A Rotten Story: Forest Decomposition

The woods can be pretty messy, with all of those leaves, branches, twigs and logs falling over and cluttering up the forest floor, making it hard to walk around.

What is Mother Nature thinking? Oh wait, now where does soil come from? Do these organic inputs actually help fuel the amazing and rich forest ecosystems we nurture, exploit, and enjoy?

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Douglas-fir log subject to fungal work in Eastern Washington (Photo: Ken Bevis)

According to U.S. Forest Service research, one acre of managed conifer forest in Washington averages around 107 tons of above-ground organic material at any given time (Campbell et al. 2010).  In the lush, west-side timberlands Douglas-fir and hemlock/spruce forests often contain 300-450 tons per acre, and this doesn’t even count what is below ground!

Photosynthesis and growth are continuously adding material to this system by pulling carbon dioxide out of the atmosphere and creating tissue through this amazing, miraculous process. This material continuously builds up, and we might wonder, why aren’t we simply overwhelmed with old tree and plant parts? A complex ecosystem under our feet breaks all of this material down and turns it back into basic components that recycle and feed the system.

Most of the essential break-down work is done by fungus. Yep, good old fungus.

In fact, the moist forests of the Pacific Northwest are a great kingdom of fungus, with enormous biomass of fungal life all around us. Kneel down and pull apart some of the forest duff and rotting wood. See the white threads of fungal mycelium down there? These tender “roots” are the main body of fungus, and move through the downed material, breaking it down to basic components using enzymes and other chemicals. The fungus uses some as food and nutrients, processes it again, and releases further broken-down material that is picked up by the next organism in the soil ecosystem.

There is a zone called the “rhizosphere,” which refers to the immediate area around roots and root tips, where a high degree of the biological activity in the soil occurs. Here, fungus, bacteria, nematodes, springtails, worms and many other organisms interact with each other and the plants to support the forest (Molina & Amaranthus, 1990). Sometimes, nitrogen (a limiting nutrient in soil) is pulled from the atmosphere and “fixed” by nodules of bacteria attached to the roots of plants, including alder. The alder doesn’t do it, the bacteria do. An amazing example of symbiosis.

It gets even more complicated …

There are also mycorrhizal fungi. They form an essential symbiotic relationship with plants by attaching to root systems with fungal hyphae (threadlike fungal “roots”). These help the plant by absorbing moisture and nutrients. In return, the fungus gets sugar from the plant’s photosynthesis. This is an amazing relationship that is being rigorously studied, and is now known to be critical element of a healthy forest.

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Mushrooms on the forest floor near Sequim, Washington. (Photo: Ken Bevis)

And don’t forget the mushrooms. Most of a fungus is in the form of hyphae, invisible above the ground, performing the quiet, unglamorous work of digesting organic material. But when conditions are right, the fungus needs to reproduce, mix genetics and spread their growth around, the mushrooms appear.

Mushrooms are the fruiting bodies of fungi. These can provide food for a variety of forest-dwelling animals, including the northern flying squirrel, which then spreads the spores through their droppings and help the fungus move about the forest.

Some of these above-ground fruiting bodies are tasty to us homo sapiens too, including chanterelles, matsutake, and morel mushrooms. Some fungi have below-ground fruiting bodies, such as truffles, but the effect is the same. These “fruits” are often meant to be eaten by something to help spread the fungal wealth in the ecosystem.

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Forest floor duff near Adna, Washington (Photo: Ken Bevis)

Fungi are the “engines of decay” in the forest ecosystem, beautifully described in David George Haskell’s excellent 2012 book, The Forest Unseen. Haskell looks closely at one square meter of a Tennessee forest over the course of a year, and shares observations of life, both large and small, that apply to forests everywhere.

Meanwhile, glamorous megafauna such as our banana slug, will eat fungal elements, including mushrooms, and can play their own role in breaking down organic material by shredding, eating, and defecating as they slide around the forest floor (see recent article in DNR’s Small Forest Landowner News).

