Paige Embry

Writer

Aphids: Evolutionary Wonders, Maddening Neighbors

April 23, 2026 / / 0 Comments
Aphid adult and nymphs

Green peach aphid (Myzus persicae) adult and nymphs. Photo: David Cappaert, Bugwood.com

The Winkenwerder Forest Science Laboratory Building is, aptly, tucked into a grove of trees on the UW campus. I sat in one its classrooms sometime in the early 2000s while Bob Gara, entomologist extraordinaire, explained that aphid females can make babies without any input (ahem) from a male. I was stupefied—and strangely charmed. I’ve since learned that parthenogenesis (offspring from un-fertilized⁠ eggs) isn’t that rare, and even some vertebrates (sharks, lizards) can procreate this way,1 but aphids were my first introduction to male-less baby-making. It’s just one of the traits that makes aphids a wonder and an annoyance, and occasionally, a serious problem.

Gara also said that aphids have a life stage where they look like a birthday cake. When I went looking for this festive version of an aphid, I didn’t find anything that looked like a birthday cake to me, but aphids do have protuberances near their hind end called cornicles, perhaps they seemed candle-like to Gara? Or perhaps my note-taking ability is crapola? Wisconsin Extension calls them “exhaust pipes⁠”2 and I can see that. Cornicles are unique to the aphid family (although in some species they are nonfunctioning). Aphids with working cornicles may spew out a variety of chemicals, from alarm hormones to “noxious adhesives used to smear natural enemies.”3 Emitting the alarm pheromone causes nearby aphids to skedaddle as best they can; they walk away or maybe drop off the plant.4 A few species of aphids (about 1%) don’t just fart out deterrent or “beware” chemicals; they have soldier aphids. These soldiers may inject a substance that digests proteins or jab predators (or their defenseless eggs, see photo) with their horns or even squeeze their foes with their robust hind legs.5

aphid

Aphid excreting fluid from its cornicles. Photo: By Sanjay Acharya – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=969288

Aphids’ evolutionary marvels extend to their food procurement and handling. They use thin, piercing-sucking mouthparts to slurp up sap from phloem cells. They have two handy types of saliva to aid in their food theft. One type creates a protective sheath along the path to the phloem cells. The other, secreted inside the phloem cells, may prevent the plant from marshaling its defenses and shutting down that phloem tube.6

Made-to-order spit, male-less birth and death by squeezing—there’s a lot more to aphids than most of us knew, and the marvels continue. It can take 25 minutes to 24 hours2 for an aphid to stealthily advance its mouthparts to the sap-carrying phloem cells—which contain sugars and an array of other life-sustaining molecules, like amino acids. (Nice diagram here under feeding.) Once there, the aphid begins to eat–and eat. It has to ingest a lot of sap to get enough amino acids and it offloads the excess sugar by shunting it out its back end (as potentially problematic honeydew). An aphid needs more amino acids than it gets from the plant and relies on its trusty bacterial symbiont, Buchnera aphidicola, to provide them. The aphid gives back, supplying proteins and other molecules that the bacteria need to live.5

The excess sugar that aphids offload as honeydew can grow black sooty mold or serve as a food source for ants that protect the aphids from predators and parasitoids. Honeydew sticks to leaves and can drip onto whatever is below, including cars and patio furniture if susceptible trees are planted in the wrong place. This happened at a Target in Oregon in 2013 where linden trees (an aphid magnet) were planted in the parking lot. The resulting drippy honeydew led to (off-label) spraying of the trees during bloom, killing tens of thousands of bumble bees. New pollinator protection laws resulted from this and similar bee kills.7

POTENTIALLY USEFUL BACKGROUND INFO

The US has about 1350 species of aphids; few are considered serious pests.2 The feeding itself rarely causes extreme damage or kills established plants⁠,8 but aphids transmit nearly 50% of insect-borne viruses (275 out of 600),9 and they can be passed along swiftly. Trying to prevent viral infections by controlling aphids is nigh on impossible—it only takes one virus-laden proboscis a couple of minutes to do the deed.8 Aphid feeding can cause chlorotic spots, leaf curl, distortions, stunting, and other damage. Aphids are more likely to be seriously harmful to herbaceous2 plants than woody ones and young vs established plants.

