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Yellow Sigatoka screening – agronomic evaluation trial (September 2018)

Posted on by Sarah Williams

Yellow Sigatoka screening – agronomic evaluation trial (September 2018)

Katie Robertson, Jeff Daniells, Carole Wright and David East, Queensland DAF (Dec 2022)

Four CIRAD hybrids demonstrated good resistance to yellow Sigatoka, but they did not measure up on their other agronomic characteristics. Seventeen Cavendish lines were assessed for resistance, but non were any better than Williams. All were rated as very susceptible to yellow Sigatoka.

Yellow Sigatoka, also known as Sigatoka leaf spot, is the major leaf disease affecting the north Queensland banana industry and is caused by the fungus Pseudocercospora musae.  Most of the bananas grown are of the Cavendish type (mainly Williams), as well as a small amount of Lady Finger, both of which are very susceptible to the disease. The annual cost of controlling leaf disease in the north Queensland banana industry is estimated to be in excess of $25 million. The disease is particularly difficult to control under hot, wet conditions and an integrated disease management program involving both cultural and chemical measures is required for effective control. Fungicides are usually aerially applied to the leaf canopy at regular intervals throughout the year and represent the major ‘pesticide’ applied in the production of bananas in north Queensland.

Yellow Sigatoka leaf spot symptoms – the larger oval shaped spots show Cordana leaf spot which has invaded via the yellow Sigatoka lesions.

It would be a great advantage to the industry if a commercially viable variety possessed disease resistance. The cost of production could be significantly reduced, as well as the industry’s overall pesticide input and any associated environmental impacts – perceived or otherwise.

As part of the project ‘Improved plant protection for the banana industry’ (BA16001), 24 varieties were screened for resistance to Sigatoka leaf spot at South Johnstone Research Facility during the 2022 wet season. The same block of bananas where the plant and ratoon crop agronomic evaluations reported previously (see here), was used for the disease screening trial. After the final ratoon crop, fungicide applications for leaf disease control ceased. The block was then nurse-suckered to synchronise development so that leaf spot could be rated on plants prior to bunching during the wet season in 2022. Counting from the first fully unfolded leaf down, the youngest leaf with 10 or more mature lesions (youngest leaf spotted – YLS) was recorded and the youngest leaf with 33 per cent necrosis of the lamina (YL33). The total number of functional leaves (TFL) was recorded if no leaf spot symptoms were present. Ratings were done on three separate occasions in the last week of March, April, and May 2022, respectively. For simplicity, just the YLS or TFL results averaged over the three rating occasions are presented here. 

The new varieties have been given an overall disease reaction rating relative to three reference varieties that have had their susceptibility/resistance categorised in previous studies. All the Cavendish varieties were very susceptible and their YLS values were not significantly different to Williams, except for two of the TR4 resistant selections from Taiwan (GCTCV 105 and GCTCV 119) which had slightly lower YLS values. Our intermediate reference variety, Inarnibal, had on average two more leaves present with less than 10 mature lesions compared to the Cavendish varieties. 

The CIRAD hybrids exhibited no leaf spot symptoms but only had 8 – 9 upright leaves on average. Nevertheless, they were considered highly resistant along with Dwarf Ducasse – the highly resistant reference variety.

Rating banana varieties for leaf spot severity in the South Johnstone trial.
The four CIRAD hybrids all demonstrated resistance to yellow Sigatoka (CIRAD 938 pictured).

 

The CIRAD hybrids certainly have leaves with good resistance to yellow Sigatoka, but those same leaves are relatively brittle and are prone to snapping, thus reducing the functional leaf area. Additionally, their cumulative yields in the preceding crops were 28-36% lower than that of Williams while also being 15-30% taller. CIRAD 924 and 938 had an acceptable taste and have also shown to be resistant to TR4 in the NT (along with CIRAD 931) but when all their characteristics are weighed up, there seems to be little commercial prospect for these varieties despite their good Sigatoka leaf spot resistance.  

