small areas of sentinel trap plants comprising of barley (Baudin and Planet) and wheat (Scepter and Mace) with no fungicide protection were sown at the trap sites. The spore traps were monitored weekly from April to the end of November to visually assess spore trap slides for presence and partial quantification of known endemic pathogens (eg. net blotch, powdery mildew, loose smut). Weekly updates (as required) were made through social media or PestFax of disease risk associated with detections and reports of what was seen in trap plants. Please contact Kith Jayasena for results.

Exotic disease surveillance

Surveillance for high priority exotic pathogens was conducted at over 400 site visits across the WA grainbelt. None were detected. The surveillance program assists with the department’s biosecurity efforts to demonstrate area freedom from diseases exotic to Australia. Area freedom is crucial to secure market access, which gives the Western Australian grains industry a market advantage over its international competitors.

Implications for 2021 Season 

2020 surveillance results corroborate the expectation of no major changes in disease spectrum or major new outbreaks since previous studies in 2018 & 2019, the most common diseases were those that have stubble borne inoculum, such as STNB, YS/SNB, canola blackleg. With favourable seasons, these diseases will continue to be the most common issues facing grain growers throughout the WA grainbelt. In the absence of enduring green bridge (and favourable variety resistance in some crops) the incidence and impact of biotrophic diseases, such as rusts and mildew, has generally diminished in recent seasons. However, widespread green bridge in the summer and autumn of 2021 poses a risk of rusts and mildew in 2021 crops so regular crop monitoring is recommended.

Some areas of concern arising from 2020 surveillance are worthy of ongoing attention:

• Increased occurrence of barley powdery mildew in 2020, including altered virulence for MlLa resistance affecting commonly grown varieties such as Rosalind and Spartacus CL.
• Identification of Ramularia leaf spot in locations in the Kwinana, Albany and Esperance port zones, indicating this disease is potentially widespread across the WA grainbelt
• Increased reporting of flag smut in wheat and loose smut in barley, these can be effectively managed with fungicide seed dressings and variety resistance.
• Occurrence of wheat powdery mildew in the Esperance zone and the ongoing issues with control of this disease in the heading growth stages of crops.
• Increasing incidence of sclerotinia in lupin, particularly in the northern production zone, and the difficulties in predicting disease and management options available.
• Increased incidence of Chickpea ascochyta in the 2020 season and role of seed borne inoculum
• Detection of oat rusts in wild oats is a salient reminder of the role of green bridge in harbouring and multiplying rust, virus and insects leading into a cropping season.
• High incidence of SFNB in barley crops (>80% crops affected) including in LRZ is concerning considering the detection in 2020 of resistance to SDHI fungicide (CCDM), a major component in disease management in continuous barley cropping.

Surveillance activities in 2021

The surveillance activities for endemic and exotic disease will continue in 2021 with in-season reporting including incidence and severity assessments of endemic diseases across all crop types in spring. Surveillance is done in commercial cropping paddocks and experimental sites.

Help us with surveillance

2021 Green Bridge survey

As a result of summer rainfall, weed and crop regrowth are occurring in many areas across the wheatbelt and unless controlled will likely be continuing into May in many areas. It is important to consider potential disease carryover into the upcoming crop growing season as this vegetation can serve as a ‘green bridge’ for diseases and pests. Growers and agronomists are encouraged to monitor any persisting green bridge for aphids and disease so that timely action can be taken to identify the pathogen, and limit the spread and build-up of inoculum that are a risk for this season's crops.

Please report green bridge aphid/disease reports to PestFax. This can be done online from the paddock to PestFax Reporter App, by emailing the PestFax editor PestFax@dpird.wa.gov.au or calling one of the DPIRD staff members below. Should you find rust on volunteer cereals or grasses, you are encouraged to send samples for pathotype analysis in paper envelopes to the national rust survey, instructions and submission form available here. Thank you for helping us with this important surveillance work that will be a helpful guide for what biotrophic diseases are around and posing a risk for 2021 crops.

