The secret agents protecting our crops and gardens


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Lacewings are fantastic predators and are easy to rear and release.
Dan Papacek & Tony Meredith (Bugs for Bugs), Author provided

Lizzy Lowe, Macquarie University and Manu Saunders, University of New England

Insect pests cause a huge amount of damage to crops globally. In Australia alone, pests are responsible for around A$360 million of crop losses a year. Controlling pest outbreaks is crucial for food security and human health. Since the 1940s, our primary defence against crop pests has been synthetic pesticides. But using pesticides comes at a huge cost.

Not all bugs are bad!

Bees, flies and butterflies help to pollinate our plants. Decomposers like beetles and worms help break down wastes and return nutrients to the soil. Meanwhile, predators and parasites help control the species that are pests. One of the biggest environmental problems with pesticides is that they can affect these beneficial species as well as the pests they’re targeting.

Predatory insects and spiders control pests with none of the health and environmental risks of chemicals. So when we kill these species with insecticides, we are shooting ourselves in the foot.




Read more:
The real cost of pesticides in Australia’s food boom


Losing insects also has flow-on effects for larger animals that rely on them for food. Because invertebrates have such important roles to play in our environment, losing them to insecticides can completely change how ecosystems function.

An alternative to insecticides

Biological control (or biocontrol) relies on “secret agents” – the natural enemies (predators and parasitoids) of pests that live freely in the ecosystems around us.

There is a huge range of predatory invertebrates that eat pests. They include dragonflies, preying mantids, beetles (including ladybugs), lacewings, spiders, mites, wasps, and even some flies.

Parasitoids, meanwhile, are insects that lay their eggs in the bodies of other invertebrates. Their larvae extract nutrients from the host during their development, which ultimately kills the host. Wasps are best known for this strategy but there are also parasitoid flies and beetles.

Lady birds are voracious predators ready to eat pests in crops and gardens.
Manu Saunders

Predators and parasitoids are useful because they use pest insects, like caterpillars and aphids, as food to reproduce and grow their populations. We walk past many of these hard working agents every day without knowing it.

One biocontrol method that gardeners and land managers use is called augmentation. This simply means raising lots of live individuals of particular natural enemies, like ladybirds or wasps, and releasing them into an area to control pests.

Alternatively, gardeners might change the local environment to encourage these natural enemies to move in on their own. They might include natural insectariums or planting different types of vegetation to encourage diverse invertebrate communities. There is increasing evidence of the success of these strategies in organic farming so we should be thinking about using them more broadly.

Selecting your insects

If you want to release biocontrol agents, you need to choose them carefully, just like human special agents. Like any introduced plant or animal, there is a risk that good bugs could become pests (if they feed on the wrong insects, for example).

Selecting biological control agents requires close collaboration between managers, skilled entomologists and other scientists. For each new species, they identify the pest and some potential predators. They look at the predator’s life cycle and resource needs, and consider how it interacts not just with pests, but with other insects too. If agents are coming in from overseas, they also need to be cleared by government biosecurity.

Parasiotid wasps, lacewings, predatory mites, ladybird beetles, and nematodes are all common biocontrol agents. These species are relatively easy to raise in large numbers and work well when released into the field. Spiders are also a really important predator of many pest insects, but they’re often overlooked in the biocontrol game because they are harder to breed – and for some reason people don’t always like releasing large numbers of spiders.

Many biocontrol agents are enemies of pests in general, preying on aphids, caterpillars and fruit flies alike. It’s important to have generalists around for every day pest control, but sometimes a more targeted approach is needed. This is when specialised predators or parasitoids come in. These are species that only target specific pests like leaf miners, beetles, scale insects or spider mites. This way the target pest can be managed with no risk of the parasitoids accidentally attacking other beneficial invertebrates.

Raising good bugs

It’s very exciting to get live insects in the mail!
Lizzy Lowe

Once a biocontrol agent has been selected, greenhouses or lab facilities start raising a large population. This is an emerging market in Australia, but there are already a number of companies in Australia who specialise in rearing biological control agents.

This is a tricky job because demand for the product is variable and is not easy to predict. Warmer seasons are the peak time for most pests, but problems can arise at any time of the year. In most cases the biocontrol company will maintain breeding colonies throughout the year and will be ready to ramp up production at a moment’s notice when a farmer identifies a pest problem. Each company usually provides 10-20 different biocontrol agents and are always looking for new species that might be useful.




Read more:
Birds, bees and bugs: your garden is an ecosystem, and it needs looking after


When it comes to getting the agents to the farmers, the bugs can be shipped as eggs (ready to hatch on arrival), or as live adults ready to disperse and lay their own eggs. The packages are express posted in boxes designed to keep the insects cool and safe.

Once the farmer or natural resource manager receives the bugs, applying them is quite simple. The secret agents are released among the crops, usually by hand, but in some special cases they may be airlifted in via specialised drones!

Drones can be used to deploy biological control agents.
Nathan Roy (Aerobugs)

It’s important to monitor the pests and the biological control agents after release to check that the agents are working. Some farmers are happy to do this themselves but most biological control companies have experts to visit the farms and keep an eye on all parties.

Can I use good bugs in my garden?

The ConversationIf you have a problem with a pest like aphids it is possible to buy predators such as ladybirds or lacewings to quickly deal with the problem. But for long term pest control, there are probably already some natural enemies living in your garden! The easiest and cheapest way to help them is to put the insecticides away and ensure your garden is a friendly environment for secret agents.

