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Carole Wright

Posted on by Better Bananas

Carole Wright

Number crunching to help researchers understand their trials

Carole Wright plays a vital role in many of the banana trials conducted by Department of Agriculture and Fisheries. She works with researchers in trial design and helps make sense of their data. As a biometrician she develops and applies mathematical or statistical theory and methods to collect, organise, interpret, and summarise data to provide insight and meaningful interpretation of results. Carole is based in Mareeba and has been involved in banana research since 2008. She has applied her biometry knowledge to analyse a 

Meet a researcher

vast range of banana research including variety trials, bunch pest trials, nutrient rate trials, soil biology trials and crop timing, just to name a few. Carole also works with other industries and is currently developing a model to predict the meat fullness of mud crabs using near-infrared spectroscopy.

‘I get excited when I find something unexpected in the data that the researcher wasn’t necessarily looking for.  I enjoy the variety of work that comes my way and the satisfaction of extracting interesting conclusions from the data that excites the researcher’, Carole said.

Carole grew up in Hastings, New Zealand and attended Waikato University in Hamilton, completing a bachelor degree and Masters of Computing and Mathematical Science.  She worked in agricultural research for 5 years, before returning to university to complete a PhD. Her doctorate involved developing an algorithm to generate resolvable row-column designs which are often used to evaluate large scale field trials. She worked in Victoria, Northern Territory and England, prior to moving to Far North Queensland in 2008.


Carole says she is not renown for her cooking but finds banana and bacon cooked on the BBQ delicious.

In her free time Carole enjoys scuba diving and always looks forward to minke whale season.

Why is Banana Bunchy Top Disease so hard to eradicate?

Posted on by Better Bananas

Why is banana bunchy top disease so hard to eradicate?

By Dr. Kathy Crew and Dr. John Thomas

Banana bunchy top disease (BBTD) occurs in many locations throughout northern NSW and southern Queensland. The disease was first recognised in Australia in 1913 and by the mid-1920s had devastated the Australian industry, which was based in this region at that stage, causing losses of 90 to 95% of production. The research work of Charles Magee at the time revealed that the disease was caused by a virus (banana bunchy top virus, BBTV) which was transmitted by the banana aphid and in infected planting material. He devised a successful control program which enabled the resurrection of the industry. His strategy of inspection, destruction of infected plants, use of clean planting material, and quarantine remains the basis of BBTV control to this day. 

However, despite the generally low incidence of BBTD in the region today, occasional flare-ups still occur, and the virus has rarely been eradicated from a district. Despite the low incidence in many subtropical plantations, the virus remains a potential threat to the banana industry. Why is this so?

BBTV symptoms in an infected plant. Symptoms include stunted, upright, “bunched” leaves with upcurled, yellow margins and discontinuous dark green lines/dots and dashes are visible on the underside of leaves when viewed with transmitted light. Photo: K.Crew, DAF.

In his research, Magee was only able to transmit the virus by aphids when they fed on a symptomatic leaf. Excellent subsequent epidemiological and computer modelling work by Rob Allen predicted that aphids were only likely to spread the virus after about four new leaves had been formed on the newly infected plant. This allowed enough time for the infected plant to develop symptoms and for the aphid vector to acquire enough virus to be infective. The BBTD control program is based on inspection intervals timed to allow the location and eradication of most infected plants within this window.

The strategic levy investment project “Understanding the role of latency in Banana Bunchy Top Virus symptom expression” (BA19002) is part of the Hort Innovation Banana Fund. As part of BA19002, we have been studying an outbreak of BBTD on a plantation in northern NSW where the disease persists at a high level, despite the control program.

The banana aphid, Pentalonia nigronervosa. Adult aphids are about 1 mm long. Photo: J. Thomas, UQ.

By selecting “hot spot” areas in the plantation and carefully inspecting all plants in the area individually, stem by stem, we have shown that the inspectors’ high rate of positive identifications (>80%) is being maintained here. However, using laboratory tests on leaf samples from these plants, we found that BBTV was detectable in some recently infected plants before they showed symptoms. In other plants, the virus was detected in the symptomless leaf formed immediately prior to the first leaf to show symptoms.

This should not be a concern for disease spread if the virus was not transmitted from these symptomless, but infected, leaves. However, to our surprise, when we fed aphids on these leaves, the virus was transmitted to healthy banana plants. Furthermore, the rate of virus transmission was similar regardless of whether the aphids fed on infected leaves with symptoms or without symptoms.

The map shows a survey area where symptomatic (red) and pre-symptomatic (yellow) plants were located amongst the healthy (green) plants. We found that the virus was transmitted from thirteen symptomless leaves, eight of which remained symptomless over the whole three-week observation period.