Youngest leaf with 10 or more necrotic lesions (YLS) for 24 varieties at South Johnstone (average of 3 rating occasions; error bars represent area 95% LSD). If the YLS stage was not reached for a variety (i.e. the CIRAD hybrids and Dwarf Ducasse) the leaf number represents the total number of functional leaves present. Williams (very susceptible), Inarnibal (intermediate) and Dwarf Ducasse (highly resistant) were used as references to assess the disease reaction of the new varieties.

More information

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.

Panama disease TR4 variety screening trial – Northern Territory (2020)

Posted on by Sarah Williams

More varieties showing resistance to TR4 in NT trials

By Sharl Mintoff, Samantha Bond, Chris Kelly, Maxine Piggott, NT Department of Industry, Tourism and Trade, Darwin; and Jeff Daniells, Queensland department of Agriculture and Fisheries, South Johnstone.

Seven varieties in a banana variety trial in the Northern Territory have demonstrated TR4 resistance, in the plant crop, as good or better than that of Goldfinger.

In December 2021 we described a new TR4 varietal screening trial (see here), which had commenced in December 2020 and ran for the final 12 months of the project- Improved plant protection for the banana industry (BA16001). Over the 12 months plant crop data was collected to determine the TR4 reaction of several new varieties that had become available for evaluation from plant breeding programs.

Overview

In this trial, 24 varieties were screened for resistance to TR4, and included three Cavendish selections, four novel hybrids from the CIRAD program in the French West Indies, four Lady Finger hybrids from the EMBRAPA program in Brazil, some parental lines used in the breeding program and three Goldfinger mutant selections.

The Goldfinger mutant selections were generated as part of an earlier project (BA14014) in Queensland, to improve the eating characteristics of Goldfinger, whilst hoping to retain its TR4 resistance in the process (see more here).

Methods 

As per the previous trials, all plants were artificially inoculated at planting with millet colonised with TR4. Disease assessments commenced at the first signs of external disease symptoms, with assessments occurring every two weeks, taking note of the presence of external and internal symptoms. The trial included three reference varieties of known susceptibility or resistance to TR4; 

CIRAD X17 displaying resistance for Panama disease TR4.
  • Williams - Very Susceptible
  • Formosana (GCTCV 218) - Intermediate
  • Goldfinger (FHIA-01) - Resistant

The disease resistance of each variety was determined by scoring the severity of the disease and by grouping them into one of the following categories:

Results

Highly resistant and resistant

Parental lines M61 and Calcutta 124 both rated as highly resistant, as did the True-to-type Asia Pacific #1 and CIRAD hybrid X17. Encouragingly, two Goldfinger mutants 144 and 417, both showed no signs of infection by TR4. The Goldfinger reference material and Goldfinger mutant 544 both fell into the resistant category as a low amount of disease was noted in a small number of plants.

Intermediate

Cavendish varieties Formosana (Intermediate reference control) and Short Fruit Williams (Williams off-type) both fell into the intermediate rating. As did the EMBRAPA Lady Finger hybrid PA12.03, the Highgate hybrid 2390-2 and Yangambi km5.

Goldfinger mutant 144 in NT
Goldfinger mutant 144 displaying resistance for Panama disease TR4.
Parental line M61 displaying resistance for Panama disease TR4.
The Williams variety showed significant signs of disease.

Susceptible and very susceptible

Cirad hybrid lines 925, 918 and L9 all displayed susceptibility to TR4 in the plant crop, as did the EMBRAPA lines PV03.44, JV42.41, PA03.22 and the Highgate hybrid Buccaneer. Two Cavendish varieties Williams and GCTCV 106 selection both rated as very susceptible to TR4.

Although this trial only ran for the plant crop cycle, some interesting results were obtained. The TR4 resistance of the Goldfinger mutants is encouraging, as they were originally selected for their improved eating characteristics and appear to have retained their resistance to TR4 as hoped. The true-to-type Asia Pacific #1 had not yet completed harvest in the plant crop at the time the trial had to be wound up. However, it had no symptoms of TR4 externally or internally.

Interestingly, the Short Fruit Williams, showed a similar intermediate disease reaction to that of Formosana. Short Fruit Williams is, as the name suggests, a selection of Williams which has shorter fruit. It had occurred as a tissue culture off-type in north Queensland. We included it in this screening because it had some traits in common with TR4 resistant selections from Taiwan, noticeably its slightly longer crop cycle. This could indicate an association of certain characteristics, such as selections with slower crop cycles, possessing TR4 resistance, and thus the ability to locate potentially resistant variants when TR4 is not present.