Potential actions depend on aphid numbers and possibly where they are in their life cycle. (See Table 1 and Management Options below.) For most of the growing season, frequent, sexless births predominate. Young aphids (nymphs) look like little adults and are also sap-suckers. Most aphids are wingless but when things get crowded or the food supply runs short, winged females are born2 and fly off to colonize new plants. Come fall, many species give birth to males and females that mate. The females deposit eggs, sometimes on a host that is different from the summer host,10 and the adults all die. The eggs hatch the next year and the cycle begins anew. There’s a lot of research about specific aphids. A search of aphid, plant name, and “site:.edu” will take you to a lot of extension sites.

From Davidson and Antonelli, 2003

 

 

 

 

 

MANAGING APHIDS

It’s easy to see that aphids are evolutionarily well-equipped to do their job—eat, multiply, serve as a banquet for others–and annoy us by expelling copious amounts of honeydew, damaging plants, and occasionally passing on diseases. How does one manage aphid problems?

1) MONITOR OFTEN—twice a week or more. Ten just-born nymphs could have 1000 babes in a month.2,11 Since some of their daughters, granddaughters and maybe even a few great-granddaughters will be popping out offspring before the month is up, it will be way more than a thousand aphids piercing and sucking away. Monitor to catch infestations early.

SIGNS AND SYMPTOMS: Presence of aphids, honeydew. They sometimes cause obvious damage. See here (scroll to plant symptoms associated with aphids) for some pics.

ACTIONS: Wash aphids off the plant with a hose, prune off affected branches, or squish aphids when only a few are around.

2) Finding aphids on one kind of plant likely doesn’t mean they’re about to take over the garden. Most species of aphids feed on only one or a few related species of plants. Keep plants healthy; provide adequate water, appropriate light conditions, and enough but not too much fertilizer. Healthy plants can better handle the sap loss.

3) Be careful with nitrogen fertilizer. Aphids like succulent new growth. Studies show that high nitrogen levels in plant tissues make plants more prone to attacks from pests.12 Apply quick release nitrogen in small bits8 or use slow release. Nitrogen in organic materials, which has to be broken down before plant uptake, are naturally slow release.13

4) If clients are worried about aphids hiding up in the tree canopy, they can put out paper to check for honeydew drips and look for aphid-herding ants crawling up the trunk. The University of California Statewide IPM Program (UC IPM) web page⁠ on aphids has info on this kind of monitoring and ant control. Other resources below.

5) Before turning to pesticides, people should see if predators and parasitoids have moved in. Aphid numbers build quickly, and predators and parasitoids tend to come along only once the aphid feast is well-established. People should look for lady beetle (ladybug) and syrphid fly larvae, lacewings, and mummified and messed-up looking aphids (which show that the parasitoids and diseases have been at work). (Pics here.) If they find evidence of attackers and untimely death, they can revel in the dead aphid husks and take heart. UC IPM notes, “Substantial numbers of any of these natural control factors can mean the aphid population may be reduced rapidly without the need for treatment.” If they need info on chemical methods, look to Pestsense14 and Hortsense15 for more info.

parasitized aphids

Parasitized aphids. Photo: By Norbert Nagel – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=19834679

A note on purchasing lady beetles for release: research out of the University of California found that “One large, heavily infested rose bush required two applications, spaced a week apart, of about 1,500 lady beetles each.”8

Lastly, KEEP MONITORING. It’s as a chance to go out and enjoy the garden.

 

REFERENCES

RESOURCES

University of CA IPM. Home and Landscape Aphids.  7/2013. https://ipm.ucanr.edu/home-and-landscape/aphids/#gsc.tab=0 Very useful background

Steven, H. Keep aphids under control with low-risk, natural strategies. OSU Extension. 2024. https://extension.oregonstate.edu/news/keep-aphids-under-control-low-risk-natural-strategies

OSU Extension. Aphids. https://agsci.oregonstate.edu/nurspest/insects/aphids

WSU Extension. Aphids. https://pestsense.cahnrs.wsu.edu/fact-sheet/aphids/  Good for management options

Davidson and Antonelli. Aphids. WSU-Puyallup. 2003. https://s3.wp.wsu.edu/uploads/sites/408/2015/02/PLS-106-Aphids.pdf

University of Maryland Extension. Aphids in Home Gardens. https://extension.umd.edu/resource/aphids-home-gardens/ Very useful background

European Chafer Beetles Run Amok in Seattle?

