Is Nemasys harmful to bumble bees?

Recent study finds consumer biological control lethal to bumble bee Bombus terrestris in laboratory tests

For many years, gardeners and horticulturists have been using biological control products as a means to eradicate garden pests such as weevils, carrot root fly, thrips and slugs. Many gardeners, including myself, have used these products as a more natural pest control over ‘nastier’ chemical alternatives, but a recent study has shown that these seemingly harmless nematodes could pose a threat to the invertebrates gardeners do like to see and actively encourage – such as bees.

Scientists at Liverpool John Moores University, found that entomopathogenic nematodes in two Nemasys products; ‘Grow Your Own’ and ‘Vine Weevil Killer’ were lethal to the bumble bee Bombus terrestris in controlled laboratory experiments. Results showed high mortality in bees exposed to soil containing nematodes from each of the products. These products are both currently widely available and largely unregulated.

Entomopathogenic nematodes are a parasite, causing death in their hosts through an association with bacteria. Juvinile nematodes are infected with bacteria in the soil then seek and enters it’s host, such as a weevil or moth larvae. The bacteria causes septicemia and kills the host, providing a food source for the nematodes before they proliferate, sending more infected parasites out to find their next victim.

This study has highlighted the potential threat that these methods of biological control could have on our wild bee species, especially those such as Bombus terrestris in which the queen often overwinters under the soil. Worryingly, due to the delay between infection and mortality, if the nematodes are able to proliferate in the dead bees, there is a risk the whole colony could become infected.

Further field research is definitely needed into the safety of available biological control products on non-target species, and the effect that such products have on species outside of the laboratory.

The full article can be found here  in the open access journal PeerJ. Thank you to Steve Head from the Wildlife Gardening Forum for sharing this in the latest newsletter.

-Larissa

Header photo taken in the Natural History Museum’s Wildlife Garden.

Gathering inspiration

The summer holidays have been here for a few weeks already and it’s been quite busy. So busy the garden has become slightly overgrown and neglected. When I went on maternity leave I had envisioned lots of free time to lay in the sun and read books, potter in the garden become a lady of leisure. I was very wrong, and with the eldest off school as well, the garden has definitely taken a backseat.

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The Garden before the summer holidays – relatively tidy!

At the beginning of the holidays the kids and I spent a week away in Norfolk visiting friends and family leaving my partner in charge of the garden. While we were away it gave me a chance to pinch a few ideas and get some inspiration from other people’s gardens. My Dad has recently become quite keen on attracting wildlife to his garden and had added a few insect hotels since our last visit, one of which was being used by a leaf-cutter bee.

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A couple of holes have been blocked off with vegetation – suggesting a leaf cutter bee has been busy.

I was also quite impressed with my Dad’s use of pots in their small garden. Without the pots, there wouldn’t be nearly as much colour. A great idea for a rented garden, especially as the plants are easy to take with you if you need to move. He even had a pot with wildflowers which the bees were enjoying. I picked up a box of all white wildflower seeds at hampton court which I am saving for next year. I was going to sow them into the flower border out the front to create a white garden, but I think I might sow them in a pot. This also might protect them from the slugs too.

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Wildflowers grow in the pot below an ornamental tree

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A nice arrangement of pots can bring splashes of colour or year-round foliage and structure

We also went to visit my partner’s mother who has a beautiful cottage garden, as well as a vegetable patch. The flower beds are gorgeous and look like they belong in a Gardener’s World feature. I also love that there are surprises around every corner; a hedgehog house, and old wheelbarrow filled with plants, raspberries and blueberries hidden in the hedgerow and magnificent tomato plants in the greenhouse! The tit boxes were used this year and so were the bat boxes – but by tits too! Looking at the veg patch also made me realise a mistake I had made with my own at home – I hadn’t grown enough peas!

These flower beds have inspired me to extend ours for next year

These flower beds have inspired me to extend ours for next year

Blue tits using their nesting boxes earlier in the year

Blue tits using their nesting boxes earlier in the year

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The Vegetable patch – peas protected by netting earlier in the year. By the time we visited they were doing really well.

 

When we got home I was please to find the garden not only alive – but thriving. Having had quite a few days of rain the vegetables had exploded and everything was doing really well. Lots of different plants had also flowered including the purple loosestrife Lythrum salicaria (one of my all-time favourites) and teasel Dipsacus fullonum, both growing by the pond.

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The vegetables had grown a lot while we were away

The vegetables had grown a lot while we were away

Bees love teasel

Bees love teasel

As August has progressed, much of the time in the garden has spent harvesting the crops, but more on this later.

One final note – while we were away my partner spotted what we are pretty sure was a silver-washed fritillary in our garden. A first record for us and one I have yet to see myself.

