Lubber grasshoppers in Florida - I found a solution!

[Merlyn]

I thought this would be the most appropriate spot for this thread, since lubbers rarely seem to eat palms in my yard.  They love Crinum Lilies, Canna Lilies, and occasionally eat bananas, agaves, and a few other random plants.  But the big plant on the dinner menu is always the Crinum Lily.  I've tried for years to get rid of them, but every spring hundreds more hatch in my yard and start new colonies.  My attempts in the past have been mechanical (i.e stomping them, grabbing them with gloves and smashing them on the concrete and then stomping on them, whacking them with sticks, throwing small rocks at them, cutting down trees to fall on them, etc), and chemical (Malathion, Acephate, Carbaryl, Imadicloprid, etc).  This was with limited success, at least on the chemical side.  I'd spray a whole colony of the nymphs and they'd scatter off, then the next morning there were just as many hanging around a plant a few feet away.  Manually killing them worked, but was time consuming and they are good at hiding in the spiky plants unless actively eating my Crinums. 

So last fall I was spraying some wasp nests on the eaves and I saw a big 4 inch fat lubber.  I sprayed it...and it died!  It might have died from drowning in it too, or from the propellant, so I vowed to try this again in the spring.  It's now lubber season in Central Florida.  The wasp spray was a generic RAID product, with Tetramethrin and Phenothrin.  I picked up a two pack of RAID Ant & Roach spray and test sprayed a cluster of about 50-75 nymphs.  They jumped off of the agave immediately and started dispersing, but then in about 30 seconds started jumping haphazardly and then croaked.  So I went through the whole yard and used about 3/4 of the can on at least 20 clusters of nymphs.  One cacti in the backyard had at least 100 on it.  I'd estimate I sprayed 400-500 of them.  At lunch I went out and sprayed again, but only found 3 significant clusters of 10-30 insects.  I'd guess I killed 80% of them yesterday and another 15% or so today.  One thing I noted is that there was a BIG difference between clusters that I'd sprayed yesterday, and ones that I had missed.  The survivors that had taken a non-lethal dose yesterday were sluggish and died in about 5 seconds after contact.  They only jumped once or twice and only a couple of inches.  The clusters that I missed yesterday were super active upon being sprayed, and immediately spread out to 3+ feet in all directions.

For future reference, the RAID Ant & Roach spray is Cypermethrin 0.3% and Imiprothrin 0.06%.  UFL recommends Carbaryl, Bifenthrin, Cyhalothrin, Permethrin, Esfenvalerate, and Spinosad.  I found that Sevin Dust (Carbaryl 5%) didn't kill the nymphs.  I haven't tried the others. 

https://entnemdept.ufl.edu/creatures/orn/lubber.htm

[Silas_Sancona]

8 minutes ago, Merlyn said:

I thought this would be the most appropriate spot for this thread, since lubbers rarely seem to eat palms in my yard.  They love Crinum Lilies, Canna Lilies, and occasionally eat bananas, agaves, and a few other random plants.  But the big plant on the dinner menu is always the Crinum Lily.  I've tried for years to get rid of them, but every spring hundreds more hatch in my yard and start new colonies.  My attempts in the past have been mechanical (i.e stomping them, grabbing them with gloves and smashing them on the concrete and then stomping on them, whacking them with sticks, throwing small rocks at them, cutting down trees to fall on them, etc), and chemical (Malathion, Acephate, Carbaryl, Imadicloprid, etc).  This was with limited success, at least on the chemical side.  I'd spray a whole colony of the nymphs and they'd scatter off, then the next morning there were just as many hanging around a plant a few feet away.  Manually killing them worked, but was time consuming and they are good at hiding in the spiky plants unless actively eating my Crinums. 

So last fall I was spraying some wasp nests on the eaves and I saw a big 4 inch fat lubber.  I sprayed it...and it died!  It might have died from drowning in it too, or from the propellant, so I vowed to try this again in the spring.  It's now lubber season in Central Florida.  The wasp spray was a generic RAID product, with Tetramethrin and Phenothrin.  I picked up a two pack of RAID Ant & Roach spray and test sprayed a cluster of about 50-75 nymphs.  They jumped off of the agave immediately and started dispersing, but then in about 30 seconds started jumping haphazardly and then croaked.  So I went through the whole yard and used about 3/4 of the can on at least 20 clusters of nymphs.  One cacti in the backyard had at least 100 on it.  I'd estimate I sprayed 400-500 of them.  At lunch I went out and sprayed again, but only found 3 significant clusters of 10-30 insects.  I'd guess I killed 80% of them yesterday and another 15% or so today.  One thing I noted is that there was a BIG difference between clusters that I'd sprayed yesterday, and ones that I had missed.  The survivors that had taken a non-lethal dose yesterday were sluggish and died in about 5 seconds after contact.  They only jumped once or twice and only a couple of inches.  The clusters that I missed yesterday were super active upon being sprayed, and immediately spread out to 3+ feet in all directions.

