Tag Archives: insecticide

How to kill spotted lanternflies

Below are tips for homeowners who’d like to kill spotted lanternflies (Lycorma delicatula), invasive planthoppers from Asia that use bark-piercing mouthparts to suck out phloem from a wide variety of trees, shrubs, and vines. They can aggregate in the thousands when they find a suitable host plant. An additional reason to dislike them is that they exude a sugary exudate that coats plants and surfaces with a sticky, slippery film that eventually turns black due to fungal growth.

Lycorma delicatula (spotted lanternfly) showing underwings

Although it is impossible to eliminate all of the spotted lanternflies from a yard, with a little vigilance you can minimize their numbers and thus protect your favorite trees from being weakened. Below are suggestions on how to kill them at the egg stage (September to March), the nymph stage (April to May), and the adult stage (June to November).

Egg cases

The easiest way to kill large numbers of these insects is to find them at the egg stage and squish them. This can be done by applying enough force with a hard, flat object (stick, trowel, stiff credit card) to create a popping noise as you progress from one side of the case to the other. You should see juices being exuded.

I also think that a mini rolling pin would be ideal, as would the smooth end of a meat-tenderizer mallet (but don’t hurt your trees!). A meat tenderizer is better than a hammer primarily because it better protects the user from the resulting spray of liquid as the eggs are crushed.

PRO-TIP: In late winter and early spring the egg masses becomes brittle, so apply a section of wide tape over the egg case before hitting them. This prevents eggs on the edges from being launched to safety.

If you can’t stomach the sound and the goo, an alternative is to scrape the eggs into a container filled with a fluid such as alcohol or hand sanitizer, or into a container or bag that can be sealed and thrown in the trash. The important consideration here is that simply scraping them off the tree onto the ground will not kill the eggs/larvae that are inside.

There are several challenges to killing them at the egg stage. The first is that the egg masses are covered with a shiny purple/gray substance that tends to weather and blend in with tree bark over time, so finding them is difficult. Here are some photographs that illustrate the variability (click to expand).

Second, the egg masses are often high up in the canopy of a tree, sometimes on thin branches that you’d never be able to reach even if you are a good climber. Third, the adults have a habit of ovipositing in areas that are completely hidden from view, such as underneath a loose piece of bark, behind a seat cushion on the deck, or in a wheel well of a car. There’s just no way to find all the egg cases in a yard.

PRO-TIP: as the egg cases weather the eggs beneath the waxy substance sometimes become more visible. So make a habit of reexamining surfaces in February and March when leaves are not blocking your view. Take a cup of coffee or a glass of wine with you on patrols, to keep your spirits up. As motivation, remember that each egg case has 20-50 eggs, and they are much easier to kill than 20-50 nymphs.

As far as I know, spraying the egg cases with insecticide is not especially effective. A propane torch is likely to do the trick but I wouldn’t recommend that if eggs are attached to a tree or your house.

Nymphs

Here are ways to kill nymphs (followed by details for some):

  1. Flyswatter
  2. Rolled-up newspaper
  3. Attach circle traps to trees
  4. Sticky trap with wire guard
  5. Cordless hand-held vacuum
  6. Bug-A-Salt rifle
  7. Electric flyswatter
  8. Pathogenic fungi (?)
  9. Insecticides

Flyswatter: If you are protecting just one tree, insert a pushpin into the trunk so that you have a convenient place to hang the flyswatter.

Circle traps: These involve a little time to make but they look fantastic. Here’s a page that gives detailed instructions.

Sticky traps: The nymphs crawl up and down trees starting in April so you can trap hundreds if you wrap trunks with sticky tape. If you want to go low-tech, duct tape works OK (use push pins to attach) but you’ll need to replace after every rain. You can also buy commercial tapes that are weather resistant. These commercial tapes often have two issues, though. The first is that double-sided tapes will leave a band on your tree forever, so protect the trunk with plastic wrap (underneath) before applying. The second is that some tapes are so sticky that they’ll easily trap birds (and squirrels, snakes, and bats) so you MUST cover the band with chicken wire. Here’s a photograph of a bird trapped on sticky paper in case you think this risk is overblown. Penn State has a good summary of using sticky traps. As does Farm & Dairy.