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5 Easy Ways to Help Pollinators in your Garden

For Pollinator Awareness Week here’s a quick guide on ten ways you can help pollinators in your garden whether you rent it or not.

1 – Plant as many different pollinator-friendly flowers as you can

Variety is key. The more different flowers you plant, the more likely you will attract a range of different pollinators. For example, studies have shown that bees have gone to marjoram flowers, whilst butterflies preferred Bowles mauve. When you are out take note what plants are buzzing with bees, hoverflies and butterflies and remember that there are many more plants out there than buddleia to attract these beauties!

Bees love alium flowers too

Bees love alium flowers too

2 – Aim to have flowers from early spring to late summer/early autumn

By having flowers in your garden throughout the season you will be providing food for the early pollinators as well as the ones still taking advantage of the milder autumn days. Primroses Primula vulgaris are a great plant for spring pollinators whilst ivy Hedera helix is an excellent late-flowering plant.

Native primroses are edible too!

Native primroses are edible too!

3 -Leave the lawnmower in the shed

By leaving the grass to grow long (or even just a little patch) will help to attract butterflies such as meadow browns, speckled woods and ringlets who use grasses such as cocksfoot Dactylus glomerata as a larval food-plant. Grass also provides a home for many other invertebrates too as well as creatures such as frogs, toads and slow worms. I keep finding many teeny froglets in our long grass.

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Our patch of long grass at the back with a mown path (and campfire!)

4 – Plant a mix of native and non-native plants

Many of our pollinators have adapted to use our native plants either as a nectar source or as a larval food. Plants such as the ragwort Senecio jacobaea attract specialist species such as the cinnabar moth, whilst there are many native plants used by our butterflies to lay their eggs on and feed the caterpillars. A couple of good lists of these plants can be found here and here.

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Suspicious eggs (probably large white butterfly) found on the kale growing in our veg patch. Turns out I am the only one in the family who likes kale, so I’m happy to share it with the butterflies!

Caught in the act!

Caught in the act!

I just looked out of my bedroom window to see this gatekeeper on the ragwort. Luckily it stuck around for me to take a photo!

I just looked out of my bedroom window to see this gatekeeper on the ragwort. Luckily it stuck around for me to take a photo!

5 – Make a bee hotel

Bee hotels have become very popular and can be found in lots of stores and supermarkets which is great. However, they are also very easy to make too. It is really as easy as drilling some holes in wood or filling an empty bottle with bamboo. The key thing to remember is to make sure that the holes or bamboo are at least 10cm long. There are lots of great tutorials online such as this one or this one.

Made by my daughter from common reed and a plastic bottle

Made by my daughter from common reed and a plastic bottle

Another bee hotel made by my daughter, no visitors in this one yet.

Another bee hotel made by my daughter, no visitors in this one yet.

Add any of your own tips in the comments below!

Choosing Garden Plants for Pollinators; Natives or Non-natives?

This week (13th – 19th July) it is ‘Pollinator Awareness Week‘ and a perfect time to discuss the different plants that we can, as gardeners, provide for pollinators in our own little patches of green space. I’d like to to so by looking into some of the different native and non-native plants in my own garden which are often alive with the buzz of busy bees.

Why do we need to help pollinators? Pollination of our crops is an essential ecosystem service that we just can not do without and pollinators do this job for us for free. The term ‘pollinator’ covers a wide range of invertebrates including bees, butterflies, moths, flies, hoverflies and wasps. There are thought to be over 1500 different species of pollinators in the UK.

The most well known and frequently discussed group are the bees of course. There has been a lot of research over the last few years into the notable decline of bee populations with theories ranging from habitat loss, climate change and the use of neonicotinoids – a group of insecticides thought to effect bees – however, other pollinator groups are also suffering from similar environmental and anthropogenic stressors, so by adding a range of plants to suit different pollinators is in my opinion, a really good start in helping these important creatures.

Lungwort flowers early and the bees loved it this year!

Lungwort flowers early and the bees loved it this year

It has long been debated whether you need to plant native plants and have a wild and ‘weedy’ garden for wildlife or whether you can still attract wildlife with garden exotics.

Studies have found some non-natives to be useless to pollinators because the flowers are either nectar poor, too fussy for the insects to reach the pollen or the flowers are too long for the bees to get their tongues in. The RHS found in their ‘Plants for Bugs’ study that this isn’t the case for all non-natives and that some were as good as, or even better than the native plants chosen. It was at a Wildlife Gardening Forum conference a couple of years back that I heard all about this research and was swayed from being a dedicated ‘native only’ advocate to considering alternative garden plants.

The two plants that really stood out at the time were the native hemp agrimony Eupatorium cannabinum and the non-native garden plant Bowles mauve everlasting wallflower Erisimum linifolium. Both of these plants are excellent for pollinators and for me are definitely on the list of essentials for the garden. My Bowles mauve are awash with insects and also fill a space in my rockery/herb garden on my patio, providing a constant splash of colour throughout spring and summer.