There are a lot of other animal characters acting in the forest duff as well, including mites, millipedes, centipedes, springtails, protozoans, worms, spiders, snails and gophers. The food chain down there is stunningly elaborate, with fungus (and bacteria) in foundational roles, breaking leaves and wood down initially in a myriad of ways. Then small animals such as springtails, (some smaller than the period at the end of this sentence!) feed on the fungus and the released compounds. These critters are in turn fed upon by larger creatures such as millipedes, who are in turn fed upon by larger critters, such as shrews, who could be eaten by a small owl, who could be eaten by a larger owl or coyote, etc. It is boggling when the various energy pathways are identified.

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Forest floor megafauna – Red-backed salamander. (Photo: Ken Bevis)

Salamanders live in the decaying duff and wood of the forest floor. These ancient life forms live slow and deliberate lives, mostly in the dark tunnels underground, making dramatic appearances on wet days in our forests. They eat small insects and worms, and are the apex of the rotting wood food pyramid.

How our forests are managed can greatly influence what happens in the soil. The soils we began managing in the late 19th and 20th centuries were the products of many thousands of years of development by way of fire, ice, geology, organisms and time. Human impacts in forestlands today are generally in the form of changing vegetative structure, removing organic material and soil compaction.

What can small woodland owners do to help promote and protect the precious habitats and soil ecosystem below our feet? A few suggestions:

  1. Retain organic material across the land, especially decaying logs
  2. Keep portions of the land shaded to lessen soil drying
  3. Minimize compaction from machinery
  4. Scatter large organic pieces after harvest
  5. Retain patches of natural forest at regular intervals on managed landscapes to enable soil flora and fauna to persist and return to managed areas
  6. Get down on your hands and knees with a hand lens and marvel at the life in a patch of duff, rotting wood, and forest soil

 

This is only the proverbial tip of the soil ecosystem. I hope you got down low on the forest floor, looking under some duff with dirty hands after reading this article. Send me your photos, ideas and experiences!

Ken Bevis, Wildlife Biologist, Washington State Department of Natural Resources, ken.bevis@dnr.wa.gov

References

Campbell, S.; Addell, K.W.; Gray, A.; (2010). Washington’s forest resources, 2002-2006: Forest inventory and analysis report.  Gen. Tech. Rep. PNW-GTR-800.  Portland, OR: U.S. Department of Agricultur, Forest Service, Pacific Northwest Research Station.

Molina, Randy & Amaranthus, Michael. (1990). Rhizosphere biology: ecological linkages between soil processes, plant growth, and community dynamics.

Helping Landowners Learn From Their Peers About Harvest Options

Northwest Natural Resource Group and Oregon State University are reaching out to forest owners for a voluntary study about timber harvesting methods to understand how they affect both financial and forest health outcomes.

The goal of this research project is to help landowners who are considering a timber harvest to learn from the experiences of others. There is limited information about the economics of commercial timber harvests that use thinning or uneven-aged management, and how those results compare with other harvest methods.

The researchers are looking to survey Oregon and Washington forest owners who harvested timber from their forest in the past five years (since 2014) and are willing to share information about the silvicultural methods and financial outcomes from these recent timber harvests. The survey asks detailed questions about the harvest techniques and equipment used, the volume of timber harvested, cost of the harvest work, and the harvest revenues.

The results of this study will be shared with forest owners through a variety of methods including articles, papers, and classes taught by NNRG, OSU, and partner organizations. Data in the study will remain confidential within the research team. Information will be aggregated so it cannot be traced to any individual ownership. Data will be collected from through June 2019.

If you are willing to share recent harvest information with NNRG and OSU, contact Lindsay Malone, one of the project researchers, at lindsay@nnrg.org. Lindsay can provide you with a copy of the survey.

Learn more about this research project at nnrg.org/thinning_study

Lindsay Malone, Director of Programs, Northwest Natural Resource Group, lindsay@nnrg.org

Wildfire Corner:  2018 Wildfire Season in Review

Depending on where you live it may be raining or snowing, but what we do not see on the landscape is wildfire.  So now that it’s over, let’s take a look at the 2018 wildfire season.