Cordless stick vacuum: A DustBuster would work fine but the long extension arm of a stick vacuum is ideal for reaching into vegetation. I own a Dyson cordless stick vacuum but there are lots of options (e.g., on Amazon).

Bug-A-Salt rifle: I also don’t own one of these, sadly, so I can’t absolutely guarantee it will work. But I’d be really surprised if they didn’t. I think it would make the daily lanternfly patrol really fun, and everyone in the family would want a turn. You can buy them on the Bug-A-Salt website and on Amazon. Do not buy one if you have children in the house … you can definitely shoot your eye out with these things.

Electric flyswatter: I own one of these and they work really well on large flies so I don’t see why they wouldn’t work on spotted lanternfly nymphs. There are dozens for sale on Amazon. I don’t, however, think they have enough power to kill the adults (I’ll check this summer).

Pathogenic fungi: There are at least two fungi (Beauveria bassiana and Batkoa major) that seem to infect spotted lanternfly, so it might be possible to coat them with a powder or a spray and watch them slowly die. Unfortunately, the experiments on whether this is worthwhile are not yet done (or not yet published), so I can’t guarantee success. But in the wild, these fungi seem to do their thing well. I’m going to buy some Beauveria bassiana from Amazon for the 2020 season, just for giggles. Batkoa major is not yet for sale, I think.

Insecticides: I don’t recommend spraying spotted lanternfly nymphs with insecticides, in part because unlike adults, nymphs tend to spread out everywhere in a yard and are therefore hard to target with contact poisons. Plus a typical homeowner (I include myself) is not in a position to apply pesticides safely and in an environmentally-responsible way. That said, nymphs are susceptible to many insecticides and researchers at Penn State University (and elsewhere) have done experiments to figure out which ones are the best. On a related note, I think homeowners should be wary of pesticide applicators and tree-care companies that offer full-yard treatments à la Mosquito Squad (i.e., fogging yard with pyrethroids several times per summer); that will likely cause bird and firefly decines.


Here’s a photograph of an early-instar nymph. Late-stage nymphs (photograph) have red patches on their backs in addition to the spots.

Adults

For all their faults, adult spotted lanternflies at least make themselves easy targets. They are large, distinctive, clump in large groups, and rarely do anything to avoid being killed even when you are squishing their neighbors. Here are some ways to kill them (with details below for some).

  1. Flyswatter
  2. Rolled-up newspaper
  3. Backpack vacuum
  4. Leaf vacuum
  5. Pathogenic fungi (?)
  6. Bug-A-Salt gun
  7. Airsoft gun
  8. Insecticides
  9. Dawn soap
  10. Propane torch
  11. Chinese mantids

Backpack vacuum: If you are serious about controlling spotted lanternflies, go buy yourself a backpack, battery-powered vacuum that has a large, clear repository. Then you can stroll around your yard in the evening and suck up hundreds if not thousands over a short period of time. Another benefit of the vacuum method is that you won’t leave half-crushed lanternflies all over your prized trees. Note: a backpack leaf mulcher will also do the job but might be tad disgusting. A shop-vac will work in a pinch but is much less convenient.

PRO-TIP: Buy a Ghostbusters costume for your gullible child and tell them sucking up lanternflies is good practice.

Leaf vacuum: Maybe something like the Black and Decker 36v Cordless (GWC3600L). I don’t own one of these but they look fun. Amazon carries a lot. Most hardware stores can set you up. Note that most leaf vacuums shred … so be prepared for some goo.