For future reference, the RAID Ant & Roach spray is Cypermethrin 0.3% and Imiprothrin 0.06%.  UFL recommends Carbaryl, Bifenthrin, Cyhalothrin, Permethrin, Esfenvalerate, and Spinosad.  I found that Sevin Dust (Carbaryl 5%) didn't kill the nymphs.  I haven't tried the others. 

https://entnemdept.ufl.edu/creatures/orn/lubber.htm

You do know that using when chemical stuff,  they will build resistance to it ...and that it will kill anything else that will eat the grasshoppers.. Which means ...more grasshoppers.

Would look into more natural means of control..

[mnorell]

I agree with Nathan, perhaps you can find a way to use natural strategies, or just relax and coexist with these native creatures...spraying these lethal neurotoxins and other chemicals is doing no favor to you, nor to the other insects and animals around, to the environment (including nearby plant materials that will be eaten by other insects and larger herbivores). And the residue of the spray dropping into the soil will kill or sicken everything from earthworms, grubs, millipedes, etc. that serve a vital purpose in the ecosystem, and most of which are food for animals up the food-chain. We had huge numbers of lubbers on our property on Big Pine Key, and just learned to live with them. Yes, they will do a number on your Crinums every year, just as the Plumeria caterpillars will defoliate your Plumerias, Adeniums, et al., then the Cordias get hit by their caterpillars as well, the list goes on and on and it's just part of the natural ecosystem. The plants are used to it, and refoliate, no problem.

The ultimate takeaway is...you will not win this battle. And lubbers are apparently only preyed upon by shrikes, who have figured out a way to eat them by denaturing their toxins...I never did witness that unusual death-ritual. But I researched and learned about lubbers and in fact enjoy their amazing Technicolor hues. I think watching their many life-stages is pretty awesome, in fact.

[Merlyn]

Nothing eats lubbers, so I'm not particularly concerned about poisoning going up the food chain.  The dead nymphs are exactly where they were yesterday.  Cypermethrin has an 8-16 day half-life when not exposed to the sun, but Imiprothrin is a longer lasting 60ish day half life.  A formulation without Imiprothrin is probably a better choice.  The Wasp & Hornet spray is Prallethrin 0.02% (3 day half-life) and Cypermethrin 0.05%, and would probably work better and be less residually dangerous to anything.  The other pesticides that I tried had no noticeable effect, which is why I mentioned them as something to avoid.  They were just throwing neurotoxins around the yard.  I don't do that casually.

Coexisting with creatures that eat entire 6 foot tall Crinums to the ground in a couple of days is not within the realm of possibility.  I barely saved one out of three variegated Crinum Asiaticum, given to me posthumously by the guy who got me into palms.  They ate the others to death.

[Silas_Sancona]

37 minutes ago, Merlyn said:

Nothing eats lubbers, so I'm not particularly concerned about poisoning going up the food chain.  The dead nymphs are exactly where they were yesterday.  Cypermethrin has an 8-16 day half-life when not exposed to the sun, but Imiprothrin is a longer lasting 60ish day half life.  A formulation without Imiprothrin is probably a better choice.  The Wasp & Hornet spray is Prallethrin 0.02% (3 day half-life) and Cypermethrin 0.05%, and would probably work better and be less residually dangerous to anything.  The other pesticides that I tried had no noticeable effect, which is why I mentioned them as something to avoid.  They were just throwing neurotoxins around the yard.  I don't do that casually.

Coexisting with creatures that eat entire 6 foot tall Crinums to the ground in a couple of days is not within the realm of possibility.  I barely saved one out of three variegated Crinum Asiaticum, given to me posthumously by the guy who got me into palms.  They ate the others to death.