Wildfire starts for the Department of Natural Resources (these are fires on DNR jurisdiction lands) was the highest on record at 1,098. Statewide, all responding agencies (federal, local and state) reported 1,744 wildfire starts.

In 2018, 47 wildfires were Type 1, 2 or 3 incidents, which are considered to be large wildfires. These fires are managed by an Incident Management Team.  Fifteen of these wildfires were type 1 and 2, and 32 were type 3 incidents. Type 1 incidents are the most complex wildfire followed by type 2 and type 3 incidents being less complex. Check out the FEMA site for detailed definitions of these incident types.

Lightning was responsible for 9 percent of the wildfire starts in Washington state*, but outdoor burning was the leading cause of wildfire starts. See the following short video on wildfire starts and outdoor burning.

If you are going to be doing any outdoor burning this winter, make sure you know the rules before you light. Check out this site for rules on outdoor burning and look here for some additional tips. Be safe!

*Fire cause data is for DNR jurisdiction wildfires.

2018 Wildfire Season by the Numbers

DNR Jurisdiction Fires

  • 1,098 fires (most fires in one year on record)
  • 93 percent of fires kept at 10 acres or less
  • 107,387 acres burned

Statewide Fires – All Jurisdictions

  • 1,744 fires
  • 433,834 acres burned

By Guy Gifford, landowner assistance forester & fire prevention and Firewise coordinator, Washington State Department of Natural Resources, Northeast Region, guy.gifford@dnr.wa.gov

You’ve Got Soil Questions, and We’ve Got Answers

If you want to know how to access soil information for your property, work with multiple soils, or learn how to adapt your forest management for the soils you have, the USDA has online resources available to all that can help guide you through those processes.

Q: How can I access soil information for my property?

A: The U.S. Department of Agriculture publishes soil survey data online through a platform called Web Soil Survey. Although some areas are still undergoing initial mapping, the vast majority of private lands in the Pacific Northwest have soil survey data available. The data is available to the public, and best of all, it’s free! The following steps will help you obtain soils information for your property:

Step 1: Start Web Soil Survey by going to websoilsurvey.sc.egov.usda.gov/App/HomePage.htm. Click the large green “START WSS” button.

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Step 2: Define your area of interest (AOI). This is the area for which you will be obtaining soil survey data. You can simply enter an address or select a state/county, click “view”, and then zoom to your desired location on the map. Other navigation options are also available, although these methods are the most common and user-friendly.

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Once you are zoomed to your property or desired location, click the rectangular AOI tool to drag a box or use the polygon AOI tool to click around your select your AOI.

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The rectangle or polygon you select should then look like this:

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Step 3: View your soil map. Click the “Soil Map” tab at the top of your screen to see the soil survey map for your AOI. The map unit legend will appear on the left side of your screen. Clicking on the name of a map unit in the legend will open a window containing a description of that map unit and its individual soil components.

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Q: The soil map unit covering my property has multiple soils in it. How do I know which one I am working with?

A: In order to answer this question effectively I first need to clarify what exactly a “map unit” is, as well as explain the different types of map units used in soil surveys.

A map unit is a collection of areas defined and named the same in terms of their soil components (unique soil types) and/or miscellaneous (“non-soil”) areas. Each polygon delineated on a soil map is assigned a label or symbol that corresponds to a map unit. There are four general types of map units, however, for the purpose of this discussion I will focus on the three most commonly seen in soil survey products.

Consociations are map units dominated by a single soil component. A consociation may include minor components that occupy a relatively small (< 15%) percentage of the map unit area, but the map unit name will contain only the name of the dominant soil. Complexes and associations are map units consisting of two or more dissimilar components that occur in a consistent repeating pattern. The soil components comprising a complex cannot be separated at the mapping scale, while the components of an association can be; however, due to land use or user needs, they are not. Both of these map unit types may also include minor components. The map unit names for complexes and associations will contain the names of multiple soils.

