Bee on a leaf

How to Get Rid of Leafcutter Bees

Hemera Technologies/Photos.com/Getty Images

You can usually tell when leafcutter bees have been around by the small, round circles they make in the leaves of plants. Seldom making a nuisance of themselves, leafcutter bees only lightly sting when they are handled. The little damage they might do to plants is minimal since they are solitary and do not collect in hives. These bees are difficult to control since insecticides are ineffective against them. Despite being beneficial to pollination, you may want to discourage them to stay away from your home by encouraging them to live in the outer areas of your yard.

Place two drops of white glue or sealing wax about the size of a pencil eraser on the end of any plants you may prune that have thick branches, such as rose bushes. This prevents the leafcutter bees from making nests in the open holes provided by pruning.

Cover your plants with a loose netting if you see any evidence of leafcutter bees.

Remove any areas where it appears the leafcutter bees have built a nest. Look for sawdust pushed out of holes in rotting boards. Either dispose of the nesting area, or move it to an area at the outskirts of your yard so the bees can still breed and pollinate your flowers, but won’t bother anyone.

Make a simple board for the bees to use as a nest to encourage them to unused areas of your yard. Drill 3/16-inch to 1/4-inch holes in any type of wood or boards you have access to, and place these boards in a little-used area.

Plant large-stemmed plants, such as elderberry or raspberry, around the boarder of your yard, or in an area of little use. The plants may encourage the leafcutter bees to make nests inside the branches.

Thorny problems: how can I deter leaf-cutting bees from devouring my bay trees?

Even if I am wrong, I would still give the same advice: do nothing. The trees won’t suffer, and you will have the satisfaction of knowing that your garden is peaceful enough for these charming bees to consider it home.

•Helen Yemm on protecting your tree again bay sucker

Dealing with a hangover

Q After very little seriously frosty weather this winter, Helichrysum petiolare, pot marigolds and lime-green-leaved golden feverfew are just three leftovers from last summer that are worrying Beth Adams, who has a small, new garden in a West Country town: the marigolds have not stopped flowering all winter, and although their leaves now look dog-eared, there are a few new flower buds forming. The helichrysum only stopped growing around Christmas and now, while some of the old leaves are a bit grey and forlorn, it looks as though it is about to start shooting off in all directions again. The feverfew carries some rather battered little white daisies on tall woody stems. So what now, Beth asks? Should she cut them back, leave them alone or chuck them out and start again?

A The helichrysum (a scrambling, felty, grey or lime-green foliage plant sold along with bedding plants in the spring as a useful annual filler container or front-of-border filler) will certainly go another year if it gets through our winter, but is much improved if it is cut back quite severely.

However, it is not reliably hardy and despite a recent sunny spring flourish, a sharp frost may yet see off Beth’s plant. For this reason I think she should control the urge to prune out the tattered remains of last year’s shoots for a bit longer, and when she does cut them back, she shouldn’t cut into the lowest woody parts, but leave plenty of greenery from which it can produce this year’s brand new, long, soft growth.

The pot marigolds, despite the brave show of flowers, should be dispatched to the compost bin forthwith. Even if they are de-dog-eared, they will flower and burn themselves out very quickly. I have no doubt that a million and one marigold seedlings will pop up where they were, and will give Beth a more than adequate zap of orange from about June onwards.

The feverfew is a short-lived perennial, and if the stems with the rather worn-out flowers are cut right back, the plant will once again provide a pleasing hummock of ever-bright foliage and will then go on to flower again on brand new stems this summer.

Seedlings of golden feverfew are easy to recognise because of their colour, so a few young plants can always be earmarked as potential replacements for worn-out ones.

•The top ten all weather perennial plants

Sour soil

Q We are about to demolish a 25-year-old garden shed and plan to plant an apple tree in the exact spot where the shed was. What do you recommend we should do to the soil which has been under concrete slabs and in darkness for such a long time?

Nick Taylor, London


Improve soil left under concrete with compost before planting (Alamy)

A When you lift the concrete slabs you may be quite surprised to find a lot of earthworms enjoying the constant damp that they have provided despite the fact that there would appear to be little there in the way of plant debris to sustain them. The presence of worms, and the fact that the soil will also be weed and weed-seed free, are all to your advantage.

What you must do, before you return the soil to cultivation and plant a tree, is to improve it by digging in masses of organic matter in the form of well-rotted compost or manure: spread a layer at least 4in (10cm) thick over the area and turn it in to the topsoil to at least a spade’s depth, digging slightly deeper and adding a couple of fistfuls of blood, fish and bone in the square metre that will be home to your apple tree. Ideally you should then let the soil settle for a week or two before you go ahead and plant. If your apple tree is bare-rooted, plant it using Rootgrow (mycorrhizal fungi processed for gardeners that greatly aids plant establishment).

•Our guide to making your own compost

Saving young Hercules

Q Could you give any help please with a 3ft-high stone statue of a boy with a snake that has always been know in the family as “Young Hercules”?