I highly doubt nothing is munching on "Lubber Chips", lol..  Birds like Grackles, Warblers, Mocking and Catbirds eat them, Lizards / Snakes  ..and any frogs / toads love that protein-rich food source too. Certain wasps and spiders eat them as well ..That's a lot of Lubber control.. 

Using chemicals, you're poisoning that control to the point that everything is wayy out of balance, in favor of the grasshoppers dominating everything.. Even if you can't see the collateral damage being done.

Reason the nymphs are where fell is likely because anything that would consume them probably sense the chemicals used to kill them..

As far as the Crinums, Doubt the grasshoppers caused their demise.. Bulbs might have rotted, but not from the leaves being eaten, even if gnawed to the bases. Grasshoppers, like Cattle or Goats, eat a lot of stuff to the ground 99.9% of those plants grazed return in full glory w/ out any ill effect after being pruned.

[Merlyn]

@Silas_Sanconanothing eats lubbers.  From the UFL link I posted in the OP: "Overall, the natural enemies of lubber grasshoppers are poorly documented. Vertebrate predators such as birds and lizards learn to avoid these insects due to the production of toxic secretions by the adult hoppers, though this is not absolute (Chapman and Joern 1990). Naïve vertebrates often gag, regurgitate, and sometimes die following consumption of lubbers (Yousef and Whitman 1992). However, loggerhead shrikes, Lanius ludovicianus Linnaeus, capture and cache lubbers by impaling them on thorns and the barbs of barbed wire fence. After 1-2 days the toxins degrade and the dead lubbers become edible to the shrikes (Yousef and Whitman 1992)."

[Silas_Sancona]

18 minutes ago, Merlyn said:

@Silas_Sanconanothing eats lubbers.  From the UFL link I posted in the OP: "Overall, the natural enemies of lubber grasshoppers are poorly documented. Vertebrate predators such as birds and lizards learn to avoid these insects due to the production of toxic secretions by the adult hoppers, though this is not absolute (Chapman and Joern 1990). Naïve vertebrates often gag, regurgitate, and sometimes die following consumption of lubbers (Yousef and Whitman 1992). However, loggerhead shrikes, Lanius ludovicianus Linnaeus, capture and cache lubbers by impaling them on thorns and the barbs of barbed wire fence. After 1-2 days the toxins degrade and the dead lubbers become edible to the shrikes (Yousef and Whitman 1992)."

Fairly skeptical of this research... I mean, if only one predator consumed them, the Lubbers would have overwhelmed everything long ago, and there'd be no Crinums  -and related plants they consume, -native and introduced...  anywhere  within the range of the Grasshopper.   Every critter, even those that concentrate the chemicals of certain " toxic" plants they consume has another critter  ..or several   that balances things out.  To assume there is only one animal that acts as natural  "Lubber Control" is highly questionable..


Regardless, as is the case w/ all sorts of animals these days,  because of Pesticide overuse / abuse, and constant destruction of habitat for unnecessary development, Loggerhead Shrike populations, inc there in FL, are in steep decline..  

https://myfwc.com/media/19730/bba_losh.pdf

https://abcbirds.org/bird/loggerhead-shrike/

.....Another reason greatly restrict Pesticide use when dealing w/ annoying bugs...   Just had a similar conversation w/ some " Eco- Friendly " Pesticide salesmen roaming the neighborhood this week looking for new business  ..using classic, salesperson scare tactics as a way to generate that business..   Our monster, flying Cockroaches and Black Widows don't scare me..  14" Reptile Tongs, and / or matches, ..and a flashlight  sure scare Black Widows though, lol.

  Just about that time of year to start patrolling the yard after dark, looking for babies to squish ..or set on fire, haha..


 

[mnorell]

Nathan, lubbers are very cyclical (annually) and have a limited period where they're really consuming Crinum leaves (actually, they will eat anything toxic, anything else in the Amaryllidaceae, and then they move on if necessary. Last year at our place in the Keys, we had a bumper crop, and after C. asiaticum, they for the first time started in on Jatropha integerrima (Euphorbiaceae), and even started eating Chrysalidocarpus lutescens. Note that both of these latter species are toxic to some extent (Carl Lewis and Scott Zona tested and discovered that C. lutescens contains Hydrogen Cyanide...I knew long ago there was something going on in this species because the Key Deer wouldn't even go near them.)