Our next step is to determine whether these infectious, asymptomatic leaves are produced by BBTV-infected plants year-round or in a seasonally dependent pattern.

This plantation was poorly managed, with limited de-leafing, providing a sheltered environment for the banana aphids to multiply. De-suckering was also limited, thus providing more susceptible young plants (favoured by the aphid) that are often obscured by the dead leaf skirts. We suspect that the higher aphid numbers along with the higher number than expected of infection sources present as symptomless, infected leaves and obscured, infected suckers, combine to promote and prolong the epidemic.

Map of plants assessed in this study.
Checking the youngest leaf of each stem for symptoms. L-R: Dr Nga Tran, A/Pro John Thomas, Dr Mona Moradi Vajargah. Photo: K. Crew, DAF.
The laboratory testing team subsampling field samples. L-R: Dr Kathy Crew, Dr Nga Tran, A/Prof John Thomas, Dr Mona Moradi Vajargah, Dr Megan Vance. Photo: D. Baker.

Remember

•   BBTV-infected plants can be infectious prior to development of leaves with symptoms.
•   Removing newly infected plants promptly slows the spread of the virus.
•   Four-week inspection cycles during the summer months in high disease pressure situations can reduce but may not         completely suppress the outbreak.
•   Any reductions in inspection frequency will allow the epidemic to take off.
•   Plantations need to be well-maintained to limit aphid vector numbers.
•   Grower participation in detection and eradication between formal inspections is likely to have a significant beneficial 
     impact on control.     

More information

This research has been funded as part of the Improved Plant Protection for the Banana Industry Program (BA19002), which is funded by Hort Innovation, using the banana research and development levy, co-investment from the Department of Agriculture and Fisheries and contributions from the Australian Government. Hort Innovation is the grower-owned, not-for-profit research and development corporation for Australian horticulture. 
Support for the establishment of research sites and identification of infected plants has also been provided through Hort Innovation Project BA21003 “Multi-pest surveillance and grower education to manage banana pests and diseases”.

 

 

Banana bunchy top disease

Posted on by Better Bananas

Banana bunchy top disease

Banana bunchy top is considered the most serious viral disease of bananas worldwide

Banana bunchy top disease (BBTD) reduces the growth of banana plants and causes bunching of newly emerged leaves (Figure 1). Infected plants rarely produce fruit and are a source of inoculum for further spread, which can lead to serious commercial losses if not promptly eradicated. The disease is caused by a virus (banana bunchy top virus, BBTV) and affects all banana varieties. Unfortunately, there is no cure for the disease, once a plant becomes infected it must be destroyed as all parts of the clump/stool/mat are also infected. 

Figure 1 Banana plant infected with BBTV. Image shortening and bunching up of new leaves with yellow margins (photo courtesy of Australian Banana Growers Council)

BBTV is spread two ways, by banana aphids and infected plant material

BBTV is transmitted by a small black insect (1.5–2.0 mm long) called the banana aphid Pentalonia nigronervosa (Figure 2 & 3). Aphids that feed on infected plants can carry the virus spreading it to healthy plants as they feed. Aphids can carry the virus for several weeks and may cover large distances when blown by the wind. The virus can also be spread to new areas from infected planting material. It’s important to note that plants can be infected with the virus without showing symptoms. It’s always recommended that you source tissue cultured planting material from a Quality Approved Banana Nursery (QBAN) to minimise the risk of introducing serious pests and diseases onto your farm, such as Panama disease, BBTV, banana weevil borer and many more. Click here for a list of QBAN accredited nurseries. 

New research discovers new findings on virus transmission and explains why this disease is so hard to eradicate.
Click here for more information. 

Figure 2 The banana aphid, Pentalonia nigronervosa. Adult aphids are about 1 mm long. Photo: J. Thomas, UQ.
Figure 3 Banana aphids on banana leaf petioles.
Figure 4 Ants and aphids living and feeding together. Image also shows numerous white cast skins of banana aphid (photo courtesy of Australian Banana Growers Council)

Control and containment activities continue to play an important role in limiting the spread of BBTV within Australia.

Banana bunchy top disease was first discovered in Australia over a century ago in the Tweed River region, located on the New South Wales and Queensland border. To date the disease has been successfully contained within the Bunchy top zone of South East Queensland and northern New South Wales. The banana growing regions of Far North Queensland, Northern Territory and Carnarvon in Western Australia remain free of the virus. However, it’s important for banana growers across all production regions to be on the lookout for BBTD symptoms. 

What to look out for?

