Pest Profile: Spotted Lanternfly

We have seen many high-profile examples of insect invasions, and as gardeners, we have probably come across some of these species in our very own landscapes and experienced their impacts first-hand.

If you live in the Eastern part of the United States, you have probably already heard about one of these invasive insect species that is currently wreaking havoc. The Spotted Lanternfly (SLF), Lycorma delicatula, is a 1 inch long planthopper native to China, and has since spread to Japan, South Korea, and the United States. This is a piercing/sucking insect (Order: Hemiptera) that feeds on the phloem of plants and excretes a sweet and sticky product called honeydew. This feeding damage, especially in large populations, can impact the health of certain plant species. Not to mention the nuisance potential, as any objects under infestations of this insect will find themselves coated in a sticky layer of honeydew.

Picture of a pinned adult Spotted Lanternfly (Photo: Lawrence Barringer, Pennsylvania Department of Agriculture, Bugwood.org )

It was first detected in Pennsylvania in 2014, and can now be found in several surrounding states including Delaware, Indiana, Maryland, Massachusetts, Michigan, New Jersey, New York, North Carolina, Ohio, Rhode Island, Virginia, and West Virginia, although most states are considered at risk for SLF invasion. Although the insect itself can’t fly long distances, it can be easily spread by moving infested materials and through their egg masses which look fairly nondescript (like a small smear of mud). Several states are currently quarantining this pest, so follow regulatory guidelines by visiting your state’s department of agriculture. Inspect your vehicles and personal effects for the insects and their egg masses (and scrape them off/squish them) especially if you are traveling through these quarantine areas to prevent spreading them to new locations.

Spotted Lanternfly egg mass on the bark of a tree (Photo: Pennsylvania Department of Agriculture , Bugwood.org )

This insect has over 100 potential host species, and this wide dietary breadth adds unique challenges to this insect’s pest potential. Its preferred host plant is another invasive species: Tree of Heaven (Ailantis altissima), which is currently widespread in the US and parts of Canada.

A group of Spotted Lanternfly adults (Photo: Lawrence Barringer, Pennsylvania Department of Agriculture, Bugwood.org )

SLF can also be problematic for some important fruit crops such as grapes, where it has the potential to reduce fruit yield, impact fruit quality, and potentially reduce hardiness and winter survival. There are also other economically important trees that this insect feeds on, including apple, maple, black walnut, birch, willow, etc.. Feeding damage can stress plants leaving them susceptible to other pests and diseases. If this pest continues to spread it could have significant impacts on the US grape, horticulture, and forestry industries.

Invasive insect species can also have significant impacts on natural ecosystems, and can tip the balance of a well-functioning food web. Adding a pest that often has very few adapted natural enemies, and especially those that can reduce the availability of an important food and shelter source for other native organisms can result in cascading ecological effects that can be difficult to understand and manage.

Photo: https://www.aphis.usda.gov/aphis/resources/pests-diseases/hungry-pests/the-threat/spotted-lanternfly/

It is important to stay vigilant in keeping an eye out for invasive species such as Spotted Lanternfly, so if you see this insect outside of a currently quarantined area, before you squish the bug; take note of where you spotted it and report it!

State-specific reporting guidelines for Spotted Lanternfly can be found here: https://www.aphis.usda.gov/aphis/resources/pests-diseases/hungry-pests/the-threat/spotted-lanternfly/

If you are curious about other current/potential invasive pests in the US (and state specific guidelines for invasive pests) visit: https://www.aphis.usda.gov/aphis/resources/pests-diseases/hungry-pests/pest-tracker

To learn more about this insect, visit: https://ag.umass.edu/landscape/fact-sheets/spotted-lanternfly

You can also reach out for more information to your state department of agriculture, or your local and regional extension offices.

Bee Lawns: What’s all the buzz about?

A bee lawn is a way to benefit pollinators in our landscapes by providing additional floral resources, and often utilizes a mix of low-growing flowering plants in addition to turf species. Although flower gardens also provide flowering plants for pollinators, bee lawns can be multi-functional in their usability for recreational purposes with the added benefit of providing food for bees.

Habitat loss is one of the major factors implicated in the global declines of native bee species. Providing resources utilized by these critical pollinators can assist in mitigating this. Research through University of Minnesota has found 50 species of bees utilizing the flowers in bee lawns.