I think the concern with pesticide residue also is that once the lubbers die, after a couple of days the naturally assimilated plant toxins denature and the lubbers become edible to a much wider variety of creatures, so pesticide residuals without a very short half-life will present a problem. As far as natural enemies goes, this rather comprehensive article states they are heavily parasitized, and also that invertebrates in general have no problems with the toxins when feeding on these...only vertebrates.

While I have noticed that they really prefer Crinum asiaticum over some of the other species (they would always eat them before really going near the giant-flowered C. x amabilis), since the lubbers are native, and Crinum asiaticum isn't, there are many other plants that might be used as decoys to deter predation. Probably Crinum americanum would be the natural species to use as a basis for experimentation. This might be a good way to tackle the problem...plant C. americanum, oleander, the little native Euphorbia (poinsettia weed) found all over Florida, Jatropha, many others...the article noted above has a decent list.

And I am in agreement about the overblown reputations of so many "dangerous" insects. Once you look at the world as a functioning ecosystem, it becomes easier and easier to "live and let live" with most of our many wild neighbors. Roaches are not a problem, they are great detrivores and they are removed safely to mulchy areas of the garden from the house. And while I don't like the fact that we have so many black widows all over here in the low desert, and despite the fact that we were warned as small children to carefully look out for them...there are MANY of them here, they seem to be everywhere so one has to be aware. But after studying up on them and demystifying/upending a lot of our unfounded fears/concerns...we just keep them out of the house, and also remove those that are in heavy traffic areas, especially in the garage, the barbecue, or in plant-containers (and under the rims of big containers!) The good thing being that they rarely move, stay tucked up in their place capturing roaches and crickets, and they have very little interest in biting humans (unless you don't check that old pair of shoes or gloves before putting them on...as it is the extreme "squishing" pressure along their entire bodies that makes them bite). Plus there is a huge "black widow hunter" mud-wasp here that will be showing up soon to scour the property for some of these ladies. these wasps are fascinating to watch as they move about on their hunting expeditions.

[Merlyn]

@Silas_Sanconathe entomologists are pretty consistent on the Eastern Lubber grasshopper.  This is not a regular grasshopper.  Regular grasshoppers live in my yard all the time, I ignore them.  In small numbers the Eastern Lubber is also a minor annoyance, and were easy to ignore or manually kill the adults by hand.  But when you get an explosive population of 500+ nymphs in 0.75 acres they are a destructive pest.  Killing the nymphs is the preferred method of management by all the entomologists, as they are small enough for pesticides to work quickly with low doses.  I looked at Spinosad, but I'm skeptical that a poorly-understood microbial agent is actually better than a short half-life nerve agent like Prallethrin or Cypermethrin.

The Eastern Lubbers ingest toxic substances from plants and make themselves poisonous to predators.  They also secrete a foul-tasting foam, hiss and vomit at predators.  I've watched the local lizards grab a nymph, immediately spit it out, and run away.  Birds ignore them, as do snakes.  The only animals that appear to love a Lubber snack are fire ants, which instantly swarm any adult that I've stomped.  Monarch butterflies are famous for being toxic to predators, but apparently Lubbers are much, much worse and can actually kill their predators:

https://entomologytoday.org/2018/03/22/eastern-lubber-grasshopper-hard-miss-occasional-pest/

"For its own defenses, the eastern lubber grasshopper sequesters and synthesizes chemicals from the plants it eats, turning them into toxic secretions that predators learn quickly to avoid. The monarch butterfly is a primary example of this capability, but Schowalter says the eastern lubber grasshopper “displays a much wider variety of chemical sequestration.”"

From the entomologist Schowalter who wrote this Journal of Integrated Pest Management article (bolded text by me):

https://academic.oup.com/jipm/article/9/1/10/4938808?login=false

Mortality Factors

Lubber grasshoppers are protected from most vertebrate and invertebrate predators by the combination of chemical defense and warning coloration (Jones et al. 1987, 1989; Blum 1992; Whitman et al. 1992; Hatle and Spring 1998). The bold coloration of lubbers advertises toxic chemicals to would-be predators, but even young nymphs that produce less chemical defense are avoided by lizards (Hatle and Townsend 1996, Hatle et al. 2001). Birds and mammals vomit violently after ingesting a lubber (Fig. 6) (Blum 1992, Yousef and Whitman 1992). Yousef and Whitman (1992) reported that 21 tested bird and lizard species were unable to consume lubbers and some died. Loggerhead shrikes, Lanius ludovicianus L. (Passeriformes: Laniidae), captured lubbers and impaled them on thorns or barbed wire fences. After 1–2 days the toxins degraded, and the shrikes were able to eat the dead lubbers (Yousef and Whitman 1992).