It has aged naturally outside with algae and lichens but I am cautious of “attacking” any of the small areas in need of cleaning and mending.

Julia Barnett, Devon


Algae and lichen are common on old statues (National Trust Images/ Arnhel de Serr)

A I was happy, a few weeks ago, to give readers my two pennyworth on how to quickly age glaringly new garden features, but to offer advice here would take me into unknown territory. So I called Steve Clark, general manager of Chilstone, a company that makes and restores stone statuary, balustrades etc, for some relevant pointers.

First the commonsense bit: once stonework and statues start to deteriorate, frost is the big enemy. But even without any restoration work, they will last a lot longer if they are covered in winter so that frost doesn’t penetrate cracks, making matters rapidly worse.

Then Steve got more technical: if the state of young Hercules has got beyond this, you could try a little careful reconstruction. Crumbly parts can be gently scraped away and rebuilt using a special pointing mix that Chilstone can supply. This will of course look bright and new to start with, but can be dulled down with a product called Liquid Weather, or painted with natural yogurt that will fairly quickly encourage the spread of existing algae.

There is also a product called No-More Nails (available from DIY stores) that is useful for mending breakages (to limbs, snakes etc) in conjunction with careful drilling and pinning.

Steve said he would be happy to talk you through things. I wonder if he knows what he has taken on.

•The ten best places to see garden sculpture

Leafcutter bee. Photograph by Sam Droege, USGS

I have gotten several phone calls about leaf notches on redbud trees. This characteristic damage is caused by leaf cutter bees in the genus Megachile. Leafcutters in Megachile and other genera are solitary bees that nest in hollow grass stems or other pithy stems they can easily excavate. They will also make nests in existing holes in wood but do not bore their own holes in wood (those are carpenter bees). Adult leaf cutter bees can be about as big as honey bees. They cut out round pieces of leaves to line their nests and pack in between brood cells. Damage by leaf cutter bees is general insignificant. In this area they seen to prefer redbuds but will cut other plants including maples and roses.

Leaf notches cut by leafcutter bees on a redbud tree. Photo: S.D. Frank

I have never seen more than a few leaves damaged on any particular tree and the damage is not enough to affect tree growth or health. Leafcutter bees are important pollinators of many native plant species and fruit and vegetable crops. In many urban and rural areas the plant species bees use for nesting have become less common than they used to be. Thus, bees cannot find suitable reedy grasses of tree holes to nest in. You can help conserve leaf cutters and other bees species by creating nest tubes. These are fairly simple contraptions that just require tying together bundles of reeds or drilling holes in blocks of wood to replace the nest substrate that used to be provided by plants. Visit April Hamblin’s other recent blog post for details. April is conducting research on how urbanization and urban warming affect bee communities, individual survival, and nesting. Visit her guest blog on yourwildlife.com or project description for details of her work.

Leafcutter bee nest with cells divided by rolled up leaves. Each cell holds a pollen ball and one egg to develop into an adult bee one day. These bees are also solitary. Photograph by Joel Gardner, Wild Bees and Building Homes.

Overall leafcutter bees are far more beneficial than harmful (they also rarely sting unless handled). My suggestion is to tolerate the subtle damage these bees cause and use it to teach other people about bees. If you are growing plants for sale you may not be able to do this but I rarely see leaf cutting on nursery stock.

MS student April Hamblin contributed to this post.

LEAFCUTTER BEES (Megachile)

Aussie Bee > Native Bee Photo Gallery > Leafcutter Bees

Videos of Leafcutter Bees

The amazing handiwork of the Leafcutter Bees makes them one of the most fascinating bees in Australia! The Leafcutter Bee snips a neat circle or oval from a leaf. She will use these leaf pieces to weave tiny cradles for her eggs inside her nest burrow.

Our Leafcutter Bees are in genus Megachile and range in size from about 6 to 15 mm. They belong to the family Megachilidae and are found all over Australia.

Erica Siegel of Queensland kindly contributed the following amazing photographs about Leafcutter Bees in action:

Above: Erica Siegel captured this fantastic close up shot of a Leafcutter Bee in the process of snipping a piece from a leaf! Notice this bee’s powerful mandible or jaw that the bee uses for cutting the leaf pieces. Leafcutter Bees carry pollen back to their nests by packing it on the array of stiff bristles that you can see here underneath the abdomen.

Above: Another beautiful shot by Erica Siegel of a Leafcutter Bee in action. Leafcutter bees use these leaf pieces to weave cells for their young inside their nest burrows.

Above: the characteristically uniform cuts made in soft leaves by Leafcutter Bees.

“Peter O’ captured this furry Leafcutter Bee snipping a leaf piece for her nest:

Above: Leaf cutter bees grasp the leaf pieces with their legs to carry them back to their nests.

