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Banana Roadshows 2024

Recent Banana Roadshows apeel to participants!

The recent banana roadshows were well attended by over 120 growers, agronomists, ag resellers and industry stakeholders. The four roadshow events were held during August and September in Carnarvon, Western Australia, along with Tully, Innisfail, and Mareeba in FNQ. This year marks 10 years since the first banana roadshow events commenced!

The events were delivered as part of the National Banana Development and Extension Program and provided the opportunity for attendees to hear updates on an array of different research and development topics. The series highlighted recent findings on research including biological bunch pest control, yellow Sigatoka, Sooty blotch, nematodes, soil health, nitrogen rate trials, and an update on variety development. Also included was an update on the Australian banana marketing program and benchmarking.

This year also featured a “walk and talk” session, which included interactive displays to spark further conversation between researchers and participants.

The roadshows were well received with 92% of FNQ participants who provided feedback saying that they learnt something new that would assist their business as a result of attending. Participants had positive feedback on the half-day events.        

One participant said ‘The short direct presentations worked well and conveyed a good amount of info.’

Another participant said ‘Loved the quick & sharp presentations. The layout was great, especially being time poor with the option to stay back to chat… Great researchers and crew.’  

The extension team would like to thank all growers and industry stakeholders who attended, as well as banana researchers Jeff Daniells, Daniel Farrell, Richard Piper, Kathy Grice, David East, Alex Lindsay, Andrés Morera, Tony Pattison (DAF) for their contribution along with Belinda Van Schaik (Hort Innovation), Andrew Burns (ABGC), Geoff Wilson (ABGC) and Eric Schluter (Aglytica). The team would also like to thank ABGC’s communication team and Valerie Shrubb and Mel Ford (WA DPIRD) for their support.

Keep an eye out in industry communications for info about NSW Roadshow activities later in the year.

Extension events are funded as part of the National Banana Development and Extension Program (BA19004). This project is funded by Hort Innovation, using the Hort Innovation banana research and development levy, co-investment from the Queensland 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.

Nectaries

Unravelling the mystery of banana tips

What is the black spot at the tip of my bananas? This was a question recently asked by a grower. The DAF extension team set out to investigate the issue and find out the cause.

It was suggested that the discoloration could be Mokillo disease, a bacterial infection that causes dry rot at the end of the finger, starting in the same area on the fruit that the grower was questioning. Mokillo typically only affects a few fingers in a hand, these fingers are often smaller and narrower or pinched at the tip. Mokillo infection will continue to move through the fruit over time and have a rusty red gummy appearance (internally). It was evident that the issue in question was not Mokillo given that the blackened areas were present in all examined fruit, and the symptoms did not match.

From a market perspective, the team firstly wanted to demonstrate that these black areas did not progress into the fruit pulp nor display Mokillo-like symptoms as it ripened.  The extension team took a sample of mature fruit and cross sectioned them at the different ripening stages. The black tips were present in ALL of the fruit and there was no progression into the fruit throughout the ripening process. Consequently, the DAF extension team was confident that this wasn’t Mokillo.

After this initial investigation, the query persisted as to the nature of this blackened internal tip. With a theory that the blackening was associated with the physical make-up of the fruit, a review of banana literature, including the basics of banana ‘anatomy’, found that this blackened area is called a nectary (Septal nectary). Nectaries are structures in plants, often found at the base of stamens (male flower parts) that provide food rewards for insect or bird pollinators and therefore play a role in the fertility of plants. Studies found that the nectary cells disintegrate/oxidise in Grand Naine when the flower ends are ‘unfurling’ allowing the reproductive structures (style and stamens) to be accessed by insects to pollinate. An interesting fact, is that this disintegrating/oxidising of the nectary acts as a ‘roadblock’ for the growth of the pollen tube towards the ovary. It has been suggested that this may be a contributing factor in why Cavendish is sterile and doesn’t produce seeds.

Nectaries female parts of banana flower
Floral structures of a banana finger showing oxidised/disintegrated nectary.
The project team cross sectioned fruit at different floral developmental stages and confirmed what previous research found, in that the blackening of the nectary in Williams Cavendish occurs when the flower end reproductive structures are exposed to pollinating insects.

