Free virus testing available

Virus testing is currently available at no cost to Queensland grain and pulse growers through the GRDC-funded project Effective virus management in grains and pulse crops. Submissions from the field help improve our understanding of virus distribution and support the development of effective diagnostics and management strategies for Queensland.

Chickpeas, faba bean and other pulse crops

Last season, a significant level of alfalfa mosaic virus (AMV), along with several other viruses, were detected in chickpea crops across southern Queensland.

Chickpea with AMV

In chickpeas, be on the lookout for symptoms such as:

• Shoot tip necrosis
• Reddening of leaf edges
• Purple-red leaf discolouration
• Pale or chlorotic leaves
• Stunting or poor plant growth

In other pulse crops such as faba bean, look out for:

• Mild and severe leaf mottling
• Shoot tip necrosis
• Stunting

For more information, see the Beatsheet article: Alfalfa mosaic and other viruses detected in Darling Downs chickpeas.

Grain crops

Virus pressure in grain crops was generally low across Queensland last season, although barley virus G (BVG) was detected in several barley crops on the Darling Downs.

This year, reports from the southern grains region have indicated increased incidence of yellow dwarf viruses (YDVs) in cereal crops.

Example of BVG symptoms

In wheat, barley and oats, watch for:

• Yellowing leaves
• Yellow discolouration beginning at leaf tips
• Red or purple discolouration in some varieties
• Stunting and reduced vigour
• Patchy areas of affected plants

For more information, see the Beat sheet article: Barley virus G (BVG) found in barley crops across the Darling Downs.

Sample collection tips

• Send at least one whole leaf from plants showing symptoms.
• If aphids are present, collect live aphids attached to the leaf sample or place them in a sealed container or bag.
• Include paddock location, crop type, crop growth stage and contact details.

Questions or sample submissions?

If you’re seeing unusual symptoms in grain or pulse crops, or would like to discuss virus testing options, please contact:

Dr Fiona Filardo
Senior Plant Pathologist
Queensland Department of Primary Industries
(07) 3708 8449
Fiona.Filardo@dpi.qld.gov.au

For information about submitting samples of fungal or bacterial diseases in Queensland, see the Beatsheet’s Submitting samples for diagnostics page.

New South Wales

NSW pulse and canola growers can have their crops tested for the presence of virus by sending samples to the Tamworth Agricultural Institute. Contact Jule George (0419 143 811, jule.george@dpird.nsw.gov.au) or Joop van Leur (0427 928 018, joop.vanleur@dpird.nsw.gov.au) for sampling and mailing instructions.

For further information about disease testing in NSW, contact NSW DPIRD pathologists:

• Joop van Leur 0427 928 018 joop.vanleur@dpird.nsw.gov.au
• Solomon Maina 0474 252 411 solomon.maina@dpird.nsw.gov.au

The post Free virus testing available for Queensland growers first appeared on The Beatsheet.

Researchers in the Centre for Crop Health at the University of Southern Queensland have been looking at barley seed from Queensland paddocks, and the results are a real eye‑opener. The latest diagnostics show that barley seed can carry net blotch pathogens, including fungicide‑resistant strains, meaning resistance can hitch a ride into the next crop before plants even emerge.

Net blotch continues to be a major challenge for barley growers in Queensland, and with more reports of fungicides not performing as expected, it is important to investigate how fungicide resistance might be spreading.

The project tested 16 barley seedlots, primarily sourced from grower fields. Net blotch pathogen DNA was detected on 13 of the seedlots, which matched the disease expression in crops. It’s a clear indication that seed source matters when managing net blotch risk.

The investigation then went a little deeper, and searched for DNA markers associated with fungicide resistance, an emerging issue for net blotch in Queensland. Molecular tests picked up reduced sensitivity types linked to the fungicides growers rely on most, such as DMIs (FRAC Group 3) and SHDIs (FRAC Group 7). This lined up with grower reports of fungicides not performing as well in certain fields.

The research team also planted one of the high-risk seed lots and watched the disease emerge on the seedlings. The same reduced fungicide sensitivity types found on the seed showed up in the leaf lesions. In other words: fungicide resistant net blotch was moving from the seed into germinating seedlings.

