Home » Posts » News and Views » Pesticides versus Hong Kong mosquitoes killing too much other wildlife
Email to director of the Food and Environmental Hygiene Department, after multiple correspondence with other FEHD officials failed to achieve progress on issue of over zealous use of pesticides versus mosquitoes killing considerable other wildlife:
Pesticide squirted, as if just for the sake of squirting by a path
I’m a birdwatcher living on Cheung Chau, and have made numerous complaints to FEHD regarding fogging and spraying insecticides for mosquito control.
Yes, I appreciate that mosquitoes – including Aedes albopictus – are important vectors for diseases including dengue fever, and now chikungunya.
However, I also believe the use of pesticides versus these mosquitoes is too often excessive, and often extremely poorly targeted
– and that this in turn kills substantial other wildlife.
Also, FEHD officers have contacted me sometimes, perhaps saying the FEHD contractors’ teams would adopt better approaches, but there has been little real progress.
Disastrous impacts on other wildlife
Numbers of moths, beetles and other insects have plummeted around our home in recent years, surely as a result of the pesticides.
This in turn has reduced numbers of insectivorous birds, which I used to find in fair numbers. Also frogs and toads.
Importantly, too, this is surely not just a Cheung Chau issue.
Pesticide fogging at Tamar Park: does not look like habitat for mosquito breeding; surely few here
Kowloon Park, for instance, was formerly a birdwatching hotspot; but has become significantly worse for birds in recent years. Birdwatchers have seen abundant pesticide being applied there – surely no coincidence.
Perhaps in response to my complaints, there was some change, from a reliance on a wide-spectrum insecticide [permethrin], to at least some use of bti toxin.
Bti toxin: not an answer in itself
At first, use of bti toxin seemed to me excellent, as I read it is specific to mosquito larvae; hence should avoid killing other species.
But, I have seen this or other insecticide readily squirted at various places with no water for mosquito breeding; like short grass, even bare earth with almost no plants.
Plus, there seems to be quite a smell after bti is applied, so it seems there are other chemicals accompanying it?
Contractors don’t care??
It appears that the contractors and some of their team members don’t really care; I believe they are just aiming for zero or near zero mosquitoes trapped in sampling places. Perhaps that’s the viewpoint of the contractors; worried that FEHD will complain if mosquitoes are detected.]
Maybe the teams are simply not really trained, educated in just what is being attempted, which should be targeting places where there may actually be mosquito larvae. So even small amounts of water, maybe in trees, but especially in lap sap etc.
Squirting pesticide at vegetation by a path; seemingly random
Alternatives???
More careful application of pesticide
I have often been told that contractors’ teams will be advised to use pesticide more carefully.
Yet seen it still applied carelessly.
An improvement here would be welcome. Including bti toxin applied where there is some water where Aedes mosquitoes may breed.
More publicity about mosquito breeding places around people’s homes
I remember Hong Kong having promotions about “No standing water. No mosquito breeding”
But nowadays, not seeing such promotions.
I’ve looked online, various places like Australia aim for eye-catching, memorable public relations campaigns.
Aussie promotion re eliminating mosquito breeding places around homes
Then, if people help by checking their homes, might also impact mosquitoes overall.
– we check around our home. Did have some water with mosquitoes breeding; after watering an indoor plant. Of course, made sure this place is now dry.
Non pesticide spraying approaches: traps
I have also seen that mosquitoes can be trapped, killed, as the females lay eggs.
Information on In2Care claims their mosquito “stations” can decrease mosquitoes within around 4300 square feet, so around 400 square metres.
I see you use these traps, but mainly for monitoring mosquitoes?
What about increasing the numbers, densities, see if these traps can have a significant impact?
No need to be over wide areas, perhaps; but along the most used sections of paths, such as by housing – where people are more likely to be bitten if there are mosquitoes.
I know a public housing area that perhaps uses such traps; has few or no mosquitoes, but also enough insects that it is a hotspot for small migratory birds.
Well, I am sure your team in FEHD can come up with better, if you agree it is worthwhile finding how to control mosquitoes with minimal impact on other wildlife.
Hope so!
Facebook Comments
I posted the above to Facebook; here are some comments:
We live on Lamma and stress about the same. Would be good to find out if we can build some sort of coalition around this as it is a HK wide issue. Any sense of whether there are any local NGOs working on this?