Overall, these nectaries which have disintegrated/oxidised don’t appear to impact fruit quality. It is possible that these areas allow for secondary infections, like Mokillo, which explains some of the similar symptoms. However, further investigations would be needed to better understand the risks and conditions which may favour these infections. The DAF extension team will continue to keep tabs on the blackening of nectaries at ad hoc times throughout the year in the course of their work and make observations in other varieties.

References

  • Soares, T.L.; Souza, E.H.; Costa, M.A.P.C.; Silva, S.O.; Santos-Serejo, J.A. In vivo fertilization of banana. Ciênc. Rural 2014, 44, 37–42.
  •  dos Santos Silva, M.; Santana, A.N.; dos Santos-Serejo, J.A.; Ferreira, C.F.; Amorim, E.P. Morphoanatomy and Histochemistry of Septal Nectaries Related to Female Fertility in Banana Plants of the ‘Cavendish’ Subgroup. Plants 2022, 11, 1177.
This article has been compiled 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.
Hort innovation logo

Agronomic evaluation Lady Finger-like varieties

Agronomic evaluation of Lady Finger-like varieties (December 2022)

Lady Finger-like varieties from Brazil under trial at South Johnstone

By Jeff Daniells, Katie Robertson, Sharan Muthukumar and Carole Wright (August 2024)

Latest update...

Several Fusarium wilt Race 1 resistant Lady Finger-like varieties are being assessed for agronomic performance at the South Johnstone Research Facility. The plant crop data and a summary of the results is available below. 

The first ratoon harvest is already underway with harvest commencing in May 2024. The trial will be completed after the first ratoon harvest. Local taste panel results for varieties will be available then. Results from Panama disease Race 1 screening available next year will help guide any future on-farm studies.

Those who attended the September 2023 field walk had an opportunity to see plant crop bunches of these Lady Finger-like varieties. A video field walk through the block, prepared for the 2023 Industry Roadshows in NSW at about that time, is available.

Background

According to the ‘Australian Horticulture Statistics Handbook 2022/23’ the annual production of Lady Finger banana in that year was 11,228 t compared to 363,023 t of Cavendish, so Lady Fingers represent only about 3% of overall banana production. However, the farmgate value of Lady Finger production can be estimated as worth about $30 million, which because of the higher price paid for Lady Finger per kg of fruit, represents about 5% of the overall banana industry. But whatever way you want to look at it, the Lady Finger industry is an important industry in its own right.  In New South Wales the Lady Finger industry is proportionally much more important than it is overall for Australia.

In the April 2024 edition of Australian Bananas (see here pp 26-27) we drew attention to the constraint that Fusarium wilt Race 1 has placed on Lady Finger production in Australia. Varieties with resistance have been sought and evaluated over time, but while many have been identified with resistance, none have so far measured up as replacements for the Race 1 susceptible Lady Finger in the marketplace. So where possible, affected growers have sought new ground not infested with the pathogen.

In 2019/20 some new Lady Finger selections, Lady Finger hybrids and Sugar hybrids were imported from banana breeding programs in Brazil to evaluate in Australia. As described in the April article in Australian Bananas, some of these are being screened against Race 1 on the Atherton Tablelands. Here in this article, we present results from the plant crop of their agronomic evaluation at South Johnstone. This evaluation is part of the project BA21002 – ‘New varieties for Australian banana growers’.

Trial results in plant crop

Tissue cultured plants of 3 Lady Finger selections, 4 Lady Finger hybrids and 2 Sugar (Silk) hybrids were field planted in December 2022 at South Johnstone DAF. Pacovan, SCS451 and the hybrids all came from Brazil. The 6 hybrids from the program of EMBRAPA are all reported to be resistant to both Panama disease Race 1 and yellow Sigatoka. Japira and Pacoua are also reported to be resistant to black Sigatoka. SCS451 is from the program of EPAGRI and was purported to have tolerance to Panama disease Race 1. Bunch emergence commenced in May 2023, and harvest was completed in December 2023.

