Insects

The value of a pile of sticks in your yard or garden

March 10, 2023March 13, 2023Maryland Grows11 Comments

With spring coming up, many of us are already starting to get our yards and gardens ready for the growing season. Among the activities we may take on, there can be the managing of branches, sticks, and wood that may have been trimmed from trees and shrubs in the fall, over the winter, or just recently. In today’s post, I want to talk about how to integrate these resources into our green spaces, to support wildlife and the natural services they provide.

a pile of stick in a yard — Wood and stick piles can provide welcoming habitat to beneficial organisms. Photo: A. Espíndola

Increasing the diversity of our green spaces

In several of the posts that we publish on this blog, we recommend different actions that can be taken to increase biodiversity in our green spaces (see local ecotype plants, helping pollinators in small green spaces, and conserving parasitoids for some ideas). We know that increasing biodiversity improves the ability to control and restrain pests, increases wild and crop plant pollination, and in many cases leads to better soil quality. Among these practices, there is one that increases the physical complexity of our green spaces, providing nesting, shelter, and food resources to beneficial organisms. The practice I’m talking about consists of building wood and stick piles that can be established in our green spaces. The idea behind this practice is to create a space where birds, small mammals, insects, and even pest predators can find their preferred resources, and thus be attracted and present in our environments (learn more about the landscaping rationale for using dead wood).

What organisms are attracted by these piles?

Depending on the size of the pile and its composition (e.g., large logs, smaller sticks, a mix of them), different organisms will be attracted and may establish themselves in our green spaces. The presence of a mix of logs and sticks usually attracts birds, which may nest within the pile or may just spend time within the pile searching for food or finding shelter at different points during the day. These birds will certainly contribute to increasing the diversity of animals present in our green spaces and can also in some cases participate in the control of insect pests that we may not want in our gardens and yards.

Carolina wren bird with a caterpillar in its mouth — Carolina wrens are very attracted to shrubby habitats, meaning that piles of wood and brush represent a great way to provide resources to these little cute birds who in turn can help us keep herbivore populations in line. Photo: Shenandoah NP.

Other animals we can observe in these piles are a variety of insects then may be associated with the decomposition of wood or that may use wood as a nesting or overwintering resource (e.g., bees, solitary wasps). While the former can help recycle the wood material and reintegrate it into the habitat, the latter may participate in the pollination of plants and crops that we may grow in that area or predate on unwanted pests.

Similarly, ground-dwelling invertebrates like millipedes and ground beetles can also find shelter under these piles, while the brush can also contribute to the nesting of pollinators such as (ground-nesting) bees, the overwintering of some butterflies and moths, and help improve the quality of the soil in that part of our yard.

Larger organisms may also be attracted to these piles, such as small mammals, amphibians, and even reptiles. Although we may tend to dislike these groups of animals, many of them feed on unwanted soil organisms and may help with soil quality, while others can actually control vermin through their predatory abilities. This is particularly the case of snakes that may find shelter in these spaces, which, while harmless to humans (the vast majority of snakes in Maryland are non-venomous, readily feed on rats and mice that may be present around the house.

a pile of wood branches and sticks in a yard makes a habitat for beneficial organisms — A mix of thick and thin pieces of wood can provide a diverse habitat to many different organisms. Photo: A. Espíndola.

How to build these piles?

These piles can take many different shapes and sizes, which depend in part on the materials and space available. When very large spaces are available (e.g., in the woods), it is recommended for these piles to be relatively large – at least 10 to 20 feet in length, and up to 8 feet in height (read more about these larger brush piles). In smaller spaces such as in urban or suburban gardens, these piles can be much smaller, occupying areas that may not be regularly used for other purposes. In all cases, it is ideal to build these piles using a combination of different types of materials, such as twigs and branches of different thicknesses, some logs, and even some branches that may still have dead leaves attached to them…always using healthy materials.

An important consideration when putting together these piles is that they should not be built leaning on or very close to wood-based structures or the foundations of our buildings. This is because of the potential risk of termite infestations of buildings if the piles are not physically separated from them. However, it is important to stress that establishing these piles has not been shown to be associated with higher termite infestations if the pile is not in contact or very close to the built structure. (You can read a very good discussion about mulch and termites from Iowa State Extension).

So, as you work on your spring garden, I encourage you to think about plant stems, logs, and branches not as waste that needs to be cleaned up, but as beneficial resources that you can incorporate into your available space.

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!