In-season crop surveillance

We are keen to receive your disease reports through PestFax from all cereal, oilseed and pulse crops this season. Regular crop inspection throughout the growing seaosn is the key to staying on top of disease risks. Inspect different parts of the crop by carefully examining plants (including lower stems and heads/pods). Prioritise inspections on susceptible varieties. A systematic way to inspect a paddock is to walk through it in a 'W' pattern and collect or check 100 random plants from the crop (that is, 10 plants in 10 locations) for disease symptoms. Please report disease finds to PestFax, even if you are unsure of the diagnosis by submitting your photos the PestFax team can assist with identification. PestFax reports can be submitted online from the paddock through PestFax Reporter App, by emailing the PestFax editor PestFax@dpird.wa.gov.au, or using the online PestFax Map to make an on-line report.

2020 Green Bridge Survey Results

Significant rainfall in the south west of WA in late February 2020 (BOM map) resulted in weeds and regrowth crop plants emerging in March in all WA port zones. A survey for presence of green bridge was conducted from mid-March to early-May in the WA port zones: Geraldton, Kwinana, Albany and Esperance. Despite many growers spraying/burning/grazing this regrowth, volunteer cereals have been observed at growth stages up to grain fill in many areas. Some parts of the central and southern regions received further rain in March/April resulting in more recent germination of volunteer cereals that range from the 4 leaf growth stage upwards. The most significant areas of regrowth cereals were found in the central wheatbelt, predominantly north of the Great Eastern Highway up to Coorow, corresponding with areas that received over 50mm of rain in February followed by a further 50mm rain in March/April (BOM map). In this area whole paddocks of volunteer cereals were observed in April ranging from newly emerged to grain fill (Figure 1).

The areas visited by the surveillance team are shown in Figure 2, with the different colours of the markers relating to what was seen at that site. The green dots show sites where volunteer cereals were found. Cereals were a particular focus as they can host rusts and powdery mildew. Only some of the volunteer cereals observed during the survey could be inspected for disease, at locations where we were able to obtain permission from the property owner for closer inspection. Barley net blotch was found on volunteer barley plants at nine sites, these were all in either the Albany or Esperance port zones except for one that was in the Kwinana port zone. Three observations were made of leaf rust on grass weeds (wild oats and veldt grass) in the Esperance port zone at the end of April (Figure 2).

Surveys of green bridge in April by the Entomology group found very few aphids present but alot of caterpillars in some areas. Caterpillars and other pests such as aphids/mites may transfer from the green bridge into vulnerable emerging crops if the green bridge isn’t destroyed before crop emergence. You can view a recorded webinar about the pest risks found on green bridge this season here.

Implications from Green Bridge survey results

Due to the presence of green bridge in some areas, monitoring of crops this season is very important. Where green bridge persists there is an increased chance of development of rust or mildew. Monitoring and reporting any disease finds is the key to early and effective disease management.

• Grass weeds (incl. wild oat) with leaf rust in Esperance demonstrates capacity of a susceptible green bridge to host rust. These finds indicate there is some seasona rust risk in that zone and also potential for crown rust in oats this season where wild oats have germinated as part of green bridge.

• In areas where green bridge is present – need to monitor persisting green bridge closely particulary for rust or powdery mildew in cereals and also closely monitor susceptible crops regularly after emegence.

• Despite a dry season in 2019, stubble borne diseases still persisted. Presence of net blotch on regrowth barley demonstrates presence of inoculum for this year's crops, continuous cropping exposes new crops to greatest inoculum load.

• Know the resistance ranking of your variety (note: several new wheat varieties are leaf rust susceptible) and monitor for those diseases it is susceptible to.