Pacovan Ken
Pacovan Ken were more pendulous than Lady Finger
Plantina lady finger hyrbid
Platina is shorter in stature than the other Lady Finger hybrids
Pacovan
Bunches of Pacovan were more pendulous than Lady Finger

Unfortunately, all except one of the Lady Finger (Improved) control plants were tissue culture offtypes. Thus, there are serious limitations when wishing to compare the new selections with the industry standard, Lady Finger. Nevertheless, reliable comparisons can be made amongst the new varieties. The agronomic and yield results from the plant crop are presented in the table below. Relative comparisons from previous studies suggest that for the Lady Finger data included in the table, the pseudostem height is indicative, but the duration from planting to harvest would usually be a little slower resulting in bunch weight/12 months being more in line with that obtained for SCS451.

Table: Selected yield and plant characteristics of varieties in the plant crop

Summary of results

A summary of the results and observations made are as follows:

  • The highest yielding varieties (per unit of time) were Pacovan, Pacovan Ken and SCS451, which were all significantly higher yielding than Tropical, Princesa and Japira. 

  • The tallest variety was Japira and the shortest in stature was SCS451. Several aspects of crop management are more difficult with the taller varieties.

  •  Japira, Pacovan Ken and Pacovan had significantly longer fruit on the 3rd hand, while fruit of Tropical and Princesa was significantly shorter.

Where to from here?

The first ratoon harvest is already underway with harvest commencing in May 2024. The trial will be completed after the first ratoon harvest. Local taste panel results for varieties will be available then. Results from Panama disease Race 1 screening available next year will help guide any future on-farm studies.

More information will be made available as the trial progresses.

This research has been funded as part of the project New varieties for Australian banana growers (BA21002), 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.

Panama disease Race 1 variety screening trial Atherton Tablelands, FNQ (2023)

Variety trials seeking resistance to Fusarium wilt Race 1 commence on the Atherton Tablelands

By Jeff Daniells, Kathy Grice, Katie Robertson, Kaylene Bransgrove and Sharan Muthukumar (April 2024)

Latest update...

Eight new Lady Finger-like bananas – some from Brazil and some from Queensland DAF’s mutagenesis efforts have been field planted on cooperating grower’s properties at Mareeba. They will be assessed for resistance to Fusarium wilt Race 1 over two crop cycles. 

Background

Fusarium wilt of banana, also known as Panama disease, has plagued production of Lady Finger (AAB, Pome) in the subtropics of northern NSW and southern Queensland since early in the 20th century. That widespread distribution of Fusarium wilt in southern production areas, combined with improved transportation and ease of mechanisation in the north, has contributed to major development of the Lady Finger industry on the Atherton Tablelands in the past 30 years or so. Currently about 280 ha are grown there – an industry worth about $15 million/year (Figure 1). It wasn’t too long though, before Fusarium wilt found its way onto a commercial Lady Finger farm on the Tablelands, with the first detection confirmed in 2008. Since then, several more farms have become affected, but damage on the Tablelands is typically not as severe as that in the south, because of the milder winters experienced.

Lady finger production
Figure 1 Lady Finger production near Walkamin and Mareeba has grown substantially since the 1990s.

Fusarium wilt is caused by the fungal pathogen Fusarium oxysporum f. sp. cubense. The relevant races described in Australia are Race 1, Race 2, Subtropical Race 4 (SR4) and Tropical Race 4 (TR4) which have to do with their banana variety host range. Lady Finger is susceptible to Race 1, SR4 and TR4. Within the races there is another division known as Vegetative Compatibility Groups (VCGs) which is particularly helpful for correct identification purposes. The VCG present on the trial farms is identified as VCG 0124/5 which is grouped in Race 1. This is the same as in previous trial sites in NSW and the north Queensland wet coast and is the most prevalent VCG recovered from diseased Lady Finger in Australia.

In previous banana plant protection projects, Fusarium wilt Race 1 screening has occurred at a field site in the subtropics of NSW. But due to budgetary constraints in the current Hort Innovation project – ‘New varieties for Australian banana growers’ (BA21002), the feasibility of conducting such trials on cooperating grower’s properties is now being examined on the Atherton Tablelands. So, two potential cooperating growers, that had sufficient Fusarium wilt disease present in their Lady Finger plantations, were identified at Mareeba in April last year.  Tissue culture plants of the required varieties had been multiplied, were grown on in the glasshouse at South Johnstone and field planting occurred in October/November (Figure 2).