April 4, 2026 / / 0 Comments

European Chafer Beetle damage, Seattle, minor on left, significantly worse on right, in fall 2025
Photos: Paige Embry

I first wrote this article for for Master Gardeners. Since it wasn’t available to the public, I’m posting it here as a pdf. This entire thing was written, laboriously, entirely by me. I hope it proves both helpful and enjoyable. A pdf is also available. European Chafer Beetles Running Amok in Seattle

The lawn was in trouble, but you didn’t realize it until the end of summer or early fall when the crows descended and began ripping up plugs of grass with what looked like glee. There may have been portents earlier in the year, brown patches in the grass that could be put down to the lawn just needing a little TLC and soon you’d:

1) de-thatch

2) aerate,

3) fertilize,

4) overseed,

5) check the irrigation system because the watering seemed spotty,

6) water the lawn for a change this year, or

7) all of the above.

In scattered areas along the I-5 corridor in Washington,⁠1 the crows delighted destruction of lawns likely means that the larvae of European chafer beetles (Amphimallon majale) lurk below.* These immature beetles (larvae, aka grubs) eat the grass roots and the crows find these fine, fat, protein morsels and thank you for the all-you-can buffet by wreaking a bit of havoc. The crows (or raccoons or other hungry beasties) won’t stop as long as the larvae live and prosper.

HOW TO RECOGNIZE EUROPEAN CHAFER BEETLES

European Chafer Beetle Adult
Photo: Bruce Watt, Bugwood.org

Beetles, like butterflies and some other insects, go through complete metamorphosis: egg, larva (=caterpillar for butterflies and moths), pupa, adult. The adult European chafer beetles (EC) emerge in late spring/early summer, fly, mate, deposit eggs, and die. The eggs hatch into larvae which have exoskeletons that they need to shed periodically to grow. Each version between those molts is called an instar; EC have three. From late summer/early fall until mid to late spring the next year, they are in their large, easily visible, 3rd instar form. (See photo.) They pupate between April and early June,2 making the radical change from crawling grub to winged adult.

EC larva with dirt accumulation in its hind end.
Photo: David Cappaert, Bugwood.org

During that 3rd instar period, it’s easy to find out if EC are in a lawn. Go dig down several inches where the crows were partying, or in a still green area next to a brown one. If you come across whitish, C-shaped grubs with strange-looking heads, they’re probably EC. The heads are small, smooth and tan/brown and look like someone lopped them off some other creature and glued them onto the bulbous white bodies. The grubs have 3 pairs of legs clustered right up near the head. The opposite end is blackish-brown. As the grubs eat the grass roots, they also eat soil and you can see it through the exoskeleton. Other insects in our area that feed on turf include European crane flies and cutworms.⁠3 (See similar beetles with id pictures here⁠.4)

Around here, adult EC fly from late spring to early/mid-July. They are drably beetle-ish, ~1/2” long⁠ and brown, although sometimes with a nice golden or reddish tone. You probably won’t notice them. They come out at sunset, forming a mating swarm in the trees before the females settle on items silhouetted against the still light-washed sky. The males follow, jostling for the chance to mate.2 Preliminary research at two golf courses in Seattle had the adults flying between May 2 and July 9.⁠5

IF YOU HAVE THEM, WHAT DO YOU NEED TO KNOW?

EC are new to our area. They were first seen on the west coast in 2001 (in British Columbia⁠), found in Washington in 2008⁠, and had established populations around Seatac by 201⁠6.2

Are these new arrivals dire enemies or merely disruptive neighbors? Do they call for all out war or only some accommodations to make living with them easier because, be sure, EC are here to stay. Since they are so new to the west coast, I looked to the east coast, where they were found in the 1940s, for insights into how they live.