Thinking about getting honeybees? Some food for thought

January 9, 2023February 9, 2023Maryland Grows6 Comments

With the huge losses of biodiversity that we are seeing across the world, a prominent example that became very close to people’s hearts is that of the large pollinator losses and the very important consequences that they could have on the well-being of our ecosystems and ourselves. In this context, a very large movement started seeking to “save the bees,” which has had a number of expected and unexpected consequences. One of the latter is the very significant increase in the adoption of honeybee hives by homeowners with little to no experience in honeybee husbandry, especially with the goal to “help bees” so they won’t go extinct. Although the goal of doing this is very genuine and well-intentioned, there are a number of complexities that come with this decision, which I would like to talk about in this post.

Are the bees dying?

The short answer is yes… kind of. Let me explain. As we mentioned in previous posts, there exists a very large diversity of bees (for example, only in Maryland there are about 400 native bee species!), and it is very clear that trends in biodiversity are negative for bees, as for many other groups of insects, plants and other animals. From that respect, we can say that many native bees are indeed dying, and it is key that actions are taken to provide more healthy habitat for them to survive.

That said, it is important to understand that honeybees are actually non-native livestock in our region (the group of bees that honeybees belong to are native to Eurasia and Africa, not to North America). Honeybees are managed and non-native insects that are reared by beekeepers to produce honey and other materials (e.g., wax, propolis). In places where honeybees are native, local peoples have been using their materials for generations, and in those regions, honeybees have not only been important from a production perspective, but also from a cultural one (read here to learn a bit more about some of these traditional systems).

As for all livestock, honeybees have health issues that need to be treated if they occur. For example, honeybees suffer from serious parasite and viral infections, appear to be negatively affected by certain pesticides applied to the plants they collect pollen and nectar from, and seem to also be affected by environmental stressors such as changes in the diversity of the landscape and the quality of the plants they feed on. All of this increases the real potential to reduce the health of colonies and, if left untreated, decimate them.

bee on orange milkweed flowers — Photo: M. LaBar (CC).

Will I help the bees if I get honeybees?

Again, the short answer is probably not. As I was saying above, honeybees are non-native to our region, so increasing their populations (for example, by increasing the number of hives) in our region is not likely to positively affect our suffering native species. For example, it has been shown in some studies that honeybees can be pretty competitive in the way they visit plants, displacing native species. Further, and especially if the honeybees are not properly managed (which is, unfortunately, the case for many new unexperienced beekeepers), they can become sick and spread diseases to native bees and other insects, also leading to increasing the pressures on these already-struggling native organisms.

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Dealing with little stinkers

December 7, 2022December 2, 2022Maryland Grows2 Comments

brown marmorated stink bug — Brown marmorated stink bug, one of the little stinkers that try to get into the house in autumn. Photo: Kristie Graham, USDA ARS, Bugwood.org

Q: The bugs trying to spend the winter in my home aren’t a hazard, right? I’m going to try to seal up where they may be getting in, but there are already some that have managed to appear inside that would be hard to track down.

A: They don’t bite, aren’t attracted to indoor plants (though they might be drawn to grow lights, as they are to any light source), and are generally just a nuisance. If not easy to find, you can let them wander around until they expire, then dispose of them. Live bugs can be vacuumed or caught and released outside to meet their fate. Boxelder bugs, brown marmorated stink bugs, and multicolored Asian lady beetles are the trio of common culprits here in Maryland. Crickets, pillbugs, and millipedes come inside too, but at least they don’t fly.

Our homes must look like giant boulders to them, basking in the waning sunlight and retaining relative warmth, riddled with inviting crevices in which they can wait out the winter. Our abodes might be especially attractive since our groomed landscapes don’t have as many natural tree cavities, fallen logs, brush piles, or layers of leaf litter to tempt them instead.

If anyone is still puzzled by how they’re getting in, check your door and window weather-stripping for degradation or gaps, look for torn window screening, and inspect vent covers and conduit or pipe entry points on the exterior of the home. Seal any gaps and cracks that you can. If you use a window air conditioner, take it out for the season or plug up any access points around it.

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.

We are still alive! How to protect pollinators in the slow season

November 14, 2022November 22, 2022Maryland GrowsLeave a comment

Even when they look dry and “dead,” our green spaces are full of life. When we think about plants, for example, we can see that herbaceous perennials seem dry but they are actually just retreating underground, while annuals continue their life cycle by spending the winter as seeds in the ground. The same is true for other organisms that live in our green spaces: squirrels become less active, snakes retreat to sheltered spaces, and insects may overwinter as adults underground or in crevasses or as juveniles in their nests or chrysalises. Among these insects, there is a particular group that we seem to take a lot of effort to protect in season, but that we may then forget about in the fall and winter: our pollinators. In today’s post, I would like to talk about some specific ways that allow us to take care of our green spaces in the fall, all while continuing to support these organisms we worked so hard to support throughout the growing season.

