You’re in the garden on a hot, sunny day. You haven’t had enough to eat or drink, and you’re really hungry and thirsty, though you feel that if you eat anything you might get sick. You’re getting sunburned here and there, and the rest of you is unnaturally pale and weak. Probably you shouldn’t be in the garden at all—look how weird and variable the weather’s been! Speaking of which, here comes a storm. You can’t get to shelter, and there’s rain everywhere; accidents are bound to happen, and yes, before you know it—snap!! Something’s broken.
Call 911! Or maybe not. The question in this scenario is: are you a gardener, or are you a plant?
In the middle of the summer, when the cacophony of insect sounds fills the air and it feels like insects are flying at you from all different directions, the threat of “the insect apocalypse” seems to fade into the background. The “insect apocalypse,” more generally called the “insect decline in abundance” or “insect biodiversity crisis”, could potentially lead to the demise of terrestrial and freshwater ecosystems. Scientists have long documented the loss of insect species at a rate exceeding historical extinction rates, but the loss in abundance has been surprising to entomologists. Currently, the loss in insect abundance is at a rate of 1-2% each year, which at first glance doesn’t sound all that dramatic, but in 5 years, that’s about a 10% loss in insect abundance. Why is this a problem? Insects are hugely important to the functioning of ecological systems and not only in our gardens. It was calculated that insects have at least an annual value of $70 billion for their ecosystem services. That would put insects 22nd out of 200 in the Forbes Billionaires List!
Insects are well known as pollinators but less recognized is their importance in degrading wood and other plant debris in forests and parkland, the decomposition of dead animals left on the ground, and their value in cleaning flowing water. They have been key to medical and biological research and have provided goods such as honey, silk, wax, dyes, and food to human culture. Additionally, they are critical components of the food chain: they feed on plants that might otherwise become weeds, they feed on insects that become our pests, and they provide food to the birds, reptiles, and mammals we love so much.
Despite the profound ways we rely on insects, I noticed that most students at the University of Maryland were fearful of insects or viewed them with a sense of disdain. Then I realized that their fear of insects is a result of the few interactions they have with insects like mosquitoes, ticks, cockroaches, and bed bugs. So, I set out to provide a new way for students to interact with insects and understand the importance of insect biodiversity and ecosystem services.
Creating a visual display
In 2023, with funding from the UMD Sustainability Fund, three undergraduate students, (Felicia Shechtman, Yasmine Helbling, and Fiona Torök) helped me build three eye-catching physical displays to show the diversity of insects and the importance of their ecosystem services. Now, when you walk through the library, you’ll see a glass case with an array of neatly pinned insects categorized by ecosystem service, surrounded by colorful fact sheets, and striking infographics. QR codes on the infographic posters direct students to the Lamp Lab website with a drop-down menu detailing how insects are relevant to their academic major and future career endeavors. The final displays represent the work of my three undergraduate students, as well as several student organizations on campus (i.e., the UMD Origami Club, which made and donated the paper insects). In the end, before these displays were even installed, students were already talking about insects and their ecosystem services.
Display 1 on 1st floor of the STEM Library with Fiona Török, Helen Craig, and Yasmine Helbling. Photo: Clare Gallagher
Display 2 on 4th floor of McKeldin Library. Photo: Helen Craig
Positive outcomes…so far
Once the displays were in place, I overheard several conversations among students about how insects play a role in their own lives.
“Yesterday I saw the most beautiful butterfly land on a black-eyed susan!” – anonymous student
“One time, I was hiking in the woods, and I came across a vole carcass covered in flies and maybe a beetle?” – anonymous student
Display 3 on 1st floor of Plant Science building. Photo: Clare Gallagher
Our displays encouraged students to talk about their relationship with insects in a different context. These conversations were pushed further to a broader audience with features in Maryland Today and Progress Hub, authored by UMD student Clare Gallagher. Meanwhile, on a more individual level, the students who were directly involved in cultivating these displays can point to them when walking through the library with friends and say with pride “hey I made that!” Re-building relationships with insects takes time. The first step is to see them in a new context, such as these aesthetic displays.