I have also complained about this on Lamma
We used to have bees, butterflies and dragonflies everywhere, ladybugs too. It’s quite worrying to have them spraying everyday and at every drains, along pavement and at every park in our area. Now we are left with tons of mosquitoes and cockroaches.
Couldn’t agree more that a public info campaign is needed about standing water. Trays under potted plants are seen everywhere. If people know they’re putting themselves at risk of mosquito-borne diseases there will surely be behavioural change
Auto-translated: Thank you for your efforts. Everyone knows that the work you are doing is thankless. We understand that officials, to cope with pressure from higher-ups and complaints from the public, often resort to the simplest actions to prove that they have actually done something. Widespread spraying of insecticides is one of the most direct methods. At least it shows people that something is being done, and in the short term, it seems effective in reducing mosquito problems. For officials or most citizens, other forms of life simply don’t matter, and most people, for the sake of convenience, won’t consider using sustainable or environmentally friendly methods to replace the existing system. In this regard, those of us involved in bee conservation feel this deeply. Breaking this deadlock seems extremely difficult at the current stage.
多謝你嘅付出。
次次噴完之後果日，仲多左俾蚊咬。
都唔知係唔係上一級掠食者俾殺蟲水攪掂左。
蚊又大量第二係度飛過黎。
Auto-translated: Thank you for your efforts. Every time after spraying, the next day I end up getting bitten by mosquitoes even more. I don’t know if the higher-level predators have been taken care of by the insecticide. The mosquitoes are swarming again in large numbers.
我都住長洲，以前行山頂道的確好多唔同種類昆蟲，逢夏天會見到手掌咁大既
仲有蟬，近5-6年
差不多已絕跡在路邊，蟬亦少了很多，唔想比蚊咬自己噴蚊怕水好了！
Auto-translated: I live in Cheung Chau. In the past, there used to be many different kinds of insects along the mountain trail. Every summer, you could see ones as big as a palm, and there were also cicadas. Over the past 5-6 years, they have almost disappeared along the roadside, and there are far fewer cicadas. To avoid being bitten by mosquitoes, it’s better to just spray mosquito repellent!
Thanks so much!!! Pesticides is no doubt one of the biggest environmental problem.
below data is from Cheung Chau volunteer of HKBWS (SSRG). Although we can not confirm the reasons of the rising mortality rate from year 2021, we think that it may related to decrease of all insect by increasing usage of insecticide.
[[from surveys of nesting Barn Swallows]]
Reply to my email, from FEHD
Received on 11 December 2025:
Thank you for your email dated 10.11.2025 concerning mosquito control in Hong Kong.
Mosquitoes are vectors for various diseases that can threaten human health and they may also cause nuisance to our daily life. The Food and Environmental Hygiene Department (FEHD) plays a crucial role in the control of mosquitoes in Hong Kong, including abating mosquito infestations in the public areas as well as providing technical advice on mosquito prevention and control to other departments and stakeholders. FEHD adopts the principle of Integrated Pest Management (IPM) in our mosquito control strategies, with emphasis given to environmental control and source reduction, which is the most fundamental, effective and sustainable approach.
Environmental control by elimination of stagnant water weekly could effectively interrupt the life cycle of Aedes albopictus, the local vector of Dengue Fever and Chikungunya Fever, which mainly breeds in small water bodies, including small containers. In addition to environmental control, our mosquito control operation is also supplemented by biological control, chemical control, legislative control and health education.
Whilst our major mosquito control strategy is mosquito breeding source reduction, larvicide which can control mosquito larvae would be applied to stagnant water that could not be removed immediately. FEHD is conscious on the fact that pesticides might pose hazards to our environment and non-target organisms; therefore, the use of B.t.i. – a biological control agent that specifically targets at larvae of some Dipteran flies, including mosquito – has been introduced for mosquito control in ecologically sensitive environment. Both liquid and granule form of B.t.i., which are being used by the FEHD, do not produce a strong chemical odour. No other pesticides are required to be applied together with B.t.i.
Adult control by Ultra-low Volume (ULV) fogging only provides a short-term and temporary suppression of adult mosquito population and would only be conducted when the situation warrants. Adult control by ULV fogging only targets at densely vegetated areas that provide resting places for adult mosquitoes. In view of the short activity range of Aedes albopictus, ULV fogging operation only targets at densely vegetated areas that fall with 100m radius from areas of high human concentration, e.g. housing estates, schools, hospitals, etc., and would be extended to 250m during the focal control of Aedes-borne disease cases to ensure complete coverage of mosquito activity range. These areas are minimal when compared to all green areas in Hong Kong, which cover about 78% of the total land area in Hong Kong where most wild lives inhabit.