Early symptoms of BBTD can be difficult to detect to the untrained eye. If you have stunted or unthrifty banana plants, examine the leaf lamina of the newest banana leaves for short dark green on lighter green dot-dash lines starting from, and sometimes extending or ‘hooking’ into, the mid-rib (Refer to photos below). You can see them best if you hold the leaf up to the light and look through from the underside of the leaf. There may also be dark green stripes running along the mid-rib. Plants with advanced infection have stunted looking leaves and a bunched appearance (bunchy top). If bunches are present, they may be small and deformed. 

Do not cut or disturb plants or move plant material off your property as this can spread the disease. 

Key symptoms

  • Dark green on lighter green, dot-dash flecks (sometimes called Morse code streaking/patterning) on leaves.
  • Dot-dash flecks are initially visible along the lower edge of the leaf’s midrib, then progress to the leaf veins adjacent to the midrib, and gradually becoming more prominent across the leaf blade. 
  • Eventually dot-dash flecks can form into irregular streaking. 
  • Leaf flecks and streaking are most visible when viewed from the underside of leaves.
  • Flecks in veins can form a characteristic ‘hook’ shape at the point where the midrib meets the leaf blade.
  • Vein-flecking can also be seen on the petioles and in the leaf sheaths of stems.
  • Growth of the whole plant is reduced and emerging leaves develop a choked or ‘bunched” appearance.
  • Affected leaves often appear more upright with pale yellow margins, and may have wavier leaf edges than normal.
 
Image of advanced BBTV symptoms in a banana plant. Shortening and bunching up of new leaves with yellow margins (photo courtesy of Australian Banana Growers Council)
Image of advanced BBTV symptoms in a banana plant. Stunted growth and emerging leaves develop a choked or ‘bunched’ appearance
Dark unbroken stripes along the leaf midrib (not always present) (photos courtesy of Australian Banana Growers Council)
Dark unbroken stripes along the leaf midrib (not always present) (photos courtesy of Australian Banana Growers Council)
Dark green on lighter green, dot-dash flecks (sometimes called Morse code streaking/patterning) on leaves (photo courtesy of Australian Banana Growers Council)
Do your staff keep an eye out for Banana bunchy top?
Do your staff keep an eye out for Banana bunchy top?

ABGC have produced the following video on how to detect Banana Bunchy Top Virus symptoms in commercial plantations. 

How to report

It’s important for banana growers across all production regions to be on the lookout for BBTD symptoms.
Growers or members of the public that suspect BBTD must immediately notify their state’s biosecurity agency or through the bunchy top hotline 1800 068 371. Early detection and destruction are critical to limit its spread. Strict quarantine restrictions remain in place to prevent the movement of contaminated planting material.

Surveillance and containment work within the known bunchy top zone is continuing as part of Hort Innovation’s ‘Multi-pest surveillance and grower education to manage banana pests and diseases’ project, led by the ABGC. This important work is aimed at controlling and containing the disease within the known BBTV zone, supporting the commercial industry within this zone and aims to prevent its spread to other commercial growing regions within Australia. Click here to read more information about this project.

Currently, there is no cure for BBTV and there are no known resistant banana varieties. Control is only achieved through the destruction of infested plants and banana aphids. Early detection and destruction are critical to limit the spread of BBTD.

Latest research update

Click here to read about the latest new research that helps explain why banana bunchy top disease is hard to eradicate.

More information

In collaboration with ABGC, this information has been compiled by the National Banana Development and Extension Program (BA19004). This project has been funded by Hort Innovation, using the banana research and development levy, co-investment from the Department of Agriculture and Fisheries and contributions from the Australian Government. Hort Innovation is the grower-owned, not-for-profit research and development corporation for Australian horticulture.

Grower case study. Bagging technique improves fruit quality for Sellars Bananas

Posted on by Better Bananas

Grower case study

Bagging technique improves fruit quality for Sellars Bananas

Experienced premium Cavendish grower Naomi Brownrigg is confident that their bagging technique which leaves a ‘flue’, has improved fruit quality by reducing fungal and mould issues.

Naomi continues to see the benefit of this technique, implementing it on their family farm over 20 years ago.

Naomi says the flue bagging technique has dramatically reduced fungal and mould issues. ‘From that moment on (leaving a flue in the bag) we haven’t really had an issue. It will only be if the flue closes up you might get a mouldy bunch, after that we were free of it,’ Naomi said.

‘We’ve adopted that technique on our family farm for 20 years now and it’s so easy to do.’

Tianara Takai and Naomi Brownrigg from Sellars Bananas

Sharing lessons learnt for the benefit of industry

Naomi is passionate about helping other growers improve their fruit quality and is willing to share her knowledge and experience of lessons learnt. 