Net form net blotch lesions on barley plants grown from barley seed determined to be positive for the net blotch pathogen.

Loose smut DNA was also detected in many seed lots. This pathogen has recently been shown to carry fungicide resistance traits too, adding another layer of complexity to the story. Unfortunately, there are no visual symptoms to identify seeds that are carrying either net blotch or loose smut, so knowing the background of the seed source crop is important.

Alongside the established disease management recommendations of choosing the least susceptible varieties, reducing in-field inoculum, and rotating and mixing fungicides, this research indicates that growers should avoid planting seed harvested from net blotch or loose smut affected crops.

The findings highlight the potential impact of seed source decisions within a disease and fungicide management strategy. However, disease management still relies on fundamental principles.

Future research and development should invest in improving our understanding of environmental conditions that promote transmission of seed-borne pathogens, the impact of fungicide resistance on seed treatment efficacy, and commercial seed testing services to improve decision making.

This research was performed by Noel Knight, Barsha Poudel and Levente Kiss at the Centre for Crop Health, University of Southern Queensland (UniSQ). The project was funded by the Broadacre Cropping Initiative (Project V1) — a joint investment of UniSQ and the Queensland Department of Primary Industries.

The post Barley seed as a pathway for the spread of fungicide resistant net blotch first appeared on The Beatsheet.

Cluster caterpillar larva consuming mungbean flowers

Over the past few years we have received an increasing number of reports of cluster caterpillar (Spodoptera litura) populations causing significant damage in soybean, mungbean and peanut crops (see A Spodoptera season: Cluster caterpillar outbreak in summer pulses).

In 2025, and again this summer, soybeans in the Burdekin have been heavily defoliated by cluster caterpillar. Agronomists have reported that cluster caterpillar populations have survived insecticide applications targeting helicoverpa, and resultingly built up to very high population densities in crops (e.g. >25 medium-large larvae per m²).

In April 2026, a population of cluster caterpillar from the Burdekin was screened for resistance to chlorantraniliprole and emamectin benzoate by Dr Lisa Bird (New South Wales Department of Primary Industries and Regional Development). This testing revealed very high resistance to chlorantraniliprole (group 28, for example in: Vantacor ®, Shenzi®, Clorantragen®) and very high resistance to emamectin benzoate (group 6, for example in Affirm®, Warlock®, Skope®).

Products with these actives will NOT provide sufficient control of cluster caterpillar to prevent significant crop loss when pest pressure is high.

The use of Group 6 and Group 28 insecticides is widespread in both broadacre and horticultural crops (where cluster caterpillar is often present at low levels). It is likely that repeated applications of these actives to treat helicoverpa and other caterpillar pests has selected for an increased proportion of resistant individuals in the cluster caterpillar population.

Cluster caterpillar in capsicum

The soybean crops in the Burdekin with resistant cluster caterpillar populations are in close proximity to horticultural production areas and movement of resistant moths between broadacre and horticultural crops is almost certainly occurring.

Genetic studies conducted by NSW DPIRD at Tamworth have confirmed that chlorantraniliprole resistance in cluster caterpillar is recessive. This means that when resistant insects mate with susceptible insects, such as those coming from crops and non-crop vegetation that are not exposed to insecticides, their offspring are susceptible. This natural mixing may help dilute resistance in the population.  However, at the frequency of resistance detected in the Burdekin population, it would take many years of dilution before resistance frequency would revert to a level where cluster caterpillar is susceptible again.

Recent studies on Australian cluster caterpillar populations have shown that cross resistance within the Group 28 is highly likely, which means that other Group 28 actives, e.g. tetraniliprole, cyantraniliprole and flubendiamide will also have reduced efficacy against the resistant cluster caterpillar population.

In contrast, resistance to Group 6 insecticides (e.g. emamectin benzoate), recently isolated by NSWDPIRD at Tamworth, was found to be strongly dominant, so even if resistant moths mate with susceptible ones, the offspring will still be resistant. Because of this, resistance to Group 6 insecticides cannot be diluted effectively through mating, making it much harder to manage once it appears. If the exposure of cluster caterpillar to emamectin benzoate continues, we can expect the level of resistance to increase rapidly. It is worth noting that resistance to Group 6 is not the result of cross-resistance to Group 28, it has developed independently.

