EcoLincNZ

Category: Food

  • Fire-resisting superpowers in plants

    I don’t know what you like to eat at barbecues, but I like some nice roasted veggies! What I don’t fancy are burned broccoli or charred cauliflower. Who would want to eat that, right? Do you have an idea what causes huge amounts of burnt veggies each year? It’s wildfires!

    Seasoned vegetables,
    by polaristest (Flickr)

    With 8-11% of wildfires globally occurring on agricultural land you can imagine that these cause a lot of unenjoyable vegetables. Agricultural wildfires mostly derive from accidental ignition from machinery use or through the escape of fires initially deliberately lit for management purposes. Because 38% of land worldwide is used for grazing and cropping, there is a lot of potential for fire, which highlights the importance of reducing the fire risk to secure our major food sources.

    We don’t have to go far to realise the significance of this topic, as Canterbury accounts for around 20% of New Zealand’s total farmland, roughly 2,600,000 hectares of land. That is about the size of 3,700,000 rugby fields! Canterbury has a climate characterised by low precipitation and dry winds, good ingredients for an easily flammable outdoor barbecue.

    Local wildfires take away many people’s chance to roast their veggies themselves as well as causing a huge amount of economic and ecological loss. But what if we could use farmland for fire prevention? What if some crops actually had the superpower to fight against wildfires, or at least survive them?

    Canterbury NZ, by Simon (Flickr)

    There is a lot of information on how to plant mindfully, using low-flammability plants to create buffer zones that allow us to keep wildfires under control and stop them from spreading. Those ‘green fire breaks’ were tactically planted after the Port Hill fires in 2017 to prevent history from repeating itself. As green fire breaks can only help reduce the impact of wildfires to some extent, planting smart on farmland might add to the best practice, especially in fire-prone areas like Canterbury.

    That is exactly what was tested in a study by Lincoln University in 2023. Masters student Tanmayi Pagadala, with colleagues Azhar Alam, Tom Maxwell, and Tim Curran, tested 47 different agricultural plants for their flammability superpowers, following a simple recipe.

    Ingredients:
    – 47 different shoots and plants of the following groups: cereal crops, forage crops, fruit trees, grazing forbs, pasture grasses, weeds, pasture legumes, vegetables, and wine grapes.

    Utensils:
    – Infrared laser thermometer
    – Lighter
    – Plant barbecue (“a 44 gallon drum cut in half with a grill on top”) 

    Plant barbecue
    (Image by Hanna Hoeffner)

    Instructions:
    – Heat the grill by turning on the burner (125-199 °C)
    – Place your sample on the grill in a horizontal position and leave for 2 minutes
    – Turn on the blowtorch for 10 seconds to ignite the sample
    – Wait until the plant stops burning

    Following this recipe, one can evaluate the ignition time, the maximum temperature reached, the burning time, and how much of the sample was burned.

    After many days of barbecues, Tanmayi’s team was able to tell which plants have the superpower to resist fires better than others. Fruits and cereal crops had significantly higher flammability compared to vegetables, weeds, winegrapes, forage crops, grazing herbs, pasture grasses and legumes. Or, to make it more understandable, easily flammable crops dry faster, are generally dryer, and retain more dead material. Veggie superheroes were bell peppers, spring onions, and potatoes.

    Tanmayi’s team created “A fire-wise mixed cropping farm system” as a guideline for purposeful planting on farmland. The idea of fire-wise cropping is similar to green fire breaks. Using low-flammability native tree, grass and legume species as boundaries around higher flammable crops. 

    Broccoloid, by CaptainEdawardTeague (deviantart)

    Higher flammability species are then protected from wildfires that start outside of the farmland and also prevent fires started on the farm from spreading to neighbouring properties. While you must consider other factors, like local environmental conditions, economics, and goals like enhancing biodiversity, this approach can add to existing green fire breaks. By redesigning farms, we can utilise the fire-resistant superpowers of some species to safely plant non-super-powered plants and minimise increasing the wildfire risk.

    Even though this research was conducted in New Zealand, many of the species tested are common crops worldwide. Therefore, their superpowers could come in handy in many places with continuously increasing fire risks, putting veggies at the forefront of the fight against wildfires!

    This article was prepared by Master of International Nature Conservation student Hanna Hoeffner as part of the ECOL608 Research Methods in Ecology course.

    Pagadala, T., Alam, M. A., Maxwell, T. M., & Curran, T. J. (2024). Measuring flammability of crops, pastures, fruit trees, and weeds: A novel tool to fight wildfires in agricultural landscapes. Science of the Total Environment, 906, 167489. https://doi.org/10.1016/j.scitotenv.2023.167489

  • Fighting fire with farming: flammability of pastures and crops

    The Port Hills are a highly valued geographical feature of Chirstchurch. Located southeast of the city, they are home to a wide range of activities, including rock climbing and mountain biking, as well as being popular among walkers and joggers. Vegetation throughout the Port Hills is varied, containing a range of tussockland, pine forestry blocks, native scrub, farmed grassland, gorse and broom scrub and small pockets of remnant forest.

    On the 14th of February 2024, over 700 hectares of land was ravaged by wildfire in the Port Hills of Christchurch, New Zealand. Over 80 residents were evacuated, and around 130 firefighters with 12 helicopters were involved. Drought conditions and vegetation structure contributed to this event, but could the damage caused by the blaze have been reduced? Could grazing these hills with livestock have reduced the amount of tall dry grass present which fuelled the fire, or could different pasture or shrub species have helped to reduce the flammability of the Port Hills.