A 1969⁠ paper6 by a group of entomologists in New York State summarized just about everything a person might want to know about EC—what they ate, the problems they caused, the intricacies of their live cycle, what could be done about them. They went deep, deep into the weeds. For example, the authors state that newly deposited eggs are “shiny, milky white, ellipsoidal” but become dull gray as they age. They note that the outermost part of the egg stretches as the embryo grows and this stretchiness, “makes the eggs resilient, and they can bounce like rubber balls from a hard surface without injury.” The authors also write that each egg is deposited in a little chamber created by the “extrusion and evagination of the vagina to form a bulbous organ.” An EC female turns her vagina inside out and sort of punches out a tiny baby bedroom with it. Ouch.

The paper is full of potentially useful nuggets, three key ones:

1) The “population density” of larvae was higher in drier soil. Where the ground was quite wet (averaging 90% of field capacity over larval life) there were ~2 grubs/yd2 when field capacity averaged between 41% and 65% there were 23-85 grubs/yd2. (Understanding field capacity here⁠7 and here.8)⁠

From University of Maine Cooperative Extension website

2)The researchers did two studies on where females preferred to deposit their eggs: short grass vs long and grass vs bare ground. EC preferred the short grass (20.9 grubs/ft2) over long (11.9) and seemed to hate bare ground with only 0.3 grubs/ft2 vs 12.9 in the grass.

3) Pupae were “tender” (presumably they didn’t bounce). A couple of days of soils saturated from rain “may nearly eliminate the population.”

Combining what has been found elsewhere (not just NY) with what has been gleaned locally, what do we know that might be useful?

In a land where many lawns are left to go summer-dormant, and hell strips tend to be grassy zones of neglect, the big takeaway is these areas will be havens for EC. Healthy, well-watered, well-fertilized lawns are more likely to be safe from the beetles and the destruction wrought by hungry crows, raccoons and others. (See video⁠2 and references9,10 below on lawn care.)

Monitor (=dig around periodically) for pupae starting in mid-April. (In NY, they could be up to 10” deep.) Pupae are nearly straight (~16mm, 2/3” long),⁠6 larvae are curved in a C. (In NY, the pre-pupal + pupal period lasted ~ 2 to 3 weeks.) Once you find pupae, consider watering heavily for a few days in a row to try and kill off some of those tender pupae. Keep soils moist throughout the entire egg deposition period.

Also, the BC Ministry of Agriculture and Food has some commonsense advice, “Do not remove soil from infested areas, as chafer can be spread to new areas by movement of infested soil. Do not bring plants in from infested areas.⁠”11

POTENTIAL ACTION PLANS

Plan 1: Remove the lawn. You’ve now removed the food source for the larvae, and therefore, the crows and their hungry friends. (The larvae have been known to eat other roots, but it seems to be a desperation move.3,11 You could wait to replant until the larvae are dead or gone.)  Consider it an opportunity to try something new–you could even thank the crows for doing a good chunk of the pesky lawn removal for you.

Plan 2: Treat your lawn like you love it (and cross your fingers). Water, fertilize, aerate, etc. Appreciate its cool greenness under bare feet. Watch the WSU video⁠2 and check out the links below on lawn care.  Monitor. WSU researchers⁠ note that 5-10⁠ grubs/square ft2 “warrant management tactics.”2 Look to Plan 3 (or Plan 1 if you’ve had enough).

Plan 3: Engage in battle. Engage in battle. Options include parasitic nematodes, Bacillus thuringiensis subsp. galleriae (Btg) and chemical insecticides. Using these correctly is critical. The Master Gardeners have a guide⁠12 and I’ve listed other links below that have resources on what to use and how and when to use them if you go that route.

Good luck. For a while, I was in a Sun Tze “know your enemy to defeat them” kind of place with respect to EC, but the bouncy eggs and the inside out vaginas made me see EC as rather wondrous. Nevertheless, I found a Sun Tzu quote that embodies my attitude toward pest- and disease-prone plants, “If a battle cannot be won, do not fight it.”  In this instance, it’s easy for me to say. I have no lawn.