Now to answer the original question: The map unit description (accessible by following step 3 above) will provide descriptions of typical site the soil characteristics for each component in the map unit. The type of map unit covering your property can be inferred from the map unit name. If the map unit is a consociation, the soil component that you are most likely working with is going to be the single dominant component for that map unit. However, if the specific area on your property is not representative of the map unit’s typical landscape/landform, you may be working with a minor component.

If the map unit covering your property is a complex or association, you will have to look at the map unit description to determine the component(s) you are working with. Soils tend to correlate strongly with topography, so focusing on the “setting” category for each component’s description is recommended. If the setting details alone don’t allow you to confidently determine your soil, the “properties and qualities” category under each component’s description would be the next best place to look. The goal is to find the component that has both a setting and soil characteristics that best match the point on your property that you are interested in. If that area on your property is rather large and not uniform, there is a high probability that multiple soils will exist in that area, especially if the map unit is a complex.

Q: How can soil information help me make management decisions?

A: Having a basic understanding of the distribution and characteristics of your soils can be extremely beneficial to you as a landowner. Knowledge of soil properties such as texture, drainage class, depth to a restrictive layer, and flooding or ponding frequency can influence management decisions including road and structure placement, as well as species selection and planting density strategies.

The summary information found in the map unit description provides a great overview of site and soil properties. However, the Web Soil Survey platform also contains hundreds of interpretations and thematic maps specifically designed to aid in the making of management decisions. Again, these tools are free and available to the public! The following steps will walk you through how to access and use these valuable tools.

Step 1: Define your AOI and access your soil map, as shown in steps 1-3 above. Click on the “Soil Data Explorer” tab. Then click either the “Suitabilities and Limitations for Use” or “Soil Reports” tab.

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Step 2: Both the “Land Management” and “Vegetative Productivity” categories have several interpretations concerning various aspects of forestry operations. Click the downward facing arrow for these categories and then click the downward facing arrow for any interpretation you would like to run. Look through the options and customize them to best apply to your situation. For example:

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Step 3: Once you have your options selected, click the “View Rating” button to see your customized interpretive map. Click the yellow “Legend” tab on the upper-left side of the map to see the map legend. Below the map will be tables containing more detailed results for the selected interpretation.

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Step 4: Explore the many reports and interpretations available under the “Suitabilities and Limitations for Use” and “Soil Reports” tabs. You may save the results of any report or interpretation by clicking the “Add to Shopping Cart” button located in the upper-right of the screen.  You can save numerous interpretations and reports by adding them to your cart. When you are finished, simply click on the “Shopping Cart (Free)” tab, review the table contents, and then click “Check Out” to download a PDF copy of your comprehensive report.

Max Ross, Soil Scientist, USDA Natural Resources Conservation Service, max.ross@wa.usda.gov

Wasps in the Woods

By Melissa Fischer, Northeast Region forest health specialist, Washington State Department of Natural Resources, melissa.fischer@dnr.wa.gov

As many of you may have noticed, there were a lot of angry wasps flying about this past season. I was stung on multiple occasions while working in the woods.

I really thought I was going to get away with not stepping on a nest this year, but those hopes were dashed in late fall after I stepped on one over in Loomis State Forest. One of those stings left a welt unlike any I’ve had before (Image 1).

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Image 1. Welt on the back of my leg from a yellow jacket sting. (Photo: Melissa Fischer)

I am originally from Pennsylvania and was quite surprised at how aggressive the yellow jackets are here in Eastern Washington. I’ve been stung plenty of times in Pennsylvania, but not aggressively hunted in the woods as I am here. I also noticed that in some years (2015, 2018), yellow jackets seem more numerous and extra-aggressive. Wasps are not a focal insect for forest entomologists. I found myself curious as to why they are so aggressive some years and not others, so I decided to do a little research …

What are wasps?

Wasps are insects in the order Hymenoptera, which also consists of ants and bees. The wasps we will focus on are in the family Vespidae.

Sometimes people refer to wasps as bees, but they are not actually bees. Although the two have some similarities, they also have some significant differences. Some species of both wasps and bees are social; they live and work together, and both wasps and bees can be beneficial pollinators. Unlike bees, wasps are also predators and scavengers, killing pestiferous insects such as defoliating caterpillars and house flies.