Another wonderful Leafcutter photograph contributed by ‘Peter O’:

Above: notice the Leafcutter’s characteristic thick pad of bristles under the abdomen.

The Leafcutter Bee always cuts extremely neat circles and ovals, unlike caterpillars which leave irregular holes in leaves.

They take the pieces of leaf back to their nests which are in burrows in the ground or in a narrow crevice. There they weave the leaf pieces into a cylindrical brood cell for their young.

Above: this neat brood cell was woven by a Leafcutter Bee for her young in her nest in a hollow bamboo tube. She stocked the cell with nectar and pollen, before laying a single egg in the cell and sealing it up.

Above: this Leafcutter Bee is snipping a circular piece from a rose leaf. This excellent photograph was contributed by Shirley Woods.

Whilst rose leaves are one of the Leafcutter’s favourites, other soft leaves that they like to use include Buddleja (above) and wisteria.

Above: Thank you to Noah Hunt for this wonderful action photograph of a Leafcutter Bee returning to her nest in a limestone wall with a pink leaf!

Erica Siegel’s beautiful photos of Leafcutters and Resin Bees.
More photos of Leafcutters and other native bees.
Videos of leafcutter bees.

Leafcutter Bees: The mystery behind circular holes in leaves

There are about 27 species of leafcutter bees in Australia. They are found in all states in both coastal and drier inland areas. They range in size from 6-15 mm and most are black with white or orange-gold stripes of hair on their abdomen. They carry dry pollen on special bristles under their abdomen.

The introduced African Carder Bee looks very similar to native leafcutter bees, but has hairless, white abdominal stripes.

Leafcutter bees and resin bees look similar but leafcutter bees can usually be distinguished by their relatively wide abdomen, which tapers into a point while resin bees have a narrower, cylindrical abdomen. Leafcutters alight on flowers with their wings spread, while resin bees fold their wings.

Very similar to leafcutter bees is the introduced African Carder Bee. It is 5-8 mm long and has white abdominal stripes that lack hairs, unlike the hairy bands on the native leafcutter bees.

Leafcutter bees cutting out soft leaves to construct their nests.

Bee watchers often first discover leafcutter bees when they notice rows of neat circular or elongated cuts on the edges of some leaves in their garden. Leafcutter bees use the discs of leaf to build nests. They particularly like the soft leaves of desmodiums, sennas, roses, ginger, bauhinia, buddleia and bananas. They very quickly snip the leaf and then carry it in between their legs to their nest site.

Leafcutter bees may nest in many different spaces such as existing holes in timber or masonry, hollow stems, gaps in door/ window frames, old folded towels left outside, rock walls and outdoor furniture. They may also use artificial bee nests consisting of varies size holes drilled in untreated hardwood and/ or bundles of hollow stems (e.g. bamboo), hung in trees. Each female builds her own nest. The cut leaves are used to make a tube as a nest for the eggs or to line an existing hole with it. The leaves are cut in various shapes, round and elongated, to suit the construction of the cell for the egg. The cell is then stocked with a mixture of nectar and pollen in which the leafcutter bee lays her eggs.

This leafcutter bee is covered in pollen showing the valuable role native bees play as pollinators, dropping pollen from flower to flower.

She lays female eggs first and the last couple are male. More circular leaves are cut to close off the cell. She then moves on to constructing the next cell until the hole or tube is filled with cells. The hole is then plugged with rough leaf cuttings.

When the eggs hatch, tiny larvae eat the provisions and, when fully grown, they spin silky cocoons and then develop into pupae, finally emerging as adult bees. Male eggs mature earlier and the adult male bee breaks open the nest to emerge first. Immature bees may hibernate through winter and finish developing into adults the next spring.

This leafcutter bee nest (total length about 6-8 cm) shows the neatly layered leaf discs.

You can attract native bees to your property by providing a diverse range of native leafy plants, creating small rock walls, leaving hollow branches and fallen timber on the ground and, possibly, consider constructing a small native bee wall.

Dollin A, Batley M, Robinson M & Faulkner

B (2000) Native Bees of the Sydney Region:
A Field Guide. Australian Native Bee
Research Centre.

Personal communication – Dr. Michael

Batley, Australian Museum; Dr. Ken
Walker, Victoria Museum and Dr. Anne
Dollin, Australian Native Bee Research
Centre. www.aussiebee.com.au

Article and photos by Erica Siegel
Native bee enthusiast

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Learn About Leaf Cutter Bees

By Stan V. Griep
American Rose Society Consulting Master Rosarian – Rocky Mountain District

Do you ever see half moon-shaped notches that appear to have been cut out of the leaves on your rosebushes or shrubs? Well, if you do, your gardens may have been visited by what is known as the leaf cutter bee (Megachile spp).

Information About Leaf Cutter Bees

The leaf cutter bees are seen as pests by some gardeners, as they can make a mess of the foliage on a favorite rosebush or shrub by making their half moon shaped precision cuts out of the leaves. See the photo with this article for an example of the cut outs they leave on the leaves of their plants of choice.

