Asian Hornets

[Karol]

Thanks. I shall remove the offending snap

It would be a shame to remove the picture. Perhaps just correct the description? Might help others with their wasp recognition. Germanica typically has diamond markings down the top centre line of the abdomen flanked by spots either side. Crabro tends to have inverted crowns (i.e. the flanking dots join laterally to the periphery of the diamond markings) and it's rustic colouration is a give away although Median queens are frequently mistaken for Crabro because of their similar resemblence and large size.

 

[RichardK]

All I want to know is worth hanging outside my hive for an hour every day killing Asian Hornets with a badminton racket or am I wasting my time?

In short, yes it's worth it. Generally I get between 10 to 20 over the course of an hour if I wait with a badminton racket. Generally I get most in the first 20 to 30 minutes. My take on it is if I can kill ideally all of the asian hornets 'working my hives' at a given time they can't go back and tell their mates about them. It works in the short term. By me I rarely see European hornets - I'd guess 1 for every 50 or more asian hornets.

I've joined some good French Facebook groups for my area (Occitanie) which offer advice and views more attuned to my area. It's definately worth doing - we compare asian hornet kills from time to time . Where abouts are you in France?

 

[plain_hunt]

All I want to know is worth hanging outside my hive for an hour every day killing Asian Hornets with a badminton racket or am I wasting my time?

Judging from the short time I spent in Jersey learning how to tract AH, you’re better off trying to find the nest and kill that than trying to kill a few AH at the hive site. That way you’ll get next years queens as well. They did put up bait stations, which also caught wasps, and they killed a lot, but it didn’t make much difference to those around the hives.

 

[RichardK]

The

Judging from the short time I spent in Jersey learning how to tract AH, you’re better off trying to find the nest and kill that than trying to kill a few AH at the hive site. That way you’ll get next years queens as well. They did put up bait stations, which also caught wasps, and they killed a lot, but it didn’t make much difference to those around the hives.

The theory is good, unfortunately in practice at least my way it doesn't work that way. Yes absolutely you could try to track down the nest. And if it's on public land then the mairie (town hall) will during spring and summer take responsibility and sort it out. However, vast areas of land are not public, rather private and the land owner is under no legal obligation to do anything. Whilst I'm sure in a town it might be different, much of France is rural or rural'ish. The most promising advice I've heard is in our region some people use Frontline (the flea treatment for dogs) - they mix some with a bait like tuna I believe for the asian hornets to feed off of. They then take it back to the nest and with enough taken, poison the nest. Someone else spends hours each week as necessary catching individual asian hornets using a net by his hives, then in effect watering them with a frontline mixture and releasing them with the same end in mind. I haven't tried it myself - my badminton skills are rapidly improving though .

 

[robbohenn]

I'm in Brittany and am conscious of the Asian problem. However, I haven't seen many around this year yet. Asian hornet traps are easily available in supermarkets but they are not selective and will attract any insects that want to enter them. They need checking a couple of times daily to release any Europeans or other beneficial insects. Apparently using beer in the attractant doesn't attract bees! I put one out in the spring and caught 25 Asians - hopefully they were all foundress queens. Swatting will only exercise your arm as there are thousands of them in the "nid"! If you know where the "nid" is, contact your local pompiers and they will destroy it. At least getting rid of it now could mean less of them surviving the winter to start a new colony next year.
Good luck.

 

[RichardK]

I'm in Brittany and am conscious of the Asian problem. However, I haven't seen many around this year yet. Asian hornet traps are easily available in supermarkets but they are not selective and will attract any insects that want to enter them. They need checking a couple of times daily to release any Europeans or other beneficial insects. Apparently using beer in the attractant doesn't attract bees! I put one out in the spring and caught 25 Asians - hopefully they were all foundress queens. Swatting will only exercise your arm as there are thousands of them in the "nid"! If you know where the "nid" is, contact your local pompiers and they will destroy it. At least getting rid of it now could mean less of them surviving the winter to start a new colony next year.
Good luck.

Again fine in theory, however as many nests will be on private land and there is no obligation on the landowner to do anything likely nothing will happen. I'm a first year bee keeper so I don't know what is a bad / good year relative to asian hornets. I still think (as do others in my region) that killing those hornets preying on the hive(s) will at least in the short term relieve pressure on the hive. Gut feel the poison route I mentioned above is the best route. Last year the lady who runs the local bee shop simply moved her hives as the pressure was too great.