Bowles mauve flowers in tall spikes which can last for the whole season

Bowles mauve flowers in tall spikes which can last for the whole season

Hemp agrimony is a native wetland plant, which is suited to damp areas such as fens or pond margins. It will however also grow in dry areas making it ideal for garden flower borders too if you don’t have a pond. I tried growing hemp agrimony by sowing seeds around my pond last year but had no success which is surprising as this plant can be invasive so be prepared to manage it if you have more luck than me. This year I planted hemp agrimony plugs around the pond but these seemed to be smothered by the other plants and I haven’t had any flower. As a last attempt, I put the final few plugs I had into a basket planter and placed at the edge of my pond. So far they haven’t died and hopefully will flower next year.

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Hemp agrimony

Another non-native plant which I think is an essential is red valerian Centranthus ruber. An introduced species now naturalised in the UK, it is great for pollinators, easy to grow and looks beautiful too.

Red valerian about to flower

Red valerian about to flower

In spring our steps are awash with bellflowers, and these attract so many bees that you can hear them buzzing all day, and they are very pretty. If you have any walls with holes in then these are perfect to fill the gaps.

I love these little flowers

I love these little flowers

My partner introduced me to cosmos; a plant he grew with a lot of success in Canada. Although we have tried for the past few years to grow them, we have never achieved the large bushes he did before. However, we have managed a few smaller plants and this year have decided to grow them in pots as the slugs just can’t seem to resist them. Neither can the bees, and if you keep deadheading them they will continue to produce flowers. When the are finished, allow a few to go to seed and collect them for next year.

This bee went from flower to flower.

This bee went from flower to flower.

When it comes to native plants, my favourites are red clover Trifolium pratense, greater birds-foot trefoil Lotus pedunculatus  and foxgloves digitalis pupurea. These are all great for pollinators and look fantastic too. For me, another important group of plants are native grasses. I leave a patch at the back of the garden to grow long for the grass-loving butterflies and by doing so, we have seen gatekeepers, meadow browns and ringlets this year. Finally, if you can provide ivy Hedra helix then the bees will be grateful of the late pollen supply, whilst the birds will be happy with the late supply of berries!

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Foxglove flowers are perfectly designed for pollinators

This is only a few of the plants we have to attract pollinators but some of my personal favourites. The RHS has done a much better job at coming up with a list of plants here. The key things to consider are to provide lots of nectar and pollen-rich plants which together, flower throughout the season offering this food supply as long as possible. Whether the plants are native or not is really up to you the gardener, as after all – it is your space too!

If you are unsure of whether the plants you are buying are good for pollinators – look for the RHS Perfect for Pollinators logo.

Ragwort – dispelling the myths

Ragwort – Senecio jacobaea is a contentious topic I’ve noticed recently. When ever a photo is posted for identification on different Facebook groups I am following, the comments show a big divide of opinion and the same myths are often used in arguing for its eradication.

For those of you who are unaware of this native plant from the asteraceae family , ragwort is often known for its toxicity to horses and cattle. Some people believe that its toxicity is to be feared and that just by touching it the plant can cause liver failure and so must be removed at all costs – and there has been plenty of media hype to continue this prejudice. However, whilst it is potentially harmful to horses, it also has plenty of benefits to wildlife.

I want to write this because when we moved in last year and the garden was overgrown, there were quite a few ragwort plants in flower around the garden and my first instinct was to go around and pull it all up. I’m glad I didn’t and that I looked into it a little bit, because I later discovered a plant with a few caterpillars of the day-flying cinnabar moth Tyria jacobaeae happily munching away at the leaves. These beautifully distinct larvae with their stripy bodies rely on ragwort as a food plant and without it these critters can not complete their life cycle. Because of the control of ragwort a decline in the numbers of cinnabar moths has been noticed.

Ragwort is also an excellent nectar source for pollinators; bees, butterflies and hoverflies in particular. We had gatekeepers Pyronia tithonus visiting our plants last year which was a new butterfly for me and very exciting. Ragwort is thought to be essential to at least 30 invertebrates, so it really is in my opinion much more of a friend than a foe. This year, I have also planted marsh ragwort Senecio aquaticus around my pond because of how great it is for invertebrates.