Where are our pollinators in the winter?

As we mentioned in a previous post, pollinators don’t disappear in the winter. Instead, they either migrate to warmer conditions (like monarchs do; check out this website to know where they are now!) or stick around and overwinter right here in protected spaces such as crevasses, underground nests, and within plant stems. If we have been enjoying supporting them throughout the season, it may be a good idea to continue to do so also throughout the winter. Let’s see some ways to do this.

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Get to know your local mantis

November 9, 2022November 22, 2022Maryland GrowsLeave a comment

Carolina mantid — Carolina mantis adult female in early autumn. Notice how her wings don’t reach the end of her abdomen, as they would with our other local mantids. Photo: M. Talabac

Q: I’ve heard that not all of our praying mantis types are native. They’re all good for garden pest control though, right, or are some bad instead?

A: Maryland is currently home to five species of praying mantis, but only one is native, which is the Carolina mantis. The others are the European, Chinese, Narrow-winged, and Asian jumping mantids, with the latter being the most recent introduction. While non-native, the other mantids have more-or-less been integrated into our ecosystem for some time now, so they don’t necessarily need management or removal. Evidence of this includes the fact that insect-eating birds and other predators will readily consume them, and their eggs can also be parasitized by the tiny wasps that presumably evolved to have a relationship with our native mantis. In the grand scheme of things, other invasive species deserve more attention. Plus, at least they also eat various other non-native insect pests.

If you prefer to support native mantids found in your yard, make sure you’ve identified them correctly. Maryland Biodiversity Project has image galleries for each mantis species and provides a few ID tips for telling the difference between them, at least for adults and egg cases (called ootheca). Put “mantids” in the search box to see the species list.

Comparison of 5 mantis ootheca. The native Carolina mantis has a narrow gray ootheca. — Photo: Pawel Pieluszynski

Mantids are generalist predators, so can consume pest insects and beneficials like pollinators alike. They’re opportunists, nabbing anything they can subdue (including each other), so are neither universally good nor bad. Gardeners generally consider them helpers since they do consume pests, though we don’t know to what extent the non-native species may be depriving the native species of a food source due to competition. (Given how many other non-native insects exist in our area, I imagine this impact isn’t that significant, especially when compared to the greater problem of habitat loss and degradation.)

Bats!: The Garden Thyme Podcast

October 17, 2022October 12, 2022Maryland GrowsLeave a comment

It’s Spooky Season! In this month’s episode, we sit down with Leslie Sturges of the Bat Conservation & Rescue of Virginia to talk about bats. We chat about how much we love bats and why you should also. She tells us all about the types of bat you can find in Maryland (9:53), Whitenose syndrome (17:03), how bats rear their young (23:24), and echolocation (25:50). We also put some of the vampire and other bat myths to rest (40:30).

We also have our:

Native Plant of the Month – American Persimmon (51:15)
Bug of the Month – Twisted winged parasites (45:01)
Garden Tips of the Month (58:25)

The Garden Thyme Podcast is brought to you by the University of Maryland Extension. Hosts are Mikaela Boley- Senior Agent Associate (Talbot County) for Horticulture, Rachel Rhodes- Agent Associate for Horticulture (Queen Anne’s County), and Emily Zobel-Senior Agent Associate for Agriculture (Dorchester County).

Theme Song: By Jason Inc

The good and the bad of carpenter bees: Can we get along?

October 10, 2022September 30, 2022Maryland Grows3 Comments

Although we may love them with all our hearts, it is true that every one of our most beloved friends and family have sides that at times make us mad… and that’s no reason for us to love them less. I feel our relationship with pollinators and other beneficial insects is similar to that which we have with our loved ones: pollinators pollinate and play an important role in native plant reproduction and food production… and sometimes can become a nuisance if not properly managed. As for our loved ones, the fact that pollinators can become a nuisance shouldn’t stop us from supporting them; we just need to learn how to sustain our relationship while controlling its negative aspects. In today’s post we’ll talk about one pollinator in particular, with which our relationship can sometimes become complicated. Let’s talk about carpenter bees.

What are carpenter bees?