Sellars Bananas transitioned from bunch dusting with chlorpyrifos and talc to using a bunch spray with chlorpyrifos. This was to eliminate the risk of fruit being rejected at market due to talc residue. When they made the switch Naomi said they experienced significant decline in fruit quality due to increased fungal and mould issues. ‘At first we weren’t leaving any air hole (flue) in the bag. The bags did have perforated holes in them and we were just tying them up like normal and putting the spray in,’ Naomi said. It was her husband Dave who first noticed they had an issue ‘he said we have a huge problem out there. He said I can see all the fruit sweating and the mould starting,’ Naomi said. 
Naomi said the type of bags they used at the time also contributed to the problem, as they didn’t hold their shape and instead closed around the fruit. Naomi explained it’s important for growers to ensure the bags they use don’t close up. 
With chlorpyrifos currently under review by the Australian Pesticides and Veterinary Medicines Authority (APVMA), the permit to apply chlorpyrifos mixed with talc may be cancelled or not renewed once the current permit expires. This will leave only spray application of registered insecticides to control banana bunch pests. 

Some growers have reported increased incidence of mould and fungal issues using a bunch spray compared to dusting. It’s suggested that bunch spraying increases the amount of moisture in the bag and combined with high temperatures, may lead to increased humidity and fungal issues. Market agents have also confirmed fruit continues to be rejected due to talc residues. Naomi hopes that sharing their bagging technique will help growers who are currently experiencing fungal issues affecting fruit quality, and those who are looking at transitioning from dusting to bunch spraying in the future.

In light of the APVMA review and continued market rejections due to talc residues, Naomi encourages growers to start trialling it. ‘Now is the time to be trialling these things. People are getting rejected at the supermarket level for talc at the moment and that pressure isn’t going to go away,’ Naomi said.

Flue bagging technique

The term ‘flue’, simply refers to an opening. Its use in this circumstance is designed to increase air flow through the bag and reduce humidity.

The key points to the bagging technique used by Sellars Bananas are:

  ⦁ A liner is applied first to emerged bells and tied tightly around the bunch stalk with no flue (Figure 1).
  ⦁ At pruning, bags are tied with a knot tightly around the stalk, not wrapped. The excess bag is left open (Figure 2).
  ⦁ The bag around the opening is folded down on itself to improve integrity and stop it from closing.
  ⦁ All bracts are removed to further reduce moisture within the bag.

Figure 1 Bells are bagged early with a liner which is tied tightly around the stalk with no flue
Figure 2 Bags are applied at pruning and are tied tightly around stalk leaving a flue to the side

Sellars Bananas achieve control of rust thrips

When the banana extension team discussed this technique with growers, some have raised concern  the flue may provide an avenue for rust thrips to enter the bunch.

Naomi said this has not been their experience and believes that the bag being tied tightly around the stalk, acts as a barrier preventing rust thrips from moving down the stalk. In addition, the use of a liner, also tied tightly around the bunch stalk (without a flue) may help limit movement of rust thrips into the bunch.

Of course it is never one single practice in isolation and other bunch protection practices are also important for control of rust thrips. ‘If it has been injected on time, bagged on time and sprayed properly, we haven’t had a drama. We throw very little fruit away to rust thrips,’ Naomi said.

Figure 3 Sellars Bananas achieve good control of bunch pests and supply premium grade fruit

Every farm has different management practices and pest pressure and it’s therefore recommended that growers trial this bagging technique to make their own assessment before implementing it as a standard practice. 

Watch the video below for a demonstration of the bagging technique

Thank you to Naomi Brownrigg and the team at Sellars Bananas who provided their time and gave permission to use this case study for the benefit of the wider industry.

Download this information as a fact sheet

If you would like further information or assistance with bunch pest practices, please contact the National Banana Development and Extension Team on email betterbananas@daf.qld.gov.au or phone 07 4220 4152.

This case study has been produced as part of project BA19004 the National Banana Development and Extension Program which is funded by Hort Innovation, using the banana industry research and development levies, co-investment from the Department of Agriculture and Fisheries and contributions from the Australian Government. Hort Innovation is the grower-owned, not-for-profit research and development corporation for Australian horticulture.
 

Grower case study. Tiger Mereider has more than just his footbath covered.

Posted on by Better Bananas

Grower case study

Tiger Mereider has more than just his footbath covered

John Mereider, better known as Tiger, has been farming in the East Palmerston area for over 23 years. He is no stranger to biosecurity, having endured Panama disease race 1 on his farm when he grew Ducasse and some Lady Fingers in his early years on the block. Back then he built a drive through vehicle dip to help protect his farm. So, when Panama disease tropical race 4 was detected in Tully in 2015, Tiger didn’t hesitate in quickly putting more on-farm biosecurity practices in place to protect his farm. 