    A recent paper from Lincoln University’s own Tanmayi Pagadala, Azharul Alam, Tim Curran and Tom Maxwell has highlighted the differences in flammability between different pasture, crop, weed and shrub species found commonly on farms throughout Canterbury.

    Marley’s Hill on fire. February 15 2024. (Image CC BY-NC by Jon Sullivan)

    A good range of scientific work is available which has investigated the flammability of various plant species in New Zealand, but this has been mainly focused on species in natural areas (both native and exotic), rather than in agricultural environments. Gorse, eucalypts, pines and long grass are well known to be extremely flammable, so why is it that certain areas of the port hills were allowed to return to their same fuel rich state following the 2017 blaze which destroyed over 1600 hectares? It must be acknowledged that efforts were made to replant some of the previously burnt areas in green firebreaks and others in less flammable native species, which were shown to survive the previous blaze in well-established areas.

    Species that regrow following a fire are often also very flammable (eg. gorse and pine). Unfortunately, a significant proportion of the burned land was in pines for forestry, which has since been replanted and will likely create another significant fire risk for the foreseeable future. Continuing the efforts of plant firebreaks of less flammable tree species throughout the Port Hills, as well as within pine forestry blocks, should not be underestimated.

    Individually these breaks may not appear significant, but a thorough network of them throughout the Port Hills could be exactly what is needed to slow the spread of the next blaze and allow firefighters to gain control sooner. Minimising the presence of long, rank grass could also help to slow the spread of the burn.

    Could additional efforts be made in to reducing the presence of long rank grass through the addition of cattle to grazed areas which would trample and eat this dry plant material? Or perhaps planting more drought tolerant, water-efficient forages which can be grazed down during dry periods to minimise the fuel loading of grasslands could be beneficial.

    Dry, rank grass fuelling the blaze on Christchurch’s Port Hills. (Image CC BY Francis Vallance)

    There is a huge range of flammability in different crop and pasture species common to Canterbury farming systems. Assessments carried out on Lincoln University’s trusty ‘plant BBQ’ tested 47 different plant species and varieties common throughout Canterbury farms (see table below), including cereals, forage crops, fruit crops, forage herbs, forage grasses, forage legumes, vegetable crops, weeds and a range of wine grape varieties.

    Unsurprisingly, the majority of forage and pasture species showed very low flammability, as did some vegetable crops and wine grapes. Cereal crops behaved as expected, showing high flammability as they matured and dried off. Surprisingly, apple trees, pears and raspberries showed a high degree of flammability.

    Table of plant species and their relative flammability assessed by Pagadala and colleagues

    The slope of the Port Hills, and an average annual rainfall of 700 mm, means that using low flammability crops like potatoes or peas is not practical. There are, however, a range of pastoral species that show the potential to be beneficial in reducing the flammability of farmland. Forage crops, herbs, legumes and grasses all showed very low flammability scores, which is due to their high moisture content and quality traits meaning they carry very little dead material (the ideal fuel for fires).

    Knowing these flammability scores in addition to the the drought tolerant traits of species, such as lucerne, cocksfoot, red clover, plantain and chicory, raises the question: why are these species currently not implemented throughout the fire prone Port Hills as a method of reducing fire risk? Yes, these forages will become flammable if they are allowed to turn to a reproductive state. However, their drought tolerance and palatability will allow them to be well grazed during dry periods and not contribute to the fuel loading of hills anywhere near the amount that browntop and other native grasses will.

    Chicory next to native pasture in Taranaki. (© Blake Gunn – used with permission)

    The photos above paint a picture of a potential solution to the Port Hills fire woes. At the very least, an effort should be made to ensure that flammable biomass throughout the Port Hills is minimal. Minimising the presence of flammable species, such as gorse and pines, through manual removal or switching to planting less-flammable alternatives, such as native shrubs, are some potential solutions.

    Preventing the planting of pine plantations near the city and other populated areas seems like another fairly logical solution to reducing the fire risk in populated areas, as does surrounding these potential high-risk areas with low flammability and native shrub species. Another area of focus could be to focus more on the management of cattle and/or sheep to intensively graze the hillsides and ensure that a bank of highly flammable fuel does not build up over time. Intensive grazing will not only prevent grass banks from building up, but the ‘hoof and tooth’ activity from grazing may also prevent other flammable species, such as gorse and broom, from re-establishing.

    Lucerne transforming a Central Otago farm system (© Allister Moorhead – used with permission)

    Functional firebreaks could also be of huge benefit to these hillsides. In areas where tractor access is possible, consideration should be given to the establishment of drought-tolerant, low-flammability species, such as red clover, chicory, or lucerne. These will create ‘green zones’ throughout the hillsides that could slow the spread of the next inevitable fire, especially compared to the current vegetation which is prone to turning to a dry, reproductive state over summer.

    To wrap up, logic suggests that previous fires in 2017 and 2024 on the Port Hills, in combination with the presence of flammable vegetation, make another blaze in the future almost inevitable. The findings from recent research on the flammability of pasture and crop species commonly found on Canterbury farms, combined with modern grazing regimes present a real opportunity to significantly reduce the fire risk on the Port Hills. The use of firebreaks planted with native, low flammability species around high risk areas such as pine forestry blocks, along with the protection of existing pockets of native scrub/forest should also help to reduce the fire risk on the Port Hills.