[Tomas]

Cypermethrin and Imiprothrin are both neopyrethroids and the warm blooded animals decompose them very quickly and get not harmed. The exception are cats, if in contact with some pyrethroids, they can even die

[Scott W]

While I do limit my pesticide usage in my yard, I'm with Merlyn on this one.  I've found the use of pyrethrin or bifenthrin do the trick on these little demons.  I buy the concentrate at the local farm supply or you can find it on Amazon.

[Merlyn]

I did some additional research on the pesticides, and tried the RAID Wasp & Hornet spray on a small cluster.  It is Prallethrin 0.02% and Cypermethrin 0.05% and had ~10 second kill on the nymphs.  These are both relatively rapid disintegration in soil, but the spray was difficult to aim the long distance stream.  An ant spray type uses a lot less actual pesticide for a given number of kills.

• Permethrin – 40 day half life, binds directly to soil and lasts over 1 year. Derivative of Chrysanthemum, faster degrading types are a better choice
• Prallethrin – fast pyrethroid instant kill, used in wasp sprays at 0.02%. Lubber killer, extremely fast. Repel-X concentrate at 0.27% possibility.  Half-life 3ish days, this is a great choice.
• Cypermethrin – fast ant & roach kill, effective against Lubber nymphs with 0.3% plus Imiprothrin 0.06%. Unsure as to which is most lethal, but combo is 99% lethal in 30 seconds. Half life is 8-16 days.
• Imiprothrin – This is the persistent ingredient in ant & roach killer, 60 day half-life. Combined with Cypermethrin it's good against Lubbers, 99% lethal in 30 seconds.
• Carbaryl – Sevin Dust ingredient, tried on Lubber nymphs with no noticeable deaths. This seemed like it just annoyed them.
• Lambda Cyhalothrin – binds to soil, so no chance of groundwater contamination, 5 day half-life on plant leaves, 9-30+ day half-life in soil.  If this works it's a good choice.
• Bifenthrin – 90-250 day half-life, 100-150 in sunlight, avoid this one due to very long half-life.

For fast action and short half-life, Prallethrin, Cypermethrin and Lambda-Cyhalothrin are possibilities.  The first two definitely are quick killers on the nymphs, but I have not tried Lambda-Cyhalothrin.  Hot Shot Ant Killer spray is Prallethrin 0.025% and Lambda-Cyhalothrin 0.03% and is probably a great short distance aerosol with short half-life and rapid kill.  As a concentrate, Repel-X might be a really effective killer with a super short 3 day half-life.  The downside is that once you mix it, the ticker may start on the mix...since many of them degrade in slightly acidic water.  But the "fast kill" types also appear to be some of the quickest to decay in sun/soil/air/water, which is really nice!

[JLM]

On 3/14/2023 at 2:11 PM, Merlyn said:

cutting down trees to fall on them

Oh....

Ive never heard of these and the way it sounds, i should be thankful.

[Merlyn]

As a followup, I tried three different sprays on 1-1.5" black nymphs with yellow stripes. 

• RAID Wasp & Hornet killer (Prallethrin 0.02% and Cypermethrin 0.05%) is extremely effective (~10s kill) but difficult to aim and wasteful. 
• RAID Ant & Roach (Cypermethrin 0.3% and Imiprothrin 0.06%) is fast and effective (~30s kill) and easy to aim and spray. 
• Hot Shot Ant, Roach & Spider killer (Imiprothrin 0.075% and Lambda-Cyhalothrin 0.025%) is much slower acting but initial tests on large nymphs shows fast incapacitation but 1-2 hours to actually kill.

Based on the results so far, the fastest seem to be Prallethrin and Cypermethrin, and the least effective are Imiprothrin and Lambda-Cyhalothrin.  My next test will be Hot Shot Ant Killer, which is 0.025% Prallethrin and 0.03% Lambda-Cyhalothrin.  It seems like Cypermethrin could be a good choice (Cyper WSP or Demon WP) for a storable concentrate with a short half-life.