Plant crop disease ratings of assessed varieties

HR = Highly Resistant,  R = Resistant,  I = Intermediate,  S= Susceptible,  VS= Very Susceptible

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.

Yellow Sigatoka resistance – Goldfinger mutagenesis trial

Posted on by Ingrid Jenkins

Yellow Sigatoka screening - Goldfinger mutagenesis trial

Katie Robertson, Jeff Daniells, David East and Carole Wright, Queensland DAF (Dec 2023)

The screening trial assessing Goldfinger mutant selections’ resistance or susceptibility to the fungal leaf disease, yellow Sigatoka is now complete. Most of the selections had a similar reaction to yellow Sigatoka as the Goldfinger control, however GMS 766 was significantly more resistant, while four others were significantly more susceptible. This latter result demonstrates that mutagenesis can significantly change a plant’s level of yellow Sigatoka resistance.

An estimated $25-30 million per year is spent on controlling yellow Sigatoka leaf spot (Pseudocercospora musae) Identifying varieties with better resistance to the disease, provided they were otherwise commercially viable, would be of great benefit to the industry by reducing input costs and reliance on fungicides. 

Over the 2023 wet season, a yellow Sigatoka screening trial was conducted at the South Johnstone Research Facility on the top-twenty Goldfinger selections which had been developed through DAF’s mutagenesis project.

The block had been nurse suckered to standardise plant development stage. Leaf disease control ceased a few months prior to nurse suckering to build up inoculum levels and ensure adequate disease pressure. Plants were assessed for severity of leaf spot disease on 3 occasions, at monthly intervals leading up to bunching. The assessment consisted of determining the Youngest Leaf Spotted (10 or more mature necrotic lesions (YLS), and the Youngest Leaf with greater than 33% of the leaf lamina destroyed by disease (YL33). The Total number of Functional Leaves (TFL) was recorded if the disease was not present or had not progressed to the >33% necrosis severity level. For the purposes of this article, only the YLS and TFL data will be discussed.

While Goldfinger has resistance to black Sigatoka, this is not the case for yellow Sigatoka, to which it is better described as having an intermediate reaction.  Of particular interest was how the new selections compared to Goldfinger and the possible effect mutagenesis may have had on the plants ’ reaction to this disease.  Figure 1 below shows the average YLS of Goldfinger was 6.4, which was similar   to fifteen of the twenty mutant selections. ‘GMS 766’ was the only selection that demonstrated better resistance to leaf spot than Goldfinger, having an average YLS of 7.9.  

On the other end of the spectrum, ‘GMS 602’, ‘GMS 211’, ‘GMS 145’, and ‘GMS 255’ had average YLS values of between 5.4 and 4.4, demonstrating  they were significantly more susceptible to the disease. Although not the original objective of the project, these results demonstrate mutagenesis can significantly change a plant’s level of yellow Sigatoka resistance. The dwarf Lady Finger selection ‘Dwarf Rossi’ was planted as a single guard plant at the beginning of each row of Goldfinger. 

The level of disease was comparable to the ‘Dwarf Rossi’ plants in the variety evaluation, allowing comparisons to be made between the two trials. It was not significantly different to Goldfinger in its reaction to yellow Sigatoka. 

Figure 1: Youngest leaf with 10 or more necrotic lesions (YLS) for the 20 Goldfinger Mutant Selections, standard Goldfinger, and the Lady Finger variety ‘Dwarf Rossi’ (average of 3 rating occasions; error bars represent +/-1 standard error ). The different coloured bars indicate varieties that were statistically similar (yellow) or significantly different (red/green) to Goldfinger (patterned fill).
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. 
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Yellow Sigatoka resistance – agronomic evaluation trial (October 2020)

Posted on by Ingrid Jenkins

Yellow Sigatoka screening - agronomic evaluation trial (October 2020)

Katie Robertson, Jeff Daniells, David East, and Carole Wright, Queensland DAF (Dec 2023)

The screening trial assessing new varieties’ resistance or susceptibility to the fungal leaf disease, yellow Sigatoka is now complete. Varying degrees of leaf spot resistance were observed among the Cavendish (highly susceptible), Lady Finger (intermediate resistance) and CIRAD hybrids (resistant).