They do not eat the foliage

as pests such as caterpillars and grasshoppers will. The leaf cutter bees use the foliage they cut out to make nest cells for their young. The cut piece of leaf is formed into what might be called a nursery chamber where the female cutter bee lays an egg. The female cutter bee adds some nectar and pollen to each little nursery chamber. Each nest cell looks a bit like the end of a cigar.

Leaf cutter bees are not social, like the honeybees or wasps (yellow jackets), thus the female cutter bees do all of the work when it comes to rearing the young. They are not an aggressive bee and do not sting unless handled, even then their sting is mild and far less painful than a honeybee sting or wasp bite.

Controlling Leaf Cutter Bees

While they may be considered a pest by some, keep in mind that these little bees are beneficial and essential pollinators. Insecticides are not usually all that effective to prevent them from making their cuts to the foliage of the rosebush or shrub they choose as they do not actually eat the material.

I advise those that are being visited by the leaf cutter bees to leave them alone due to the benefits we all reap because of their high value as pollinators. Leaf cutter bees have a large number of parasitic enemies, thus their numbers can vary greatly in any one area from year to year. The less we as gardeners do to limit their numbers, the better.

Africanized honey bee with the corbicula full of pollen

Yummy, yummy! is the phrase that comes to our minds when remembering Winnie the Pooh eating all those pots of honey. Many of us may only have thought about honey bees for the first time when we were kids, thanks to that cute bear with the sweet tooth. Then we learned that we are not only indebted to honey bees for the wonderful miracle of honey, but also for the privilege of eating many of our delicious vegetables and fruits every day. Yes! Honey bees (Apis mellifera) are one of the most important pollinators of the crops that we the humans use all the time.

Some of us got so enthusiastic about this insect that we fell in love with it and became backyard beekeepers — we spend hours watching them buzzing around our sunflowers, pumpkins, lemons, sage and many other beautiful plants in our gardens.

What many of us do not know, however, is that there are other bees that can live and work in our gardens — and perform very important roles within them.

Leaf cutter bees are very interesting solitary bees. They belong to the family Megachilidae and they nest inside cavities and build their egg cells with pieces of leaves. They build multiple egg chambers per nest hole and in every one of them they deposit an egg with a little bit of pollen, nectar and saliva for the further development of the larvae (1, 2, 3).

You may be surprised and feel like you have never met one of these guys. Well think again and remember those times when you were walking around the garden and discovered some circular holes in your Roses’ leaves. You probably thought they were leaf cutting ants and were upset about them, but bee happy — there’s a good chance they were actually the female leaf cutting bees taking the material they use to lay their eggs.

Megachilidae are wonderful insects. Watching them carrying leaves and working to cover their nests is very beautiful, but they are also very important pollinators of crops like clover, alfalfa, fruits, some vegetables — such as onions and carrots — and wildflowers (5, 6, 7, 8).

Leaf cutting bee coming home

You probably don’t know it, but the pollination of alfalfa improved after the 1940s, when the leaf cutter bee from Asia (Megachile rotundata) entered the United States by accident. Suddenly, more alfalfa flowers got into seed and farmers began to reproduce these solitary bees and to create appropriate nesting boxes for them. This species is now present on all continents but Antarctica and keeps doing its job very efficiently, giving us the benefits of Alfalfa seeds (4, 9, 10).

How can you recognize leaf cutter bees? They are the size of a honey bee and for an untrained eye they look very similar, but here is the tip: while honey bees carry pollen in their corbicula (special structures in the tibia of the hind leg), leaf cutter bees carry the pollen that they collect on their scopa (elongated hairs on the abdomen). Also, many times you will see these bees carrying parts of leaves back to their nest and honey bees do not have this behavior.

Leaf cutter bee. Appreciate the long hairs on the abdomen for carrying pollen (scopa)

How can you attract these allies to your home garden?

  1. Take a wood block or a log (it doesn’t have to be too thick — 10 inches would be more than sufficient).
  2. With a drill, make some small holes
  3. If you want you can put a small roof onto the block to protect it from rain
  4. Hang the “leaf cutter bee house” in a sunny or partially sunny part of your garden
  5. Wait for the bees!

Read more on making a leaf cutter bee house here.

For those of you who are scared of bees, you’ll be glad to know that leaf cutter bees are not aggressive; they do not defend their nests like honey bees do. They only sting if they are manipulated and usually they bite before they sting. Furthermore, the sting is not as painful as those from honey bees.

Other friends of your garden will hopefully also inhabit some of the holes in the box.

Wasp

Suddenly your small construction can become a very interesting community of amazing and very useful insects!