Figure 2 Field establishment of tissue cultured plants being completed last November. Fusarium wilt affected Lady Finger in neighbouring row in the background (yellow circle).

About the trial

Varieties

  • SCS451 ‘Catarina’ reported to have tolerance to Race 1 in the Brazilian subtropics has been planted. It is certainly the one to watch. In our agronomic trial at South Johnstone it has performed well with bunches of SCS451 throwing well clear of the throat, not choking like what often occurs with Santa Catarina Prata, which we have had in Australia since the late 80s (see Figure 3).
  • The four best tasting Goldfinger variants from the mutagenesis program have been included to confirm that they have retained resistance to Fusarium wilt Race 1.
  • Three Lady Finger and Silk hybrids from the EMBRAPA program in Brazil are also being evaluated.
  • As with other Fusarium wilt screening trials in the past we have included a few reference varieties with a range of known levels of disease reaction. They are the key to correct interpretation of results. It is not so much the absolute level of severity of disease present in the new varieties being tested, but rather how their level of disease severity compares with that of the reference varieties. Here we have included Dwarf Ducasse (very susceptible), Lady Finger (susceptible), High Noon (intermediate) and Goldfinger (resistant).
Figure 3 The new import from Brazil, SCS451 (right) which is reported to be tolerant to Fusarium wilt Race 1, has bunches more pendulous than Santa Catarina Prata (left).

Disease inoculum

  • The trials were established in locations on the farms where Fusarium wilt was fairly widespread. Additionally, diseased pseudostem disks (about 5 cm thick) obtained from nearby blocks on the farm were placed in the bottom of each planting hole (Figure 4). This was to help enhance the uniformity of distribution of the pathogen and ensure that the roots of each plant in the trial were in close proximity.
  • The previous crop of Lady Finger on the sites was ‘knocked down’ in early/mid 2023 to allow for plant breakdown and cultivation of the rows prior to planting.
  • When any variety becomes diseased, the plan is to confirm by laboratory testing that the symptoms are due to VCG 0124/5.
Figure 4 A diseased pseudostem disk was placed in the bottom of each planting hole.

Trial progress

  • Disease ratings will get underway as soon as disease symptoms become evident which is expected in the next few months.

  • Disease development will be assessed in a plant and ratoon crop. 

  • Hopefully, we will get good indications from the Tableland trials of the disease response of the varieties. Selected varieties could then be considered for inclusion later, in pre-commercialisation sites in NSW and elsewhere. 

More information will be made available as the trial progresses.

This research has been funded as part of the project New varieties for Australian banana growers (BA21002), 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.

Banana scab moth Nacoleia octasema

Scab moth

The banana scab moth (Nacoleia octasema) is a significant threat to banana crops, with the potential to cause up to 100% damage to fruit if left uncontrolled. The larvae of this moth feed on emerging banana bunches, leading to cracking, scarring, and disfigurement of the fruit. Damage is usually confined to the outer curve of the fingers (the area nearest to the bunch stalk) but, in more severe cases, damage can extend to the stalk, areas between touching fingers, or even extend to cover the whole fruit surface.  While the damage is usually superficial, severe cases can render the fruit unsuitable for the market.

BSM adult moth
Adult banana scab moth. Adults are approximately 22mm in width or wingspan.
Banana scab moth damage evident on back of hands close to bunch stalk.
Banana scab moth damage. Scarring on fruit makes it unsellable to market.
Severe damage close to the bunch stalk.

Banana scab moth is present throughout the year but is favoured by moist and warm conditions, hence the greatest potential for damage is during the wet season.

Being proactive and regularly checking bunches or getting feedback from baggers can help growers discover infestations before the fruit reaches the packing shed. Although damage can’t be undone, identifying, and addressing problems (re-training or integrating alternative control options) sooner can save other bunches from impact.

To manage infestations, year-round treatment is essential, most growers use chemical control through bell injection is recommended to prevent banana scab moth damage. Proactive monitoring and management are essential to minimize the impact of this pest on banana crops.

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.