An estimated $25-30 million per year is spent on controlling yellow Sigatoka leaf spot (Pseudocercospora musae) in Australian banana plantations. Identifying varieties with better resistance to the disease, provided they were otherwise commercially viable, would be of great benefit to the industry, by reducing input costs and reliance on fungicides.

Over the 2023 wet season, a yellow Sigatoka screening trial was conducted at the South Johnstone Research Facility. This was after the agronomic assessments on 15 varieties had been completed in the 2020 Variety Evaluation and the block was nurse-suckered. 

Leaf disease control ceased a few months prior to nurse suckering to build up inoculum levels and ensure adequate disease pressure. Plants were assessed for severity of leaf spot disease on 3 occasions, at monthly intervals leading up to bunching. 

The assessment consisted of determining the Youngest Leaf Spotted (10 or more mature necrotic lesions) (YLS), and the Youngest Leaf with greater than 33% of the leaf lamina destroyed by disease (YL33). 

The Total number of Functional Leaves (TFL) was recorded if the disease was not present or had not progressed to the >33% necrosis severity level. For the purposes of this article, only the YLS and TFL data will be discussed.

Figure 1 shows four of the varieties had comparable disease severity to the very susceptible reference variety, ‘Williams’, which had an average YLS of 4.5. These included the TR4 resistant Cavendish ‘Asia Pacific #1’, along with the two tetraploid ‘High Noon’ selections (one with a ‘clean’ rachis [HNC] and one with a ‘dirty’ rachis [HND]) , and the Pendulous Lady Finger selection. 

The other four Lady Finger varieties demonstrated slightly better resistance and were statistically similar to ‘Pacific Plantain’ (YLS = 6.2), which has a documented intermediate level of resistance to leaf spot. Overseas, the hybrid ‘CIRAD 925’ has demonstrated both yellow and black Sigatoka (Pseudocercospora fijiensis) resistance (Risède et al. 2019). 

It was anticipated that the other three CIRAD hybrids may also possess this characteristic, which proved to be the case. Although no leaf spot was present, ‘CIRAD 925’ and ‘CIRAD 918’ only maintained around seven functional leaves throughout the assessments, with older leaves snapping due to petiole weakness, while ‘CIRAD L9’ and ‘CIRAD X17’ sustained over 10 functional leaves. 

The common leaf fungi, Cordana leaf spot (Neocordana musae) and banana leaf speckle (Mycosphaerella musae), were likely present on all varieties, but more obvious along the leaf margins of the CIRAD hybrids due to the absence of yellow Sigatoka. ‘Dwarf Ducasse’ was included as the resistant reference variety and supported an average of 13 functional leaves with no yellow Sigatoka present.

While the CRIAD hybrids remained unaffected by yellow Sigatoka (CIRAD X17 pitcured here), there were other common pathogenic fungi, primarily Cordana and banana leaf speckle present on some older leaves.
The TR4 resistant Cavendish 'Asia Paific #1', was as susceptible as Williams to yellow Sigatoka.
Figure 1 Youngest leaf with 10 or more necrotic lesions (YLS) for 15 varieties at South Johnstone (average of 3 rating occasions; error bars represent +/-1 standard error). If the YLS stage was not reached for a variety (i.e. the CIRAD hybrids and Dwarf Ducasse) the leaf number represents the total number of functional leaves present. Williams (very susceptible), Pacific Plantain (intermediate), and Dwarf Ducasse (highly resistant) were used as references to assess the disease reaction of the new varieties. The different coloured bars illustrate varieties that were statisically similar to the reference varieties (patterned fill).
References
Risède, J.-M., Achard, R., Brat, P., Chabrier, C., Damour, G., Guillermet, C., de Lapeyre., Lœillet, D., Lakhia, S., Meynard, P., Tixier, P., Tran Quoc, H., Salmon, F., Côte, F.-X. and Dorel, M. (2019). The agroecological transition of Cavendish banana cropping systems in the French West Indies. In The agroecological transition of agricultural systems in the Global South. Côte, F.-X., Poirier-Magona, E, Perret, S., Roudier, P., Rapidel, B., Thirion, M.-C, eds. (Agricultures et défis du monde collection, AFD, CIRAD, Éditions Quæ, Versailles). Pp. 107 – 126. https://agritrop.cirad.fr/592993/1/ID592993.pdf 