Bees and wasps both consist of species that are capable of stinging. Only females sting though, as the stinger is actually a modified ovipositor (body part used to deposit eggs).

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Image 2. Morphological differences between wasps [Western yellow jacket (Vespula pensylvanica) on the left (Image: Buck et al. 2008)] and bees [sweat bee (Halictus farinosus) on right (Image: Top: Laurence Packer, 2014/ http://www.discoverlife.org and Bottom)
Although bees and wasps may have a similar morphological appearance, bees tend to be more hairy and stocky, whereas wasps are shiny, have much less hair, and have slimmer bodies with a petiole or “waist” (Image 2). Many species of wasp build paper nests from wood pulp; bees build their nests from a waxy substance. There are no wasp species that produce honey.

Yellow jackets

There are several species of wasp in Washington, the most aggressive of which are yellow jackets. Yellow jackets are about half an inch long, they are black and yellow, and feed on insects and sweet nectar. Although most people think of yellow jackets as one particular species, there are actually several, including the common (Vespula vulgaris), western (Vespula pensylvanica), aerial (Dolichovespula arenaria) and German (Vespula germanica) yellow jacket.

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Image 3. Four species of yellow jacket that can be found in eastern Washington; the common (Vespula vulgaris), western (Vespula pensylvanica), aerial (Dolichovespula arenaria) and German (Vespula germanica) yellow jacket (Images: Buck et al. 2008)

Aside from some morphological differences (Image 3), there are also some differences in the nesting habits of these yellow jacket species. The western and common yellow jacket build papery nests located underground. The aerial yellow jacket builds small, round papery nests above ground (Image 4). These nests are commonly located on roof overhangs and other protected exterior building surfaces.

The German yellow jacket, which was introduced into the northeastern U.S. in the 1970s and arrived in Washington in the 1980s, build above-ground nests as well, but they are not round, they are typically larger than that of the aerial yellow jacket, and they are often located within wall voids or attics.

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Image 4. Paper nest of the aerial yellow jacket (Dolichovespula arenaria) (Image: Buck et al. 2008)

Paper wasps

Similar to bees, paper wasps are often mistaken for yellow jackets. They are morphologically similar to yellow jackets with black and yellow coloration, very little hair, and slim bodies, but there are some noticeable differences.

Paper wasps tend to be slightly larger (about three-quarters of an inch long) and slimmer, and rather than black on the upper side of the antennae, they have orange (Image 5). Paper wasps fly with their legs hanging down, while yellow jackets tuck their legs against their bodies during flight.

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Image 5. Morphological differences between the western yellow jacket and the European paper wasp. Note that the upper side of the yellow jacket’s antennae is black and the paper wasps’ is orange.
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Image 6. Typical European paper wasp nest (Image: Buck et al 2008).

Two common paper wasps species in Eastern Washington include the golden paper wasp (Polistes aurifer), which is native, and the European paper wasp (Polistes dominula), which was introduced into the U.S. in 1981 and reached the Pacific Northwest by 1999.

Similar to yellow jackets, paper wasps are beneficial predators that also feed on nectar. They do not scavenge non-living food as yellow jackets do though. They make paper nests, but their nests are built so that the comb cells are open to view from below (Image 6). These nests are often found in protected sites such as under eaves, and typically contain 20 or fewer cells.

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Image 7A. Bald-faced hornet (Dolichovespula maculate) worker and B. typical bald-faced hornet nest (Images: Buck et al 2008).

Bald-faced Hornets

The bald-faced hornet (Dolichovespula maculate) is another common wasp species that occurs in Eastern Washington. The bald-faced hornet in not really a hornet; hornets are in the genus Vespa and none actually occur in Washington. Bald-faced hornets are about three-quarters of an inch long and black and white/pale yellow (Image 7A).

Bald-faced hornets build a large papery nest that may have leaves and twigs on the outer nest wall (Image 7B). They are considered beneficial, as they feed almost entirely on living insects, including yellow jackets.