This included converting his existing drive through dip into an automated disinfecting spray down facility for vehicles. Pick-up and delivery trucks accessing the packing shed drive through this automated spray facility and are disinfected with Steri-max. These vehicles movement is restricted to the driveway to the shed and turn around area.

Tiger Mereider showing his covered footbath
Entrance to Tiger's farm showing biosecurity infrastructure

To address the risk of the driver’s footwear, Tiger installed a footbath next to the vehicle spray down. Tiger supplies drivers with a pair of boots to change into prior to using a covered footbath. 

Keeping it simple, Tiger purchased a 70 litre shallow plastic tub and a boot scrubber that he placed in the footbath. Because the footbath is not undercover, he had a stainless-steel lid built with a handle to place over the plastic tub. The lid ensures that the liquid does not evaporate when the weather is sunny or diluted when it rains. All up the covered footbath cost around $300. 

Another important consideration for Tiger was placing the footbath on a concrete surface to reduce contamination and make cleaning easier. He also painted large arrows on the concrete to direct traffic.

Tiger changes the disinfectant in the footbath every 2 weeks to ensure it is effective. He has used Quaternary Ammonium test strips to check the concentration of his footbath solution and is confident that it is doing the job when changed at this frequency. 

Tiger said, ‘The pickup and delivery drivers are good and always use the footbath, but I think it helps that I can see the footbath from the packing shed.’

In addition to his vehicle spray down and footbath, Tiger’s entrance to his farm is gated and clearly signed to limit unauthorised access. 

 

Simple footbath design with lid
Footbath located on hard paved surface

Thank you to Tiger Mereider for providing his time and giving permission to use this case study for the benefit of the wider industry. 

Tips on disinfectants!

  • Use disinfectant products containing Didecyl dimethyl ammonium chloride (DDAC) or Benzalkonium chloride (BZK). These quaternary ammonium (QA) compounds have been tested and solutions mixed as per the label rate do kill the fungal spores that cause Panama disease.

  • It is important to remove all soil and organic matter before applying any disinfectant product.

  • Easy-to-use test strips can be used to regularly test QA concentration of solutions in footbaths, spray shuttles and wash-down facilities. 

Click here for information on disinfectants.

Download this information as a fact sheet

If you would like further information or assistance with setting up or improving biosecurity practices for your farm, please contact the National Banana Development and Extension Team on email betterbananas@daf.qld.gov.au or phone 07 4220 4152.

This case study has been produced as part of project BA19004 the National Banana Development and Extension Program which is funded by Hort Innovation, using the banana industry research and development levies, co-investment from the Department of Agriculture and Fisheries and contributions from the Australian Government. Hort Innovation is the grower-owned, not-for-profit research and development corporation for Australian horticulture. 

Meet a researcher – Tegan Cavallaro

Posted on by Better Bananas

Tegan Cavallaro

From soil scientist to extension specialist: the focus has always been bananas.

Tegan has worked with the banana industry since graduating from university in 2009. Completing an undergraduate degree at James Cook University in Cairns, Tegan commenced her career with the Department of Agriculture and Fisheries working with renown soil scientist and nematologist Dr Tony Pattison. Under Tony’s mentorship, Tegan’s honours project looked at the effects of ground cover management on the biology of soils in banana production systems. Tegan continued working in the field of soil science for six years. 

Meet a researcher

Tegan Cavallaro
Senior Development Horticulturist
Department of Primary Industries
Centre for Wet Tropics Agriculture
South Johnstone

With a passion for the banana industry, Tegan decided on a career change taking on an industry development role in 2015, leading the banana industry’s National Development and Extension Project. This decision saw Tegan hitting the ground running, as commencement of her new role coincided with the detection of Panama disease tropical race 4 in Far North Queensland. Tegan played an important role as part of the incursion response, developing information packages and facilitating extension services for the banana industry. This also led to Tegan and the extension team developing an important resource for industry, the on-farm biosecurity best management practices guideline. 

Tegan is a local to the north Queensland area and was lucky enough to call Kurrimine Beach her home, growing up with all the beach and boating experiences the area has to offer. She now loves spending time with her young family, enjoying these and other outdoor adventures.

Tegan suggests you try a dessert pizza with Nutella, banana, and marshmallows.

Further to her experience in biosecurity extension, Tegan also leads key extension activities and initiatives for industry including banana roadshows, field days and workshops, NextGen activities, Better Bananas website, tailored on-farm biosecurity advice and assistance on general banana agronomy for growers.