More information

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.
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Sharan Muthukumar

Posted on by Sarah Williams

Sharan Muthukumar

The potential of banana diversity is what fascinates Sharan

Sharan is a Technical Officer working at the Department of Primary Industries (DPI), South Johnstone. Born in a town called Mettupalayam in southern India, Sharan moved to Australia to pursue his Master’s in Agricultural Science (Horticulture) at UQ Gatton campus. He has been working with DPI since September last year (2023). His primary research areas include the agronomic evaluation of new TR4 resistant Cavendish varieties and Race 1 resistant Lady Finger-like varieties. He’s also responsible for the maintenance of the Australian field collection of banana varieties at South Johnstone, which is a significant undertaking to ensure that the collection remains available for future research.

Sharan is passionate about working with different banana varieties and learning how to identify them. He finds the diversity of bananas fascinating and believes that exploring their genetic intricacies could reveal potential solutions to emerging challenges. One of the most exciting aspects of Sharan’s work is taste-testing different varieties, which allows him to experience firsthand the diverse flavours and textures they offer. In his free time, Sharan enjoys listening to music and going bushwalking. He’s excited to be a part of DPI and being able to make a positive contribution to the Australian Banana Industry.

Sharam meet a researcher
Sharan Muthukumar
Technical Officer
Department of Primary Industries
Centre for Wet Tropics Agriculture, South Johnstone, Qld

First ratoon observations and results (2020 agronomic trial)

Posted on by Ingrid Jenkins

First ratoon results - agronomic evaluation trial (October 2020)

By Katie Robertson & Jeff Daniells, Queensland Department of Primary Industries

Trends observed in the plant crop (see here) continued in the first ratoon. Williams outproduced the TR4 resistant Cavendish varieties. All the Lady Finger selections performed well compared to the standard Lady Finger, with either improved plant or bunch characteristics and no yield reduction.

Productivity declined in the short statured TR4 resistant Cavendish Asia Pacific #1, while GCTCV 106 continued to perform comparably to Williams.

The yield reduction measured in the plant crop of the TR4 resistant Cavendish variety Asia Pacific #1 (AP#1) was further amplified by the end of the first ratoon. AP#1 yielded 33% less than Williams over the 2 crops (29.3 versus 44.1 kg/year). This was due to their longer cycle time and a lower average bunch weight (26.7 versus 37.9 kg). AP#1 pseudostem height only increased by 8% between the plant crop and first ratoon (2.2 to 2.4 m), remaining significantly shorter than the other Cavendish varieties. Most other TR4 resistant Cavendish selections from Taiwan are taller than Williams. Finger length also remained shorter, with only 17% of AP#1 fruit falling into the premium size grade (22 – 26cm), compared to 56% for Williams. The GCTCV 106 selection – which originated from a vigorous plant identified in the previous 2018 South Johnstone variety evaluation (BA16001) – again performed comparably to Williams with regards to cycle time and yield (see table). Unfortunately, this variety has not demonstrated TR4 resistance in the Coastal Plains (Northern Territory) screening trials (see here for more).

The TR4 resistant Cavendish selection, Asia Pacific #1, remained shorter than Williams with reduced bunch weights, a longer crop cycle and shorter fruit lengths.

There were no yield differences among the six Lady Finger varieties, with some selections displaying reduced pseudostem heights and better bunch conformation.