There is no formal resistance monitoring program in place for cluster caterpillar, so we do not know how widespread this resistance is; whether there are other growing regions in Queensland where similar selection pressure has resulted in the emergence of resistance, or movement of resistant moths between regions has occurred.

However, Group 28 and Group 6 insecticide resistance in cluster caterpillar was detected in populations from Broome and Carnarvon in Western Australia in 2023 following reports of uncontrollable infestations in horticultural crops. Further investigations of populations from a number of production regions in WA detected resistance to carbamates (Group 1A), organophosphates, and synthetic pyrethroids (Group 3A) (see Take action to prevent rise in cluster caterpillar insecticide resistance). What this experience shows is that cluster caterpillar has the capacity to develop resistance to a wide range of mode of action insecticides if selection pressure is sufficiently high. This has been the trajectory in Asia, where the pest is resistant to almost all modes of action.

Where to from here?

The management of further insecticide resistance in cluster caterpillar will depend on the implementation of strategies that reduce the repeated exposure of this pest to each mode of action.

Initially, this will be very challenging as the efficacy of products like Vantacor® and Affirm® has resulted in a high level of reliance on them for the management of key pests like Helicoverpa spp. (heliothis). Additionally, these modern products demonstrate benefits in terms of their selectivity (i.e. ‘softness’ on natural enemies), compared with carbamates and synthetic pyrethroids, which are highly disruptive to natural enemy populations.

Each time another caterpillar pest is targeted with a Group 28 and/or Group 6 product, this increases the selection pressure for cluster caterpillar, if they are present in the crop.

Actives other than Group 28 and Group 6 listed in the table below are i) registered for use in summer pulses, and ii) likely to have some efficacy against cluster caterpillar, based on industry experience and registrations of the same actives for S. litura in horticulture. There have been no recent controlled in-field evaluations of the efficacy of these insecticide options in summer pulses, but such information would undoubtedly increase confidence in their use. Note that this list has been generated for Queensland producers; registration may vary by location – always check the product label.

¹ must target very small to small larvae only
² these actives are registered for use against cluster caterpillar in horticultural crops
³ trade names provided as examples only and are not an exhaustive list.

A note of caution: Helicoverpa armigera is already moderately resistant to Group 1A and highly resistant to Group 3A products. Using products from these groups runs the risk of flaring helicoverpa (and other pests) when natural enemies are killed and thus increasing selection pressure for these products.

Go soft early

Larvae tend to remain aggregated after hatching from an egg mass (hence the name ‘cluster’), creating noticeable localised damage. Here young larvae have ‘windowed’ a mungbean leaf (a couple are still visible bottom right)

One strategy for managing both helicoverpa and cluster caterpillar in vegetative soybeans is to revisit the “go soft early” approach that was recommended before chlorantraniliprole and emamectin benzoate were available for use in summer pulse crops. This approach, advocated by Hugh Brier, promoted the use of Dipel (Bt) and Vivus Armigen (Helicoverpa NPV) for the control of cluster caterpillar, loopers and helicoverpa in vegetative crops. Bt is effective against several caterpillar pests – particularly small cluster caterpillars, small helicoverpa, and various sized loopers. Vivus, on the other hand, selectively targets helicoverpa. These biopesticides are effective enough against caterpillar populations that are at or just above threshold to reduce the risk of ongoing crop defoliation. To detect small larvae and implement timely application of biopesticides (if warranted) it is recommended that vegetative crops are scouted twice a week.

Going forward, cluster caterpillar in summer pulses is going to prove challenging. We encourage agronomists to record and report any issues of spray failure, particularly in regions outside of northern Queensland. Applying the principles of insecticide resistance management may help prevent further resistance evolving.

The fundamentals of insecticide resistance management are:

1. As few applications of insecticides as possible – abide by thresholds and avoid prophylactic insecticide use
2. Rotate modes of action and avoid consecutive applications of the same mode of action
3. Do not spray a field failure with the same mode of action group

For more general information, see the Beatsheet page on insecticide resistance.

