Banana flower thrips

Posted on by Better Bananas

Flower thrips

Banana flower thrips (Thrips hawaiiensis) are a tiny pest frequently present in banana bunches. For most growers in Far North Queensland flower thrips are not the main bunch pest which leads to economic losses. However, large enough infestations can cause damage to fruit that does not meet market specifications. Damage caused by flower thrips is more significant in warm dry conditions with lower relative humidity, such as South East Queensland and northern New South Wales.

female Flower thrips to scale
Adult female flower thrips measure 1mm in length

Correct and timely bell injection is critical for the control of flower thrips. It must be performed when the bell is upright to ensure the insecticide solution provides protection to the entire bunch. Flower thrips are from the same family as Banana rust thrips (Chaetanaphothrips signipennis). Unlike banana rust thrips, flower thrips spend their entire life cycle on the banana plant, therefore, soil treatment does not provide control of flower thrips. 
 

Flower thrips cause damage to the peel of banana fruit from feeding and ovipositing (egg laying). These ovipositions resemble minute raised pimples on the young immature skin. These are readily seen because of a dark raised centre and can be confirmed by lightly touching the raised area with your fingertip. These oviposition marks almost disappear as the fruit matures. However, extensive damage from feeding from adult flower thrips can cause superficial scarring known as ‘corky scab’. This damage is usually confined to the lower hands (as flower thrips damage increases on lower hands as populations increase as they move down the bunch if it hasn’t been treated). Usually it is first noticeable on the outer whirl,  where the neck meets the cushion, but can extend to the outer curve of the fruit.  

Close up of flower thrips damageovipositions (pimples) on young banana fruit.
Severe flower thrips damage causing corky scab damage.

More information

This information has been prepared as part of the National Banana Development and Extension Program (BA19004) which is funded by Hort Innovation, using the banana industry research and development levies and contributions from the Australian Government. Hort Innovation is the grower-owned, not-for-profit research and development corporation for Australian horticulture. The Queensland Government has also co-funded the project through the Department of Agriculture and Fisheries.

Agronomic evaluation of new varieties – South Johnstone screening trial (October 2020)

Posted on by Better Bananas

Latest update...

Evaluation of the 2020 variety screening trial is progressing. Assessment of the plant crop is now complete and results are now available. Harvesting of the first ratoon was completed late in 2022 with data analysis underway. The new varieties are now being screened for yellow Sigatoka resistance.

About the trial

This agronomic evaluation screening trial was planted at South Johnstone Research Facility in October 2020. Building on previous variety evaluation work, the trial is looking at new introductions that may have commercial potential for the Australian banana industry, forming part of the recently completed project ‘Improved plant protection for the banana industry (BA16001)’.  

Assessment of agronomic traits is being collected over a plant crop and first ratoon with leaf spot screening performed in a nurse-suckered third crop cycle.

Trial five months after planting in March 2021.

Below is a video of a field walk of the evaluation trial taken in September 2021.

About the varieties being evaluated

Three Cavendish selections, four CIRAD hybrids, and six Lady Finger selections were included in the evaluation trial, including two varieties with TR4 resistance.

Observations and results

Observations and results are now available for the plant crop and will soon be available for the first ratoon.

What's next?

Currently, screening is underway to evaluate these selections for their tolerance to yellow Sigatoka. Plants will be assessed over three months during the wet season (March, April, and May 2023) and compared against control varieties with known resistance/susceptibility to this fungal leaf disease.

In December 2022, a new variety evaluation was planted as part of the project ‘New varieties for Australian banana growers (BA21002)’. This will again look at the agronomic traits as well as disease tolerance of recently imported varieties.

More information...

If you would like further information, feel free to contact the Better Bananas team via email at betterbananas@daf.qld.gov.au.

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 contributions from the Australian Government. Hort Innovation is the grower-owned, not-for-profit research and development corporation for Australian horticulture.