Tegan Cavallaro and Rob Mayers at banana industry field day at South Johnstone research facility.

Panama disease TR4 variety screening trial (2018) Sub-trial results (plant and first ratoon)

Posted on by Better Bananas

Contributions by:
Sharl Mintoff1, Samantha Bond1, Chris Kelly1, Maxine Piggott1 and Jeff Daniells2
1Northern Territory Department of Industry, Tourism and Trade, Darwin, NT
2Queensland Department of Agriculture and Fisheries, South Johnstone, QLD

Latest update

Good parents produce better progeny.

Four parents with stellar TR4 resistance have been identified. This will assist international banana breeding programs to incorporate TR4 resistance into new varieties.

Sub-trial results (plant and first ratoon)

Disease assessments

Disease assessments were carried out fortnightly once external symptoms became apparent in a susceptible variety. Assessments included noting the appearance of external disease symptoms and internal symptoms at plant death or harvest.

Disease resistance was determined by scoring the level of disease in each variety then grouping them into one of the following categories: 

Highly Resistant (HR) – No disease symptoms were observed within the crop cycle and may not show symptoms under high inoculum pressures.

Resistant (R) – Plants normally show no signs of infection in the presence of the pathogen. However, under high inoculum pressures low amounts of symptoms or losses may occur.

Intermediate (I) – Plants which can withstand some infection and suffer low losses under natural infestation conditions, with most completing their crop cycle. However, its susceptibility or resistance can be highly dependent on the inoculum pressure already present. With the appropriate crop management or environment to lower the inoculum levels, these should be commercially viable.

Susceptible (S) – More than 50% of plants show symptoms and/or killed due to pathogen infection.

Very susceptible (VS) – Majority of plants (more than 70%) showed severe symptoms, most of which died due to TR4.

Results

Highly resistant and resistant

The four parental lines – Inarnibal, M53, Manang, and Tjau Lagada, were highly resistant in both the plant crop and first ratoon, with no symptoms of TR4 infection. One of the Goldfinger plants (TR4 resistant reference) expressed disease symptoms resulting in the death of the mother plant, yet no disease symptoms were observed in the subsequent ratoon crop for the same plant or any of the other Goldfinger ratoon plants. Mild disease symptoms were observed for Pisang Bangkahulu
in the plant crop and this was repeated in the first ratoon.

Surprisingly, the two varieties, Sinwobogi and Pisang Sapon, made a major recovery – with no disease symptoms in the ratoon, compared to the plant crop where the disease was clearly prominent.

Intermediate

In the case of Formosana and Paka there was an increase in the number of diseased plants in the ratoon crop cycle, moving them into the intermediate category. Pisang Batu retained its intermediate rating whereas some improvement was observed in Pisang Madu where fewer diseased plants were noted in the ratoon crop cycle compared to its susceptible plant crop cycle.

Susceptible and very susceptible

The most susceptible lines were Heva and Nzumoheli, which were the most susceptible of the parental lines in both crop cycles, consistent with the Williams TR4 reference variety. Pisang Pipit showed an increase in disease symptoms in the first ratoon crop moving it into the susceptible category.

Table 1: Panama TR4 resistance ratings for the plant and ratoon crop cycles, with reference varieties in bold

HR = highly resistant, R = resistant, I = intermediate, S = susceptible, VS = very susceptible

The images below are representative resistance response in first ratoon plants exposed to Panama  disease TR4. Most Williams plants died due to infection, whereas parental lines such as Inarnibal and Tjau Lagada showed little to no symptoms in their first ratoon. 

Williams
Inarnibal
Tjau Lagada

Inarnibal, M53, Manang, and Tjau Lagada had no disease symptoms in the plant and ratoon crops. A few of the other lines also had reasonable levels of resistance. Identification of these resistant parental lines is very encouraging for international breeding programs and helps strengthen our linkages and access to their germplasm. When these results were shown to the breeding programs which use these lines they were very grateful:

• this provided CIRAD with – “…valuable information for planning better crossing schemes…”

• and from the breeding program of EMBRAPA (Brazil) “…Excellent news about the improved diploid – M53. He is the parent of many EMBRAPA hybrids…”

The information from this sub-trial could also be useful in identifying existing hybrid varieties bred from resistant parental lines to source and screen for TR4 resistance and general agronomic and market suitability.

Interestingly the varieties Sinwobogi and Pisang Sapon recovered from being symptomatic in the plant crop to exhibiting no disease symptoms in the first ratoon. A somewhat similar response was also noted in the main trial with CIRAD 06 and High Noon. Further study on this recovery phenomenon could be advantageous for identifying potential crop management strategies to mitigate disease severity in the field, particularly during the plant crop cycle.