The wasp lifecycle

In the winter, mated wasp queens overwinter in protected areas, such as under bark or on the ground in weedy areas. The paper wasp may overwinter in attics or other parts of buildings, and can become stinging pests when temperatures inside the house increase.

Wasp queens will emerge in the spring, beginning to feed on nectar and build new nests. (Old nests are not reused.) Yellow jackets and bald-faced hornets work as individual queens to construct their own nests. European paper wasps sometimes work together as cooperating queens to make a shared nest.

A single egg is deposited in each cell. The queen cares for her larvae by feeding them chewed-up insects. The larvae emerge as adult worker wasps about one month after eggs are laid. The workers are infertile females; males are not produced until September.

As summer progresses, the workers that are produced maintain the nest, forage for food, and tend to the larvae; the queen just lays eggs. Bald-faced hornets and some species of yellow jacket may have nests consisting of hundreds to thousands of workers by late August or early September. Paper wasp nests are substantially smaller, seldom exceeding 100 individuals and often comprising fewer than 20.

In the fall, new reproductive males and queens are produced. These reproductives leave the nest and mate. The old queen dies, and the colony begins to die out thereafter. All workers and males die with the first freezing temperatures.

Back to last summer … 

So what happened this past season? Why were there so many wasps? To start with, neither the Washington State Department of Natural Resources, nor the U.S. Forest Service (nor anyone else for that matter), release Vespidae wasps to control bark beetles or any other insect. Although wasps are beneficial predators, they are generalists and would not even begin to put a dent in the bark beetle population. On top of that, because bark beetles spend most of their lives under tree bark, they are largely inaccessible to Vespidae wasps.

There are many species of parasitoid wasps that are insect predators, some of which are specific to bark beetles. These wasps use their ovipositors as they were originally intended — to deposit eggs. Some parasitoids have very long ovipositors that allow them to deposit eggs under tree bark and into bark beetle tunnels. These eggs hatch into larvae that feed on bark beetle eggs, larvae, and sometimes adults.

Some species of parasitoid wasp deposit eggs inside insect larvae and feed on the larvae from the inside out. Others deposit eggs inside eggs, and the larvae feed on the eggs from the inside out. If you’ve ever wondered where people come up with alien scenarios in horror movies, you can look to parasitoid wasps!

Parasitoid wasps have been released for control of mostly invasive, nonnative insect species. One of the reasons nonnative species have the ability to become invasive is because they do not have natural enemies in their new habitat.

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Image 8.  The parasitic wasp, Agathis pumila, released for control of the larch casebearer (Image: Roger Ryan USFS PNW Station/ forestryimages.org).

If eradication of an invasive species does not work and other controls measures are not working, sometimes entomologists will look for native enemies (often parasitoids) of these invasive species in their home habitats. These natural enemies are collected and studied in quarantine labs. If, after many rigorous tests, they are found to be safe to release in the U.S., they may be released as biological control agents. A good example would be the release of Agathis pumila (Image 8) for control of the larch casebearer (Coleophora laricella).

Biological control agents are rarely released for control of native species because native species typically have a suite of natural enemies with which they have evolved.

So if DNR and U.S. Forest Service didn’t release the wasps, why were there so many? Insect populations in general are largely controlled by the weather, and wasps are no exception. Spring weather in particular largely determines if we will have wasp problems. Mild springs allow overwintering queens to survive, whereas cold, rainy weather may reduce the likelihood that queens can build a nest and collect enough food to feed her offspring.

Summer weather can also contribute to wasp issues because warm summer weather accelerates wasp metabolism and growth rates, resulting in more wasps at a faster rate.

Wasps become most troublesome in late summer and early fall as colonies reach their maximum size. Yellow jackets are more readily provoked into stinging during this time, as natural foods become scarce and workers aggressively scavenge food scraps. Additionally, workers are more likely to vigorously defend their nests as new reproductive queens and males are produced.