Banana scab moth – monitoring and control

Banana scab moth – Nacoleia octasema

Monitoring and control options

Monitoring

Being proactive and regularly checking bunches or getting feedback from baggers can help growers discover infestations before the fruit reaches the packing shed. Although damage can’t be undone, identifying, and addressing problems (retraining or integrating alternative control options) sooner can save other bunches from impact. 

The method for monitoring for banana scab moth is to inspect freshly emerged bunches (bract fall) for the presence of damage and/or larvae. Pay attention to the underside of the fingers in each hand (closest to the bunch stalk) and the cushion area. In very young bunches, lifting the developing hand away from the bunch stalk may be necessary to reveal any larvae and/or fresh damage.

Banana scab moth larvae in feeding waste (frass and jelly).

Also, examine the base of the bunch stalk where the larvae enter the throat of the plant. Larvae can be detected by separating the base of the flag leaf and removing the bract that is attached to the stalk. Often a clear jelly-like substance or frass feeding waste, which appears to be associated only with banana scab moth feeding in bananas, is present at these sites. Monitoring known ‘hot spots’ such as rows adjacent to scrub or creek lines is also a good idea. Banana scab moth has been documented to use Pandanus spp. and Heliconia spp. as alternative host plants.

Managing banana scab moth

Treatment for banana scab moth should be performed year-round as damage results in immediate downgrading or rejection of fruit. Management of banana scab moth is particularly important if heavy bunching is anticipated and/or the forecast weather conditions are favourable (hot and wet).

Biological control

Banana scab moth can be controlled by application of Bacillus thuringiensis subsp. Kurstaki based biopesticides (also known as B.T.) that will not adversely affect other beneficial insects. Some insects (parasitic flies and wasps, ants, spiders and other predators) feed on banana scab moth caterpillars and provide some level of control.

BSM adult moth
Adult banana scab moth. Adults are approximately 22mm in width or wingspan.

Cultural control

Selecting followers of equal size which equates to synchronised bunch emergence over a block will ensure that the application of chemical control methods is more efficient.

Chemical control

Bell injection is the preferred method of insecticide application to prevent banana scab moth damage. Bell injection is a targeted application of insecticide into the newly emerged bunch and the technique is unlikely to impact beneficial insects on other parts of the plant. The correct site for injection is approximately one third of the way down from the top of the upright, vertically positioned bell. Bells which are injected later than this (i.e., when horizontal) have an increased risk of insect damage.

Initial trial work completed by the Department of Agriculture and Fisheries (DAF) has also indicated that the volume of insecticide applied in bell injection is an important consideration. As insecticides require larger volumes to ensure good coverage, initial trial work showed that using 40mL volume wasn’t sufficient to get appropriate control at times of high pest pressure. It is recommended that growers use a 60mL volume at the specified label (or permit) rate for bell injection to provide adequate coverage.

Always check the APVMA website for current chemical registrations before use. Below are insecticides currently registered (August 2024) and permitted for bell injection to control banana scab moth.

For more information contact:

The Better Bananas team
Department of Agriculture and Fisheries
South Johnstone
13 25 23 or email betterbananas@daf.qld.gov.au 

This information is adapted from: Pinese, B., Piper. R 1994, Bananas insect and mite management, Department of Primary Industries, Queensland

This information has been updated 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.

Banana Scab Moth – general information

Banana scab moth Nacoleia octasema

General information

Occurrence

Banana scab moth is present throughout the year but is favoured by moist and warm conditions, hence the greatest potential for damage is during the wet season. Bunches that emerge from December through to the end of May are most at risk of severe fruit damage. The cooler and drier winter months are relatively free of banana scab moth damage. However, damage can occur if unseasonal rain occurs at this time. Research has shown adult moths do not mate or produce eggs under low humidity and dry conditions.

Life cycle of banana scab moth. Arrow indicates part of plant affected (bunch).

Description and lifecycle

The tiny (1.2-1.5mm) transparent or yellow flattened eggs are laid in clusters (of up to 30 eggs) that resemble miniature overlapping fish scales. These egg clusters are very difficult to locate because of their small size and the fact that they are laid near the throat of the plant. The eggs are usually laid on the emerging bunch and the surrounding leaves, but eggs have occasionally been found on the pseudostem below the new bunch. Larvae (caterpillars) are pink to brown in colour and range in length from 1.5mm when first hatched to about 25mm when fully developed. If disturbed the larvae wiggle violently and drop on silken threads to avoid predation. When larvae are fully mature they generally pupate in the trash at the base of plants or beneath dry leaf sheaths.