Airsoft gun: Don’t get one of these if you have kids. But if you have a semi-responsible adult who enjoys killing spotted lanternflies, this would be an amazing gift. I see them as especially valuable in killing the adults that are high up in branches, out of the range of your vacuum. Buy only biodegradable pellets, opt for lightest pellets you can find (to minimize tree damage), and wear safety goggles (the pellets ricochet off tree trucks). Note that Airsoft guns are illegal in some areas (e.g., Arkansas, parts of Michigan, Washington D.C., San Francisco, Chicago, NYC). And, of course, you always run the risk of being shot by police even if you are on your own property. To minimize the risk of being shot, DO NOT remove the blaze-orange tip.

Pathogenic fungi: As I mentioned in the nymph section, Beauveria bassiana is for sale on Amazon. It might not work effectively (or at all) but if you’d like to experiment it might be worth a try. Here’s an adult I found that I think is infected.

Insecticides: Again, I don’t recommend spraying them with insecticides — this is a nuisance insect, not a health threat, and mechanical controls work well. But if you like chemicals, please follow the directions so that pollution of waterways and death of bystander arthropods (and amphibians) are minimized. For more details on which pesticides work, consult the table under “Chemical Control” on this page from Penn State University.

I also don’t recommend that homeowners treat tree-of-heavens (Ailanthus altissima) with systemic insecticides to create bait trees, currently a popular idea. It seems like a perfect solution: because tree of-heaven is their favorite host, you could potentially kill thousands of adults as they arrive to feed on insecticide-laced trees. And it’s touted as being safe for other insects because few other insects eat the foliage (the trees are invasives from Asia). The huge downside, in my opinion, is that many systemic insecticides find their way into nectar and pollen, and thus these bait trees will likely poison large number of pollinators. This downside should be especially worrying to suburban beekeepers because those chemicals could potentially end up in honey. And, more generally, the bulk of systemic insecticides is likely washed into waterways or taken up by nearby plants in your yard.

Dawn soap: This is one of many home remedies that has gone viral but should not have. Detergents pollute waterways and can also damage plants. I.e., there are actually reasons why Dawn soap is not an approved insecticide.

Propane torch: This looks extremely satisfying (see video) but it’s just going to result in forest fires and home losses. Don’t be that guy. If you’re married to that guy, hide the propane tank.

Chinese mantids: Please do not buy mantid egg cases and release in your yard. Chinese mantids are invasive and mainly eat butterflies (even monarchs, even hummingbirds). They are not beneficial insects, despite claims to the contrary on Pinterest.


Just in case you haven’t seen adults before, here are three:

Lycorma delicatula (spotted lanternfly) on tree

Kill tree-of-heaven trees

Tree-of-heaven (Ailanthus altissima) is the preferred host for spotted lanternfly so if you have one in your yard it will attract thousands of adults from all across your neighborhood. Kill it right now. And don’t worry, it’s an invasive plant and deserves to die. Note that to kill a tree-of-heaven you need to chop it down and treat stump with herbicide (instructions). Alternatively, treat with herbicide, wait, then chop it down. And if you notice tree-of-heaven in your neighborhood, alert the authorities so that it can be destroyed. Below is a photograph of one in Springfield, Pennsylvania. By the way, that building was covered with egg cases. I’d bet that car (with Massachusetts plates) got egged, too.

Similarly, get rid of Amur cork trees (Phellodendron amurense), another invasive tree from Asia that spotted lanternflies adore.

More information

Much of the above is pulled from presentations I made in 2019 to the CRC Watersheds Association and the Scott Arboretum. If you have any questions or suggestions, please contact me. I live in Swarthmore, Pennsylvania, by the way — deep inside the spotted lanternfly quarantine zone, and just 60 minutes from Berks County, PA, where the pest was first imported, circa 2012, on decorative rocks shipped from South Korea.

My photographs of spotted lanternflies (flickr).

Latest map of where spotted lanternfly is found in United States, from the New York State Integrated Pest Management Program:

Links

© COLIN PURRINGTON

Effects of mosquito sprays on humans, pets, and wildlife

Mosquito Authority, Mosquito Joe, Mosquito Platoon, Mosquito Shield, Mosquito Squad, TruGreen, and many other companies often imply that the insecticides they spray on yards are safe for everything except mosquitoes. This page contains information on what, exactly, they spray and what effects those chemicals have.