    This article was prepared by Master of Science postgraduate student Kaylee Spain as part of the ECOL608 Research Methods in Ecology course.

    Reference article:
    Pagadala, T., Alam, M. A., Maxwell, T., & Curran, T. (2023). Measuring flammability of crops, pastures, fruit trees, and weeds: A novel tool to fight wildfires in agricultural landscapes. Science of the total environment, 906(1). https://doi.org/10.1016/j.scitotenv.2023.167489

  • Induced resistance, Sting, and the blades of Westernesse

    It’s a big, bad world out there and it is nice to find something that adds to our protection.This can range from vaccines against viruses, to seatbelts in cars, to laws against causing physical harm. As a naked ape we are not especially intimidating on our own and we often seek out tools to make us safer.

    “With both hands he held the elven-blade point upwards …; and so Shelob, with the driving force of her own cruel will, with strength greater than any warrior’s hand, thrust herself upon a bitter spike. Deep, deep it pricked, as Sam was crushed slowly to the ground.
    No such anguish had Shelob ever known, or dreamed of knowing, in all her long world of wickedness. Not the doughtiest soldier of old Gondor, nor the most savage Orc entrapped, had ever thus endured her, or set blade to her beloved flesh.” Lord of the Rings, JRR Tolkien (Image by Tony Galuidi; main image by Alan Lee)

    One of the key points of “The Lord of the Rings” (and all of Tolkien’s writing) is that small, seemingly ineffectual, individuals can make a real difference in the world. It’s not by chance that hobbits are smaller than humans, weaker than dwarves, less knowledgeable than elves. Tolkien emphasised their ‘normality’.

    Hobbits do have their strengths though, especially in resilience. They are able to withstand the corruption of the ring far longer than other races. Boromir, a doughty man, only has to see the ring once before plotting to ‘borrow it’ for helping with his people. Both Bilbo and Sam, ordinary hobbits, are both able to wear the ring and give it up freely, which no others have done.

    Still, even Tolkien realised that the hobbits needed a little bit of an assist, something that would help to bring out their resilient traits. Tolkien chose to give each hobbit a long dagger with an ancient pedigree. Sting was found by Bilbo. It was a blade that shone with a faint light when evil was near. Sting was made long ago in the first age by elves of Gondolin. Tom Bombadil rescues the hobbits from a barrow wight and gives them each a dagger of Westernesse. These were made a couple of thousand years before in the early Third Age by men of the Dunedain Northern kingdom.

    Each of these blades become crucial to the hobbits achieving beyond their expectations. Pippin stabs a troll chief, who are largely immune to most weapons, and makes a difference at the Battle of the Moranon. Merry cuts the Witch King’s sinews allowing Eowyn to destroy the head Nazgûl in the Battle of the Pelennor Fields, when no one else can touch him. Sam uses Sting to wound Shelob and scare her off, when nothing else would work.

    Importantly, the blades were built with different foes in mind. The blades of Westernesse were built to fight the Witch King and his minions but are useless against giant spiders. Sting was built at a time when Ungoliant’s spider brood were numerous and roaming the world, and so it is effective against Shelob and her webs.

    Merry stabs the Witch King and breaks the spell allowing Eowyn to destroy him.
    “No other blade, not though mightier hands had wielded it, would have dealt that foe a wound so bitter, cleaving the undead flesh, breaking the spell that knit his unseen sinews to his will.” – Lord of the Rings, JRR Tolkien

    So, the hobbits left the Shire with their natural hardiness and common sense, but were primed with blades to make themselves more resilient to the difficult situations that they were to face.

    There is a similar concept when it comes to immune systems. Most plants and animals have evolved sophisticated immune systems that respond to pathogens in the surrounding environment. Having a complex immune response is especially important in dense populations where disease and parasites can quickly spread. One such situation is with crop species.

    Crops, where individuals from one species are packed tightly together, are targets for various pest species that can infect an individual and easily move to the next. For the last 100 years or so we have had the luxury of applying chemicals to help keep the plants healthy by reducing pathogens. This is no longer an an attractive option as it once was as pathogens have become resistant and people have become less tolerant of nasty chemicals in their landscapes and food sources.

    One solution is to create induced resistance through biological and chemical inducers. These inducers can artificially trigger immune defences and enhance their responses. For example, grape crops can suffer from downy mildew. Chitosan, a sugar obtained from the shell of crabs, can be sprayed on vines, triggering immune responses that can reduce downy mildew by 90%, compared to what would happen if grapes responded ‘normally’!

    “His little sword was something new in the way of stings for them. How it darted to and fro! It shone with delight as he stabbed at them.” The Hobbit, JRR Tolkien (Image by J. Catlin)

    Just like the blades of Westernesse helped the hobbits, these inducers allow the individuals to respond faster, more intensely, and achieve more than they would otherwise be able to do. Some inducers are useful for a variety of pathogens in many crops, such as Acibenzolar-S-methyl (ASM), and some are very specific, such as Saccharomyces yeast extract.

    Helen Rees, Lincoln University, and colleagues from Plant and Food, University of Auckland, and Scotland’s Rural College have put together a review in the journal Phytopathology about where the field of induced resistance in crop species stands. They look at what has worked on particular crops and the future roles and opportunities for inducers. They conclude that it is an exciting time for this field and that future crop protection may revolve around the next generation of inducers, playing a pivotal role in moving to a reduced pesticide future.