[flplantguy]

Apparently they are pretty numerous this year:

https://www.wfla.com/video/giant-orange-grasshoppers-take-over-florida-home/

[Merlyn]

@flplantguywow that video is crazy!  I've never seen that many in one spot before, typically 4 or 5 or so of the mature white/yellow/black at a time.  Right after they hatch I'd find 30-50 nymphs on a single plant.  That guy's going to have 10,000 of them next spring...I hope his dog learned it's lesson and won't eat another one.  Fortunately it didn't die! 

[flplantguy]

It popped up random online too not long after i saw your topic post. Its a bad year i guess.

[SubTropicRay]

Lubbers are cannibalistic so they don't need an outside predator to control their numbers.  Nolo bait, which may no longer available, took advantage of this behavioir.  It is (was) an environmentally safe product that lubbers would eat.  The then poisoned grasshopper would die a slow death but not before wandering around and getting eaten by another lubber and so on.  This would happen until the local population was gone.  I'm sure a new version of this product is available if the original is out of production.  

[Merlyn]

On 6/1/2023 at 1:11 PM, SubTropicRay said:

Lubbers are cannibalistic so they don't need an outside predator to control their numbers.  Nolo bait, which may no longer available, took advantage of this behavioir.  It is (was) an environmentally safe product that lubbers would eat.  The then poisoned grasshopper would die a slow death but not before wandering around and getting eaten by another lubber and so on.  This would happen until the local population was gone.  I'm sure a new version of this product is available if the original is out of production.  

It looks like Nolo Bait would be a great solution, if they could get back into production.  Nosema Locustae was also sold as Semaspore, but that one appears to be out of production too.  It's supposed to be very effective on the nymph stage, but questionable on the adult stage.  Azadirachtin is an Insect Growth Regulator (IGR) derived from the neem tree and might be an option too. 

As an example of how voracious they are, this was a 2' diameter Crinum Asiaticum highly variegated, that had just finally recovered from last year's lubber attack.  On Sunday morning it looked fine...on Sunday evening it was 99% eaten, with only one half-dead leaf remaining.  The lubbers managed to squeeze through plain 1" chicken wire, which they had not done last fall.  This is the last remaining plant from my late gardener friend:

And this is the 1/4" hardware cloth cage I just built for it.  I might have to re-level the pavers to make sure they can't walk under the edge at some spot.

[Guest Farmboy]

As for things that eat lubbers, my wife puts on her garden gloves, picks a few lubbers off our plants, takes them across the street to a lake inlet, and throws them to the 2ft long alligators, who promptly go after them.  The gators seem pleased, and though I suppose in 20 years they could develop a toxic bite, for now we are not using chemicals, and keeping gators content.   So gators as well as shrikes chomp lubbers, and our cat sometimes kills them as well.... he has learned not to chomp them, but certainly plays with them successfully. NoloBait was not available this year, and the lubber population has certainly grown. They are really awful little critters, if you are trying to grow anything. Still, roach spray seems a bit over the top. I like the idea of a molasses-water trap, but have not tried it yet.

[TammyT]

I for one appreciate this information @Merlyn  For those saying “live and let live” I don’t think they’ve experienced the devastation these lubbers can do. Last year, I paid my neighbor’s daughter and her friend (middle school aged) a quarter for every one they put in a bucket of water. However, it became apparent when I discovered almost 100 of them feeding on my banana trees and lilies that this was going to be a too expensive option. Plus, the girls started freaking out the bigger they grew. I have no problem strategically & responsibly using Raid to kill these grasshoppers. It’s a direct contact kill that is required and as you stated, not much will feed on these monstrosities bc of their toxicity. Today, a neighbor of mine from across the street just asked me if I had seen any bugs like the ones he is seeing. He pointed to his neighbors fence. Looks like the season has certainly kicked off. Let the games begin!  Thanks again!

[Scott W]

Yep, saw my first ones today as well.  Unfortunately I'm off on vacation in the morning so eradication will have to wait....

[Merlyn]

@TammyT and @Scott W yep, I wiped out 6 clusters on 3/13 and another 5+ clusters since then.  Any of the sprays with cypermethrin or prallethrin seem to work extremely well, and have very short half-lives in air or soil.  Given how poisonous the nymphs and adults are to lizards, snakes, frogs, and birds, I'd rather take them out young than have animals eat them and die.  They seem to group together around dusk, so one short spritz of pesticide can easily take out 50+ at once.