Article by Melina Miles, Trevor Volp and Lisa Bird.

Acknowledgements

Screening of cluster caterpillar was undertaken by Dr Lisa Bird (NSW DPIRD at the Tamworth Agricultural Institute), and Dr Duong Nguyen NSW DPIRD at the Elizabeth Macarthur Agricultural Institute). This work is supported by the Cotton Research Development Corporation (CRDC Project ID 11621) and builds on the identification of resistant cluster caterpillar populations in northern Western Australia horticultural regions in 2024-2025 (CRDC Project ID DAN2301).

We are grateful to the agronomists in the Bowen-Burdekin and Darling Downs regions who have reported unusual cluster caterpillar activity and collected material for screening.

The post Insecticide resistance to Group 28 and Group 6 insecticides detected in cluster caterpillar population in north Queensland soybeans (with implications for horticulture) first appeared on The Beatsheet.

Alfalfa mosaic virus (AMV)

AMV was the most prevalent virus detected in this year’s survey, with 14 out of 15 fields showing moderate to high levels of infection. It was also found at one site in burr medic plants growing next to a chickpea field. AMV is a non-persistent virus, meaning aphids that transmit the virus remain infective for only a short period (a few minutes to a few hours). It is spread by a variety of common aphids, which transfer the virus from seed-infected plants to healthy plants.

Chickpea with AMV (left) and a plant with a more advanced infection (right)

While AMV can be transmitted through seed, the recorded seed transmission rates in chickpea are low (0.1–1%). The virus is commonly found in lucerne and weeds such as burr medic (Medicago polymorpha), common sowthistle (Sonchus oleraceus), clover (Trifolium species) and blackberry nightshade (Solanum nigrum).

Symptoms to look for in chickpea:

• Shoot tip necrosis
• Reddening of leaf edges

Other viruses

Burr medic with AMV and PBMYV

The viruses below are all transmitted persistently by aphids, meaning aphids remain infectious for life after acquiring the virus from an infected host.

Phasey bean mild yellows virus (PBMYV) was detected in 9 fields. The main weed host for PBMYV is phasey bean (Macroptilium lathyroides).

Turnip yellows virus (TuYV) was found in 2 fields, primarily around Dalby. It is transmitted by green peach aphids (Myzus persicae) and has an extensive host range, including wild mustard.

Bean leaf roll virus (BLRV) was detected in just 1 field east of Chinchilla. It is transmitted by several aphid species, with pea aphid (Acyrthosiphon pisum) being the primary vector. BLRV hosts are limited to the Fabaceae (legume) family, including weeds such as clover.

Symptoms of PBMYV, TuYV, and BLRV in chickpeas

The symptoms of these viruses vary depending on the chickpea variety:

• Kabuli chickpeas: Pale, chlorotic leaves and stunting
• Desi chickpeas: Purple-red leaf discolouration

Managing viruses in chickpea crops

Chickpea with AMV and TuYV

Effective management of chickpea viruses relies on reducing the presence of virus host plants and aphids. Key strategies include:

• Controlling weeds and self-sown volunteer crops that can harbour aphids and viruses between cropping seasons.
• Sowing chickpeas into cereal standing stubble to reduce aphid landing rates.
• Removing infected chickpea plants to limit virus spread (ideally after virus testing, as symptoms can resemble other issues such as nutrient deficiencies).
• Monitoring crops regularly to assess aphid levels.

Note, insecticides should only be applied if aphid numbers are high.

Questions or sample submissions?

If you’re seeing symptoms or have concerns about viruses in your crop, contact Fiona Filardo at the Department of Primary Industries (DPI) Queensland:

[07] 37088449
Fiona.filardo@dpi.qld.gov.au

This initiative is part of the GRDC and QLD DPI-funded project DAW2305-Effective virus management in grain crops.

The post Alfalfa mosaic and other viruses detected in Darling Downs chickpeas first appeared on The Beatsheet.

What is BVG and how is it transmitted?

BVG is a Polerovirus that was first reported in South Korea in 2016.