Bee and wasp

  1. “Leaf Cutter Bees”. 2012. WS Cranshaw, Colorado State University Extension
  2. “Leaf Cutter Bee”, Megachile centuncularis. The Wildlife Trusts.
  3. “Leaf Cutter Bee, Genus Megachile” Aussie Bee Homepage.
  4. “The Domestication of the Leaf Cutter Bee”. 2008. Pollination Canada
  5. “The Leaf Cutter Bee”. 2014.
  6. “Leaf cutter bees-harmless, useful and often neglected pollinator”. 2011.
  7. “Leaf Cutting Bees”. 2005. David Serrano.
  8. “Leaf Cutting Bees, Megachile spp.” Beatriz Moisett
  9. “Alfalfa Leafcutting Bee, Megachile rotundata (Hymenoptera: Megachilidae). 2008. Mark S. Goettel. Encyclopedia of Entomology, pp 98-101.
  10. “The Alfalfa Leafcutting Bee, Megachile rotundata: The World’s Most Intensively Managed Solitary Bee”. 2011. Theresa L. Pitts-Singer and James H. Cane. Annu. Rev. Entomol. 56: 221 – 37.

Leafcutter bees in the genus Megachile are common visitors to Sydney gardens where they feed at a number of different flowering plants. Not all of the species in the genus are leafcutters; some construct nests using resin.

Identification

Male Leafcutter Bees have highly modified feet with a number of dark markings. Different species of leafcutter bees have different markings. Females usually have stout mandibles for cutting leaves, large heads in proportion to the body, and stout parallel-sided abdomens.

Habitat

Leafcutter Bees live in urban areas, forests and woodlands, heath.

Distribution

Leafcutter Bees are found in all states and mainland territories. A single species is found on Lord Howe Island.

Life history cycle

Gardeners may notice circular holes in soft-leaved plants, such as roses. These are made by the female leafcutter bee, which uses the leaf to line her nest. She provides each egg she lays with a pollen and nectar mixture, and leaves the eggs to hatch into grubs, which will eat the provisions before pupating.

Breeding behaviours

It is believed that during courtship the male leafcutter bee passes his feet over the female’s eyes in a rubbing motion. She uses the patterns to identify the male as the correct species and potential mate.

LEAFCUTTER BEES ARE GENERALLY BENEFICIAL ^

Leaf cutter bees are a solitary insect. This means each nest is independent of others. However, it is most common to find several nests in close proximity of one another without conflict. Their territories can be quite extensive – over several acres – depending on local food and shelter. And since there are hundreds of species found throughout the lower 48 states of America, they can vary in color and size. Many look like common honey, bumble and carpenter bees but the one sure clue they’re leaf cutters is when you’re finding solitary nests with plant parts inside.

A macro shot of a leaf cutter bee.

Leaf cutter bees will overwinter in prepupal and pupal stages. They are among the earliest if not the very first bee to begin pollinating. They are not too sensitive to bad weather and will readily work when most other bees will remain home in the comfort of their colonies. For this reason Leaf cutter bees are highly desirable – except when they’re damaging your plants!!

In fact, leaf cutter bees are so desirable many gardeners and farmers actively install LEAF CUTTER BEE HOUSES around their property. Hang them on fence posts or trees and you too can attract them to your land.

Nesting bees will work the landscape in and around your property insuring healthy pollination. With Honey Bee populations declining, the installation of these homes can have a big impact on local plants.

Furthermore, making leafcutter houses readily available around the yard, they will help reduce nesting activity on your house!

LEAF CUTTER BEE BIOLOGY

As the weather warms, Leaf cutter bees will begin to emerge and immediately start looking for plants to fix old nests or build new ones.

Nest sights will be cavities which range from 1 inch to several feet deep. Such cavities can be found anywhere and are generally preferred to be around 9/32 to 5/16 of an inch wide in diameter. Such cavities can be found in old tree stumps, rocks, the ground or even live trees. In fact, they will readily take advantage of old mud dauber and paper wasp nests! Once a suitable nest is located, queens will actively search for food – pollen – along with nest sealing material. During this time she will mate so fertile eggs will be produced as the nest is constructed.

LEAF CUTTER BEE NESTS

Nests are constructed by first placing food in the chamber, next laying an egg on the food and lastly by sealing the egg and food with a type of plaster. This plaster is usually made from mud or some cellulose product like paper or old wasp nests. It can also be made from plant parts like leaves (their favorite material to use).

Once sealed, the eggs will have all they need to develop and grow and one day they will emerge ready to continue the process. Since nests are dependent on a healthy supply of pollen, expect to have activity during any one growing season. For this reason northern territories may only have one generation active per year but southern regions could have several develop.

Leaf cutter bees are generally passive and not very aggressive. However, they can sting and will do so if handled or aggravated. For this reason they are best left alone. However, the opportunity for nest sights on homes is great. This is why this bee can become a major nuisance if nesting is ignored. Furthermore, they can cause damage to both homes and plants which is unsightly and unacceptable.

WHERE DO LEAF CUTTER BEE NEST?