All Lady Finger selections, except Pendulous Lady Finger (PLF), remained significantly shorter in stature than standard Lady Finger in the first ratoon (11 – 30% shorter). In the plant crop, PLF had yielded 19% more than Lady Finger per 12-months, but by the end of the first ratoon the yields compared over the 2 crops was not different. The standard Lady Finger experienced a 33% increase in bunch weight between the plant crop and first ratoon, going from 12.2 to 18.5 kg, while PLF only had 15% heavier bunches in the first ratoon (17.7 to 20.9 kg). The fruit in PLF bunches took longer to fill (22.3 weeks) than standard Lady Finger (17.1 weeks), and had issues with premature ripening, likely influenced by the timing of bunch emergence and the environmental conditions during fruit filling. Nonetheless, the PLF plants lived up to their name and continued to produce bunches with a more desirable conformation. The four other Lady Finger varieties did not yield significantly differently to the industry standard.

The yield of 'Dwarf Lady Finger' was comparable to standard Lady Finger but was 30% (or 1.4 m) shorter in stature.

The novel hybrids from CIRAD continued to perform poorly in the first ratoon, in terms of bunch size and pseudostem height.

In the plant crop, 40% of the CIRAD hybrid 918 plants had snapped before harvest despite being similar height to Williams. The incidence of pseudostem snapping in this variety rose to 87% in the first ratoon, meaning there were not enough data plants to include in the analysis. The remaining three CIRAD hybrids had bunch weights 25 – 64% lower than Williams per 12-months for the 2 crops, and CIRAD 925 and X17 were taller by 10 and 17%, respectively. X17 has demonstrated a high level of resistance to TR4 in the NT (see here for more).

Where to next?

The trial block was nurse suckered at the beginning of the year to manage the cropping cycle, and the varieties were rated for yellow Sigatoka over the wet season. These results will be reported on later in the year.  

The TR4 resistant CIRAD hybrid X17 yielded 34% less than Williams per 12-months over the two crop cycles.

More information

This research has been funded as part of a project funded by Hort Innovation, using the banana research and development levy, co-investment from the Queensland 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.

 

Insect sanctuaries for beneficial predators and parasites

Posted on by Sarah Williams

Insect sanctuaries for beneficial predators and parasites in bananas

By Daniel Farrell

Beneficial insects are species that provide a positive effect or interaction in an ecosystem, such as pollinators, predators, or decomposers. Predators and parasites, known collectively as natural enemies, play a critical role as beneficial insects by suppressing and controlling pest insects in ecosystems.

Beneficial predators and parasites: hover fly, green lacewing, and orange caterpillar parasite (left to right)

In most agricultural ecosystems, including bananas, beneficial insects aren’t considered in management programs. Farming practices, for instance, pesticide usage, monocropping, tillage, and weed control along with the lack of suitable habitat can cause these ecosystems to be unhabitable for beneficial insects to remain, thrive and continue to provide biological control.

Insect sanctuaries are areas of non-harvested companion plants grown free from disturbances of farming practices and grown to encourage and attract beneficial insects to establish and remain in the ecosystem.  Insect sanctuaries may consist of flowering or herbaceous plants, native shrubs or trees, or areas of specific weeds and grasses.

Insect sanctuaries are important for creating an agricultural ecosystem that is sustainable and suitable for beneficial insects by providing them with alternative food sources including important proteins and carbohydrates. In addition, sanctuaries provide harbourage and shelter increasing insect longevity and reproduction. An ecosystem with high biodiversity is generally more resilient to changes and less likely to experience pest outbreaks as natural enemies are available.

Insect sanctuaries can be planted externally or internally in existing production systems, as interrow or guard row (strips), or as a border or hedgerow (see below). Multiple small insect sanctuaries are just as significant to beneficial insects as large-planted areas, as they provide greater cross-over throughout the crop to optimize pest control and safe areas.

Designs of how insect sanctuaries can be incorporated into a cropping system

This DAF innovation-funded project aimed to use a Conservation IPDM approach to alter the banana ecosystem to provide more favourable conditions to enhance the population of beneficial insects. Seven flowering plants were evaluated including dill, fennel, Salvia, lemon balm, Thai chilli, garlic chives, and Impatiens (pictured).