2019 Season Surveillance 

2019 season overview

2019 was the warmest year and second-driest on record for Western Australia. Monthly rainfall was below average for all months for WA, and record dry in spring. Rainfall across the grainbelt ranged from lowest on record up to decile 3, but on average most places had decile 1 for the year (see BOM map). Dry warm weather did not favour many diseases. The main diseases found at high incidence were endemic stubble-borne diseases, where disease from the 2018 season was carried into 2019 on stubble. There was minimal green bridge (weeds/regrowth crops that harbour disease) found in WA in summer/autumn 2019, with a predominantly hot dry summer until some regrowth came up in the Albany port zone in March. There were, however, no reports of rusts or powdery mildew on regrowth cereals and so the season started with low risk of biotrophic disease carryover.  The break to the season was late and occurred in early June in most areas, so most crops were at least a month behind in growth stage for much of the year. There was above average rainfall in June in some areas but then the rest of the season was significantly below average and some areas were affected by frosts. The season ended abruptly in many areas with hot dry weather in September which did not allow some crops, particularly canola, sufficient time to fill grain and yields were generally below average.

Objectives

The aim of this monitoring program is to determine the occurrence and severity of endemic diseases across the western region and will not be specifically targeted to high disease risk zones or biased to regions in which known disease outbreaks occur.

Carry out random stratified surveys in commercial cropping paddocks or experimental sites of cereals (wheat, barley oat), canola and pulses (lupin, chickpea, lentil, field pea) across grain belt.

Methods

Endemic disease surveillance

Standardised sampling and data recording protocols were developed to ensure uniformity of data collected across the Western region, across seasons and to be comparable with data being collected in other parts of Australia. The total sample numbers / crop were stratified according to crop area in the WA grainbelt. Major crops wheat, barley, canola, oat had greater sampling intensity than minor crops, such as pulses. Regional sampling was stratified by area of crops within designated regions (CBH port zones) and the size of the zone, from minimum five to maximum of 15 paddocks / port zone (numbers are shown in Table 1 below). On top of the stratified sampling strategy, a further number of barley sites were visited as the surveillance work incorporated plant sampling for Ramularia testing as part of project DAW1909-003RTX 'Distribution of ramularia across the Australian grain belt'. At each site multiple individual plants (>20) were assessed using a 0-9 scoring protocol depending on defined degrees of disease intensity on various leaf levels of cereals (0 =low on all levels, and 9 =severe disease on all levels). Sampling was conducted during the head emergence / flowering / grainfill stage of plants to maximise chance of disease incidence.

Exotic disease surveillance

All paddocks visited for the endemic disease survey were also assessed for high priority exotic pathogens if the crop was at the appropriate growth stage for that disease. Staff were trained by DPIRD diagnostic pathologist Dr Dominie Wright in recognition, biology and host range of high priority pathogens.

NVT sites surveillance 

A number of national variety trial (NVT) sites in high risk environments were surveyed across the WA cropping regions and assessed for disease incidence and severity, if measurable levels were detected. Disease severity in different varieties was assessed on a plot by plot basis with severity (0-9 rating scale) assessed for each plot. Data was reported to Western Australian NVT disease monitoring project. 

Number of NVT sites monitored for each crop:

• Wheat – Kwinana west (2), Esperance (6), Albany (2) and Geraldton (3) port zones.
• Barley - Kwinana west (7), Esperance (5) and Albany (4) and Geraldton (5) port zones.
• Oat – Geraldton port zone (1).
• Canola – Kwinana west (1), Esperance (3), and Geraldton (2) port zones.
• Lupin - Kwinana west (2), Esperance (1), and Geraldton (2) port zones.
• Pulses – no pulse NVT sites were visited in any port zones as it was not a high risk season for pulse diseases.

Plant sampling

Plant samples were collected where foliar disease or viruses were observed or suspected to contribute plant disease isolates to local, regional and national pathotype monitoring surveys and isolates added to the WA culture collection. Targeted sampling of crops and non-crop hosts of endemic plant viruses was done to determine what virus species are present across the WA grainbelt.

Spore trapping in the Lower Great Southern

Nine passive wind vane traps were set up near nine commercial paddocks in the Lower Great Southern district of the Albany port zone to monitor the airborne spores in the region during the 2019 cropping season. In addition, small areas of sentinel trap plants comprising of barley (Baudin and Planet) and wheat (Scepter and Mace) with no fungicide protection were sown at the trap sites. The spore traps were monitored weekly from April to the end of November to visually assess spore trap slides for presence and partial quantification of known endemic pathogens (eg. net blotch, powdery mildew, loose smut). Weekly updates (as required) through social media or PestFax of disease risk associated with detections and reports of what was seen in trap plants.