Close-up of insect display boxes color coordinated by ecosystem service (orange = biological control, yellow = pollination, green = medical research, pink = cultural services, blue = water quality, brown = decomposition). Photo: Helen Craig
Key takeaways
Although the need for insects and their ecosystem services seems clear to some, it’s not always obvious. Like the saying “out of sight, out of mind” insects are simply so small, it’s easy to lose sight of their massive ecological contributions. Elevating insect biodiversity in new ways opens conversations about the importance of our tiniest friends and how they relate to us. For example, a mechanic might not see the beauty in pollination, but they might be fascinated by the intricacies of wing folding and joint movement. Conversely, a foodie or nutritionist might be more interested in the abundance of food sources insects provide. To summarize, all insects in our gardens have an important job, but how you relate to those jobs might vary from person to person. Once you find that common ground between you and your insects, hold onto it and explore that relationship.
Creative ways you can explore insects
So, when you’re in your garden this spring and summer, grab a writing utensil and a notebook and take a moment to just observe which insects you see, what they’re doing, why they’re doing it, and how their actions play a role in the larger environment. You might see a butterfly finding a perch, a beetle digging into the ground, or a fly cleaning itself. As you’re thinking, start to draw your insect subject, letting your creative side fuel your pondering. And it doesn’t have to be a good drawing! I, for one, am not the most “realistic” artist, but providing a space for a quiet, observational, and creative outlet can be a great way to explore insects on a different level. Who knows, you might see your garden completely differently along the way.
By Helen Craig, M.S. Entomology Graduate Student, Lamp Lab, University of Maryland Entomology Department
Mulch piled high around trees is harmful. Photo: D. Clement, University of Maryland Extension
I’ve been a bit twitchy lately. I keep seeing mulch piled high around trees and it makes me more than a little crazy. Those mulch volcanoes are so very bad for trees.
Why? They hold moisture against the bark, inviting rot, pests, rodents, and disease.
With mulch, less is more. One to three inches is all you need.
Done right, mulch can be a good thing. It suppresses weeds, holds moisture, prevents soil compaction, moderates temperature, and improves soil structure when it breaks down.
Proper mulch is 1 to 3 inches deep. Photo: UME-HGIC
Mulch can be attractive and create a protective barrier between lawns and plantings. It creates a no-go zone, keeping mowers and weed whackers from damaging tree bark.
A ring of mulch around trees also keeps thirsty grass from robbing tree roots of much-needed water. Water passes more easily through mulch than turf.
But too much of a good thing is bad. Very bad. So many plants die an early death due to excessive applications of mulch.
One client had lost three trees in one spot and called me for help. I nearly drove off the road as I approached her home. There were 17 inches of mulch, the bark was black and mushy, and the tree was dead as a doornail.
Once you start looking for them, you’ll notice mulch volcanoes everywhere. My phone is full of photos of these dastardly cones.
Chipped leaves applied too deeply around a tree as mulch. Photo: Jennifer Foltz
I can’t save all the trees, so I’m enlisting your help. Don’t let mulch volcanoes happen on your watch.
Know that the type of mulch you choose is important, too.
Shredded bark mulch is the most popular choice for flower, tree, and shrub beds. It resists compaction, looks good, and is readily available.
Avoid using chunkier nugget mulches where water flows regularly. Those nuggets float, so they tend to move – sometimes quite dramatically – in heavy rains.
Consider stone mulches carefully. Leaves, debris, and weeds are difficult to remove, and stones can dry plants with the heat they reflect. Baked Alberta spruce, anyone?
Also, avoid mulch made from recycled tires. It blocks the flow of air and water to plant roots and can leach harmful chemicals. Plus, it doesn’t break down to feed the soil.
Regardless of the type of mulch you use, keep it an inch or two away from trunks. This avoids moisture buildup that can cause rot and invite insects and disease.
I also encourage you to look at mulch alternatives. Not only are they more sustainable, they can save the cost and effort of applying and reapplying traditional mulch.
Plant groundcovers or a mix of perennials and groundcovers around trees to create a plant community that supports pollinators, beneficial insects, and wildlife.
Try using groundcovers instead of mulch in your flower beds. Newspapers and straw or untreated grass clippings work well in vegetable beds as does an inch or two of compost.
Untreated grass clippings can be used to mulch vegetables.
So join in the mulch mania. Toss it forth with glee but not too deeply. Or explore some mulch alternatives that not only block weeds, hold moisture, and feed the soil, but provide vital habitat.
By Annette Cormany, Principal Agent Associate and Master Gardener Coordinator, Washington County, University of Maryland Extension.
Photo: C. Carignan, University of Maryland Extension (UME)
Plant identification is a taxing task for gardeners and outdoor enthusiasts. Whether the plant is a weed with an invasive tendency or a plant that is bringing something positive to the landscape/natural area, solving the mystery of the correct genus and species is the first step that must be completed correctly. A plan of action for control, further research, or even just being able to share the correct ID with friends and family is then possible.