Agronomic evaluation of new varieties South Johnstone (planted October 2020) Plant crop observations and results

Posted on by Better Bananas

Latest update…

Two TR4 resistant selections are among the new varieties being assessed for agronomic performance at the South Johnstone Research Facility. Those who attended the September 2021 field walk saw the varieties as they were approaching harvest in the plant crop (available to watch online here). The results of the plant crop are presented here.

By Katie Robertson, Jeff Daniells and Ashley Balsom

The agronomic characteristics of the new varieties are being compared with industry standards over a plant crop and first ratoon. Three Cavendish selections, four CIRAD hybrids, and six Lady Finger selections were included in the evaluation. The trial was established in October 2020, and bunch harvest was spread from July to November 2021 for the different varieties.

Within the Cavendish varieties, Williams and the GCTCV 106 Selection had the fastest cycle times (planting to bunch harvest) of 8.9 and 9.0 months, resulting in yields of 31.5 and 28.9 kg/year, respectively. In contrast, Asia Pacific #1, a TR4 resistant selection from Taiwan, took 1.5 months longer to reach bunch harvest than Williams, resulting in a 21% yield reduction (24.9 kg/year). This longer cycle time has been a common feature of other TR4 resistant Cavendish varieties previously evaluated. Asia Pacific #1 was 24% shorter in stature than the other Cavendish varieties, standing at 2.2 metres. Fruit length was also shorter. Only 26% of its fruit was in the 22–26 cm finger size category compared to 64% for Williams.

The dwarf selections of Lady Finger (Dwarf Rossi, Dwarf Lady Finger, and Santa Catarina Prata) were 25–28% shorter in stature than standard Lady Finger at bunching. Pendulous Lady Finger (PLF) and Tall Rossi were also shorter than regular Lady Finger by 7 and 13%, respectively. Additionally, PLF had an 18% yield increase per year and displayed much better bunch conformation than Lady Finger’s typical sub-horizontal bunch angle.

The TR4 resistant Cavendish selection, Asia Pacific #1, was 24% shorter in stature than Williams but was 21% lower yielding in the plant crop and had much less fruit in the premium size grades.
The bunch conformation of Pendulous Lady Finger (L) compared to standard Lady Finger (R).

The French CIRAD hybrids were developed to have resistance to Sigatoka leaf diseases. One of them, CIRAD X17, has also demonstrated to be highly resistant to TR4 in the Northern Territory screening trials (Read here, pages 18 -19). Like other CIRAD hybrids we have evaluated previously (Read here,  pages 16 – 17), these four selections had long, narrow leaf petioles which are brittle and prone to breaking. Although the height of CIRAD 918 was comparable to Williams (average height of 2.9 m), its pseudostem snapped before harvest for 40% of the plants. There were no notable losses from snapping or rolling out in the other three hybrids. These varieties were bred and selected in a tropical region, and they do not seem to handle the relatively cooler winters and some other environmental stressors of north Queensland particularly well. There were also inconsistencies with the rate and capacity of fruit filling. The CIRAD hybrids took 14 – 21% longer to reach harvest maturity and had bunches that yielded 41 – 70% less than Williams per year.

CIRAD 918 was a similar height to Williams but experienced greater rates of snapping due to its more fragile pseudostem.

Harvest of the first ratoon crop is nearing completion and will be published when made available. 

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 contributions from the Australian Government. Hort Innovation is the grower-owned, not-for-profit research and development corporation for Australian horticulture.

Maturity bronzing

Posted on by Better Bananas

Maturity bronzing - stretching the limits on fruit quality

By Ingrid Jenkins and Jeff Daniells

Several growers have reported a higher incidence of fruit affected by maturity bronzing in early 2023. In response to grower enquiries regarding what causes maturity bronzing and how to reduce its impact, it seems timely to give an overview of past research and recap on the best management options available to growers.

Maturity bronzing has been a long-term problem for Australian commercial banana producers, with research into the disorder dating back to the early 1970s in Australia. Much of the research was undertaken in Far North Queensland over 30 years ago by Jeff Daniells and other state government researchers at the time and has provided some interesting insights into what has proved to be a complex disorder. 