 

[manek]

To the OP: check out Eric Darrouzet's YouTube channel. There's tons of good info on there about Vespa velutina and their behaviour etc. https://www.youtube.com/channel/UCh2Tf0seuUfK-Dm0TkmDFDQ

 

[Karol]

Again fine in theory, however as many nests will be on private land and there is no obligation on the landowner to do anything likely nothing will happen.
<snip>

Therein lies the issue which is why Mazzamazda's method of catch, dose & release in areas of heavy established infestation provides some relief from landowner apathy. The method is a trojan horse which does not require tracking down the nests as the hornets know where home is. Treat consistently for a period and the numbers of asian hornets visiting the hives drops off appreciably and then it's just periodic maintenance to keep numbers down. The fears of collateral damage to non target species really isn't justified especially in the face of the carnage caused by Velutina as an invasive species.

 

[jenkinsbrynmair]

The fears of collateral damage to non target species really isn't justified

In your view - many think the opposite to such reckless (and some would say selfish) action.

 

[Jules59]

I'm pleased to say that this year the hornets have returned to the apiary having been absent last year (in lockdown I suppose). They dont seem to bother the bees but they like to tuck into my pears.
Here's a pic I took earlier this week.

 

[Karol]

In your view - many think the opposite to such reckless (and some would say selfish) action.

The fear isn't justified because of the short half life of the formulation, i.e. the pesticide stops working within a short space of time, so there's just about enough time for the pesticide to be taken back to the nest and shared within the colony. Dosing is small and highly targetted - probably enough for trophallaxis for only several nest mates one of which hopefully is the queen. So unlike the 3 million times excess pesticide applied in typical nest treatments the method does not pose anywhere near the threat to non target species that orthodox nest eradication does. And in terms of vector failure this appears to be minimal judging by the rapid drop off in Velutina numbers meaning that either nests appear to be failing (most likely explanation) or there is interruption in communication (less likely because only a small proportion of the number of hornets are treated meaning other nest mates are still able to communicate location).

 

[jenkinsbrynmair]

I'm pleased to say that this year the hornets have returned to the apiary having been absent last year (in lockdown I suppose). They dont seem to bother the bees but they like to tuck into my pears.

hornets were few and far around here until a few years ago, then I had a call from an acquaintance of the family (during the first Asian hornet hysteria) and I identified a nest of crabro in their soffit (they left them alone after I explained - and showed them a 'real' Asian hornet preserved in alcohol) since then I regularly see them or hear them as they motor past. This season I have seen quite a few in the garden so there must be a nest not far away and I also have a hornet nest at two apiaries - neither have been any trouble and in fact weren't noticed until a few weeks ago.

 

[jenkinsbrynmair]

The fear isn't justified because of the short half life of the formulation, i.e. the pesticide stops working within a short space of time, so there's just about enough time for the pesticide to be taken back to the nest and shared within the colony. Dosing is small and highly targetted - probably enough for trophallaxis for only several nest mates one of which hopefully is the queen. So unlike the 3 million times excess pesticide applied in typical nest treatments the method does not pose anywhere near the threat to non target species that orthodox nest eradication does. And in terms of vector failure this appears to be minimal judging by the rapid drop off in Velutina numbers meaning that either nests appear to be failing (most likely explanation) or there is interruption in communication (less likely because only a small proportion of the number of hornets are treated meaning other nest mates are still able to communicate location).

again, your opinion although I'm sure you will quickly make up some 'data' to back it up

 

[Erichalfbee]

Fipronil is reported to have a half life of between 36 hours ( exposed to uv) and over 7 months ( not exposed)
https://pubmed.ncbi.nlm.nih.gov/12442503/It is highly toxic to birds

https://ec.europa.eu/environment/in...nd_fipronil_harm_fish_and_birds_402na5_en.pdf

 

[user 819]

Yes and it is the factor that birds may well predate a dead out nest treated as such as the protein from insects are a good meal. Fortunately the UK has all but escaped bar a few incursions meanwhile my garden birds tuck in to a feast of Silkworm pupae, dried crickets, mealworms and black fly larvae.

 

[Repwoc]

It is highly toxic to birds

Some birds. From the article cited:

Fipronil is highly toxic to bees (LD50 = 0.004 microgram/bee), lizards [LD50 for Acanthodactylus dumerili (Lacertidae) is 30 micrograms a.i./g bw], and gallinaceous birds (LD50 = 11.3 mg/kg for Northern bobwhite quail), but shows low toxicity to waterfowl (LD50 > 2150 mg/kg for mallard duck). It is moderately toxic to laboratory mammals by oral exposure (LD50 = 97 mg/kg for rats; LD50 = 91 mg/kg for mice).

According to @mazzamazda's recipe, he adds 10 drops of 0.25% w/v Fipronil to a teaspoonful of 'custard'. 10 drops is ~ 0.5 mL (Drop (unit) - Wikipedia) which corresponds to 1.25 mg of Fipronil. This mixture is then dabbed onto stunned V.Velutinas which then carry the mixture back to their nest. @mazzamazda says it's " Ideal if you can catch 5-10 hornets".