In addition to the conventional mosquito control measures, FEHD keeps updated on and continues to explore the applicability of new mosquito control methodologies and technologies. In recent years, the FEHD has widely adopted the use of a new mosquito trapping device as a supplementary tool to our mosquito control programmes. The mosquito trapping device utilises the female mosquito itself as an auto dissemination medium of an insect growth regulator to control other small water bodies that could not be reached or detected by humans and prevents immature mosquito from hatching into adult. The FEHD has also introduced this new trapping device to other government departments as well as relevant stakeholders.
To monitor the distribution and density of the local vector of Dengue Fever and Chikungunya Fever, FEHD carries out routine dengue vector surveillance with the aid of Gravidtraps in selected locations throughout the territory. Surveillance result helps to identify locations with vector mosquito activity and allows better allocation of resources for mosquito control in targeted areas.
Successful and sustainable mosquito control work could not be achieved without community participation. Health promotion is one of the essential components in our mosquito control programmes. Health messages to promoting mosquito prevention and vigilance against contraction of mosquito-borne diseases to the members of the public and different stakeholders are disseminated via various channels. Territory-wide inter-departmental anti-mosquito campaign is being held every year to heighten public awareness on the potential risk of mosquito-borne diseases as well as to encourage community participation and forge close partnership of government departments concerned in anti-mosquito work, especially in the prevention and clearance of water accumulations. Furthermore, thematic seminars and outreaching talks are organised for different targeted parties (such as schools, property management offices, construction sites, etc.) every year. The health messages are further disseminated through distribution of leaflets and display of posters at different venues. The FEHD has been promoting the weekly mosquito inspection programme for years to encourage venue management to conduct inspection at least on weekly basis to identify potential mosquito breeding places for timely clearance to prevent breeding of mosquitoes.
It is important to ensure the pest control services provided by the contractors are up to standard and follow strictly to the contract requirements. Only trained and experienced operators are qualified to provide the services. Furthermore, FEHD has also taken measures to strengthen monitoring of services provided by the contractors to ensure their mosquito control work is properly discharged. Pest control service contractors are required to provide services according to the provisions of the contracts. Performance requirements of the contractors are clearly stipulated in the contracts. In the event of any irregularities, defaults or non-compliance with contract provisions, the Department will take follow-up actions, including the issuance of warnings and default notices coupled with deduction of monthly payments. Such performance records will also have a bearing on the tenderers’ future bidding for the Department’s outsourced service contracts.
The FEHD has been and will continue, on one hand, to protect the health of the public by carrying out effective mosquito control so as to lower the risk of local transmission of mosquito-borne diseases in the community, and on the other hand, to minimise the environmental impacts that might arise from the course of the mosquito control work without jeopardizing survival of non-target animals.
My delayed response to FEHD
Sent on 7 February 2026:
Thank you for your email of 11 December regarding mosquito control – and biodiversity – in Hong Kong.
While lengthy and informative, I believe your email avoided some of my queries etc, and rather glossed over the impacts of mosquito spraying on local wildlife [and potential impacts on humans, too].
It is my impression that the FEHD lacks scientific experts who can oversee mosquito control; and especially anyone with expertise in and concern for biodiversity.
Hence the great reliance on pesticides, which are too often over applied, and very badly used.
Yes, maybe following recommendations by pesticide manufacturers; but it’s my belief that is like following cigarette use advice from tobacco companies.
And yes, B.t.i. seems an excellent option.
Yet I have seen it being squirted on, for instance, small shrubs and even grass – ie not targeting water where there may be mosquito larvae.
The 100m limit for fogging seems arbitrary.
And altogether, the area affected is by no means small.
Plus, the pesticide and other chemicals used in fogging drift: I’ve smelt fogging in my home when over 50m from a fogging operations.
I believe this drift is quite enough that with repeated foggings, the biodiversity in much of Cheung Chau woodland, especially in the southeast, has been severely impacted, even devastated. Birds are fewer. Marked reductions in insects such as butterflies, lychee bugs, ladybirds and more.
Even squirting pesticide, rather than fogging, is not splendidly localised, either.
The more times there is fogging and squirting, the more pesticide is spread, and doing unintended harm.