The first identification within Australia was in Victoria in 2018. However, it’s likely not a new disease, as a 34-year-old archived oat sample from Victoria also tested positive for BVG, suggesting it has been present for decades but only recently identified due to advances in diagnostic technologies.

BVG infects barley and oats and to a lesser extent, wheat.

The virus is transmitted by aphids, primarily Rhopalosiphum maidis (corn leaf aphid), which is more prominent in Queensland, and to a lesser extent by Rhopalosiphum padi (bird cherry-oat aphid). These aphids acquire the virus while feeding on infected plants and can spread it across crops.

Corn aphid colony on barley

Symptoms to look for and impact on yield

BVG symptoms can be subtle and inconsistent, making detection challenging. Some infected plants show yellow discolouration of leaf tips and margins, similar to other yellow dwarf virus disease symptoms.

Currently, the epidemiology of BVG and its impact on yield are not well understood, either in Australia or internationally. While the virus has been detected in barley, oats, and wheat, its effect on crop productivity remains unclear.

BVG-infected compared to healthy barley. Source: Anna Erickson, Jun Jiang, Yen-Wen Kuo, Bryce W. Falk (2023). Construction and use of an infectious cDNA clone to identify aphid vectors and susceptible monocot hosts of the polerovirus barley virus G. Virology, 579:178-185. https://doi.org/10.1016/j.virol.2023.01.011

Testing available

If you notice suspicious symptoms or suspect aphid activity, consider sending in samples for testing. Both plant and aphid samples are valuable for understanding the spread of BVG in the region.

Sample collection tips

• Send at least 5cm² of leaf or a whole leaf of plants showing symptoms, and/or
• Collect live aphids attached to a leaf sample or remove them and put them in a sealed bag or container.
• Include paddock location, crop stage, and contact details

Express post is recommended to maintain sample integrity.

Questions or sample submissions?

If you’re seeing symptoms or have concerns, contact Fiona Filardo at the Department of Primary Industries (DPI) Queensland:

[07] 37088449
Fiona.filardo@dpi.qld.gov.au

This forms part of the GRDC and QLD DPI funded project DAW2305-Effective virus management in grain crops.

The post Barley virus G (BVG) found in barley crops across the Darling Downs first appeared on The Beatsheet.

Outbreaks of migratory locusts are currently occurring across quite a few shires in Central Western regions and into Northern Queensland.

See the online map (updated daily) of current sightings and estimated densities.

Migratory locust nymphs

The Department of Primary Industries (DPI) is coordinating a comprehensive response in cooperation with local government, agricultural peak bodies, the Australian Plague Locust Commission, and others.

It is likely nymphs will continue to emerge for weeks to come. Treatment in the nymph stage is the key opportunity for intervention, with each subsequent generation having the potential to increase population numbers exponentially.

Bands of locusts visible from the air

Under the Biosecurity Act 2014, landholders have a general biosecurity obligation (GBO) to control locust populations on their properties. Vigilance and early control intervention are critical to preventing locust populations from reaching plague proportions.

DPI is responsible for coordinating management efforts if populations are beyond the capacity for landholder control and threaten key agricultural regions of Queensland. We will conduct aerial spraying in an environmentally responsible manner to control locust infestations at a nymph stage that are deemed to be a threat to agricultural production. Landholders will be contacted if their property is likely be included in this treatment.

Be on the lookout for locusts

Reporting significant locust or nymph activity is essential, as it enables DPI to monitor locust density and movement across Queensland. Reports are used to inform planning and control efforts, with information provided to local councils to assist with early detection and management strategies.

Reporting options

• Report online or offline (Survey123)
• Report online (Report a biosecurity pest or disease)
• Phone Biosecurity Queensland on 13 25 23
• Email locustreports@dpi.qld.gov.au

Learn more about locusts and their management at the Business Queensland website.

Images © State of Queensland

The post Locust outbreaks in outback Queensland first appeared on The Beatsheet.

Phytophthora root rot causes yellowing in chickpea

Across all regions, growers should also monitor their crops for signs of ascochyta blight and botrytis grey mould. Fresh isolates of the fungal ascochyta blight pathogen, Ascochyta rabiei, are sought after to monitor changes in isolate aggressiveness – contact Lisa Kelly (details below) for more information.