I don't know how much of the mixture would be carried back to the nest by 10 hornets, but if it was the entire 5.5 mL containing 1.25 mg of Fipronil then:

The Fipronil LD50 for bees is 0.004 µg/ bee. Hornets are larger than bees, so assuming LD50 for hornets is 0.005 µg/hornet then 1.25 mg is enough to kill 125000 hornets if the dose is distributed throughout the nest. Clearly a lot more than a typical V.Velutina nest contains which is ~1000 workers in August (https://www.cabi.org/isc/datasheet/109164).

The Fipronil LD50 for Northern bobtail quail is 11.3 mg/kg (see above). If a bird weighing 100 g was to consume the entire dead nest, thus consuming 1.25 mg of Fipronil then there is > 50% chance that the bird would die.

It seems unlikely that ~ 6 g of mixture could be daubed onto 10 hornets and that they would be able to carry it back to their nest, so the actual Fipronil dose a nest would receive would likely be less than 1.25 mg. 10 µg of Fipronil is sufficient to kill 1000 hornets, so 1 drop of mixture containing ~11.4 µg would kill the nest, but would not harm a 100 g bird if it consumed all the dead hornets. The bird would have to consume about 100 dead nests to reach the LD50 dose.

Quite a lot of assumptions, but it seems that the tiny quantities of Fipronil involved in this method are unlikely to hurt any birds.

 

[Karol]

Thank you Repwoc. It's refreshing to encounter a little objectivity.

To be perfectly clear, I am not advocating catch, dose and release in the UK. We simply do not have a problem here in the UK that warrants such action. That cannot be said of France and Portugal where the infestation of a foreign invasive species introduced by man is wreaking havoc on local fauna.

Each hornet is daubed with one drop, circa 0.05ml - 0.1ml on the top of their thorax. The purpose of the custard is two fold but it must be made from egg yolk and sugar, not packet custard. The egg yolk allows the mixture to adhere to the waxy cuticle. Placing it atop the thorax means the carrier hornet can't get at it but its nest mates will preen it clean when the carrier hornet gets back to the nest. Aqueous formulations simply 'fall off' being lipophobic. The other is that the yolk mix inactivates the fipronil probably through strong lipid binding. Hornets that consume the fresh mix die. Hornets that consume the same mix several hours later appear unaffected.

One rarely hears of any outcry when spot on treatments are applied to dogs or cats.

 

[Erichalfbee]

Some birds. From the article cited:


According to @mazzamazda's recipe, he adds 10 drops of 0.25% w/v Fipronil to a teaspoonful of 'custard'. 10 drops is ~ 0.5 mL (Drop (unit) - Wikipedia) which corresponds to 1.25 mg of Fipronil. This mixture is then dabbed onto stunned V.Velutinas which then carry the mixture back to their nest. @mazzamazda says it's " Ideal if you can catch 5-10 hornets".

I don't know how much of the mixture would be carried back to the nest by 10 hornets, but if it was the entire 5.5 mL containing 1.25 mg of Fipronil then:

The Fipronil LD50 for bees is 0.004 µg/ bee. Hornets are larger than bees, so assuming LD50 for hornets is 0.005 µg/hornet then 1.25 mg is enough to kill 125000 hornets if the dose is distributed throughout the nest. Clearly a lot more than a typical V.Velutina nest contains which is ~1000 workers in August (https://www.cabi.org/isc/datasheet/109164).

The Fipronil LD50 for Northern bobtail quail is 11.3 mg/kg (see above). If a bird weighing 100 g was to consume the entire dead nest, thus consuming 1.25 mg of Fipronil then there is > 50% chance that the bird would die.

It seems unlikely that ~ 6 g of mixture could be daubed onto 10 hornets and that they would be able to carry it back to their nest, so the actual Fipronil dose a nest would receive would likely be less than 1.25 mg. 10 µg of Fipronil is sufficient to kill 1000 hornets, so 1 drop of mixture containing ~11.4 µg would kill the nest, but would not harm a 100 g bird if it consumed all the dead hornets. The bird would have to consume about 100 dead nests to reach the LD50 dose.

Quite a lot of assumptions, but it seems that the tiny quantities of Fipronil involved in this method are unlikely to hurt any birds.

Thank you for that
You've cleared up a lot of my misconceptions

 

[Will Kevans]

As we don’t have them we would all be guessing!!! However if you use the search function there’s a Portuguese chap who stuns them with his electric racket paints them with custard/tick treatment and sends them on the way. It works for him!

What exactly is custard tick treatment?Im into sending them back to their lair with poison

 

[Will Kevans]

What exactly is custard tick treatment?Im into sending them back to their lair with poison

Fibronil is this a chemical I can access in France what is it for?Im guessing some kind of tick insecticide?