How do you correctly determine a plant’s genus and species when you don’t know where to start?
Over the years, the tools available to identify plants have changed. Not so many years ago, you needed to be trained in botany or have a strong background or history of use with plants in order to easily identify specimens. At a young age, I relied on my family to share the common names of plants. The Horticulture Judging contest offered through my local 4-H club, was my first true opportunity to be taught scientific information about plants, and I was instantly hooked because of the time, personal interest, and previous experience that I already had from studying plants in my own landscape!
There are several books that can help you learn a plant’s identity by following a key and answering different questions about the specimen. The Maryland Native Plant Society’s Recommended Books for Plant Lovers is a nice list of plant identification books. The internet has unlimited information but navigating can be a little tricky. Lastly, we now have the opportunity to install plant photo ID applications (apps) on any mobile device, and anyone can instantly know the ID of any plant! This is just one example of how technological advances have greatly impacted our gardening world and made it easier for everyone to access information.
Examples of photo identification results from PictureThis. The right-hand photo is an example of the saved plants that are available for reference at any time. Photos: Ashley Bodkins, UME
Are all plant ID apps the same?
We are bombarded with constant options in our society and that is most certainly the case with plant photo ID apps. Just a quick search on my mobile device shows more than 10 options ready to download for easy and quick plant identification services. Some services are free and some require a payment.
In my experience, most apps will probably get you to the correct genus, and from there, you may have to resort to some of the other tools that you have used in the past. Having a high-quality, clear photo of a mature plant can help any app’s accuracy. Regardless of whatever service you are using, be sure to check the results for accuracy by cross-referencing other resources.
Rutgers analyzed the accuracy of photo identification applications based on tree species. Their study can be found on their website if you are interested in seeing how the results compare.
Many people use iNaturalist, a global social network with an application that can be added to your mobile device. It offers identification services and maps of where images were taken. This post, “Let’s find skipper butterflies in Maryland using iNaturalist!”, written by Dr. Anahí Espíndola, explains how this service works and how anyone can utilize the data. It’s a very interesting read that you should check out!
With or without a photo plant app, there are some good questions to remember when searching for a plant ID. Mature plants that are complete specimens are always going to be best for a positive identification.
Is the plant a monocot (grasses, lilies, rushes, sedges) or dicot (with two seedling leaves—many herbaceous plants are in this category)?
Remember that some plants require specific details to identify, especially monocot plants. Often monocots are keyed out in charts based on tiny features that are present or absent and use technical terminology like ligules, auricles, etc. Check out this guide from Penn State for more details.
Is it an isolated specimen, or are there several specimens of the same plant?
Is there a flower on the plant? Flowers can be very helpful with figuring out the correct plant ID.
Is the plant mature? Are the leaves complete? Remember, there are simple and compound leaves. Always look for the petiole, which is the structure/stalk that connects the leaf to the stem. Leaflets of a compound leaf will not have individual petioles.
Are there seeds/fruits/nuts? Underground plant structures like rhizomes, bulbs, or crowns?
The left photo is part one of a leaflet from a shagbark hickory (Carya ovata). The right photo is the complete leaf with all 5 individual leaflets. Photos: Ashley Bodkins, UME
Find an application that you are comfortable with using. Remember to snap clear photos of complete specimens and always include fruits or flowers in the photo when you can. Be sure to use a common-sense approach to obtaining results from any application and always cross-reference the results.
Lastly, I caution you not to get too reliant on apps and still use sources such as guide books and/or memory to keep your skills sharp. It is just too easy to snap a photo and get the identification instantly with no thought-provoking memory required. I don’t fully pay attention to the results or internalize the information. We live in a fast-paced world with constant information at our fingertips. I find it rewarding to go back to basics sometimes and just take a hike or garden walk and test my knowledge without technology.
We may have all found ourselves in that situation in which we see an insect on a flower and we wonder whether it is a wasp or a bee, and we may have also seen people panic when they encounter a bee, thinking that it is indeed a wasp. Although the two groups are very distinct and there are several ways of telling them apart (check out this previous post to see how to do it), this difficulty is in part a signature of the shared evolutionary history that the two groups have. In today’s post, I want to tell you about the evolutionary origin of bees, how it is interwoven with that of wasps, and how evolutionary studies can help us understand and explain the diversity of our charismatic bees.