The purpose of bee lawns includes providing nutritious sources of nectar and pollen for pollinators, especially in urban environments, where these resources can often be scarce and difficult to find. Additional factors include recreational usability, and reducing inputs, e.g., irrigation, nutrients, weed control, and time spent mowing. Flowering plants suited for bee lawns have a variety of common characteristics including: low-growing and flowering heights, perennial life cycles, the ability to persist with turf species, and tolerance of mowing and foot traffic.

An important consideration is that bee lawns don’t necessarily mean weedy lawns or no-maintenance lawns, but instead require different types of management and serve different functions than traditional turfgrass lawns.

Not all bee lawns are created equal, and some work better than others.

Here are some turfgrass species that can work well for bee lawns:

Cool-season turf

A mix of fine fescues (which includes species such as: creeping red fescue, chewings fescue, hard fescue, and sheep fescue) are some of the best options for bee lawns due to reduced needs for inputs including irrigation, fertilizer, and weed controls, in addition to their compatibility with flowering plants. That being said, fine fescues do not tolerate heavy foot traffic, and may not be a suitable option for turf varieties in areas with heavy recreational use.

Kentucky bluegrass (KBG) is another option for bee lawns, though it requires higher maintenance (including more frequent irrigation and fertilizer inputs). KBG is considered an invasive species in some areas so do your homework.

Warm-season turf

Although there is limited research currently available for warm season turfgrasses and their compatibility with flowering plants specifically for bee lawns, certain species require lower inputs and could be a good option.

Centipede grass is a suitable option for a low-maintenance warm season turf species, and has been utilized in studies evaluating early-spring flowering bulbs as part of a lawn ecosystem for pollinators (see resources for more information).

Bermudagrass can also be used with flowering plants, though it has higher input needs than centipede grass. For more detailed information on warm season turfgrass species suitable to your geographic area and their respective input needs, I would encourage you to reach out to your local and regional extension offices.

Here are examples of flowering plants that can work well with turfgrass species:

Dutch white clover (Trifolium repens)

Dutch white clover (often referred to as white clover or clover) is a common occurrence in many lawns. Although some consider this to be a weed, white clover can provide several benefits including its adaptability to many soil types, the ability to withstand some shade and foot traffic, and the added benefit of being able to fix its own nitrogen. Like its name suggests, white clover produces white (and sometimes pink) flowers, and grows to a height of 4-6 inches. In addition to its hardiness, white clover is also an excellent source of forage for bees due to its long bloom time, and the great quality of nectar (high sugar content) and pollen (high protein content).

Dutch white clover flowers in a lawn (Photo: Whitney Cranshaw, Colorado State University, Bugwood.org)

Creeping thyme (Thymus praecox)

Creeping thyme is related to some of our favorite culinary herbs, and produces fragrant purple/pink flowers. It has a low growth habit (<6 inches) and can tolerate some foot traffic. It performs best in well-drained sandy or loamy soils, and is also considered to be drought tolerant and deer-resistant.

Self-heal (Prunella vulgaris ssp. lanceolata)

Self-heal is native to North America, Europe and Asia, and research from University of Minnesota has shown that 95% of the pollinators that visited the flowers were native bee species. It produces purple flowers and does well in a variety of soil types (with the exception of sandy soils) and in sun or partial shade.

Self-heal flowering with turfgrass (Photo: John D. Byrd, Mississippi State University, Bugwood.org)

Common violet (Viola sororia)

Violets are another flower that some consider to be a weed in home lawns. These spring blooming yellow, purple, and white flowers can be a good source of nectar for pollinators such as butterflies and bees. Violets grow to heights of 4-8 inches, and do well in a variety of soil types in addition to sun and shade.

Purple flowers growing in grass
Violets growing in a lawn (Photo: Sarah Eilers, Montana State University)

Other flowers

Additional low-growing flowers could also be great additions to bee lawns, including early spring flowering bulbs that can persist with turfgrass for multiple years, such as crocus and grape hyacinth (Muscari spp.), which have been observed to attract pollinating insects (especially honey bees).

For more information on the regional suitability of flowering plants to incorporate with turfgrass for bee lawns, contact your local extension offices for more information.