This research has been funded as part of the project Improved Plant Protection for the Banana Industry (BA16001), which is funded by Hort Innovation, using the banana research and development levy, co-investment from the Department of Agriculture and Fisheries and the Northern Territory Department of Industry, Tourism and Trade and contributions from the Australian Government. Hort Innovation is the grower-owned, not-for-profit research and development corporation for Australian horticulture.

Why biosecurity is so important for banana businesses

Posted on by Better Bananas

Why biosecurity is so important for banana businesses

The 2001 incursion of Black Sigatoka and the 2015 incursion of Panama disease tropical race 4 (Panama disease TR4) in the Tully Valley certainly highlight the importance of biosecurity. Unfortunately, unlike Black Sigatoka, Panama disease TR4 cannot be eradicated. As of October 2021, the response over the past six and a half years has successfully limited it’s spread to five commercial banana farms in the Tully Valley. However, it will continue to spread and there is a real risk it could potentially infest other production regions within Far North Queensland and Australia. If you want to sustain a successful banana business into the future, having effective biosecurity practices on your farm has never been more important.

The devastating impact of Panama disease tropical race 4 (TR4) on a Cavendish plantation in the Philippines. Panama disease TR4 was first detected in Australia near Darwin in 1997 and has since been detected in Far North Queensland in the Tully Valley in 2015. Unfortunately, the disease cannot be eradicated.

So why are bananas so vulnerable and what can we do to protect our banana industry and the fruit that we love to eat? Accounting for 97% of the Australian market, the seedless fruit of the commercial Cavendish banana are sterile and are dependent on clonal propagation from bits, suckers or tissue culture. Growing large monoculture plantations with limited genetic diversity makes them extremely vulnerable to the impact of pests and diseases.    

For decades, breeding programs around the world have invested significant time and resources to find a commercially viable Cavendish variety, comparable to Williams Cavendish, that is resistant to Panama disease TR4. Unfortunately, bananas are very difficult to breed and the search for this ‘holy grail’ continues. This is why on-farm biosecurity is so important! Currently there are no varieties in Australia or the world, resistant to Panama disease TR4 or leaf spot, that can match the productivity of Williams Cavendish.  It may be some time before this is achieved, so why not do everything in your power, to protect what you have now.

The photos on this page show the devastating impact of serious banana plant diseases overseas, where biosecurity is limited. These are just a few examples of serious diseases, either already present in production regions of Australia or on our country’s doorstep, that pose a risk to our commercial banana industry. 

Severe banana freckle (Phyllosticta cavendishii) infestation in a Cavendish banana plantation in Indonesia. In 2013 Banana freckle (Phyllosticta cavendishii) was detected in the Northern Territory. A national response to the outbreak resulted in its successful eradication, with Northern Territory declared Banana freckle free on 1 February 2019.
Black Sigatoka streaks and lesions on banana leaf. Mature leaf symptoms of black Sigatoka are similar to those caused by yellow Sigatoka. The impact of black Sigatoka is through the early death of leaves reducing yield and green life of fruit. There have been several outbreaks of black Sigatoka in Australia, all of which have been successfully eradicated. Australia has been declared free of the disease since 2005.

Assistance is available

If you need help to get started with your on-farm biosecurity or would like assistance to improve on existing practices contact the National Banana Development and Extension Team via email betterbananas@daf.qld.gov.au or phone 07 4220 4152.

This resource has been developed as part of the National Banana Development and Extension Program ( BA19004) which is funded by Hort Innovation, using the banana research and development levy, co-investment from the Department of Agriculture and Fisheries and contributions from the Australian Government. Hort Innovation is the grower-owned, not-for-profit research and development corporation for Australian horticulture. 

Starting your biosecurity plan

Posted on by Better Bananas

Starting your biosecurity plan

The first step is to understand the potential risk pathways on your farm. Each farms layout is unique, and it may seem challenging if you must consider roads, rivers and railway tracks which pass through your property. The best way is to break it down.  
1.  Grab a map of your farm and a pen. Google Maps is a good source of satellite imagery.

2. Think about all the different ways people, vehicles and machinery move on and off your farm. With these movements in mind divide your farm into zones: exclusion, separation (The separation zone manages movement of essential vehicles entering your farm, as it acts as a buffer between the exclusion and farming zones) and farming. 

3. Choose one point at the edge of each zone where people, vehicles and machinery can move in and out.
4. Then consider what you will put in place at each of these points to cross between zones – e.g. boot exchange, footbath, spray    shuttle, wash-down pad. 
5. Think about water movement and mark down on your map any areas which flood and where you source water from. 
6. Consider where you get planting material from. Do you know the risks associated with the type of planting material you use      and are you happy with this risk?  