2019 Surveillance: Key findings summary

DPIRD plant pathology staff visited 319 unique sites during the 2019 surveillance activities and 250 plant samples were collected to assess for endemic and exotic diseases. 

A below average dry year, 2019 was not favourable to many diseases or aphids (vector of viruses) and this was reflected in low incidence and severity recorded for many of the endemic diseases. The main diseases observed across most port zones at high incidence were the stubble borne diseases: yellow spot in wheat, spot-type net blotch in barley, and septoria avenae blotch in oats. These ranged from low severity to moderate and were less severe than previous seasons due to the drier than average season. Though at low incidence and severity, there was some wheat powdery mildew observed in the Esperance region, and wheat leaf rust, barley powdery mildew and barley ramularia found in the Albany region. Disease in canola and pulses was minimal. One lentil sample was found to be positive for Phasey bean mild yellow virus (PBMYV).

A snap shot of the key results by crop is shown in Table 2. More detailed results for each port zone are presented further down.

Compared to 2018 surveillance results, the following comparisons were made for wheat and barley diseases: 

• Incidence in 2019 similar to 2018: wheat yellow spot, wheat powdery mildew, barley scald
• Incidence in 2019 less than 2018: wheat septoria nodorum blotch, wheat leaf rust (2019: 8%, 2018: 12%), barley spot-type net blotch (2019: 86%, 2018: 94%), barley loose smut (2019:5%, 2018:12%)
• Incidence in 2019 significantly greater than 2018: barley net-type net blotch (found to be three times higher incidence, predominantly in Albany port zone)

No high priority pathogens were found after close to 200 sites were assessed for exotic diseases. The surveillance program assists with DPIRD's biosecurity efforts to demonstrate area freedom from diseases exotic to Australia. Area freedom is crucial to secure market access, which gives the Western Australian grains industry a market advantage over its international competitors.

In the spring of 2019, 250 plant samples were collected and these contributed plant disease isolates to local, regional and national pathotype monitoring surveys and isolates added to the WA culture collection. Nine passive wind vane traps were set up near nine commercial paddocks in the Lower Great Southern district of the Albany port zone and monitored weekly during the growing season to assess aerial presence and partial quantification of known endemic pathogens and alert local grower groups.

The key implications of the surveillance finds in 2019 are that cereal stubble borne diseases are likely to be moderate - high risk in the 2020 season. The widespread incidence of spot-type net blotch in barley indicates this disease, in particular, is a growing concern across the WA grainbelt.

Endemic disease finds were reported to PestFax map so that you can access the results to inform disease management strategies in 2020 and changes over time can be identified. Results in detail by crop and port zone follow.

Barley

Across all the port zones, 64 barley paddocks were surveyed (five in Geraldton, 24 in Kwinana, 22 in Albany and 13 in Esperance Port Zone). The dominant disease across all port zones in these surveyed paddocks was spot-type net blotch, with the average incidence within paddocks across all zones being 75% but severity ranged from low to high (rating 0-9) (Table 3). Net-type net blotch was at low incidence in the Kwinana port zone, and high incidence (69%) in the Albany port zone where severity ranged from low to high (0-8). It was absent in the Geraldton and Esperance port zones. Scald was at low incidence in Geraldton, Kwinana and Albany Port Zones. There were few reports of loose smut, take-all, ramularia and wirrega blotch. Physiological leaf spotting and herbicide damage were noted on barley crops in the Kwinana and Esperance port zones. There were no reports of barley leaf rust, powdery mildew, BYDV, crown rot, or covered smut in any port zones during this survey though some late season observations were made of barley powdery mildew in the Albany Port Zone (observations outside project surveillance). These indicate a potential shift in barley powdery mildew virulence in the Albany zone (Rosalind negatively affected). As part of the national ramularia project, 145 barley leaf samples were submitted for ramularia testing from across all the WA port zones, only four of them were found to be positive which equates to 3% of the samples. Three out of the four were from the Albany port zone and one was from the Kwinana port zone.