After a little digging, I think I’ve uncovered most of the active ingredients used by these companies:

All of the chemicals are either pyrethrins or pyrethroids, which are natural and synthetic (respectively) neurotoxins that cause almost instant paralysis and death to mosquitoes. Below is the chemical structure for one, permethrin:

Please email me if you think I’ve made an error or if you know that a formulation has changed (which happens). I still haven’t figured out whether companies permit their franchise owners to pick and choose which insecticides to use, so when multiple chemicals are listed above that doesn’t necessarily mean the sprays will contain both.

Are these chemicals safe for humans?

Pyrethroids are relatively safe but should not be viewed as harmless. If you spill enough on your skin you might experience itchiness, numbness, nausea, and respiratory problems, among a rather long list of adverse events. At very high doses pyrethroids can kill you, a fact known because some people have injected it (suicide) and in one case because somebody ate food that was cooked in pyrethroid concentrate (it resembles cooking oil). Although you obviously can’t test whether pyrethroids harm human brains, studies on mice and rats suggest that the chemicals do act on mammalian nervous systems; that should at least give you pause if you have kids rolling around on the grass after the yard gets dosed. Indeed, there is at least one correlational study that suggests exposure to pyrethroids is not good for kids (or at least boys). There are also scattered reports that some pyrethroids are carcinogenic and estrogenic but I don’t think such effects are shockingly large, and to date they seem to be restricted to mouse studies. Each pyrethroid listed above has a slightly different toxicity, so to get more information, Google the name or read the linked material by clicking on their name.

Are pyrethroids safe for pets?

Dogs and chickens seem to be fine. Cats, however, lack sufficient levels of a liver enzyme that helps detoxify pyrethroids, and can thus they can develop what is called pyrethroid toxicosis. A good indicator of cat sensitivity to pyrethroids is the standard warning of keeping them away from pyrethroid-treated dogs. I.e., if you dose your dog with a large amount of pyrethroids (to kill fleas, e.g.), friendly cats that cuddle with the dog are at risk. If you’d like to see a video of rag doll cat with pyrethroid poisoning (you probably don’t), here’s a video.

Do pyrethroids kill other animals? 

Yes.

For example, the spray kills monarch caterpillars, even weeks later later due to the presence of insecticide dried onto milkweed leaves (Oberhuaser et al. 2006).

And the spray can kill honey bees, even if honey bees are inside their hives when the pyrethroids are spayed (workers bring small amounts back to the hive the following day if they land on treated plants or if they find small puddles of water to drink). Sublethal amounts of pyrethroids can change honey bee behavior and make workers smaller. I would imagine the pyrethroids would end up in the honey, too.

And pyrethroids kill fireflies, which are most active in a yard in the late evening when mosquito-spraying franchises like to fog.

My favorite group of unnoticed insects that are killed by evening pyrethroid applications are solitary bees, of which there are approximately 4,000 species in the United States. These are bees that collect pollen and nectar during the day but spend their evenings and nights in holes (e.g., mason bees) or clamped to low vegetation. E.g., look at this a two-spotted long-horned bee (Melissodes bimaculatus) from my front yard this summer. Everyone has dozens of species of native bees in their yards but few people realize it. But they are amazing pollinators and almost all adorable. So when pesticide applicators claim their pyrethroid sprays “don’t harm bees” or are “bee friendly”, that is entirely untrue. It’s simply a marketing slogan they were taught when they bought the franchise, and they will insist it’s true even when presented with evidence to the contrary.

Anyone using a spraying service is, therefore, killing all of the above and more. Insects are small and easy to ignore, but if you were to go out after a spraying and look very carefully, you’d find thousands of dead insects on the ground. And only an extremely small percentage would be mosquitoes.