The adult moths are difficult to find due to their small size (22mm wingspan), the fact they hide during the day and their dull brown/grey colouration. Adults are most active at dusk when mating and egg laying occurs. Adults do not appear to be attracted to lights, unlike other moth species. The total lifecycle from egg to mature adult takes around 25-32 days.

BSM lifestages

Damage

The banana scab moth is a severe pest of bananas and can cause up to 100% damage to the bunch if left uncontrolled.

Feeding by young larvae starts as soon as the first bracts lift and usually increases in severity as the larvae grow and move progressively down the bunch as subsequent bracts open. The feeding causes cracking and scarring to the fruit skin, while severe cases can cause disfigurement of fruit as the fingers enlarge. Damage is usually only superficial, where affected fruit is downgraded or deemed unsuitable for the market.

Damage is usually confined to the outer curve of the fingers (the area nearest to the bunch stalk) but, in more severe cases, damage can extend to the stalk, areas between touching fingers, or even extend to cover the whole fruit surface.  

Larvae of banana scab moth also consume foliage and can damage plants where a bunch is absent. This leaf damage is worse in varieties such as Lady Finger and Ducasse and is generally not a problem in Cavendish.

For more information contact:

The Better Bananas team
Department of Agriculture and Fisheries
South Johnstone
13 25 23 or email betterbananas@daf.qld.gov.au 

This information is adapted from: Pinese, B., Piper. R 1994, Bananas insect and mite management, Department of Primary Industries, Queensland

This information has been updated 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.

Banana Weevil Borer mass trapping

Banana weevil borer Mass trapping: A novel design, supporting long-lasting pheromone lures in NSW

Banana Weevil Borer (BWB) is one of the main issues for NSW banana growers. When BWB reach high numbers in the field, they significantly affect productivity by creating a network of tunnels in the corm. This tunnelling weakens the plant and increases the likelihood of blowdowns. BWB infestations affect nutrition uptake, contributing to slow growth, decreased bunch weights and overall poor plant health. NSW growers have successfully designed and implemented mass trapping approaches to deal with this issue, a technique proven to be effective in other countries. Mass trapping reduces pest numbers by luring them, with an attractant, in large numbers to a trap that either kills them or prevents their exit. In this article, we discuss NSW growers’ implementation of mass trapping systems and their successes. Growers who use mass trapping have found it an effective tool for monitoring and successful in reducing BWB pressure and plant damage.

Background

In Australia, typically pseudostem discs or small pitfall traps (less than 500mL volume) are used for monitoring and, to a lesser degree, management of BWB. These strategies are effective in allowing growers to understand their BWB populations and their distribution across their farms. By comparison, international research, and growers, have designed larger pitfall traps (larger than 500mL volumes), to increase rates of BWB capture. These larger pitfall trap designs are possible through the long-lasting pheromone lures which can and historically have also been used domestically in small-scale traps and which can attract both male and female BWB from over 20m away in dry weather. According to an international study (Alpizar et al, 2012), using these large volume mass trapping pitfall traps (with the pheromone lures), at a density of 4 traps per hectare, was 5 to 10 times more effective than traps without pheromone. In this study, corm damage was reduced by half to two thirds after several months of use (from 20-30% corm tunnelling to 10% or less). The resulting reduction of corm damage was shown to increase bunch weights of Dwarf Cavendish (Musa acuminata Colla) by approximately 20%. Trials in Australian growing regions and prominent varieties are yet to be conducted and caution is needed before assuming similar performance outcomes could be attained.

Earlier research by NSW DPI investigated two types of long-lasting pheromone lures (effective for 90 days), to determine the most effective for the NSW region. While both lures are effective at attracting BWB, Cosmolure P160-lure 90 (C.sordidus) is preferred as it does not contain isoamyl acetate, which attracts native turkeys and domestic chickens that damage the traps. Growers who collaborated in the earlier pheromone investigation have continued trapping and over time have developing unique trapping systems using the longer-lasting pheromone.