Wheat

Across the grainbelt, 52 wheat paddocks were surveyed (11 in Geraldton, 25 in Kwinana, four in Albany and 12 in Esperance Port Zone). The dominant disease across all port zones in these surveyed paddocks was yellow spot / stagonospora nodorum blotch complex, average incidence within paddocks across all zones was 50% but severity ranged from low to high (rating 0-9) (Table 4). Laboratory testing diagnosed the majority of the disease as yellow spot in 2019. There were no reports of stripe rust, stem rust, BYDV, WSMV, septoria tritici blotch or take-all reported. There was low incidence of wheat powdery mildew (only reported from Esperance port zone), leaf rust (only in Albany port zone), loose smut (only in Geraldton port zone) and crown rot (multiple zones). There was low incidence of false black chaff and herbicide damage in the Kwinana port zone.

Oats

Across all the port zones, 10 oat paddocks were surveyed (all 10 were in the Kwinana zone). Septoria avenae blotch was at high incidence, while bacterial blight and oat stem rust were observed at low incidence (Table 5).

Canola

Across all the port zones, 28 canola paddocks were surveyed (12 in Geraldton, six in Kwinana, and 10 in Esperance Port Zone). Despite the best intentions, no canola paddocks were able to be surveyed in the Albany port zone. Disease levels were low across all port zones (Table 6). There was low incidence and severity of blackleg foliar symptoms (21% incidence across all zones), stem symptoms and pod symptoms. Sclerotinia was only observed in Esperance port zone and was very low incidence and severity. There was low incidence of the virus beet western yellows virus (BWYV) reported in Kwinana port zone and some herbicide damage. There were no reports of downy mildew, powdery mildew, white leaf spot, alternaria or TuYV in any port zones.

Pulses (Lupin, Chickpea and Lentil)

Across all the port zones, 10 lupin paddocks were surveyed (six in Geraldton, and four in Kwinana port zone), one chickpea paddock (Esperance port zone) and five lentil paddocks (Esperance port zone). Anthracnose was reported on lupin stems and pods in the Geraldton port zone, and brown spot in lupin was reported in the Kwinana port zone (Table 7). There was no lupin sclerotinia found in any of the crops surveyed. Botrytis grey mould was found on lentil crops in the Esperance port zone at low incidence (5%) and low severity (range 0-1), and there was no ascochyta, sclerotinia or viruses observed. However, one non-symptomatic lentil crop sampled for virus specific sampling was found after testing to be positive for Phasey bean mild yellow virus (PBMYV). One chickpea paddock was inspected for asochyta, botrytis grey mould and sclerotinia but no disease was found.

Exotic disease surveillance

Surveillance for high priority exotic pathogens was conducted at close to 200 site visits across the WA grainbelt. None were detected. The surveillance program assists with the department’s biosecurity efforts to demonstrate area freedom from diseases exotic to Australia. Area freedom is crucial to secure market access, which gives the Western Australian grains industry a market advantage over its international competitors.

NVT Surveillance 

A total of 46 NVT sites in high risk environments were surveyed across the WA cropping regions and assessed for disease incidence and severity, if measurable levels were detected. Only two of the sites (both wheat, one in the Geraldton port zone and one in the Esperance port zone) had sufficient disease to score due to the very dry season. 