 

* Japanese beetles–a much more serious problem– have been found in various areas around SeaTac. The larvae also infest lawns and  look similar to those of EC. If Japanese beetles have been found near you, the state offers free treatment. See here. I’ll write about Japanese beetles soon.  WSDA website on treatment areas. Here’s a fact sheet and other WSDA resources.

REFERENCES:

  1. Per Chris Looney with WSDA (email 12/9/25) EC have been found between Tacoma and Olympia in the South and the King/Snohomish line in the North. In Whatcom, the “EC tsunami” has reached Blaine but isn’t elsewhere in Whatcom. Todd Murray with WSU (email 12/9/25) is tracking complaints and writes, “The I5 corridor is almost contiguous of EC problems with some gaps.”
  2. WSU CAHNRS, 2022, European Chafers: A Priority Pest in Washington, (video) https://www.youtube.com/watch?v=bDVpC2Woqx4
  3. Pest Watch: European Chafer, , 2012, WSU 078E, https://s3.wp.wsu.edu/uploads/sites/2070/2013/12/European-Chafer.pdf
  4. Metro Vancouver and the Invasive Species Council of Metro Vancouver, 2021, Best Management Practices for European Chafer Beetle in the Metro Vancouver Region, https://metrovancouver.org/services/regional-planning/Documents/european-chafer-beetle-best-management-practices.pdf
  5. Kowalewski, A, etal, Preliminary Finding, Biology and Intergrated management of the European Chafer, pg 3 https://www.nwturfgrass.net/pdfs/progress-reports/2022OSUWSUEuroProgress.pdf
  6. Tashiro, Haruo, et al. “Biology of the European chafer Amphimallon majalis (Coleoptera Scarabaeidae) in Northeastern United States.” (1969): 71-pp. https://ecommons.cornell.edu/server/api/core/bitstreams/bd44873b-269a-4dd0-bc6b-0105c262da65/content
  7. Datta, S. Etal, Understanding Soil Water Content and Thresholds for Irrigation Management, 2018 Oklahoma State University Extension. https://extension.okstate.edu/fact-sheets/understanding-soil-water-content-and-thresholds-for-irrigation-management.html
  8. Peters, R. Etal, 2013, Practical Use of Soil Moisture Sensors and Their Data for Irrigation Scheduling, WSU FS083E. https://irrigation.wsu.edu/Content/Fact-Sheets/FS083E.pdf
  9. Cook, T, 2014, Practical Lawn Establishment and Renovation, OSU Extension EC1550 https://extension.oregonstate.edu/catalog/ec-1550-practical-lawn-establishment-renovation’
  10. WSU Extension, King County Master Gardeners Tip Sheet #11, Lawns. https://extension.wsu.edu/king/mg-home/gardening-resources/tip-sheets/tip-sheet-11
  11. BC Ministry of Agriculture and Food, 2023, European Chafer. https://www2.gov.bc.ca/assets/gov/farming-natural-resources-and-industry/agriculture-and-seafood/animal-and-crops/plant-health/phu-european-chafer.pdf
  12. European Chafer: A Supplemental Guide for King County Gardeners, 2025. https://wpcdn.web.wsu.edu/extension/uploads/sites/29/2025/04/MG_European-Chafer_KCMG_April-2025.pdf

 

Bees in Atlanta

March 12, 2018 / / 0 Comments

I am in the Deep South. It is March and therefore there should be a high chance of lovely weather–only it’s snowing. I admit that I am in Chapel Hill, NC right now, not the deep, deep south–but still. My husband told me that yesterday he pulled out the chair cushions and was lounging in the sun on our deck in Seattle–something is wrong with this picture. Continue reading

Talking bees in Missoula

February 17, 2018 / / 0 Comments

I am in Missoula visiting my daughter who goes to the University of Montana. My great publicist at Timber Press arranged a radio interview (daunting) with Sarah Aronson at MT Public Radio. She hosts The Write Question that features western authors and you can find podcasts of old episodes online. I’ve been listening to some and thoroughly enjoying them.  My interview should come out at the end of March or beginning of April and I am preparing to gird my loins (ha! how often does one get to use that idiom?) and listen. The problem with speaking rather than writing is you don’t get to go back and edit. Continue reading

Dinosaur bee after all?