University of Minnesota’s Bee Lab has a lot of excellent information on bee lawns, their establishment, and the diversity of bees that visit them:
https://extension.umn.edu/landscape-design/planting-and-maintaining-bee-lawn#turfgrasses-for-bee-lawns-2939360

https://turf.umn.edu/news/if-you-build-it-who-will-come-evaluating-diversity-bees-flowering-lawns

Additional Resources:

https://www.canr.msu.edu/news/consider-a-flowering-bee-lawn-to-help-pollinators

https://extension.psu.edu/the-buzz-about-bee-lawns

Wisdom, M. M., Richardson, M. D., Karcher, D. E., Steinkraus, D. C., & McDonald, G. V. (2019). Flowering persistence and pollinator attraction of early-spring bulbs in warm-season lawns. HortScience, 54(10), 1853-1859.
https://journals.ashs.org/hortsci/view/journals/hortsci/54/10/article-p1853.xml

Larson, J. L., Kesheimer, A. J., & Potter, D. A. (2014). Pollinator assemblages on dandelions and white clover in urban and suburban lawns. Journal of Insect Conservation, 18(5), 863-873.
https://link.springer.com/article/10.1007/s10841-014-9694-9

Creating artificial nesting structures for cavity nesting solitary bees

Pollinators, especially bees, are an important part of our agriculture, economy, and ecosystems. Gardeners are often well-versed in the importance of bees since we get the opportunity to see these incredible animals in action. We enjoy the results of their labor in the form of fruits, “vegetables”, and seeds which feed wildlife and create beauty and interest in our gardens. In North America alone, there is an estimated 4000 species of native bees, and an estimate of over 20,000 species around the world.

Many factors have played a role in bee declines, e.g., habitat loss, pesticide exposure, pest and disease pressures. Yet there are things home gardeners can do to help mitigate some of these effect and maximize the use of their yards and gardens as a ‘bee-friendly’ landscape. Habitat loss/fragmentation is considered to be amongst the most important factors influencing the decline of wild bee. Urbanization, development, agricultural intensification, etc. have also resulted in a reduction of high-quality habitat for these mostly native bee species.  

Many gardeners even make room in their landscapes for pollinators by planting a variety of flowers that attract and help sustain their regional bee species. Although we are often well-versed in offering food for bees (in the form of these floral resources), something that can be overlooked in our endeavors of creating ‘bee habitat’ is the fact that we do not always offer them a place to live, or a ‘home’. Accessible nesting habitat for bees is just as important as floral resources and can make these pollinators’ jobs much easier as they make trips from flowers to their nests in order to provision them for their offspring.

Approximately 30% of bee species are above-ground cavity nesting bees most of which are solitary, meaning that a single female bee will do all the work to find a nesting location and provision the nest with nectar and pollen for her offspring to eat after she is gone. This can be quite a cumbersome task and offering suitable nesting habitat in close proximity to flowering plants we curate in our gardens can be a great way to simplify this undertaking for these momma bees.

Although mimicking the conditions of wild bee habitat as it’s found in nature is one of the best ways to offer a more natural nesting experience, urbanized areas with smaller spaces can often make this a difficult endeavor. In these areas where space is limited, artificial nesting structures for cavity nesting wild solitary bees, sometimes referred to as bee hotels and bee boxes, can be a useful tool for some bee species (which include mason bees, leafcutter bees, carder bees, and more). These bee hotels have been gaining popularity over the years and many people have started to jump on trend placing them around their yards and gardens. In the past 10 years, I have seen a huge variety of these nesting structures ranging from simple to very elaborate!

A bee hotel at the Montana State University Horticulture Research Farm (Photo: Abi Saeed)

Even though there is widespread availability of bee hotels for sale, not all of them are equally as effective in being ‘bee friendly’, and some of these can actually be counter-productive to the health and well-being of these pollinators.

Here are some recommended specifications for artificial nesting structures for wild solitary bees:

Materials

Common materials used in effective bee hotels include drilled wooden blocks and trays and cardboard/bamboo tubes in addition to a box to place them all in. You want these boxes to be closed in the back and open in the front with some sort of a sloped roof so water will drip off and not collect around the nesting tubes.

Avoid using plastic materials/containers (and other things that will limit the ventilation of these structures as this can result in greater pest and disease issues). Very dark colored bee hotels, especially in locations with high sun intensity, can get really hot which can kill the bee larvae inside. It is best to use untreated and unpainted wood, cardboard and bamboo.