Evolutionary histories and the big family we are all part of
Before jumping into the main topic of this blog, please bear with me so I can give you a bit of context for what I’ll tell you, and so you can fully appreciate the power of the discoveries I will tell you about in just a second. One of the foundations of today’s biology and the way we understand life is that living organisms share a common ancestry and that evolutionary processes such as natural selection, mutations, dispersal, and random processes have led to the establishment of new lineages that can evolve into new species and new groups of organisms. What this means is that all the living organisms we know can be placed in a sort of genealogical tree, where more closely related species and groups appear placed on branches of the trees that are also closer to each other (we call these trees “phylogenies” or “phylogenetic trees”). Also, this means that if we were to take these trees, and we were to follow the evolutionary process “backward” (from the tips to the internal branches; that is, from the present into the past), we would be able to identify branching points, which represent the now extinct ancestors of species we know today.
A phylogeny can be compared to a genealogical tree we may want to build for our family. In this tree, the most closely related members of our family share recent ancestors (marked with diamonds), but are still connected with more distantly related members of the family with longer branches and other more ancient shared ancestors. In the same way, a phylogeny represents the relationships between species or groups of species, with branches connected by their shared ancestors. Image: University of Iowa
Although this may sound like a biological nerd moment of mine, I hope that you will appreciate the enormity of this principle. This simple concept indicates that each of us and all species that exist on the planet have shared ancestors at some point in our history. We are all related to each other, like a huge family… and as for all families, the study of our history can teach us fun and interesting things about who we are, helping us understand and explain things we observe today. Let me tell you what the study of these phylogenies has taught us about wasps and bees (and their shared history) and why this excuses us in part from not always being able to tell them apart 😉.
Bees and wasps, and the vegetarian wasp
As you may know, bees and wasps are both insects that belong to the order Hymenoptera. Despite the fact that people knew they were related but distinct from each other, it was not until relatively recently that people understood what that relationship was. In fact, because they share a lot of common traits, scientists were for a long time confused about what the most closely related group of Hymenoptera was for bees, wasps, and ants. Some years ago, with the development of new methods that allow for more detailed studies of phylogenies, researchers found strong evidence that ants are a group of organisms that is related but distinct from another group formed by bees and by a particular group of solitary and usually ground-nesting wasps called crabronids. Besides the taxonomic and purely conceptual importance of this discovery, what this meant biologically was on the one hand, that bees are evolutionarily extremely closely related to wasps, to the point that we could consider them “non-carnivorous wasps”. On the other hand, this discovery showed that all bees we know today would have evolved from a wasp-like ancestor that was solitary and ground-nesting, like the crabronids we know today.
In 2017, Branstetter and collaborators used phylogenies to demonstrate that all bees and a group of wasps (crabronids) shared a common ancestry, indicating that bees can be considered a type of “vegetarian” wasp. In the figure, the position of the common ancestors is shown with arrows and stars. The main groups are labeled on the left. Image: modified from Branstetter et al., 2017
If you’re like me and find this fun, keep reading because it gets even more fun! 😊 So, after this discovery, the people who work on these topics wanted to know more. For example, can phylogenies tell us more about how the transition from a meat-based diet (wasps are carnivores) to a pollen-based one (bees feed mostly on pollen and nectar) could have happened? To investigate this, researchers ran a similar analysis, but this time considering a lot more species of both bees and crabronids. Constructing phylogenies using genetic information, they figured that when the evolutionary relationships of these groups were studied, it appeared that bees were the most closely related to a particular group of crabronids that is known to predate on thrips (a family called Ammoplanidae).
Bees have been shown to be very closely related to a group of tiny wasps in the family Ammoplanidae which are known to hunt on thrips. Photo: CBG Photography Group (CC).
Besides confirming the discoveries of the previous study, this one provided a logical and interesting biological and ecological context for the transition from carnivory to pollinivory in bees. Thrips are a group of insects known to feed on plant materials, often found on flowers, where they feed on pollen. This new study proposed that a possible evolutionary opportunity may have appeared when a lineage of thrip-predating wasps evolved the ability to not only digest thrips meat but also the pollen they contained in their guts (!!). This transition could have set the evolutionary foundations to eventually transition to a diet fully based on pollen, which opened opportunities to the newly emerging lineage to feed on a new dietary resource not already in use by other wasps. If this is true, this transition would have provided an important evolutionary advantage (e.g., reduced competition for food), which would have led to the huge diversification of bees, leading to the extreme diversity we see today.
By Anahí Espíndola, Assistant Professor, Department of Entomology, University of Maryland, College Park. See more posts by Anahí.