And happens multiple times per year; favouring areas close to mosquito detecting traps – surely aiming to reduce numbers caught in traps, no matter with any consideration about the overall situation [including whether ANY mosquitoes should be tolerated – it seems the aim is for zero tolerance, and of course this means hammering biodiversity
Also, a dengue vector cannot spread dengue without actual dengue; which, happily, remains rare here, albeit local resurgences are likely. And chikungunya is another concern.]
Wrecking ecosystems like this also reduces natural predators of mosquitoes.
Hence leading to more reliance on pesticides …
Community participation?
Maybe from your office you think this happens; but in practice I don’t see any – not even at the height of the dengue outbreaks near my home a few years ago.
You have terrible publicity; dull and boring posters, if any are to be seen at all.
I’ve written before of Australia etc, with far “punchier” promotions regarding reducing mosquito breeding sites.
Even remember HK radio, with “No stagnant water, no mosquito breeding” some years ago.
My wife is from Indonesia; she helped there, when a student, with talking to people about mosquito control, even giving pellets to go in water tanks and kill larvae.
So it’s left to the FEHD teams.
And, really, trained and experienced operators??
Are you having a laugh?
Or maybe from your office, you imagine this is the case.
I’ve photographed and written of FEHD contractors’ personnel squirting anti mosquito pesticides at small shrubs, grass, even bare ground; certainly with no appearance of searching for and targeting stagnant water.
It looks like they feel obliged to spray, spray and spray, with no concern about efficacy – presumably believing otherwise no pay, or some complaints especially if one person happens to report one mosquito bite. [Yes, I’ve been told there is no obligation to use all the chemicals, but I see what happens.]
Once, I picked up a receptacle to check the label – it was cypermethrin as I recall.
One of the team then made sure I cleaned my hands – but gave me water for this. The pesticide is not water soluble, however, so surely it should be washed from skin with something more like alcohol, or a soapy liquid. If trained, why didn’t he know this?
As to trapping: it seems to have potential.
But why does there seem to be so little trapping?
I know a private estate where there is trapping, perhaps including a trap with some sort of electronic power [for a lamp??]. A remarkably good place for insectivorous birds, some of which stay for days or weeks – so the overall biodiversity would seem relatively healthy.
Cheung Chau used to have insectivorous migratory birds arrive, and stay for perhaps weeks or months.
No longer.
To me, this is deeply sad; and indicative of the huge impacts of the intensive pesticide use.
I fantasise about a return to days when I could walk around, and again see birds like these; as well as the various insects etc etc.
While here, a very little from scientific research regarding pesticides, which I’ve noticed recently.
As I have sent before, there is far more information to find.
//70% of the soils in Europe contain traces of pesticides and that pesticides have a major impact on soil ecosystems and soil biodiversity:https://rdcu.be/e1bBm 1) our study demonstrates that pesticides have a clear impact on soil biodiversity and are a major disturbance to soil ecosystems (some organisms benefit, like a range of bacteria, while others are suppressed (like beneficial mycorrhizal fungi) 2) a wide range of pesticids are very persistent in soils and can stay there for years, even decades. Many pesticides are much more persistent as their half-life time indicates. 3) Unfortunately, many pesticides are not very specific and not only target pests but also other organisms including several beneficial soil organisms (such as mycorrhizal fungi). 4) if a farmer sprays pesticides, large amounts (up to 70%) do not only reach the targeted pest, but fall on the soil or end up in the air.//exTwitter thread here:
Some further reflections on our recent findings that 70% of the soils in Europe contain traces of pesticides and that pesticides have a major impact on soil ecosystems and soil biodiversity:https://t.co/bLA1tGMPCU
Also perhaps of interest: From France, signs of recoveries in insect and bird populations after some reduction in pesticide use [neonicotinoid ban, in this case] Full recovery could take years.
Dengue Suppression by Male Wolbachia-Infected Mosquitoes
Another day, another email to FEHD from me; re another form of mosquito-borne disease control that should have minimal adverse impacts:
A friend on exTwitter has just posted a link to a new paper on a study on the efficacy of Dengue Suppression by Male Wolbachia-Infected Mosquitoes in Singapore.
You will know of but failed to mention this technique; instead continuing to favour the sledgehammer/ blunderbuss-shotgun approach of pesticides – which is proven despite the known adverse impacts on other wildlife and even people.
//Insecticides, which are relatively expensive and can linger in the environment, killing other beneficial insects and damaging human health, can be used less frequently//
Well, I know of the term “smart city” for Hong Kong; yet also of there being a tendency to find reasons not to use new technologies etc.But, perhaps this control method is well worth trying; Hong Kong could become a hub for more advanced mosquito control in the Greater Bay Area/s China ??