    While inducers may not have the glamour of a Bilbo using Sting to free dwarves from giant spider webs in Mirkwood, they have world-wide contributions to make to feeding a hungry planet by countering the ravening hordes of crop pathogens. Cutting edge indeed!

    Adrian Paterson is a lecturer in Pest-Management and Conservation at Lincoln University. He likes Sting (both in the Lord of the Rings and in The Police).

  • Make boysenberries juicy again: the fight against downy mildew

    “Yes, why not!! Hi! I am Boysenberry. I will tell you the whole story, how I fight this destructive fungus. Before delving into the subject, I just want to tell you a little bit more about me.”

    Boysenberries Photo by simplyAutumn 2009 from Flickr

    I am a rich source of micronutrients and have great health benefits. My origin was in California, USA and I was introduced to New Zealand in the early 1940s. New Zealand has become a major producer and exporter of my fruits. The fruits are produced on the second-year canes ‘floricanes‘, whereas the first-year canes that only possess leaves known as ‘primocanes’. Those that grow quickly are known as ‘hurricanes’. Hah – an old joke amongst us boysenberries.

    Propagation of my plants is done either by cutting or tissue culture. Sadly, there is a fungus, Peronospora sparsa, who is my enemy and develops a disease, known as Downy mildew, systemically in tissue cultured plants. It causes huge damage and is will often cause losses of 50%, when I am grown with conventional management methods, to 100 %, when grown organically. It produces symptoms of mycelial growth of fungus, on my leaves in early spring and then later then premature reddening, shriveling, and hardening of my fruits and ultimately, the leaves become dull. That’s why it is sometimes called “Dry berry“.

    Downy Mildew of Boysenberry by Jones and other researchers

    “Unfortunately! I was struggling with this disease when some traditional methods, like removal of leaf litter, rooted ends of primocanes, and root suckers besides the fungicide sprays, that were being used to fight against it, but those were unfortunately not enough to beat it. I know, you are thinking, then how do I overcome this disease?”

    Some scientists from Lincoln University; Anusara Herath Mudiyanselage, Hayley Ridgway, Monika Walter, Marlene Jaspers, and Eirian Jones, came up with some solutions and experimented on me. They thought that heat and fungicides could help treat and stop the growth of the disease.

    To test if these ideas could work, fifteen symptomatic plants (2-year-old) were selected, repotted and cold stored at freezing temperature for 6 weeks to induce dormancy in them. Dormancy is a state where my plants hang tough and save their energy without undergoing their active growth. Dormancy allows my plants survive on their reserved food as they are cut off from the supply of food. The plants were transferred to a greenhouse until 2-3 primocanes developed. Thereafter, the plants were divided into three groups with five plants in each and given three different treatments to each group.

    The first group remained in the greenhouse for a month and was then given a heat treatment by being placed in a growth chamber at 34°C for 4 more weeks. The second group was sprayed twice with phosphoric acid and mancozeb (fungicide), the first spray was given two weeks afterward in greenhouse and second was given two weeks after the first spray. Plus, this group was also heat treated for a month. But the last group was left untreated and remained in the greenhouse for two months.

    Well! The main reason for giving the heat treatment with or without fungicide spray was to check the ability of my propagation material to limit the systemic infection of fungus prior to tissue culture to produce fungus free plants with verification done by PCR.

    Tissue Culture grown plants. Photo by EcoFert Inc. 2010 from Flickr

    After each of the treatments were complete, the plants were ready for the next step: propagation.

    “Do you remember how I am propagated? Yes, the tissue culture.“
    The single-bud stem cuttings from each plant were washed in antimicrobial soap, followed by surface sterilisation and washing in distilled water. These steps were followed in order to make my cuttings free from any contamination and washed with water to remove excessive chemicals/disinfectants. The cuttings were then placed in a liquid medium that made it possible for them to grow and multiply in a sterile condition.

    “You know what!” 125 plants survived in total and were potted after this. The largest group of survivors were from the heat treatment group.

    Cuttings/plants with roots were placed in the greenhouse for a couple of weeks where they were misted to maintain moisture. Afterwards they were shifted to the shade house and were kept for about five months under conditions that favor systemic symptoms. As the cool and wet conditions induce the growth of fungus, these conditions were provided to check the ability of my plants to resist it after given treatments.

    “Are you curious, to know what happened next, then?“

    Polymerase chain reaction machine Photo by USAID Laos 2020 from Flickr

    Twenty-two weeks after potting, all the untreated plants become sick with the disease. However, the other two treatments gave phenomenal results. Only 13 % and 17 % of plants showed visible symptoms, treated with heat only and fungicide + heat, respectively. The seventy-six plants (of 125) from both treatments (Heat and Fungicide + Heat) survived well without any symptoms several weeks after potting.

    Because some plants could have the fungus but not show any signs of infection, the researchers used the modern molecular technique (PCR) to confirm that there were no asymptomatic plants. This test was carried out regularly at certain interval for about a year and all of the tests gave a negative result. Fortunately, only a few plants with heat and fungicide + heat treatments got infected as compared to 100 % infection in untreated ones.

    “Well! this was my story, and now I can say that I can fight against this destructive disease, if I am given heat treatment with or without fungicide. I think you are also curious to know how the heat treatment affect the fungus.“

    The answer is the high temperature. The higher temperature destroys the essential chemical activities and inactivates micro-organisms like viruses. Similarly, this fungus has the nature of only being rely upon the living matter to eat and survive like the viruses. Therefore, the high temperature restricts the growth of fungus into the shoot tips and stops the infection.