Pyrethroids can kill ALL arthropods, in fact, not just insects. So if a yard is sprayed, likely 100% of spiders, mites, centipedes, and millipedes would be at risk. In total that could mean tens of thousands of individuals left twitching in treated yards. In one estimate, an acre of land in Pennsylvania contains 425 million animals … and a good portion of them would be killed by pyrethroids.

Another concern with gassing all the arthropods in a yard is that those bird species that eat arthropods will have a lot less to eat. Population levels of swallows and flycatchers, for example, have dropped in last several decades and one explanation is that there are fewer insects to eat.

And then there are fish, which are acutely sensitive to pyrethroids. Franchise owners will generally avoid spraying near people’s fish ponds and bodies of water. Indeed, by law pyrethroids can’t be used near water, though there are many reports of franchises ignoring that regulation. Even if a property doesn’t have a pond or stream, pyrethroids are rather stable in the soil and tend to get washed into nearby streams after rains. It is increasingly accepted that runoff of pyrethroids into creeks can kill fish downstream.

Finally, pyrethroids are toxic to certain earthworms. This is probably especially true for those species that come out onto lawn surfaces in the evening, when pyrethroids are often applied. To be honest, many people don’t really care about earthworms (some hate them) but for people who love aerated lawns it should be pointed out that fogging with pyrethroids might result in dramatically less aeration and dramatically more odor from rotting earthworm carcasses. And, perhaps, result in robins that wonder where all the worms have gone.

Pyrethoids are engineered to last for weeks

As mentioned above in reference to monarchs, pyrethroids adhere to plant surfaces and stay active for weeks, so the risk to all the organisms mentioned above also lasts for weeks. Here’s a nice (and hilarious) description of pyrethroid persistence that I found on a Mosquito Squad FAQ:

“How can the barrier spray continue to kill mosquitoes for 21 days? Mosquitoes will feed on plant juices. When they attempt to feed on sprayed leaves, the residual from the spray will kill them.

Mosquitoes don’t eat leaves, of course, but the quote is correct about the fate of insects that walk on treated leaves. Pesticide franchises like to claim that once their product is dry it is no longer toxic, but that claim makes no logical sense in light of their claim that the product provides protection for three weeks. Some pyrethroids can even last for 90 days if they are on shaded surfaces. One possible reason (in my view) that pyrethroids retain their ability to kill is that morning dew and guttation (see photographs) might re-suspend the pyrethroids on plant surfaces, and then insects walk through or drink these droplets (see photographs).

Signage and notification requirements

All of the above information is of course useful to those interested in getting their yard fogged, but it’s also important for neighbors of treated properties. The reason for this is because the aerosolized pesticide always drifts onto neighboring properties a bit (sometimes a lot). So if a neighbor has a patch of milkweed or a vegetable garden right along the property line, pyrethroids will kill monarchs and coat the vegetables. Homeowners should always check with neighbors before hiring a spraying service and should always personally inform neighbors when the spraying will actually take place.

There doesn’t seem to be a Federal law requiring either signage or neighbor notification when a yard is sprayed with insecticide, and state laws are variable (here’s a good review; here’s another). Many states have laws that require applicators to leave signs at properties that have been sprayed, and some require notification of neighbors prior to spraying. For example, most counties in New York require that neighbors be notified 48 hours before spraying (details). In some states (e.g., Maine) you can get your name on a notification registry that requires any applicator to contact you in advance of spraying. That’s also an option for beekeepers in some states, too; in that case the pesticide applicators need to search a database of hives in a town, then notify hive owners when spraying will happen.

I live in Pennsylvania, one of several states that allows people to be placed on a Pesticide Hypersensitivity Registry. Once on it, pesticide applicators will know you have a medical issue with pesticides and they are obliged to inform you of future spraying (so you can leave the area). Also on this registry are beekeepers, apparently.

If you want to know what rules might apply in your state, Googling “pesticide notification laws regulations residential pennsylvania” (replace with your state) will get you started. If that doesn’t help just contact your state agency that regulates pesticide use. Towns and cities will sometimes have their own rules but some states prohibit such rules.