What we know:

Maturity bronzing is not caused by a disease or insect but is a more complex physiological disorder due to certain environmental conditions.

Figure 1: Maturity bronzing damage seen on top and fifth hands of the bunch.
Figure 2: Severe banana rust thrips' damage on all hands throughout the bunch

The disorder blemishes the peel of banana fruit close to maturity and appears as bronze-red/brown streaks or blotches usually on the outer curved surface of the fruit and is more prominent in the top hands (Figure 1). The blemish can first appear when a bunch is three-quarters to full maturity stage and worsens as the fruit continues to fill. The damage is to the peel only and does not affect the yield and eating quality of the fruit. In severe cases, it can cause corking/cracking of the peel. Its appearance makes the fruit unmarketable and can account for significant losses for growers.

The disorder is associated with periods of heavy rainfall, high humidity and overcast weather conditions leading up to harvest and is therefore worse at certain times of the year. In Far North Queensland the disorder is usually more prevalent in the latter half of the wet season from March to June. Water stress at the time of bunch emergence has been shown to increase the severity of maturity bronzing.

Research by Dr Michelle Williams from the University of Sydney has shown that the high growth rates in the wet season lead to the stretching of the epidermis (outer surface of fruit peel) which exceeds its elastic limit, leading to cracks and cell disruption in the peel surface. Disruption of the cells causes the release of the enzyme called polyphenol oxidase. Oxidation of this enzyme leads to the production of melanin, which results in the bronze-red/brown markings within the peel. It is the same process in many fruits; for instance, when you cut open an apple and get brown discolouration of the cut surface.

Dr Williams’ research also found low levels of calcium in the fruit peel and low cell number in the peel epidermis have been linked to the disorder. They also found low calcium levels present in fruit suffering from water stress near bunch emergence. This stressed fruit had more severe maturity bronzing. Subsequent trials looking to increase calcium in the fruit peel to lessen maturity bronzing were unsuccessful.

There have been several trials looking into the effects of different agronomic practices on the disorder.

Trials looking into the effect of bunch covering found that normal bunch covering does not worsen the disorder but, the disorder is made worse by fruit from sealed bunch covers.

Both bunch trimming and de-belling (removal of the male bud) increase the severity of the disorder.

It is possible to reduce the severity of the disorder by reducing the leaf number to seven or less from bunch emergence. However, this is counterproductive as bunch weight and fruit green life are reduced at the same time.

How to manage and reduce the impact of maturity bronzing:

• Maintain good soil moisture levels, particularly in the period within 2 weeks of bunch emergence. The critical         period is October to January, special attention should be paid to irrigation during this time. A high moisture           level should be maintained during bunch emergence.

• Maintain even growth in the plant and the bunch, particularly from 2-3 weeks prior to bunch emergence up           to harvest.

• Depending on market specifications, bunches can be harvested early before the disorder becomes severe.             Blemished fruit losses are minimised but there is a trade-off with lower bunch weight. For every week that a           bunch is harvested earlier, 7–10 % in bunch weight is lost.

• Improve drainage and light within your paddock to ensure bunches don’t take so long to reach a harvestable         grade. Waterlogging can be minimised by mounding rows and the construction of deep drains on alluvial soils       and light penetration can be improved by planting at moderate densities.

• Ensure bunch covers are not too long and not prone to sealing at the bottom of the bunch. If this occurs                 maturity bronzing will worsen.

If you would like more detailed information on past research into maturity bronzing, please contact the Better Bananas team at betterbananas@daf.qld.gov.au.


This information has been compiled as part of 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.
qld-crest-on-top-2linestacked-b-w

Richard Piper

Posted on by Better Bananas

Richard Piper

A career exploring the big world of tiny things

Richard is the man to talk to if you want information on insects in Bananas. Richard is a familiar face to many banana growers in Far North Queensland, having worked in the industry both in a private and government capacity for over 30 years. 