    This is the first time that researchers have found a solution to a key challenge in managing dry berry disease. This opens the door to disease free propagation of my plants in nurseries with the uptake of heat treatment and without fear of fungicide resistance to fungi.

    “So now we can all be happicanes!”

    This article was prepared by Master of Science postgraduate student Manjot Kaur as part of the ECOL608 Research Methods in Ecology course.

    Reference: Herath Mudiyanselage AM, Ridgway HJ, Walter M, Jaspers MV, Jones E. 2019. Heat and fungicide treatments reduce Peronospora sparsa systemic infection in boysenberry tissue culture. European Journal of Plant Pathology. 153: 651–656.

  • Seed coating: fungi protect maize from disease

    Did you know that seeds can wear coats, just like people? Different kinds of coats can be added to seeds to protect them for improved cultivation. How do seed-coatings work and what are the benefits for seeds wearing coats? There are several distinct strengths of seed coating. You will know a lot more about seed-coating, and a recent discovery that could be applied in maize seeds, after reading throughout this page.

    Recently, Federico Rivas-Franco, with colleages at Lincoln University and researchers around the world, discovered the benefits of coating maize seed with a kind of entomopathogenic fungi (Metarhizium species). Entomopathogenic is a technical word meaning insect killing, so this is a fungus that infects and kills insects. By adding a Metarhizium coating to maize seed, Federico found that maize plants grow taller than the untreated plants, when those plants are in the presence of the plant pathogenic fungus, Fusarium graminearum. That was a useful surprise!

    What’s more, the Metarhizium hyphae (the growing threads of the fungus) were observed growing on and in root tissues in all the Metarhizium treated maize with the coating. This showed that Metarhizium can live together with maize roots and had a consistent effect on defending maize plants from underground pests and plant pathogens (like Fusarium graminearum).

    Fusarium ear rot on maize
    Fusarium ear rot on maize.
    Image CC BY-NC-SA 2.0 by Thomas Lumpkin

    Many of you may be asking, what is Fusarium graminearum? It is a causative agent of several serious plant diseases. Fusarium graminearum can cause a devastating disaster on maize and lead to huge yield losses.

    Maize seeds, roots, stems and ears can all be easily infected by this fungal pathogen, which means maize plants are susceptible to Fusarium infections throughout the cultivation period. More terribly, not only maize, but also wheat, barley and rice can be infested by Fusarium. It is quite annoying, right? It can be expensive for farmers. What if people and stock eat the contaminated crops? The answer is they will get ill, and the symptoms including vomiting, stomach ache and so on. Fusarium infected maize can not be sold as food, so farmers need a solution to protect their crop from this nasty fungus.

    Metarhizium species are a kind of fungus that is generally used to biocontrol insect pests. However, the biocontrol ability of Metarhizium not only works for insects but also against plant pathogens like Fusarium. That’s quite the superpower!

    In 1870s, Metarhizium was first extracted and identified by a Russia scientist Élie Metchnikoff (Илья Ильич Мечников in Russian). He found that there were hypha growing from dead beetles. Initially, the hypha was white, then turned green, and then a darker green. After molecular techniques were introduced at the end of 20th century, new species of Metarhizium species have continued to be identified.

    How does Metarhizium combine with seed coats? In fact, it is microsclerotia, which is a resistant structure grown by the fungus, that is added into seed coats. Over the past decade, it has been discovered that entomopathogenic fungi are able to produce high concentrations of microsclerotia when grown in liquid media.

    Microsclerotia are desiccation tolerant and have excellent storage stability. More importantly, they are capable of producing high quantities of infective conidia (asexual spores) after rehydration. All these attributes make microsclerotia an excellent agent to be used in seed coating.

    Besides preventing plant diseases and pests, different seed coatings can also make seeds grow healthier and improve cold resistance (drought & moisture resistance as well). That’s because commercial seed coatings are composite products made up of combinations of insecticides, fungicides, compound fertilizers, trace elements, plant growth regulators or more other chemical or physical components. What’s more, same size and shape of coated seeds make it much easier for mechanical sowing.

    After using seed coatings, farmers don’t need to use as many insecticides and fungicides to protect the emerging young plants. This reduces the pollution in the environment and the insecticide (or fungicide) resistance of the plant.

    This research demonstrated the excellent potential for adding Metarhizium to commercial seed coatings for maize. We have seen the good outcomes in the experimental field. Let’s wait and see the next step for figuring out how best to do this in commercial production.

    This article was prepared by Master of Science postgraduate student Xiaohan Wang as part of the ECOL608 Research Methods in Ecology course.

  • Testing new bait coatings for conservation

    Mickey Mouse and Scabbers the Rat, are causing biodiversity loss in Aotearoa, New Zealand. They are committing crimes against some of our most endangered wildlife and arriving uninvited to the party. Protecting our taonga falls into the hands of conservationists and wildlife managers. New research plays a vital role in protecting our precious taonga.

    Menacing mouse – a little creature creating a big problem. Photo by Nils Fleischeuer (CC BY-NC)

    Would you be surprised to read that mice (Mus musculus) have been recorded eating live albatross (300 times their size)? I sure was! How could a little mouse possibly kill a bird known for having the largest wingspan in the world? Sadly, lots of albatross die from mouse predation every year. When mice aren’t eating albatross, they dine on many species of insects, chicks, eggs and lizards.