Depth/width and measurement specifications

One of the most common issues I see with some of these homemade and commercially available bee hotels are the depth and width measurements. Bees have control over the sex of the eggs that they lay and these cavity nesting bee species will organize their nests so that male eggs are laid near the entrance. These males will emerge first. In mason bees, for example, eggs laid further than 3 inches from the entrance are usually female bees. If the nesting structures are too shallow it can affect these sex ratios, resulting in a lower number of female bees. This can affect the local population.

Although there isn’t a perfect formula for all cavity nesting bee species and the size preferences of their nesting tubes, we know that some sizes work better than others. You should experiment with variations of size to cater to the bee species that can potentially utilize these nests.
When drilling your own wooden blocks, drill holes of varying entrance sizes (between 3/32 and 3/8 inches in diameter) and depths (minimum 5-6 inches) into untreated wood blocks or old tree stumps/logs laying around your garden or wood pile. Don’t drill all the way through the wood, leaving one end closed. If you are buying a drilled wooden block-style bee box, make sure that it falls within the range of these depth and width recommendations.

Size recommendations from University of Nebraska-Lincoln Solitary Bee Hotel Publication (G2256)

You can also create bundles of cardboard tubes, bamboo reeds, and bundles of woody and pithy plants that can serve as a nice nesting substrate that bees will nest within and in-between. These bundles should also be placed in a container with a closed end.

Location

Bee hotels should be placed at about 3-5 feet off the ground. The entrance should have direct sunlight for the most of the day, especially early morning sun. This will help these cold-blooded animals heat up and get started on their foraging and nest building activities faster. Placing the entrance facing South or Southeast is a good location for many North American bee hotels. Make sure these are mounted on a sturdy location not be easily swayed or toppled over by the wind. It should also away from areas with a lot of foot traffic, otherwise a busy bee might crash into you as she travels back and forth while building her nest.

The nesting boxes should not be easily accessible by predators and scavengers, such as birds, raccoons, squirrels, and other rodents. Do not place these next to a bird feeder, which could attract other critters and give them easy access to the bee larvae.  

Aftercare

Another common error made with bee hotels is forgetting the aftercare involved with these nesting structures. Because these nesting structures create a more ‘artificial’ nesting environment, grouping a large number of nesting locations in a concentrated area creates a different from what bees have historically utilized in areas with large expanses of natural habitat. If left unmanaged these structures can act as refuges for pests and disease which can be detrimental to the bees that nest in them. This can be counterproductive for our efforts to protect and preserve these pollinators. If you are interested in hosting cavity nesting bees in your home gardens year after year I would strongly encourage you to learn more about aftercare

If you do intend to place bee hotels in your home gardens, here are some very basic aftercare tips to follow, in order to keep these structures a safe and useful nesting option for cavity nesting solitary bees in urbanized areas.

– Move the occupied nesting structures of these bee hotels to a safe outdoor location in the fall, such as an unheated shed or garage, to protect overwintering bees from rodents, other scavengers, and harsh winter conditions. You can also keep these in a wire mesh/ventilated container to further protect them from rodents chewing them.

– Adult bees emerge from these tubes in spring and early summer, so these should be placed back outside when spring temperatures warm up to around 50°F (10° C). After bees have emerged, discard/compost used tubes and discard/burn used drilled blocks, so pest and disease pressures don’t build up.

– Refill your nesting box with new tubes, reeds/twigs, and drilled wooden blocks for the next season of bees to use, and enjoy watching the process all over again!

For more detailed information on caring for the bees in nesting boxes, please take a look at the resources below.

Resources:

The ABC’s of Plants for Bees!

A yellow flower with a pollen-covered bee resting on top.

A bee collecting pollen from a Black-eyed Susan (Rudbeckia hirta).

Though it might not seem like it for some of us who are still in the throes of winter and it especially feels like a distant dream as I look outside my window here in Montana, but Spring is right around the corner. Along with this magnificent season filled with new life in our gardens and landscapes our world will soon be buzzing with pollinators as well!

Most gardeners have a basic appreciation for pollinators. We know they are responsible for many things including providing important agricultural and economic services by pollinating many of the crops that we eat and by maintaining the diversity of plant communities (which help feed and house lots of other wildlife who share our space). Although lots of animals are pollinators, including birds, flies, beetles, butterflies, bats, small rodents, and more, bees are the most important of them all! This is because they have branched hairs covering their body which make them extremely efficient at carrying pollen from plant to plant.