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Ragwort control is only really necessary if it occurs in or around a field which is producing hay. This is because ragwort is harmful to horses and they are unable to detect the dried ragwort in hay and the toxicity of the plant remains. Ingestion of dried ragwort can lead to liver failure which is understandably a very good reason to avoid it – although how dangerous it really is is debated given the difficulty in identifying ragwort poisoning as a cause of death. It is also perhaps a good idea to remove it from any grazing paddocks ‘just in case’ even though horses tend to avoid it when it is fresh. We remove it at work when the sheep graze just as a precaution, although I’ve noticed a few plants after they have arrived and the sheep have seemed to avoid them too. It is also worth noting that there is no legislation requiring the removal of ragwort as is often believed. If ragwort is causing a problem then there are powers for an order for removal to be made through the Weeds act 1959, but an order has to be made for this to be enforced.

Ragwort will not harm humans unless perhaps you eat a lot of it. I’ve pulled it up with my bare hands many times with no adverse effects. There is of course the chance that you may be more sensitive to it and for every ten people who are okay with it, there will be one who developed a rash I’m sure.

If you would like to find out more about the truth of ragwort then there is lots of information about it on the internet such as here, here and here. In the meantime, if you find any growing in your garden let it grow and keep an eye out for the cinnabar moth!

“Tyria jacobaeae-04 (xndr)” by Svdmolen – Own work. Licensed under CC BY 2.5 via Wikimedia Commons

The Pond – Part 1: Creating a home for the frogs

I’m going to kick this blog off with a post about my favourite part of the garden; the pond. It’s my favourite for many reasons but the main two are that it didn’t cost us anything to install and it attracts so much wildlife to the garden. I really think that having a pond, no matter how small makes such a difference if you are aiming to attract wildlife.

When we viewed the house last year we were sold when we saw the garden and was told that we were free to do as we like with it (within reason of course!). It was a blank canvas – an overgrown large patch of grass with the woodland behind our house encroaching into the back part of the garden. Perfect.

A blank canvas

We moved in and I was eager to get going. It was June, it was hot and I was pregnant so progress was slow. It took us a while to get around to mowing the lawn as we had to purchase a petrol brushcutter. The grass was so long the flymo couldn’t handle it. Standing by the edge of the garden I noticed that the ground below my feet was springy and squelched. It looked like the rest of the lawn, but something felt different. After a bit of investigating, we found a small pre-formed pond which had been filled with rocks and bricks with grass growing over the top. It had been abandoned and we decided to bring it back to life.

I emptied the pond of bricks, rocks and some of the mud, piling up the soil on the bank for the marginal plants. There was water in the pond still so I left a lot of the mud there thinking that perhaps some of the creatures had survived, especially as i found so many frogs and toads hiding out under the rocks. Also, by leaving in some mud it added an instant pond bed. I wondered whether it would be too rich in nutrients which could cause problems later on and ideally I should have carried out a nutrient test, but I took a chance and left it in (mainly because pulling all the bricks out had worn me out and I was eager to see it finished!).

Unfortunately I had to stop anyway because I managed to put a hole in the side of the pond with my spade. Tip – be careful when using tools to dig or clear a pond, especially if it is made using pond liner – seems obvious doesn’t it! I ordered some pond putty and left the pond alone for a few days.

With the hole fixed, it was time to add some structures for all the frogs and toads to get in and out and to hide in. I used the rocks to build up one side of the pond and added a couple of logs. Ideally a wildlife pond should have a shallow end or a gradual transition from the bank to the pond. This is achievable with a pond-liner but not as easy with a preformed pond. It’s also about working with what you have too when renting.

We were lucky to have a beautiful large fern growing next to the pond. My partner has a good eye for aesthetics and so to compliment the fern he suggested we piled up more rocks around the edge of the pond and under the fern. By this point, we already had a resident living in the pond. A large fat frog had moved in and every now and then popped his head above the water to check out his new digs.

Finally, the last stage was to add the plants. I planted lesser spearwort Ranunculus flammula, soft rush Juncus effusus, and purple loosestrife Lythrum salicaria in the pond itself in basket planters, and ivy-leaved duckweed Lemna trisulca and a water soldier Stratoites aloides in the middle.

Around the edge I planted a few garden plants I brought with us from our old house including purple toadflax Linaria purpurea and the following native marginal plants:

  • silverweed Argentina anserina
  • ragged robin Silene flos-cuculi
  • water figwort Scrophularia auriculata
  • teasel Dipsacus fillonum
  • marsh ragwort Senecio aquaticus
  • marsh woundwort Stachys palustris
  • rosebay willowherb Chamerion angustifolium – seeds
  • great willowherb Epilobium hirsutum – seeds
  • hemp agrimony Eupatorium cannabinum – seeds
  • Common fleabane Pulicaria dysenterica – seeds.

One the plants were in, it was just a case of letting nature take over. We were surprised just how quickly the wildlife found it. The foxes would come to drink from it each evening, dragonflies laid their eggs in it and bats came to feed on the midges emerging from it. By Autumn, the pond had established and we couldn’t wait to see what arrived in spring, but that’s a whole other blog post.

Autumnal pond