Over the past 5 years, Richard has worked as an entomologist with the Department of Agriculture and Fisheries (DAF) at South Johnstone. His work has encompassed screening of new chemistry for the control of bunch pests. These include synthetic as well as biological products such as fungi, bacteria and beneficial nematodes and botanical chemistries. Currently, he is continuing research on bunch pest management and spider mites, with a focus on integrated 

Meet a researcher
Richard Piper
Entomologist
Department of Agriculture and Fisheries
Centre for Wet Tropics Agriculture
South Johnstone

pest and disease management (IPDM) practices using a combination of existing chemistry with softer biological options.

Richard’s expertise is not only limited to bananas. He is often out in the field talking with growers about insect related problems in other crops grown in the wet tropics.

It’s not all about bugs though. The interaction between grower, industry and colleagues is what Richard enjoys most about his work. He is excited about the future in gaining a better understanding of the relationship between insects and plants. Richard considers finding biological options for control of banana bunch pests as an important part of his role, seeing an increasing need for softer alternatives for future management strategies.

Richard was born and raised at Manly on Moreton Bay and completed his early schooling there. He attended the University of Queensland, where he completed a science degree, majoring in entomology and botany and then completed his honours in entomology. He also completed a post graduate diploma at Gatton College in plant protection.

In 1984 he moved to Far North Queensland to take up a position working as a medical entomologist with Queensland Department of Health on the Dengue Program for four years, then took work with the Australian Army’s Malaria Research Unit for four years where he was based at Cowley Beach and employed as a mosquito collector. In 1990 he started work with the Department of Primary Industries on an integrated pest management (IPM) project which he did for four years before starting his own business, assisting growers to monitor and manage pest insects and other problems in the many crops in Far North Queensland. Twenty seven years later he returned to DAF at South Johnstone taking up the role of entomologist in 2017.

Richard’s favourite way of eating bananas is by mashing a banana, preferably lady finger, on toast and sprinkling it with brown sugar.

In his spare time, Richard likes to tend his extensive garden of tropical fruit and vegetables.

Sarah Williams

Posted on by Better Bananas

Sarah Williams

Bringing passion to bananas

Sarah Williams is a recent addition to the National Banana Development and Extension team. Having moved to the Cairns region, Sarah has taken up the role with the Department of Agriculture & Fisheries and is based at South Johnstone. Sarah will be working to assist growers by shaping research to address their concerns. Currently, she is focusing on determining methods to improve bunch pest management practices to reduce fruit damage, waste, and raise the bottom line for growers.

Sarah Williams
Development Horticulturalist
Department of Agriculture and Fisheries
Centre for Wet Tropics Agriculture, South Johnstone, Qld

Completing her university degree in Environmental Science at the University of Technology Sydney, Sarah spent her final honours year focusing on using natural rooting hormones from plant extracts to improve planting establishment, to reduce dependencies on fertilisers. After finishing university, Sarah knew that she wanted to work to bring science to the people, equipping them to make decisions with the most recent research. Moving from NSW to Ayr, Sarah began her career in extension working at an independent agronomy firm with the sugar industry, working on projects that focused on precision agronomy, herbicide efficiency usage and alternative fallow cropping. Here, Sarah discovered her love for working with local growers and helping them get the best crop possible.

We asked Sarah what she’s most excited about in her new role ‘ I’m really excited to provide the industry with research that’s relevant, practical, and address’ growers’ concerns and limitations within the industry.’

Outside of work, Sarah enjoys hiking, camping and playing with her dog. Her favourite banana recipe is rum-soaked BBQed bananas.

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

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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 Kukulies

Posted on by Better Bananas

Tegan Kukulies

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 Kukulies
Senior Development Horticulturist
Department of Agriculture and Fisheries
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 Kukulies and Rob Mayers at banana industry field day at South Johnstone research facility.

Panama TR4 variety screening trial (December 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.