    If mice are so terrible, what about rats? There are three species of rat in Aotearoa, the Norway rat Rattus norvegicus, Black rat Rattus rattus and the Polynesian rat Rattus exulans. They are all bad news – they kill adult birds, chicks, snails and insects. They also compete for food that should be there for our native fauna.

    Due to the negative impacts of these rodents, and other introduced predators, many of New Zealand’s most critically endangered fauna are whisked away to predator-free off-shore islands. Some are protected behind expensive predator-resistant fences. PHEW, job completed, right? Not so fast!

    Despite eviction notices, Micky and Scabbers can wriggle their way back into our protected areas. Maybe it’s a quick hop along a fallen tree that bridges the now not so “predator-resistant” fence or a long swim to an off-shore island. When they do appear, we need to have proven tools in the toolbox to deal with them. One of the tools to control them is cereal poison bait.

    These baits are like your breakfast cereal in that they are made from similar ingredients – apart from the poison! Picture this: you reach for your new box of breakfast cereal in the morning and notice an open, very much neglected, box of cereal sitting at the back of your pantry. It’s been there for so long you can’t remember opening it (or you’ve just been ignoring it for many months). It smells stale and has gone slightly soggy, so you bin it, knowing full well that it will taste nasty.

    A good rat is a dead rat! Photo by Jacqui Geux, iNaturalist NZ, (CC-BY)

    Bait stations are used to protect the bait from the rain. However, just like you with your open box of stale cereal, mice and rats also have preferences when it comes to eating their cereal. The longer that bait is stored inside bait stations, the less palatable it is to rodents, the less they eat and the longer it continues to sit and weather.

    To make things worse, the bait stations are often irregularly serviced, so wildlife managers need a bait that stays palatable to mice and rats for as long as possible. This is an issue on remote predator-free islands and fenced predator-resistant sanctuaries that have difficult access and limited funds. Stale or mouldy bait in particular will not control rodents if they aren’t even going to eat it.

    If only there was a way to prevent baits from absorbing moisture and going mouldy – keeping the bait fresh for longer so that mice and rats were more likely to eat it when they come across it …

    This is where researchers at Lincoln University (NZ), James Ross and colleagues, had an idea to coat the baits in a material that will do just these things. Also the material will not reduce the palatability of the baits to mice and rats. To test this idea, they created an experiment using two coatings, Polyvinyl butyral (PVB) and Shellac. Shellac is already used as a food glaze and as a coating to mask the bitter taste of Paracetamol/Acetaminophen. Shellac is also fully biodegradable, which makes it environmentally friendly.

    The coatings were tested using four combinations of the aforementioned substances. First, they had to ensure the new coatings didn’t reduce the palatability compared to uncoated baits. If mice and rats do not eat the new bait coatings, it would be a waste of time to test them further. If Whitakers coated your favourite chocolate bar in something strange, you might take one bite and decide that the new “sardines & whipped cream” coated chocolate bar was not your vibe.

    This image has an empty alt attribute; its file name is 518244606_bcc3409a3a_c.jpg
    An easy pill to swallow – A Panadol tablet, commonly coated in Shellac. (CC BY-NC-SA 2.0) Photo by venana, Flickr. 

    The researchers also had to measure whether coated pellets remained palatable after extended environmental exposure because this is highly likely how mice and rats will find the baits in the real world. In the experiment the coatings were placed on the food the captive rats and mice were fed on. Mice, and more so rats, are neophobic (afraid of new things). So placing new food in their cages might affect the results in such a way that the researchers are measuring the wrong thing. Putting the coatings on their food means their wary responses will be minimised, since they eat rodent pellets every day. After the mice and rats had munched their way through their favourite snacks, the bowls were weighed, and the results were in – Shellac for the win.

    There were differences between the bait coating combinations; Shellac was the most palatable, it performed the best for both mice and rats. Shellac out preformed the PVB coating and the mix of PVB/Shellac. This experiment demonstrated that mice and rats are picky eaters and highlights the importance of testing the different coating types. Coatings, although no thicker than 500 micrometers (really thin), will affect how much mice and rats will eat. Ironic given that mice and rats will eat out of a trash can – now we know they are fussily searching for the “best rubbish”.

    This research is a step in the right direction for conservation in Aotearoa. I call it a small win for the native fauna. With Shellac showing promising signs, researchers and wildlife managers can test the new bait coatings in the field. Wild Mickey and Scabbers can try out some of the mould free, ‘fresh as can be’ Shellac bait. So next time Mickey and Scabbers arrive uninvited to the party, it may be the last thing they do.

    This article was prepared by Master of Pest Management student Nils Fleischeuer as part of the ECOL608 Research Methods in Ecology course.

  • When grapes lead to war

    Would you steal a loaf of bread to feed your hungry family? Fair enough. What about a couple of grapes to save yourself the misery of wasting nine dollars on sour fruit?

    Grapes, waiting to be sampled.
    © Colin Jensen

    “Try ‘em before I buy ‘em,” is my dad’s usual response to that question, as he pops grapes from three different bags one-by-one into his mouth. A red one here, a green one there, maybe even a dark purple if the season is right. In spite of earnest pleadings from embarrassed children and grocery store placards, there would be no purchase of grapes unless a thorough investigation of both quality and taste had been completed. 