Lizzy Lowe, Postdoctoral researcher, Macquarie University and Manu Saunders, Research fellow, University of New England

This article was originally published on The Conversation. Read the original article.

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Why Iceland is set to resume whaling despite international opposition


Julia Jabour, University of Tasmania and Rachael Lorna Johnstone, University of Akureyri

After a two-year pause in the fin whale (Balaenoptera physalus) hunt, Icelandic whaling company Hvalur hf. will resume whaling this summer, with a government-issued quota.

Two factors help explain why Iceland and other countries are determined to hunt whales in defiance of international disapproval. The first is demand for the product; the second is Iceland’s interpretation of international law on whaling.

Whale meat and its buyers

Demand for whale meat appears to be stable in Iceland. Many reports suggest that Icelanders no longer eat whale meat in great numbers. Yet minke whale (Balaenoptera acutorostrata) meat is readily available in supermarkets and sells for the equivalent of A$29.80 per kilogram.

Much of this is imported from Norway, indicating that there remains a strong domestic demand that is not being met by Icelandic whaling, and suggesting that it is not just Iceland’s growing number of tourists who want to eat whale meat. The fin whale hunt, in contrast, is intended primarily for export to Japan.




Read more:
A necessary harvest: it’s time to allow Japan to kill whales


Fundamentally different rationales

The second, and far more complex, factor to understand why pro- and anti-whaling nations differ is that they have different interpretations of the basic purpose of the international regime to protect whales.

The International Convention for the Regulation of Whaling has banned commercial whaling. In line with the norms of international law, only parties to the whaling convention are obliged to observe this ban.

Iceland was an original member of the International Whaling Commission (IWC) and accepted the temporary halt on commercial whaling, which came into effect in the mid-1980s.

However, Iceland left in 1992 after the IWC refused to authorise quotas, even when scientific evidence indicated that controlled commercial whaling would not threaten the survival of the targeted species. The zero quota on all whale species, irrespective of their conservation status, has been criticised by several other countries, including Norway and Japan, as non-scientific.

Iceland later re-adhered to the convention, but with a reservation to the temporary ban. Iceland’s reservation included the statement that:

Under no circumstances will whaling for commercial purposes be authorised without a sound scientific basis and an effective management and enforcement scheme.




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Could ‘whale poo diplomacy’ help bring an end to whaling?


Iceland argued that the ban had become a permanent one and that this was contrary to the object and purpose of the convention, which was initially about regulating whaling rather than prohibiting it.

Essentially, Iceland and other pro-whaling countries reject arguments that the object and purpose of the convention has evolved into the preservation of whales rather than their conservation for sustainable use.

Iceland also objects to the ongoing situation whereby a scientific procedure adopted by the IWC to assess stocks and the potential for sustainable whaling was not followed up by the promised adoption of a non-scientific (political) scheme that would allocate actual quotas. Because of majority voting in the IWC, this standoff has created a persistent stalemate between pro- and anti-whaling countries.

Iceland’s current position

After a couple of years of heated discussions among members, Iceland was readmitted to the IWC. However, other countries (including Australia) still object to its reservation, meaning there is no universal acceptance of Iceland’s position.

If Iceland were cast out of the IWC, then it would not be bound by the convention at all. However, it would not be able to export to other IWC members, including Japan.

The whaling firm Hvalur hf. intends to resume its commercial hunt for fin whales in June. Quotas have been awarded consistently since 2006, but in 2016 and 2017 the company did not use them, citing doubts about profitability because of difficulties reaching target markets (especially Japan). A couple of shipments of whale meat were made recently (one in 2015 and one in 2016), using the Northern Sea Route to avoid customs delays and, potentially, protesters at Dutch harbours. The pause merely reflected the commercial reality of the time.

For 2018, Fiskistofa (the Directorate of Fisheries) has set a quota of 161 fin whales, with an additional 30 carried over from the unused 2017 quota. Although the IUCN listed the fin whale as endangered in 2008, there are no concerns about sustainability since the Icelandic quota represents 0.9% of the lowest estimate of fin whale numbers off the Icelandic coast.

The harvest is primarily destined for the Japanese market, which had been difficult to access for a number of reasons, including the effects of the 2011 tsunami, which disrupted processing facilities.

Minke whales are hunted by the company IP-Útgerð ehf., mostly for Icelandic consumption. In 2017, only 17 were taken. This was well within the quota of 269, although numbers were higher in previous years. The IUCN assesses the status of minke whales as “least concern”.




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Iceland is making no efforts to stop whaling and never has. Unlike Japan, Iceland does not claim that its whaling is for scientific research, which is authorised under Article VIII of the whaling convention. It agreed to the temporary ban in order to gather scientific evidence that was supposed to protect the whaling industry in the medium to long term.

Iceland has never had sentimental ideas that whales should not be hunted. Nevertheless, the country has two whale sanctuaries, in Faxaflói (the bay around Reykjavík) and in the north, to support the tourism and whale-watching industry.

The ConversationWhaling might not be popular in some countries – and indeed some Icelanders would like to see it end – but foreign interference is viewed with suspicion and is more likely to make the traditionalists who support the whale hunt dig in their heels (and harpoons) still further.

Julia Jabour, Senior Lecturer, Ocean and Antarctic Governance Research Program, University of Tasmania and Rachael Lorna Johnstone, Professor of Law, University of Greenland, University of Akureyri

This article was originally published on The Conversation. Read the original article.