In our area, carpenter bees are large bees belonging to the bee genus Xylocopa. If you enjoy being outdoors, I am pretty sure you have already seen them. A very common species in our region is the eastern carpenter bee, which is about the size of a bumblebee, has a “dot” on its back and dark wings, and when exposed to the sun, has a shiny abdomen. These bees are very common in our area, and are very regular floral visitors of many ornamental and food-producing plants.

The eastern carpenter bee (left), a native to the mid-Atlantic, has a shiny abdomen, while bumblebees (right) have fuzzy and hairy abdomens. Photos: J. Gallagher, Wikimedia: R. Hodnett.

Because they are about the same size as bumblebees, carpenter bees are often confused with them. To differentiate them, a look at their abdomen will quickly allow us to know who’s who; carpenter bees have shiny abdomens, while bumblebees have very fuzzy and hairy abdomens.

The life cycle of a carpenter bees

It’s not random that carpenter bees are called that way. Their life cycle is tightly linked to wood, in which females dig holes to build their nests. Carpenter bees have impressive mandibles that they can use to chew soft wood to dig galleries in it. Although they may seem impressive, these are peaceful bees that sting only if physically and aggressively disturbed. In the spring, males of these bees establish and defend their territories, a strategy that will win them a female to mate with. During this defense, they “chase away” other males but also people who may be close to what they consider their spaces. These males are harmless, however, since they have no stingers and thus can’t sting.

the life cycle of carpenter bees from spring to fall — Life cycle of a carpenter bee. Photo: NC State Extension.

The life cycle of these bees goes hand-in-hand with the season. In the early spring the hibernating adults emerge, mate, and the females build their nests in the wood. These nests consist of galleries, at the end of which the females lay eggs and store food (nectar and pollen) for the developing larva. The larvae develop throughout the spring and summer, and by the end of the summer emerge as adults. These adults are the carpenter bees we usually see flying in the early fall. Once the weather starts becoming chillier, at the beginning of the winter, these adults return to some of the cavities and overwinter there, emerging the following spring, to restart the cycle.

Why can carpenter bees become a nuisance?

As we saw above, carpenter bees nest in wood. If a house or any structure is built of wood, they may pick it to build their nests. When this happens, these bees have the potential to affect the integrity of our wooden buildings. So, we see that while these bees are very important pollinators native to our region, this particular aspect is the one that can be problematic in our relationship with them. The good news is that there are solutions for this!

a carpenter bee seeks a nest side in wood — Carpenter bees nest in wood, which sometimes can be a part of human buildings. Knowing how to proactively protect wooden structures is the best way to manage this helpful native pollinator, while protecting our buildings. Photo: H. Jacoba.

If there are no nests yet in the wood

The best solution is of course not the reactive, but the proactive one. If we have important wood structures that we don’t want to see occupied by these bees, the best we can do is first to use hardwood (which these bees tend to dislike) and/or to treat the wood. The treatment consists in painting or varnishing the wood, which will deter the adults from nesting in it. A very good treatment is coating the wood with almond oil in the spring, which will deter the bees from choosing that section to nest.

Another proactive action that can be taken along with wood staining is to distract the bees from the wood that we want to protect. To do this, one can use pieces of wood that one may not be interested in keeping, and displaying them in other parts of the open spaces so that females choose to nest in those surfaces instead of in the wood we want to protect. Besides protecting the wood, this also allows us to support these important native pollinators from our region, all while reducing the potential negative impacts on our buildings.

If bees are already established in the wood

If carpenter bees are already established, there are several options. First, if the number of nests is really low, and if the structure can be removed and replaced, then this should be done and the new wood structure should be stained to protect it. If possible, the piece of wood that is removed can then be placed elsewhere in the green spaces around the property, which will provide nesting resources for this pollinator, and will simultaneously protect the house and support native pollinators.

carpenter bees flying around holes in old wood — Carpenter bees can sometimes establish many nests in structural materials. If this affects the integrity of the building, more extreme actions may be needed. Photo: JoeyZ51.

If the piece of wood can’t be removed and, in particular, if the nests appear to jeopardize the integrity of the building, a more radical action should be taken. In that case, the use of insecticides can be considered. If this path is taken, it is important to not perform insecticide applications without proper knowledge, meaning that this should be done by an expert applicator. This point is really important, because non-targeted and improper insecticide treatments can lead to a lower efficiency of the treatment on the carpenter bees, and the death of other non-target beneficial insects (e.g., other bees, beneficial pest control insects, etc.) that may become in contact with the treated region.

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