Leaf cutter bees will readily nest on any structure which presents a prime location. One of the more common locations they like are the weep holes found around windows and doors. Such weep holes are common on brick homes but are used more today then ever as a way to help keep moisture from rotting the structure. Furthermore, builders will commonly use tubing in these weep holes which leaf cutter bees love! They will readily find such tubing and quickly nest in it. When sealed, the tubing will cease to function causing moisture and water problems for the building

NESTS CAN DAMAGE HOMES

Leaf cutter bees can also create their own nests when none are easily found. They will chew through wood, mortar and stucco and though such chewing is usually not going to hurt the structural integrity of the building, it will certainly be unsightly.

Cedar and masonite sided homes are not immune to this behavior and virtually any overhangs will attract them to soffits and fascia boards. Holes in such areas are usually shallow and small but will certainly be both annoying and aggravating. Leaf cutter bees have learned that most any home has an abundant supply of nest locations and taking advantage of them seems to be at an all time high. It appears that once a house has activity it will get more and more every year. This probably happens because if a structure has something unique about it which leaf cutter bees like, female queens will leave special pheromones used to “mark” structures as a good place to live. This means once your home gets “marked”, bees will be coming around looking to nest.

LEAF CUTTER BEES WILL DESTROY FLOWERS AND SHRUBS

Leaf cutter Bee nests on the home can become a problem but the damage they do to the structure is generally superficial. However, in the yard, their damage can be quite real and have major impact on targeted plants.

Leaf cutter bee damage is done when they remove leaves from plants by cutting away small circles around the size of a dime. In fact, it is very common for them to find a shrub or plant they find attractive and within a week or two, the plant has no leaves. When such damage happens rapidly, the plant may never recover from it’s loss. Remember, leaves play an important role for any plant. Without them they are not able to create food and eat. And if there are a lot of bees active, certain leaves will begin to suffer huge tissue loss and die; some will fall victim to plant disease or other insects.

HOW TO STOP LEAF CUTTER BEES

Plants which are targeted by leaf cutter bees usually have some characteristic or feature they want. For this reason a few sections of leaves removed turns into a few more and soon a lot more. Damage will happen quickly since these bees work around the clock.

If you find activity that is damaging a prized plant or some fruit or vegetable, we have several concentrates you can apply to either chase them away or kill them.

BEST LEAF CUTTER REPELLENT SPRAY

The first is CYPERMETHRIN. This concentrate mixes with water and is highly repellent to all insects. Bees will readily detect its presence and stay off any plant you spray.

Mix 1 oz per gallon of water and treat plants you want to protect in the evening, just before dark. Leaf cutter bees are most active at night so treating right before dark is a good time to get a fresh barrier in place. Within a few days of being treated, local bees will change their foraging habits and begin looking for plants elsewhere.

Cypermethrin will last 2-4 weeks so plan on treating ever 2 weeks if they come back. But once gone, once a month should keep them away.

BEST LEAF CUTTER BEE KILLER

If you’re not content just repelling the bees using the Cypermethrin above or the Permethrin below, spray the plants they’re targeting with OPTIGARD. This non-repellent concentrate is commonly used on plants to stop whiteflies and aphids. As a non-repellent, insects won’t notice its present and continue to forage where its been applied. This will cause them to pick up small doses and after 2-3 days, they’ll die.

Optigard should be mixed at a rate of .5 oz per gallon of water and should be applied to the leaves they’re targeting. In most cases there is no need to spray the flower of the plant being attacked but if you have budworms or something else eating the new growth, spray it all. But if its just the leaves, a low pressure spray on the leaves will do the job fine.

One treatment will usually do the job but if you want to make sure they don’t return, renew the application every 2 months.

BEST SPRAY FOR THE VEGETABLE GARDEN

If you have bees targeting a vegetable bearing plant or fruit producing tree, use GARDEN SAFE PERMETHRIN. This concentrate is similar to Cypermethrin in that it will repel bees from the treated surfaces. Mix 2 oz per gallon of water and plan on treating every 1-2 weeks when bees are active; every 2-4 weeks to make sure they don’t come back.

Permethrin is safe enough to use on any vegetable or fruit bearing plant so you can still eat the crop (assuming they can still produce a harvest).

When deciding how many plants you should treat, the rule to follow is simple. When a plant starts to experience leave damage due to leaf cutter bees, you need to treat. If you have several plants of the same species, treat all of them. This will be needed because if you treat only one the bees will simply move to the untreated plant since it is the same species. If you only have one plant, you only need to start by treating that plant. Next, watch to see where they move. It is possible they will move to some adjacent plant which is a completely different species altogether or they could move to vegetation which is not even located on your property. Since you cannot be sure there is no need to broadcast your applications. Instead, play a wait and see game to learn just where they appear next and then treat that plant accordingly. Once applications begun, expect to perform followup applications every 2-4 weeks depending on local activity and populations.