Anahí also writes an Extension Blog in Spanish! Check it out here, extensionesp.umd.edu, and please share and spread the word to your Spanish-speaking friends and colleagues in Maryland. ¡Bienvenidos a Extensión en Español!
Adult Japanese beetle on a ripening raspberry cluster. Photo: Miri Talabac, University of Maryland Extension
Q: Japanese beetles have been ravaging my yard for a few summers now. I heard Milky Spore can be a natural way to treat them. Is that right?
A: Japanese beetle grubs feed underground on plant roots (often in lawns), and the adults feed on foliage and flower petals on perennials, shrubs, and trees. It’s possible only one of those two life stages will pose a problem for a gardener while the other does not, so you won’t necessarily have to tackle both. In fact, a lot of lawn grub treatments are unnecessary, because any grubs encountered are not abundant enough to create noticeable lawn damage, or someone mistakenly blamed grubs for turf dieback caused by other factors.
Milky Spore, the product name for a biological control agent for Japanese beetle grubs, is a naturally-occurring bacteria that infects the grubs and kills them. Unfortunately, University field trials have found it is not reliably effective. Microbial levels might require several years of build-up from annual applications of the product to reach populations sufficient to reduce grub numbers, which can be costly.
You do have other options; the adults of this species won’t be out for a month or so yet. Beneficial nematodes can be applied to a lawn where white grubs feed, which will parasitize them and kill them. Weather conditions need to be just right during application because they are very perishable, but once nematodes get settled in, they appear to be a more promising solution.
Lower-toxicity insecticides can be used as a last resort, though check with local government rules about applications to turf since some areas restrict pesticide use on home lawns. It may be best (or necessary, for certain ingredients) to hire a certified pesticide applicator to make such treatments.
Residents who have a lawn dominated by tall fescue will rarely have any serious Japanese beetle grub issues, because this is not the turf type they prefer. (Kentucky bluegrass, fine fescue, and perennial ryegrass are those at risk.)
Adult beetles are simpler to deal with. Simply hand-picking them off of shrubs is an immediately effective tactic. Knock them into a container of soapy water to kill them, since they drop readily when disturbed. These beetles like to congregate, so removing them in the morning, before they can produce a waft of aggregation pheromone to attract others to the banquet, means that you can easily reduce the plant’s risk of damage.
It’s not necessary to nab every last beetle or prevent all chewing damage. Birds, lizards, predatory insects, and other natural helpers will help keep populations suppressed as well.
Although hanging trap bags use a pheromone lure, they attract more beetles than they capture, and the incoming beetles might still eat plants before heading to their doom, so you might as well skip that approach and just intervene by hand.
Don’t worry too much if damage sneaks up on you: even heavily-chewed shrubs may surprise you by rebounding well on their own, once the adult beetle activity has ended later in the summer. More information about their life cycle and management options can be found on our White Grub Management on Lawns and Japanese Beetles on Trees, Shrubs, and Flowers pages.
By Miri Talabac, Horticulturist, University of Maryland Extension Home & Garden Information Center. Miri writes the Garden Q&A for The Baltimore Sun and Washington Gardener Magazine. Read more by Miri.
Have a plant or insect question? The University of Maryland Extension has answers! Send your questions and photos to Ask Extension. Our horticulturists are available to answer your questions online, year-round.
You won’t find a lot of experienced gardeners—at least those who are honest with themselves—talking about “rules” in gardening. That’s because, strictly speaking, there are very few of them. There are certainly guidelines, which are created through a combination of experimentation, synthesis of results, lots of mistakes and corrections, and effective communication of principles. There’s also a lot of bad advice out there, which you can weed out in simple ways (try using “Extension” as part of your web searches) or by disregarding those helpful nuggets that use only anecdote or tradition as rationales. (“This happened to me once, so it must always be true!” “My grandmother always said…”) Personally, I think you can also ignore pundits who declare rules without exceptions. There are always exceptions.
Or maybe I’m saying that because I just broke a rule. It’s May, so time for hardening off seedlings. The guideline for hardening off is to introduce your young plants to the outdoors gradually. Carry your tray full of pots outside and put them in a sheltered spot (out of the wind and sun). Give them a few hours of outdoor conditions and then bring them inside again. Next day, lengthen the time outdoors. Over a week, expose the plants to more sun and some light breezes. Leave them outside overnight on the last few nights before you plant them in the garden. This way, they don’t get shocked by a sudden change in exposure, and they will settle into their new life more readily. Failure to make this gradual transition could result in a serious growth setback, or even in death. (Of the plant. You’ll be fine, I hope.)