Handy tips!

  • Tissue culture from a QBAN approved facility provides the best protection against moving and spreading Panama disease or other banana pests and diseases such as nematodes and banana weevil borer.

  • Some things are always beyond your ability to control, focus on the things you can do.

  • Think of your farm as an airport where everyone needs to enter through a security barrier.  Instead of a metal detector you might have a boot exchange, a footbath or something else which stops an unknown threat from getting in.  

  • Making a start is often the hardest part. Make a list of practices;  start with one practice and work your way down the list as you can. 

  • Start with temporary measures like flagging tape before installing a permanent fence to see if it works first.  

Using aerial maps of your farm is a good way to identify biosecurity risk pathways.
Flagging tape can be used to temporarily mark out zones. This allows you to trial the zones before putting in permanent structures.

Assistance is available

You’re not on your own. The following video features advice from banana growers on starting your biosecurity plan. The National Banana Development and Extension Team is also available to help you get started. Contact our team today via email betterbananas@daf.qld.gov.au or phone 07 4220 4152.

This resource has been developed as part of the National Banana Development and Extension Program (BA19004) which is funded by Hort Innovation, using the banana research and development levy, co-investment from the Department of Agriculture and Fisheries and contributions from the Australian Government. Hort Innovation is the grower-owned, not-for-profit research and development corporation for Australian horticulture. 

Grower case study. Reinventing the pod into a spray shuttle

Posted on by Better Bananas

Grower case study

Reinventing the pod
Spray down with the Randhawa brothers

1000 litre pods can be useful in many ways. After Panama disease tropical race 4 (TR4) was found in Tully, brothers Paramadeep and Harpreet Randhawa, like many banana growers, recycled one to use as a disinfectant spray down unit at the entrance to their farm.

Paramadeep and Harpreet Randhawa started growing bananas in 2015, the same year that Panama disease TR4 was found in Tully. To help protect their farm, they purchased a pod from a local fertiliser distributor and engaged a local electrical contractor to install a 12-volt pump, hose and spray wand. They used a spare tractor battery to power the pump and installed a solar trickle charger to keep it charged. The whole setup cost around $500 at the time.

Harpreet said, ‘We placed the pod right at the start of the driveway to our shed. The position of the pod is good as I can see it from the packing shed, so I can make sure everyone that comes onto the farm sprays their vehicle down.’ In busy times the pod lasts about a month, so Harpreet tops up the pod with fresh disinfectant mixture as required. 

Disinfectant spray pod located at entrance to farm.

Paramadeep and Harpreet use a quaternary ammonium based disinfectant product which has been shown to be effective in killing the fungal spores that cause Panama disease. They have also installed a water supply to make refilling the pod easier.

The only hitch the brothers have come across is the solar panel doesn’t keep the battery charged when there are long periods of overcast wet weather. On these occasions they just take the battery back to the shed to charge it.

Paramadeep said ‘Make sure that the hose is long enough to be able to spray all around the longest truck that comes onto your farm. We have found that most people that come to our farm follow our instructions to spray down to help us to protect our business.’

Pod located at entrance to farm. Boom gate to restrict unauthorised access.

Thank you to Paramadeep and Harpreet Randhawa who provided their time and gave permission to use this case study for the benefit of the wider industry.

Tips on disinfectants!

  • Use disinfectant products containing Didecyl dimethyl ammonium chloride (DDAC) or Benzalkonium chloride (BZK). These quaternary ammonium (QA) compounds have been tested and solutions mixed as per the label rate do kill the fungal spores that cause Panama disease.

  • It is important to remove all soil and organic matter before applying any disinfectant product.

  • Research has shown that DDAC and BZK disinfectants used in infrastructure such as spray shuttles, that isn’t contaminated with soil and organic matter, will be effective for an extended period of time when exposed to outdoor conditions. 

  • Easy-to-use test strips can be used to regularly test QA concentration of solutions in footbaths, spray shuttles and wash-down facilities. 

Click here for information on disinfectants.

Download this information as a fact sheet

If you would like further information or assistance with setting up or improving biosecurity practices for your farm, please contact the National Banana Development and Extension Team on email betterbananas@daf.qld.gov.au or phone 07 4220 4152.

This case study has been produced as part of project BA19004 the National Banana Development and Extension Program which is funded by Hort Innovation, using the banana industry research and development levies, co-investment from the Department of Agriculture and Fisheries and contributions from the Australian Government. Hort Innovation is the grower-owned, not-for-profit research and development corporation for Australian horticulture.