October 27, 2017 / / 0 Comments

Megachile (Xanthosaurus) fortis from Badlands National Park, SD. Photo courtesy of the USGS Flckr stream

When I was writing the book I spent a few days with Jerry Rozen, the curator for bees from the American Museum of Natural History. Jerry is the guy to talk to about the life of solitary bees in the nest, he’s been studying them for 60 year–maybe more.  When I asked Jerry how many species he’d found nests for, he picked up the Bee Genera of North and Central America by Michener, McGinley and Danforth (which sadly and oddly seems to be out of print, they start at $379 on Amazon), opened it up and started listing bees and I frantically started writing. When I looked at my notes later, I saw that I had written Heterosaurus. Heterosaurus? Sounds like a dinosaur–did I have some sort of brain warp back to my days as a geologist?  I couldn’t find any such bee so I let it go. But I was just looking through a list of the bees of Colorado (because that’s the kind of thing I do on what is probably one of the last sunny days to be seen in Seattle for months) and what did I see? Not a Heterosaurus but a Xanthosaurus!! Ha. I was only half wrong. It appears that the dinosaur-sounding bee is a sub-genus of the Megachile.

Flashforward podcast–Buzz off!

October 23, 2017 / / 0 Comments

Buzz Off

 

Rose Eveleth wondered, “What would happen if the bees all disappeared?” Then, she got in touch with folks, including me, and asked that question. The answer is that it wouldn’t be the end of food as we know it. Very few food plants absolutely HAVE to have an animal pollinator to procreate.  Of course, if you are trying to grow food to sell, it’s not just about getting enough pollination to procreate. It’s about optimizing yields, fruit size, and fruit shape so you can make a living. Without pollinators, we’d still get most of our foods but it might be more expensive and growers would have to devote more land to growing food to make up the difference. Check out her podcast. It is fun and informative.

writing about yourself in the 3rd person

September 22, 2017 / / 0 Comments

A male orchid bee from Guiana, courtesy of the USGS Flickr stream. This photo has nothing to do with the post. I include it only because it is glorious.

A science writer who is interested in pitching a review of the Our Native Bees asked me for a synopsis since advance reading copies aren’t available.  No problem, I thought, I can whip that out over the weekend.

Three weeks later, it’s finally done. I admit that life got in the way for part of that time but I found writing a synopsis was much harder than I thought.  Partly, because a synopsis seems like writing a book report. How many plodding versions of those did I write during my school years? Then to add to the agony, it’s about my book so I occasionally had to write about myself in the third person. Ick. Continue reading

A new world–getting a book published

August 31, 2017 / / 0 Comments

Don’t know where to start? Take a class.

I’m going to some posts about what it’s been like to write a book and get it published. It’s a world that I never thought I’d visit.

I’d always thought it would be nice to write a book–hasn’t most everyone?–but I never thought that I would actually do it. I didn’t think that I had the imagination to write fiction. Plus, I thought I was too nuts and bolts to get all lyrical about scenery and the like. I’d done some garden blogging over the years but those are short, and often right to the point. I didn’t really think about writing a whole book of nonfiction until I fell in love with bees. Continue reading

A random and incomplete array of websites worth visiting

June 11, 2017 / / 0 Comments

Melissodes communis female–note the amazing legwarmers. From the USGS Flickr website.

Here’s a few places (blogs/twitter/websites) to check out if you want to know more about bees of all sorts. I’ll add to this as I think of/run across other websites.

Diadasia: The Lives of Other Bees

The Bees in Your Backyard (twitter feed, also a great book worth looking at)

USGS Bee Lab Flickr page–home to fabulous bee pics

Clay Bolt’s webpage–he provided a bunch of the photos for the book

Honey Bee Suite often has blog posts about other bees too

The Encyclopedia of Life has a great set of informational cards with nice photos.

The Urban Bee Lab website at UC Berkeley has a list of the best bee plants for CA. Not only does it tell you what plants the bees’ like, it tells you which bees like the plants. The folks there have been gathering data on this for years and if you live elsewhere in the west, some of the plant may be useful to you as well.

PolliNation Podcasts I just discovered this one and am looking forward to working my way through a fascinating-looking array of interviews.

 

 

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