    As weird as it may sound, it turns out my dad is not alone in his grocery store grape grabbing. A quick google search yields numerous articles, blogs, polls and debates on the topic. A more recent article used an extensively rigorous survey of 40 people on Facebook to tackle the question, with results showing that half of respondents advocated for, and actively participated in, grape sampling while shopping. As for the other half? Some seemed to side with this NZ Herald article which refers to grape samplers as both thieves and stealers, while others suggested that this type of behaviour is a “hanging offense”. As a conservation biologist, I am not typically one for philosophical debates, so I’ll leave the ethics of grape sampling and capital punishment up for you to decide. 

    Unfortunately, a jump back into the conservation sphere does not make me immune to grape stealing dramatics. As it turns out, nature, just like the produce aisle of my parent’s local grocery store, is home to its own collection of fruity felons. Among those felons is the European starling. You may know starlings for their incredible vocal range, beautiful coloration, or the massive flocks (or mumurations) they sometimes form (check them out if you haven’t). But to winemakers in New Zealand, starlings may be more well-known for being “vicious” and “wasters of fruit.” Unfortunately the problem that starlings cause in vineyards is nothing new, and in fact, it was this very problem that was the inspiration for research at Lincoln University over 20 years ago. 

    European Starling CC courtesy of Eric Ellingson on Flickr

    Flashback to 1999 – Napster is in its heyday, Brittney Spears’ “Baby One More Time” is on the radio, and, besides a little bit of Y2K hysteria, life is good. Amidst the excitement of a new millennia, researchers Yuki Fukuda, Graham Hickling, and Chris Frampton from Lincoln University were hard at work trying to solve the problem of the grape stealing starlings. To do so, they tested out two devices designed specifically for scaring birds away from agriculture areas – the Peaceful Pyramid and eye-spot balloons. The Peaceful Pyramid, as the name suggests, was meant to be a “peaceful” alternative to other more aggressive bird deterrents like “noisy gas guns”. It featured a rotating pyramid with mirrored sides, which would reflect rays of sunlight towards incoming birds. The goal was to overload the birds vision to the point that they would no longer have the desire to land and feed. The eyespot balloon was a large balloon with yellow and black patterning designed to mimic the eyes of a large predator. 

    Peaceful Pyramid
    © Great Expectations

    Both devices were tested at a vineyard in Dunsandel, and at the University vineyard here in Lincoln. Although both were found to scare starlings away from the grapes initially, within a few days almost all the birds had become habituated to both scarers, and they quickly became ineffective. Ultimately, it was determined that both the eyespot balloon and the Peaceful Pyramid were not practical methods for protecting vineyards. Although these researchers did not find a solution to counteract the stealing starlings, they at least helped re-affirm the idea that anti-bird measures need to be thoroughly tested before they are trusted for protection. 

    In the 24 years since the research at Lincoln was done, there has been no shortage of innovation and testing of bird scaring devices. There has also been some work (here and here) on what birds are doing in the vine-yards. Among the myriad of devices tested, we have seen air cannons, chemical repellents, introduced falcons, large-scale netting, and a few of my favourites, the sci-fi sounding laser scarecrow (unfortunately, this doesn’t look as cool as it sounds), and the RobotFalcon (fortunately, this does look as cool as it sounds). 

    All of these projects have had the same goal: deter birds from pillaging in agricultural settings. Unfortunately, despite each of these ideas producing some level of protection, they all come with limitations. One is too expensive, another is too time and labour intensive, and some only work in good weather. For many, it seems as if finding a fix-all solution to the crop stealing problem is a fruitless endeavour. If it’s not the Peaceful Pyramid, and it’s not the laser scarecrow, then really what more can we do? 

    Well, researchers from the University of Sydney think that they have finally found the answer. (If you have been surprised by any of the bird scaring techniques already described, you may want to sit down for what comes next). Like something out of a Stanley Kubrick film, these researchers have employed techniques that they can only describe as “psychological warfare.” 

    The weapons of war used in this study consist of a stuffed bird attached to a drone (UAV), which is flown through the vineyard whilst playing recorded distress calls of pest birds from a loudspeaker (see image below). The idea is that visual and auditory stimuli on their own are not effective long-term. By tapping into the birds psychology through visual (dead bird) and audio (distress call) cues, they might be able to trigger the birds anti-predator behaviour, and keep them away for good.

    Early results show that crop damage in areas patrolled by this flying fearmongerer are up to four times less than areas which used visual scarers alone. It also appears that this system is just as effective as large-scale netting (currently the most effective way to protect grapes), but is much more cost effective. While these results are preliminary, and further testing is still needed, it seems that hope may be flying (and screaming) in on the horizon. 

    © Zihao Wong – UAV bird scarer as used in: Psychological warfare in vineyard: Using drones and bird psychology to control bird damage to wine grapes

    So there you have it. Starting with a couple of grapes at the grocery store, we end with a weapon of war designed to create fear and confusion. While we may not be any closer to answering the debate about grocery store grape sampling, we at least seem closer to solving the grape stealing starling situation. Will psychological warfare finally be the fix-all solution? Perhaps, but only time (and research) will tell. 

    As for me, I still don’t quite understand what it is about grapes that causes both the starlings and my dad to lose all sense of self-control. Maybe with 24 more years of research, innovation and whatever military tactic comes after psychological warfare, we will finally find that out. I am sure it will be a wild ride. 