Ascochyta blight causes spots on chickpea leaves, stems and pods

Further information on these diseases:

• Sclerotinia in chickpea (Agriculture Victoria)
• Sclerotinia-impacts-on-chickpea (GRDC)
• Ascochyta online dashboard (AscoDashboard) of submitted samples
• Phytophthora root rot management in chickpea (NSW DPIRD pdf)

If you see disease symptoms in grain crops, please contact plant pathologist Lisa Kelly (lisa.kelly@dpi.qld.gov.au, 0477 747 040) for further information on disease diagnosis and sample collection.

This research has been supported by GRDC project DAQ2407-001RTX.

The post Disease alert: fungal disease in chickpeas first appeared on The Beatsheet.

Starting trap counts for 2025 (highlighted in grey) at Roma and St George are well above the numbers found in previous years.

Continued migration of H. punctigera through spring is likely, if suitable weather systems occur, and it is likely that all susceptible crops (including chickpea, canola, faba bean, spring mungbean and spring sunflower) will experience helicoverpa pressure through September and October.

Helicoverpa punctigera proliferate on native hosts in northern South Australia and far south west Queensland. Near record rainfall in these areas over the past six months, has meant a large source of wildflowers is present in these areas to support widespread high populations of H.   punctigera larvae and moths. With further rainfall forecast over the next three months, it would be expected that breeding of this pest will continue.

Top: Rainfall over the past six months; Bottom: three month forecast from mid-August (source: BOM)

H. punctigera will migrate even when their inland hosts are still in good condition, but their movement from these inland breeding areas to eastern cropping regions requires weather fronts. Typically, these systems are the north-westerly winds that precede the passage of rain-bearing weather and can generate winds capable of carrying the moths long distances.

So what does this mean for me?

Helicoverpa damage to chickpea seed

Continue to monitor susceptible crops even if helicoverpa infestations have already been treated, as high moth activity puts pressure on the residual efficacy of products. Given the expectation of continued La Niña conditions until the end of the year, it is likely that chickpeas will continue to remain attractive to helicoverpa for longer. Large larvae that have been feeding on green terminal growth in a well podded chickpea crop can cause significant damage to maturing pods.

While winter cereals are not a host for H. punctigera, Helicoverpa armigera and armyworm activity is also expected to be high throughout spring, with reports of high armyworm activity already being received.

Management may become challenging as these populations respond differently to insecticides (for example, NPV is effective against H. armigera in winter cereals, but it has no activity against armyworm). Correct identification is therefore essential. Depending on average temperatures, most areas will start to get H. armigera emerging from late August. The graph below from 2019 illustrates a typical season in the Western Downs and Maranoa.

H. armigera pheromone trap catches in 2019

The post Higher than usual numbers of Helicoverpa punctigera moths this month first appeared on The Beatsheet.

What is TuYV and why does it matter?

Green peach aphid is a vector for TuYV

TuYV is a persistent virus that affects canola and other brassica crops. It is transmitted by green peach aphids (GPA, Myzus persicae), that pick up the virus when feeding on infected plants and can then spread it throughout a crop – even if aphid numbers are low.

Because GPA can be present without obvious colonies, infection can occur before growers are even aware of an aphid issue. Once infected, plants remain infected for life.

Symptoms to look for

Purpling and cupping of affected leaves in TuYV infected canola.

Symptoms are often subtle, especially early in the season, but can include:

• Purpling or reddening of older leaves
• Discolored leaves become thick and may cup upwards
• Stunted growth or uneven development
• General loss of vigour
• Fewer flowers and seeds produced.

These symptoms can be easily confused with nutrient deficiencies or environmental stress, so it’s worth getting lab confirmation if you’re unsure.

Impact on yield

If infected early, plants can be stunted with reduced yield.

Early infection can lead to significant yield losses. In southern states, TuYV is considered one of the most damaging viral diseases in canola, with yield losses of up to 75% reported in severe outbreaks.

If plants get infected when they are older (post-flowering) they may show leaf symptoms but are generally less affected in relation to stunting and reduced yields.