Mass trapping pitfall design 1 (5L bucket trap)

One of the new innovative methods that growers have developed and implemented is the modified 5L bucket trap. NSW growers have modified a 5-litre bucket to make large volume, mass trapping pitfall traps. To make these traps firstly, several 10-millimetre holes are drilled into the side of the bucket. Next, the bucket is firmly established into the ground. It is important that the drilled holes are flush with ground level and soil ramps need to be made (simply pile soil up into a ramp so that BWBs would be able to walk into the hole and fall into the bucket). Once the trap is established in the hill side, the pheromone bait is set by hanging from the centre of the lid via a piece of wire.

Mass trapping pitfall design 2 (PVC pipe trap)

Another innovative design that NSW growers have adopted is a PVC pipe trap. This trap is made from PVC piping which creates a narrower but deeper trap, more stabilised into the hillside compared to the larger, shallower trap, shown in design 1. In this case, the dimensions are 100mm in diameter, and 500mm in length with the bottom of the trap made watertight with end caps and the top cap left loose to be able to take off.  Similar to the pitfall trap there are drilled several holes, 10mm in size, where the trap meets the soil line to allow for BWB to enter. A wire is fixed into the lid or on the side, used to hold the pheromone lure in place. The grower used an auger to install the PVC pipe approximately 300 millimetres in depth into the soil.

“I decided to increase the size of the trap purely because the original (smaller pitfall) traps were filling up in a couple of days! After increasing the size of the traps, I now only need to revisit the trap every month for soil ramp maintenance and emptying. I’m more clued in, knowing where hot spots of densely populated BWB zones were located on their farm, and using this knowledge to inform decisions around when to apply chemical management options. Something that I didn't foresee is the increased peace of mind. Now, having the traps in the ground, I see it as a second line of defence, not just relying on chemical application to control BWB, especially within the hotter and wetter periods of the year."
-Coffs Harbour grower comments on using the 5L BWB bucket trap design

Trap maintenance and upkeep

The enlarged pitfall traps require low maintenance and only need to be checked on average once per month or after severe weather events. Emptying of dead BWB will fluctuate as BWB numbers and movements vary throughout the year. According to growers, ensuring the trap stays in place, and maintaining the soil ramps up to the trap are some of the key considerations to keep an eye on and it’s suggested to check these features more regularly.

It has been a suggestion to add soapy water to the bottom of pitfall traps to terminate BWBs once they are in the trap. Furthermore, the soap makes the walls of the trap slippery, preventing them from exiting the trap. However, growers have found that this may not be necessary when the walls of the trap are smooth, as the weevils find it hard to get traction to climb out of the traps.

Cost

The P160-Lure90, Cosomolure (C. sordidus) is approximately $11 per bait (tablet) and lasts 90 days. The current advised density is 4 traps per hectare with one pheromone bait in each trap, totalling 16 pheromone baits per hectare per year. Therefore, currently in 2024, the approximate cost is $175 per hectare, per year. This does not include the material for pitfall traps or labour costs to install and maintain them which needs to be considered. Prices will vary over time. Ensure getting quotes from relevant suppliers before implementation. For some growers, this is a relatively low cost per hectare to substantially reduce BWB numbers throughout a block in NSW. The continued pursuit of trapping innovations reflects the proactive approach NSW growers are taking in BWB management, offering a promising avenue for control. If you are interested in more information about BWB mass trapping contact Steven Norman (NSW DPI Industry Development officer) for assistance.

References

Fu, B., Li, Q., Qiu, H., Tang, L., Zhang, X., & Liu, K. (2019). Evaluation of different trapping systems for the banana weevils Cosmopolites sordidus and Odoiporus longicollis. International Journal of Tropical Insect Science39, 35-43

Alpizar, D., Fallas, M., Oehlschlager, A. C., & Gonzalez, L. M. (2012). Management of Cosmopolites sordidus and Metamasius hemipterus in banana by pheromone-based mass trapping. Journal of chemical ecology, 38, 245-252.

This information has been produced 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 with co-investment from the Queensland Department of Agriculture and Fisheries, New South Wales Department of Primary Industries and contributions from the Australian Government. Hort Innovation is the grower-owned, not-for-profit research and development corporation for Australian horticulture.