    This article was prepared by Master of International Nature Conservation student Colin Jensen as part of the ECOL608 Research Methods in Ecology course.

    Citation: Y. Fukuda , C. M. Frampton & G. J. Hickling (2008) Evaluation of two visual birdscarers, the Peaceful Pyramid® and an eye‐spot balloon, in two vineyards, New Zealand Journal of Zoology, 35:3, 217-224, DOI: 10.1080/03014220809510117

  • A giant pest problem: elephants in the backyard

    New Zealand has a huge agricultural industry. It also has a pest problem. I myself have been out to a friends’ farm and was told to “squash a mouse if you see one”! Which I think we can all empathise with to an extent. When the little b*stards are eating your food, they might as well be infesting your wallet.

    Image CC-BY-SA Diego Delso on Wikimedia Commons: Elephants and humans live in close contact in Africa

    Now, think about scaling that up a couple of levels. You no longer have nuisance, albeit damaging, mice scurrying around your farm shed. Instead you have elephants, in herds of 11+, munching through entire fields and even ripping doors off your grain sheds. Stomping won’t quite suffice here (and may go the other way).

    This is an issue that Abel Mamboleo and his PhD supervisors, Chile Doscher and Adrian Paterson, at Lincoln University investigated in their JOJ wildlife and Biology paper in 2020. Instead of the standard numbers, quantities and figures you may expect in a science paper, here they take a slightly alternative approach to the topic. What do people think is happening in their backyards? After all, fear and perceptions are powerful things.

    To start with a bit of context – who are we talking about when referring to people? This study interacted with people in the region of Bunda, a very densely populated region in Tanzania. Much of its land is a part of the idyllic Serengeti ecosystem, and boasts an internationally renowned tourism hotspot.

    Bunda location within Tanzania – right next to the Serengeti: Image CC-BY-SA Macabe 5387 on Wikimedia commons

    These people rely heavily on farming. In fact, 80% of annual income in Bunda comes from this industry. You can imagine how devastating it is to have these creatures, as amazing and majestic as elephants may be, decimate their fields of crops.

    Elephants eating crops is not a new story. In fact, there are even somewhat humorous accounts of elephants eating rotten fruit in orchards and getting themselves rather drunk in the process. Thieving behaviour may even be tolerated – these giants are big money for tourism. However, in this particular context, such interactions are becoming more and more problematic. In this area, as the human population grows, human-elephant interactions also increase.

    Mamboleo went to this area to ask local people their thoughts about these interactions. Using interviews and questionnaires in local languages to ensure clear messages, they found that 88% of those asked thought these human-elephant interactions were on the increase. Furthermore, 79% of respondents reported these events were most common on farms.

    This in and of itself is not necessarily an issue. Local people had described the elephants as generally ‘docile’ and can even be safely approached to within 50 m. In the past, farmers have sometimes been able to simply scare elephants away themselves using traditional techniques, such as patrolling and fencing. Elephant ‘friendliness’ has even been suggested in other parts of Africa, with some suggesting elephants are going as far as to domesticate themselves. However, now, elephants are beginning to ignore these scaring techniques, some becoming bolder and potentially more dangerous.

    How is this affecting people?

    You can begin to see how conflicts between elephants and humans are likely to grow, with 32% of people thinking that elephants will react to seeing a person by killing them, and guarding crops being a main way for these people to protect their livelihoods. And for another large minority, 42% of those asked, they experienced elephants simply continuing to eat their crops in the presence of humans. Evidently, these people don’t have effective tools to deter elephants and protect their farms.

    Extreme measures: what to do next?

    We can see how people would be having a hard time with their elephant neighbours here. But what about the elephants?

    Elephants are protected in Tanzania. The people of Bunda know this. However, desperate times sometimes call for desperate measures. Therefore, occasionally, when an elephant is raiding crops, people may turn to lethal measures. Whilst few people who were interviewed list this as a response to seeing elephants raiding crops, Mamboleo raises the valid point that this number could be higher. Local people know that there could be consequences of authorities finding that illegal elephant kills had taken place in the Bunda region.

    Elephants & mice – really that different? Image by GlobalP from iStock

    This may seem like a drastic response. However, killing pests such as rats, rabbits and mice that eat crops in NZ doesn’t seem so drastic, does it? Of course, this is a very different situation – elephants are native to this area, and are endangered and protected. But this comparison does make you realise that wanting to kill the problem can be a fairly universal response.

    Mamboleo notes that cheap responses can be turned to in the absence of timely support from conservation authorities…so what can be done about that?

    Well, there are some cool things being done across Africa to help with these conflicts. For example, do you know that elephants are scared of bees? Who’d have thought. Some projects actually exist to build bee hives around fences to keep elephants away, and this seems to work pretty well. It also turns out that elephants don’t like spicy food – so chilli can be used in a similar way.

    Image by Kengee8 on Wikimedia Commons: Example of elephant-bee fence

    More ideas, such as this would, be very useful to help in these situations. Answering questions such as when are elephants most likely to visit the farms may also be helpful for targeted responses, Mamboleo says.

    Knowing how people feel, how they’re responding to the situation, and what they need to do to help them resolve the situation for the best outcomes for people and wildlife is a great first step here. That’s the valuable context needed to now take the next steps and make solutions that will work. Especially when we can’t just stomp on the problem!

    This article was prepared by Master of International Nature Conservation student Sally Sinclair as part of the ECOL608 Research Methods in Ecology course.