Plant sampling

Approximately 250 leaf samples were taken during the surveillance activities, this does not include the 98 samples collected specifically for ramularia testing which were collected for the seperate Ramularia surveillance project. Approximately 145 samples were sent to DPIRD Diagnostic Laboratory Services (DDLS) for diagnosis, 34 of these were submitted specifically for virus testing. 15+ cereal samples were submitted for isolation for the WA culture collection, of which nine were successfully isolated and added to the collection. 15+ samples of barley net blotch/scald were submitted to the Barley National Foliar Pathogens project for pathotype monitoring. 30+ samples from cereals were submitted to Centre for Crop and Disease Management (CCDM) for fungicide resistance testing, 18 samples of canola for blackleg fungicide resistance testing were sent to Marcroft Grains Pathology (Vic), 12 plant samples of net-type net blotch on barley were sent to Department of Agriculture and Fisheries QLD for isolating for their collection. Project staff were also able to contribute 20 canola/pulse plant samples to a Pulse and Oilseed Root Disease survey being run by GRDC/DPIRD project ‘Soilborne Diseases Interaction’ (DJP1907-002RMX).

As mentioned above, 34 samples were collected for virus specific sampling and 12 of these were tested for viruses: nine wheat,  one canola and two lentil. Due to the dry year in 2019 there were very few high risk environments so this sample size was representative of what was considered high risk in WA cropping regions in 2019. One lentil sample was found to be positive for Phasey bean mild yellow virus (PBMYV), a virus we know little about but was found at high incidence in WA in 2018, associated with cowpea aphids, by DPIRD virology surveys.

Spore trapping in the Lower Great Southern Region

Nine passive wind vane traps and sentinel trap plants set up near nine commercial paddocks in the Lower Great Southern district of the Albany port zone monitored the airborne spores in the region during the 2019 cropping season. The spore traps picked up a variety of spores with the most common significant pathogens across all locations being barley net blotch, barley powdery mildew, loose smut and oat crown rust. Net blotch conidia were observed on slides at several locations before net blotch was observed in the sentinel trap plants at these sites. Barley powdery mildew was observed on slides at most locations but only two locations had symptoms develop on sentinel trap plants. Tweets (5) about results of spore traps and sentinel trap plants were made during the growing season to assist growers in the Lower Great Southern with timely disease warnings to allow proactive management to be undertaken. 

Implications for 2020 Season

The key implication of the surveillance finds in 2019 is that stubble borne diseases will continue to be a threat for cereals in the 2020 season. Continuous cropping exposes new crops to greatest inoculum load and is a high risk even in a dry year. Growers should use crop rotation to avoid exacerbating early disease risk caused by these stubble borne diseases. Due to presence of green bridge in some areas, there is risk of early rust and powdery mildew so monitoring of crops is very important particularly in these areas.

• Spot type net blotch present at high incidence in all port zones, will continue to be a threat this season
• Net type net blotch is a latent threat in southern regions (incidence in 2019 survey was three times greater than in 2018 survey).
• Potential shift in Barley Powdery Mildew virulence in Albany zone (Rosalind negatively affected)
• Recent incidence of rusts and mildews has diminished, most detections late in season in 2019 - seasonal weather in 2020 will determine their importance this year.

Across the board inoculum levels of foliar diseases are generally at a lower level following the 2019 season given it was dry and warm and not favourable to several diseases. There were no major changes in disease spectrum in 2019. It is important to remember though that inoculum of some diseases persists over many seasons (eg. sclerotinia, root diseases). Consider what crop was in each paddock 2-3 years ago and is there still inoculum around. Minimal or no sclerotinia in canola and lupin crops in 2019 means no/minimal sclerotia were formed to continue the disease in future years but there may already be existing sclerotia in soil from previous seasons that presents ongoing risk.

Even in a dry year, the value of this integrated surveillance and monitoring program for endemic and exotic diseases of cereals, oilseeds and pulses was apparent and allows us to compare findings across seasons. The widespread incidence of spot-type net blotch in barley, at similar levels to 2018, indicates this disease is a persisting concern and requires further development of disease management packages for all rainfall environments with particular consideration for fungicide resistance issues. Although very hard to find, ramularia was found at low incidence in barley, indicating it is a continuing risk for growers and expression likely depends on seasonal conditions. A positive test from a lentil sample for Phasey bean mild yellow virus (PBMYV) is a warning that this virus we know little about is continuing its presence since first being found in WA in 2016.