How local governments can help

All towns and cities should maintain a web page that provides mosquito information and relevant pesticide laws to residents (I designed a template if your town needs one). In addition to maintaining the page, local governments should push prevention by sending to residents timely, regular reminders — with visuals — about how to prevent mosquitoes from breeding. Such tips might be especially important for towns that strive to be pollinator-friendly (e.g., Bee City USA, Pollinator Friendly Alliance, Mayors’ Monarch Pledge). Towns can also enact ordinances on third-party pesticide applications. For example, a town might require that franchises alert neighbors 48 hours before spraying is done. Or, at the very least, towns can remind residents that neighbors can (usually) ask franchises to provide alerts before the next spraying so that cats are inside. Finally, local governments should consider banning automatic pesticide foggers (pipes that deliver pyrethroids on a timer, just like those automatic misters in the grocery aisle).

Logo that says
Image from Mosquito Squad that was removed as soon as they read this blog post.

State governments can can also make sure that pesticide franchises are not making false claims. E.g., if companies claim through words or imagery that their pyrethroid-containing sprays are “environmentally friendly,” “bee friendly,” “kid friendly,” “pet friendly,” or government approved (e.g., “EPA-approved”), sue them. Massachusetts did, and now has several restrictions on advertising including a ban on ads that “rely on images of young children to convey a sense of harmlessness“. Almost all sites I’ve looked at have misleading wording, especially the claim that pyrethroid-containing sprays “target” mosquitoes and ticks (completely false; they do no such thing).  Some sites also use misleading graphics and logos (like the one on the right, from a Mosquito Squad site in Florida) to suggest that the EPA has approved the products on a page. I could be wrong, but I’m fairly sure that the EPA neither approves any of these chemicals nor provides that logo. But a typical homeowner might be fooled into thinking otherwise — that’s why state oversight is needed.

Is spraying effective?

Although spraying pyrethroids might be a good way to kill mosquitoes near the ground and in low shrubs, some mosquito species spend most of their time high up in the canopies of trees and are untouched by sprays. For example, many species in the genus Culex (transmitters of West Nile virus, St. Louis encephalitis, eastern equine encephalitis, western encephalitis, avian malaria, etc.) are tree dwellers and only occasionally come down to feed on humans and pets. This limitation isn’t just theoretical: one study showed spraying didn’t reduce numbers of Culex at all. So if you have trees and birds, don’t expect that spraying will be effective. Continued spraying will also result in mosquitoes developing resistance to pyrethroids, something that is happening in Africa already.

But I don’t want to imply that spraying is ineffective. Pyrethroid fogs will probably kill a large percentage of Anopheles spp. (vectors of malaria) and Aedes spp. (vectors of dengue, yellow fever, Zika, etc.) because these species are more likely to be lower in the vegetation. There are more genera of mosquitoes, of course, so depending on where you live and what is growing in your yard, pyrethroids might vary in effectiveness. I think most companies suggest that their sprays might miss 10% of the mosquitoes on a property (that leaves quite a few mosquitoes).

Tips for controlling and repelling mosquitoes

Here are my 10 suggestions.

Complimentary fumigation during flight to Galápagos Islands

Before arriving in the Galápagos Islands, you get to watch the cabin being fumigated with insecticide. Because the plane is full of Prius owners who listen to NPR, it was fun to watch peoples’ faces as they slowly realized what’s going on. The audio couldn’t pick up everyone’s conversations, but trust me, it was funny. They don’t ask, “Would anyone mind if we sprayed a little insectide right now?” They just start doing it.

I think the prior to the spraying the captain should have cued up a short video on what introduced insects can do to the islands. For example, showing the devastation of Philornis downsi. Then again, people might be eating …

By the way, when you step off the tarmac after the flight you walk over a spongy mat that has even more chemicals, suspended in a soapy liquid, to kill the things that might be hiding in your treads. Pro tip: watch your step after coming off the sponge mat … it’s incredibly slippery, and will make you wonder whether the airport planners have a firm grasp of basic safety protocols.