To apply any of the products above, you’ll need a good PUMP SPRAYER. In most cases, there will be no need to pump it up much as low pressure will prevent wasteful run off unless you need to reach a height of 10 feet or more. Our sprayer can reach over 15 feet for tall shrubs.

HOW TO TREAT NESTS ON THE HOME

Leaf cutter nests on the home may not sound like a big deal but they can become a major problem. Such activity usually starts out innocently and then blossoms into a major concern a season or two later.

The areas where they nest dictates just what products you should use and how they should be applied.

If you have bee nests forming in weep holes or the tubing used for weep holes, it is important to keep these open and clean. Bee nests will quickly clog them and prevent proper water drainage. This blockage could lead to several other problems including water damage, termites and carpenter ants.

To stop this from happening, there are two things you need to do. First, try to identify all weep holes around the structure. Next, clean them out making sure to remove all nests and nest components. The best way to do this is with a small drill bit or tiny screw driver. You can use a thin rod like a coat hanger too but many times all this does is push the nest further up the tube.

Once you’re sure the holes open, inject PHANTOM AEROSOL using the included application straw. Phantom won’t kill anything quickly. It uses a new type of active known as a non-repellent. Spray into the hole for 5-8 seconds in early evening and do this for 3 evenings in a row.

Phantom will take 2-3 days to take affect. As the bees pass over the treatment, they’ll be picking up small amounts of the active which is then carried throughout their nest. Within a few days they’ll die and in theory, the treatment should kill hatching larvae. But to be sure nests don’t form again, treat all holes every month.

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Damage to rose leaves caused by leaf cutter bees.

What in the world causes the semicircular holes you see in the leaves of your rose bushes, holes so round and neatly cut they look like they were made by some sort of a punch?

The guilty party is the leaf cutter bee. And it’s actually a beneficial insect… if you can get over its leaf-cutting habit. And that’s what I hope to convince you of by the end of this article!

A Great Pollinator

Leaf cutter bee in action. Note that it carries pollen under its abdomen, giving the latter a yellow coloration.

Leafcutter bees (Megachile spp.) are small solitary bees, usually black with hairy bands on the abdomen. There are many species, usually 5 to 20 mm in length. And, other than for an annoying tendency to pierce holes in leaves, they are considered beneficial.

You see, with the population of honeybees (Apis mellifera) in decline worldwide, gardeners need other pollinators to help ensure pollination of their plants. After all, up to a third of the plants we eat depend on bees for pollination. And leafcutter bees are among the best bee pollinators around.

Why Are They Attacking My Roses?

In fact, leafcutter bees don’t stop at rose leaves. They’ll also cut semi-circular chunks out of other thin, smooth leaves like those of azaleas, black locusts, ashes, barrenworts, and others. And they also frequently cut holes in flower petals too.

A leaf cutter bee lining its nest with pieces of leaf.

Unlike leaf-eating insects like caterpillars or grasshoppers, leafcutter bees don’t eat the leaves on the spot, In fact, they don’t eat them at all. They cut pieces out of leaves and petals to prepare a nest for their offspring. Once the nest is well lined with leaf pieces, the female bee heads to nearby flowers to seek pollen and nectar… and in so doing pollinates the flowers. It then adds both substances to the nest: future food for its young.

The bee then lays a single egg per cell, seals its entrance to protect the egg from predators… and then builds another cell. There may be a dozen cells per nest, even many more. The larvae that hatch feed on the pollen and nectar left by their mother right through the summer. In fact, they only leave the nest the following spring, never to return, as there is only one generation per year.

Non-Aggressive

Leaf cutter bees are not aggressive. They rarely sting and when they do, it’s only because they feel they’re being attacked. Their sting is less painful than a honeybee sting and in fact, with some species, you’re not even likely to feel it. Because they are solitary, even if you step on a leaf cutter bee barefoot, provoking it to sting you, at least you will only suffer a single sting. There is no swarm to attack you. That’s what “solitary bee” means.

Cosmetic Damage

The damage leaf cutter bees cause to plants is strictly aesthetic. The plant does not really suffer from the attack, largely because it already produces more leaves that it really needs to thrive. Moreover, when the bees cut out sections of a few leaves, this stimulates the plant to produce more. In fact, the holes in the leaves leaves will bother you much more than they bother the plant!

Anyway, leaf cutter bees rarely stay long on the same plant. After a day, sometimes two, it will move on to “greener pastures”.

Bee Hotels

Commercial bee hotel.

You can attract solitary bees (mostly leaf cutters and mason bees) and solitary wasps to your garden by installing a “bee hotel”. (Note solitary wasps are not yellow jackets or hornets: they are smaller, non aggressive, great pollinators, and no more dangerous to people than solitary bees.) Commercial bee hotels are widely available, made up of various shapes and sizes of wood and hollow stems packed tightly together in a frame.