Free TuYV testing available now

To support growers this season, free TuYV testing is available for canola plants and aphid samples collected from Queensland paddocks.

If you notice suspicious symptoms or suspect GPA activity, consider sending in samples for testing. Both plant and aphid samples can help build a clearer picture of virus spread across the region.

Sample collection tips

• Send at least 5 cm² of leaf or a whole leaf of plants showing symptoms, and/or
• Collect live aphids attached to a leaf sample or remove them and put them in a sealed bag or container
• Include paddock location, crop stage, and contact details.

Express post is recommended to maintain sample integrity.

Questions or sample submissions?

If you’re seeing symptoms or have concerns about TuYV in your canola crop, contact Fiona Filardo at the Department of Primary Industries (DPI) Queensland:

[07] 37088449    Fiona.Filardo@daf.qld.gov.au

This information and testing form part of the GRDC and QLD DPI-funded project DAW2305 – Effective virus management in grain crops. Photos by Fiona Filardo.

Update: For more information on this topic, see GRDC’s 2026 article on virus in canola seedlings.

The post Keep an eye out for turnip yellows virus (TuYV) in canola this season first appeared on The Beatsheet.

Late bean fly infestations

Late bean fly damage was recently observed in mungbean crops in the South Burnett. Bean fly damage is more common in coastal and tropical areas, where it is typically is a pest of seedling summer pulse crops, affecting mungbean, navy beans, and black gram (but not soybean). However, it is also not unusual to find infestations during later crop stages, particularly during high-rainfall seasons.

Female bean fly lay their eggs into leaves and the larvae tunnel through leaf tissue, through the petiole, eventually making their way into the plant stem. The damage caused by this feeding includes dead leaves and even plant death in seedling crops.

Bean fly pupa in a mungbean stem. Photo: Trevor Volp.

Management

Bean fly can cause the death of mungbean seedlings. Photo: Hugh Brier.

The most severe crop stage for bean fly infestations is during early vegetative crops, where plant death due to infestations can significantly impact plant populations. The threshold during the seedling stage is 1 larval tunnel per plant. In later vegetative and reproductive stages thresholds are based on leaf damage, with thresholds of 33% leaf damage for vegetative crops, decreasing to 20% leaf damage when plants are flowering, setting and filling pods.

Dimethoate is registered for use against bean fly in summer pulses. Always follow label instructions.

If infestations of bean fly are occurring during later podding stages, such as the ones we’ve recently observed, agronomists must decide whether fly tunnelling in leaves is still capable of causing yield loss. If crops are at the black pod stage, ready for desiccation, it is unlikely a bean fly infestation will affect yield.

It is also worth examining if the infestation is still active. If you are only able to find pupal casings and no bean fly larva remain in the plants, then spraying an insecticide will have no impact on the damage that has already been done.

American serpentine leaf miner

American serpentine leaf miner adult and larva. Photos: Trevor Volp.

In addition to the regular bean fly, in recent years we have seen several invasive leaf mining fly species arrive in Australia that put summer pulse production at risk. These include the American serpentine leaf miner (Liriomyza trifoli), the serpentine leaf miner (L. huidobrensis), and the vegetable leaf miner (L. sativae).

Recently QDPI entomologists have been made aware of American serpentine leaf miner infestations in mungbean on the Darling Downs. The larvae produce obvious mines through leaf tissue, and the damage symptoms are quite distinct from traditional bean fly damage.

American serpentine leaf miner damage symptoms, with a close-up of the mines on the right. Photos: Trevor Volp.

Again, these infestations were during later crop stages where the impact of leaf damage may be limited. There was also substantial parasitoid wasp activity associated with these infestations.

No research has yet been conducted on these exotic Liriomyza spp. pests in mungbean in Australia.

Management

Dimethoate was previously available under permit for the control of Liriomyza leaf miners under APVMA permit PER89184, however this permit lapsed in March 2025.

If growers or agronomists become aware of similar infestations, please alert QDPI entomologists.

For more information contact Trevor Volp (0429 641 912) or Melina Miles (0407 113 306)

Article by Trevor Volp & Melina Miles

The post Recent infestations in mungbean fly under the radar first appeared on The Beatsheet.