Protection/ Control

For general protection around the house, you may want to keep lids on trashcans, clean up fallen fruit, and avoid wearing perfume. You don’t want to leave soda cans and food laying around. Wearing white or tan clothes can be helpful, whereas mosquito and tick repellents are not, as they don’t work against wasps.

If you do happen upon a ground nest, run away!

Keep running until the wasps stop their pursuit. Yellow jackets may chase you several feet. Wasps can sting you approximately four or five times before they run out of venom (unlike honey bees which can only sting you once).

If any land on you, flick them off. Do not swat or crush their bodies, as this will prompt them to release alarm pheromones that then stimulates a mass attack from other workers.

Although yellow jackets traps do work to trap yellow jackets (they do not attract paper wasps or bald-faced hornets), remember that there is no way you will control the yellow jacket population using them. Workers may be flying from as far as 4,000 feet away, and there may be many nests with hundreds of wasps in the surrounding area.

Traps are mainly useful for drawing yellow jackets away from areas where people congregate. Therefore, if you do invest in one, hang it away from these areas.

Homemade traps can work rather well, too. One such trap consists of a container (such as an old dishwasher tub) filled with water and dish detergent and a board laid over top with a piece of meat hanging beneath the board. Yellow jackets will remove a piece of meat and try to fly away with it, but the meat will make them heavier than normal, causing them to fall into the water.  The detergent will act as a wetting agent, trapping the yellow jacket and making it unable to fly, leading to its death via drowning.

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Image 9. Banty rooster feeding on yellow jackets from a homemade yellow jacket trap.

I made one myself last year using fish skin for my bait. At first, I thought the trap didn’t work at all, as I was coming home from work and hardly any yellow jackets were in it.  But I quickly realized that one of my banty roosters was using it as his personal snack bar (Image 9).

Thereafter, I used vegetable oil instead of dish detergent as the wetting agent. I figured dish detergent may not be good for him. The vegetable oil seemed to work just as well.

If you need to destroy a nest, hiring a professional would be my first suggestion. If you choose to do it yourself, be sure to read the label of any insecticide you decide to use prior to treatment. Many are pyrethroids, nerve poisons that can be hazardous to humans, pets, and wildlife.

If you need to eradicate aerial nests, aerosol jet sprays and foam sprays are available. Dry dust insecticides would be best for German yellow jackets located in wall voids. For ground nests, use a liquid drench. Never use gasoline, as this will contaminate the soil and could contaminate ground water.

If you would prefer not to use insecticides in the soil, flooding a ground nest with water rarely works, but vacuuming can be effective (and should only done by a professional).

Treat nests after dark when flight activity is minimal. Do not shine a flash light directly at the nest. Spray the insecticide into the nest entrance first, then spray the nest surface, then soak the entire nest. Leave it for a day or two before removing, as any workers that were not in the nest may come back and come into contact with the insecticide.

Given the fact that wasps are ecologically beneficial, I would only use control if they are a direct threat. Pay attention to what species you are considering eradicating. While yellow jackets are indeed a rather aggressive species, bald-faced hornets are less so and paper wasps are actually quite docile (although both will sting to defend their nests).

Let’s all hope next season is less exciting in the world of wasps!

References

Akre, R.D. and Antonelli, A.L. 2003. Yellowjackets and Paper wasps. Revised by Peter Landolt and Arthur L. Antonelli.  Washington State University Cooperative Extension, EB0643. 7p.

Bechinski, E., Merickel, F., Stoltman, L. and Homan, H.  2009. Homeowner guide to Yellowjackets, Bald-faced Hornets, and Paper wasps.  University of Idaho Extension, BUL 852. 16p.

Buck, M., Marshall, S.A. and Cheung D.K.B. 2008. Identification Atlas of the Vespidae (Hymenoptera, Aculeata) of the northeastern Nearctic region. Canadian Journal of Arthropod Identification No. 5: 492 pp.   Available online at doi: 10.3752/cjai.2008.05

Bush, M.R. and Murray, T.A. 2014. The European Paper Wasp. Washington State University Extension Fact Sheet, FS152E. 5p.