These treatments were compared to a bare-ground control to determine if the composition of the insect community could be altered by incorporating additional plant biodiversity. The abundance (how many individuals) and diversity (how many different species) of insects attracted to each treatment were monitored in March – September 2022 using sticky traps, pitfall traps, and physical observations at the South Johnstone research facility. Collected insects were identified to the species level and then sorted into groups based on their role in the system as beneficial (predators, parasites, decomposers, etc) or pest (sap-feeders, herbivores, omnivores, etc) insects.

Salvia – Red (Salvia splendens)
Impatiens –New Guinea white (Impatiens hawkeri)
Lemon balm (Mellissa officinalis)
Thai Chilli (Capsicum frutescens)
Dill (Anethum greveolens)
Fennel (Foeniculum vulgare)
Garlic Chives (Allium tuberosum)

In general, the results found that insect diversity and abundance significantly increased over the trial duration. This could be due to either a combined treatment effect where the addition of all insect sanctuaries increased diversity and abundance to the trial site, or a general increase in abundance and diversity over time (i.e. warmer weather). From data models, we were able to devise some general relationships between treatments and the attraction or suppression effect they had on the insect groups (see below). 

Suppression or attraction effect of each flowering insect sanctuary treatment for specific groups

From these trial findings, Salvia and Impatiens would likely be suitable plants for insect sanctuaries in bananas, due to their high attraction for natural enemies and suppression of some pests.  Dill would also seem suitable due to its good attraction to predators and suppression effect on pests; however, noting it was not a preferred host by parasites. Interestingly, Salvia, Thai chili, and Garlic chives were all suppressive to Thysanoptera (Thrips), further research could be useful to provide an alternative suppression option for banana rust thrips and banana flower thrips.

Finding the high attraction of beneficial insects to Salvia and Impatiens suggests that further studies in this area would be useful. Ideally, larger plantings with assessments for bunch pests on fruit should be conducted to explore pest-controlling relationships. Ultimately, a list of suitable plants for incorporation into insect sanctuaries associated with banana plantations considering seasonality and soil types could provide growers with options for dedicating an area on their farm for beneficial insect conservation.  

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 project was funded by the Department of Agriculture and Fisheries through an Agri-Science Queensland innovation grant.

A growers’ guide to ant related problem and their management

Posted on by Sarah Williams

A growers' guide to ant related problems and their management

By Daniel Farrell, Richard Piper, David East and Kathy Grice

Ants are commonly found in commercial and backyard plantings of bananas across Australia. Ants find suitable sites to nest including in the ground, behind old leaf sheaths, inside decaying pseudostems or on weeds and leaf trash surrounding the plants. Depending on the species, ants play a different role on the farm and have a different effect on production.

Ants – Good and bad

Different species of ants can co-exist in bananas, however, depending on management practices and the surrounding environment, only one or two species typically dominate at any given time. Ants can be broadly split into two groups, based on their food preferences, either sugar feeders or protein feeders.

Protein feeders including green tree ants, Argentine ants, and coastal brown ants can be useful biological control agents as they prey on pest insects including banana scab moth, cluster caterpillar, banana weevil borer and thrips.

Sugar feeders on the other hand, can be detrimental as they aid the build-up of sap sucking insects such as aphids, scale insects and mealybugs, which they protect (‘farm’) in return for their sugary secretions. Many species are involved, and they are commonly referred to as sugar or tramp ants.

Exotic Electric ant species farming a mealybug in bananas. (Credit: Hawaii Ant Lab.)
Sugar ants farming a colony of banana aphids. (Photo courtesy of Australian Banana Growers Council)

Invasive ant species (Electric ants, fire ants and yellow crazy ants) are also be present in Queensland. Contact Biosecurity Queensland on 13 25 23 if you suspect you have exotic ants on your farm.

Ant problems

Ants generally aren’t considered a major pest for bananas, however, damage to fruit associated with abdominal spray secretions, secondary infections and pests, or nest construction in the bunch can be an issue.

Several species of ants spray formic acid from their abdomens when disturbed, which can damage the fruit. This damage appears as dark brown to black sunken trails or marks on the fruit skin.

Formic acid spray damage by ants on fruit.
Sooty mould growth on fruit associated with honeydew from sap sucking insects ‘farmed' by ants.