You can also make your own bee hotel by drilling holes of different diameters, from 3 to 14 mm, in the end of a log or by packing hollow stems (ornamental grasses, bamboos, elderberry branches, and perennial stems are good choices) tightly together. Or just leave a piece of rotten wood lying around.

Put the hotel in your garden near flowering plants and between 1 and 10 feet off the ground (each species has its preferred height). Ideally the spot would be protected from the rain, but would heat up early in the morning, so a site facing southeast is best.

Obviously, solitary bees don’t only live in hotels provided by people! In the wild they can nest in various holes or dig nests in the ground.

Learning to Accept a Few Flaws

Since they are beneficial and not aggressive, plus cause only cosmetic damage, and modest damage at that, would it not make more sense to learn to tolerate leaf cutter bees rather than trying to eliminate them? This is the ideal situation for applying the “15 pace rule“: before treating a plant, step back 15 paces: if you can’t see the problem at at that distance, it’s probably not a problem worth treating!

You Still Want to Control The Varmints?

Well, if so, I wish you the best of luck! They are not easy insects to eliminate.

No flowers, no bees!

The one good way of keeping them out of your garden entirely is to eliminate all the plants that are bee-pollinated, that is, largely those with showy flowers. That’s because, although leaf cutter bees do harvest a few leaf parts with which to feather their nests, they are not much attracted to greenery, but rather seek out flowers rich in pollen and nectar with which to feed themselves and their larvae. A garden without flowers will not attract bees of any kind. It might also be a bit boring.

Usually when you see the holes in a few leaves, it is already too late to react. The bee has already done its damage and has gone elsewhere. But if you catch one in the act (and remember, it is alone: there will be no other), wait until it leaves, then cover the plant with cheesecloth or floating row cover. Leave this barrier in place for a few days. By the time you remove it, the bee will have gone elsewhere.

Above all, please don’t try to poison leaf cutter bees by spraying them with insecticides. Not only will you be killing a beneficial insect, but you may also accidentally harm other beneficials.

Tolerance is the Best Solution

Really, why not just learn to live with leaf cutter bees? They really don’t do that much damage and they are so useful.

Besides, live and let live is the motto of any good laidback gardener!

I found your website by googleing and I have read the info on leaf cutter bees. Still need to ask questions though. This is the second year that we have become aware of this problem, so much so that we have been so disappointed with our roses. Now that we are going into the fall and freezing will be coming on here in NW Nebraska, I’m wondering what, if anything, we should be doing now???? I even had some product intended for barnyard that had the product in that you sell(pyretherine?) and it really did a bad number on the plants(could be, I sprayed it wrong time of day). Could you please advise me as to your recommendations? Thank you kindly.

In our LEAF CUTTER BEE CONTROL ARTICLE, we have both PERMETHRIN CONCENTRATE and PERMETHRIN DUST featured. These products can be sprayed directly on your roses and will not damage them if you do the treatment in the evening after dinner. As a general rule, you should never spray any plants in the middle of the day when it’s hot outside. Early morning treatments are okay; evening treatments are the best.

Since leaf cutter bees are generally thought of as “beneficial”, you might consider repelling them and not killing them. To do this, use the INSECT REPELLENT CONCENTRATE instead of the Permethrin. This product is completely organic and won’t hurt any insects; it’s merely a repellent and will keep away pests where applied. Just mix it with water and do your spraying in the evening to avoid heat damage.

Here are direct links to the information and products listed above:

Leaf Cutter Bee Article: http://www.bugspray.com/catalog/products/page1344.html

Permethrin Concetrate: http://www.bugspray.com/catalog/products/page1344.html

Permethrin Dust: http://www.bugspray.com/catalog/products/page1348.html

Insect Repellent Concentrate: http://www.non-toxic-pest-control.com/repellents/nbs-repellent-insect-spray

On two or three occasions I have referred to the wonderfully neat work of the leaf-cutter bee, and I have just received some Marechal Niel rose leaves from Rock Ferry from which clean-edged oblongs and circles have been nibbled out. The leaf-cutter bees are not unlike our honey bees to look at, but their habits are very different. The pieces cut from the leaves are used to build the cells of their nests, and very wonderful cells they are. The cells lie end to end, and are packed into a tunnel or burrow, in some species in the ground, in others in woodwork or timber, or in a hole in a wall. The long fragments are folded one upon the other to form a thimble-shaped tube with a convex base; the round bits form the door, which is concave. The end of one cell fits into the door of the next. Each cell is half filled with pollen as food for the future grubs, an egg is laid upon this, and then the door is sealed up; the grub hatches and lives upon the food until it pupates and emerges as a perfect bee.

Presumably the eggs first laid should hatch first, but, so far as I can see, the last cell must be the first to allow its inmate to escape, and the others in turn must work their way through the tunnel of empty cells. Some of the cells are wonderfully coloured, for the bees will at times cut their bits from flower petals; but the leaves of the rose are most favoured by these neat house-builders, at any rate by the commonest species.

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