Honey bees often get most of the publicity when you think about pollinators, or bees in general. Although they are really important to our agricultural operations they are not native but were brought to North America by colonists in the early 1600s. Some gardeners can even name a few additional types of bees but many may not realize the impressive number of bee species that are native to North America, estimated to be around 4000!

We are also becoming more aware of the fact that many wild and domesticated bees around the world have been undergoing declines over the past few decades of observation- which brings up questions about what we can do to help. The cool thing about this is that we, as gardeners, can have a positive impact on our bees, by thinking about them intentionally as we design and plant our gardens and take care of them throughout the year.

Just like us, bees need a few basic things to survive. They need food, a place to live, and protection from practices that can harm them (such as improper/unnecessary pesticide use). Each of these needs can be an entire blog post of its own, and in fact might be in the coming months, but my goal for this specific post is to introduce you to some of the resources that have regional information for selecting plants for pollinators.

Pink flowers with a large bee collecting nectar from them.

A bumble bee sipping nectar from a ‘Pink Spire’ Summersweet (Clethra alnifolia).

Pollinator Partnership, Xerces Society, National Audubon Society and lots of other educational organizations have a vast array of plant lists available for the pollinator enthusiast (see the resources linked at the end of this post to find an appropriate list of hardy plants adapted to your region). As you select your favorites from these lists there are a few things you should keep in mind to ensure you have the best impact on bees with the plants you select:

  • Add a mixture of different colors, textures, and sizes of flowering plants to attract the largest diversity of bees. Some bees (like long-horned bees, leafcutter bees, and honey bees) are generalists, which means that they will forage on a variety of different flowers. Others (like squash bees and sunflower bees) are specialists, which means that they will usually stick to plants in certain families, genera, and even species. By incorporating a diversity of plants in your pollinator garden, you can also accommodate a larger diversity of bee species!
  • We know that native plants are an awesome addition to pollinator gardens (because they are well-adapted, and evolved with the native pollinators of the region). That being said, you don’t have to avoid non-native plants altogether. Recent studies show that native and non-native plantings can have a lot of overlap in pollinators. In addition, non-native and native plants will also attract different types of pollinators so you can mix it up!
  • Make sure there are flowers throughout the growing season by planting things that will be blooming while bees are continuing to forage. Certain bees are active during certain times of the year when they are collecting pollen and nectar for their nests. Having something flowering throughout the year means that a variety of bees can take advantage of these floral resources. Some of the most critical plants that you can select are those that bloom early and those that continue to flower into the fall as the growing season ends. These early and late season flowers are very important because there are fewer resources available for pollinators during the times that bees are getting started (in the early months of spring) and when certain bee species are getting ready to overwinter in the fall. Having these early and late season flowers means that bees will have a source of food throughout the growing season, not to mention the beautiful blooms that you’ll get to enjoy throughout the year.
  • Stay away from plants that don’t have nectar/pollen sources (like some modern hybridized flowers) or those that have complicated features (such as double petals) which make it difficult for bees to actually get to the nectar source.
  • Keep these plants safe for pollinators, don’t spray pesticides on plants that are flowering. Or you can wait until the blooms have gone.

Now, you get to enjoy the fun part of choosing plants that are going to add beauty and benefit for pollinators in your yards and gardens.

Large pink flowers, with a bee resting on the side of the petals. Cactus spines in the background.

A bee resting on a Prickly Pear Cactus flower (Opuntia spp.).

Stay tuned for future posts about pollinators and other beneficial insects in the coming months. If you have questions about specific plants, their suitability or pollinators in general, visit the resources below or contact your local Extension Offices for more information.

Resources:

Pollinator Partnership Planting Guides:
https://www.pollinator.org/guides

Xerces Society Plant Lists:
https://xerces.org/pollinator-conservation/pollinator-friendly-plant-lists

Audubon Society Plant Database:
https://www.audubon.org/native-plants

(Some) Fact Sheets about Gardening for Native Bees:

Seitz, N., vanEngelsdorp, D., & Leonhardt, S. D. (2020). Are native and non‐native pollinator friendly plants equally valuable for native wild bee communities?. Ecology and evolution10(23), 12838-12850. https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.6826