Ants protecting sap sucking insects in the bunches can lead to black fungal growth known as sooty mould developing on the fruit. Sooty mould is caused by a fungus growing on the honey dew produced by sap sucking insects, for example scale insects, mealybugs and aphids. This mould is superficial, but difficult to remove from fruit. If banana aphids are present, they may also transmit the virus that causes bunchy top disease.

 

During wet weather ants can build nests by carrying soil and debris up into the bunch. This contamination can result in marking of the fruit when it is harvested and transported to the shed.

Ants also pose an occupational health and safety hazard to workers, with risks of biting, stinging or injury from formic acid sprays. Ants can also cause indirect problems such as damaging and blocking irrigation lines.  

Ant management

Ants can be difficult to manage, however, they are generally suppressed with insecticide treatments used against other pests. Ground spray applications for banana weevil borer or banana rust thrips control will reduce populations and bunch protection applications will protect the fruit.

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 has been updated as part of the Banana Integrated Pest and Disease Management Program (BA21004) 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.

Daniel Farrell

Posted on by Sarah Williams

Daniel Farrell

Harnessing nature’s defenders: the work of an upcoming banana entomologist

Daniel has worked as a technical officer since mid-2019, working with Plant pathologist, David East and Entomologist, Richard Piper. Before that, he gained his introduction to bananas working as a field officer with the Banana Extension team.

‘Working under the plant pathologist and entomologist really gives me the best of both the banana pest and disease worlds,’ Daniel said. ‘I love drawing connections between the two and developing my skills in integrated pest and disease management.  Every day there is always something new to learn from my mentors and that’s always exciting to me.  I’m also extremely looking forward to conducting more project work with beneficial insects (predators and parasites) in banana production systems’.

Daniel Farrell Researcher profile

Daniel Farrell
Technical officer
Department of Agriculture and Fisheries
Centre for Wet Tropics Agriculture
South Johnstone

Daniel was born and raised just northwest of Hobart, Tasmania, in the mountains of Collinsvale. He grew up helping in his parents’ vineyard and mostly looking after sheep and horses. His family spent a few transition years on the Gold Coast at Mt Tamborine, looking after a macadamia farm, before moving further north to Cairns in 2015.  

Daniel studied a Bachelor of Science majoring in Zoology and Ecology at James Cook University, at the Cairns campus. He started his Masters of Philosophy with James Cook University (JCU, Cairns Campus) in May of 2023. His thesis focuses on the mite predator ladybird, Stethorus fenestralis, looking to develop a methodology to mass-produce ladybirds for biological control and to explore the influences of pesticides on Stethorus populations.

On the weekend, you can normally find Daniel playing tabletop games with his friends or hunting down a new house plant and treats at the markets.

‘I’m also have a strong passion for my visual arts projects and like using my spare time as a creative outlet,’ Daniel said.

Daniel loves some banana bread fresh out of the oven with vanilla ice-cream topped with honey! But they are also a great snack on their own.

Banana Roadshows 2024

Posted on by Sarah Williams

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.

Kathy Grice (DAF) and David East (DAF)
Grant Leahy and Sarah Strutt (Hort Innovation)
Gavin Mackay and Stewart Lindsay (DAF)
Naomi Brownrigg and Louis Lardi
Paul Lardi and Tegan Cavallaro (DAF)
Ben Barton, Kieren Borgna and Sarah Williams (DAF)
Richard Piper (DAF) and Cameron Flegler
Tully Roadshow
Eleanor Sibree (ABGC) and Will Darveniza
Innisfail Roadshow
Andrés Morera (DAF), Tony Pattison (DAF) and Geoff Wilson (ABGC)
Thi Dieu Hien Nguyen (Sophia), Koichiro Otsubo (Koshie), Daniel Farrell (DAF) and Trang Thu Nguyen
David Ruiz, Kathy Grice (DAF) and Nandita Pathania (DAF)
Mareeba Roadshow
Sharan Muthukumar (DAF) and Daniel Farrell (DAF)
Jeff Daniells (DAF) and Ben Gu
Carnarvon roadshow
Graeme Sinclair, Valerie Shrubb (WA DPIRD)
Sarah Strutt (Hort Innovation) and Luke Posma

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.