FEHD emails recognising importance of balancing effective mosquito control with the preservation of biodiversity
From FEHD:
Thank you for your email dated 7, 8 and 12 February 2026 concerning mosquito control in Hong Kong.
This department understands your concerns about the application of pesticides and the potential overuse of chemicals, which may adversely affect both local wildlife and human health. We recognize the importance of balancing effective mosquito control with the preservation of biodiversity.
This department has consistently implemented comprehensive and targeted mosquito control measures. Our pest control approach follows the recommendations and technical guidelines of the World Health Organization (WHO), adopting the principle of Integrated Pest Management (IPM) in our mosquito control strategies, with emphasis given to source reduction and environmental control targeting at the immature stages of mosquitoes which must develop in water. ULV fogging is necessary when handling mosquito-borne diseases with an aim to suppress density of adult mosquito vectors swiftly.Insecticides used in ULV fogging, following recommendations of the WHO, only have brief knockdown effect.The active ingredients break down in hours when come into contact with air under sunlight. Adverse effect to non-target animals / wildlife should be minimal.
This department has been actively exploring and adopting more eco-friendly methods.This includes the introduction of innovative technologies such as the new type of mosquito trapping device (“MTD”), which is specifically designed to attract gravid mosquitoes to lay eggs. The device contains an insect growth regulator (IGR) and a fungus as active ingredients which target at the larval and adult stages of mosquito respectively. The principle of this trap is to attract female mosquitoes to lay eggs inside the trap where they come into contact with IGR and the fungus. The female mosquitoes then carry the IGR to other breeding places, preventing the larvae in those breeding places from developing into adult mosquitoes.The female mosquitoes themselves will also die within a few days due to infection of fungus.This department has deployed these MTDs in suitable places across the territory and has recommended that other government departments consider using this device appropriately within their managed areas as an auxiliary tool for mosquito control.
Additionally, we are currently exploring the use of Wolbachia-infected male mosquitoes as a biological control method against Aedes albopictus.The department is considering conducting laboratory and field trials to assess its applicability / efficacy in local environment.This approach aims to suppress mosquito populations while minimising harm to non-target species and ecosystems.
To ensure the pest control services provided by the contractors are up to standard and follow strictly to the contract requirements, this department has taken measures to strengthen monitoring of services provided by the contractors to ensure their mosquito control work is properly discharged, including safety and proper use of pesticides. We are committed to enhancing staff training and monitoring. This includes oversight to reduce environmental impact and protect biodiversity. This department has been and will continue to minimise the environmental impacts that might arise from the course of the mosquito control work without jeopardizing survival of non-target animals.
We value your input and are dedicated to improving our practices to achieve a balanced approach to mosquito control. We believe that through the integration of advanced technologies, community engagement, and continuous staff training, we can better protect public health while preserving our natural ecosystems.
Yet to me it seems FEHD doesn’t care about biodiversity
My response:
Thanks for the reply of 16 March.I’m cc’ing a few others here [WWF HK, Green Power, HK Birdwatching Society]; but sadly there is about zero interest in the pesticide issue among conservationists/“conservationists” here. Yet it remains a real issue. Quick note of points here:
It seems you don’t care about biodiversity; so much damage done, on Cheung Chau and elsewhere
Biodiversity impacts far lower with trapping in a private estate; not poisoning the wildllife
Are you controlling disease if there is no disease present?
Insecticides can persist in soil for weeks.
It seems you have only trivial attempts at eco-friendly methods.
Oversight seems minor too.
There is a long way to go to balance protecting health
Biodiversity Battered by Toxic Pesticides
Biodiversity: what do FEHD really know of this? I get the impression awareness is theoretical only.Here on Cheung Chau, since over zealous fogging started with Dengue Fever outbreak, terrible reductions in wildlife.Insects like bees, lychee bugs, dragonflies [scarlet skimmer, say], moths were common before this fogging; but scarcer or even absent now.In turn, insectivore numbers depleted. Blue-tailed Skink – once common, with Cheung Chau among the best places in Hong Kong, now hard to find. Painted Frog especially reduced among amphibians: I suspect this is also from direct contact with pesticide, as tree frogs are still in evidence. Birds likewise. I’m a keen birder; lived here almost 40 years and I used to have some good records of migratory songbirds, some staying for weeks or months. No longer the case; birdwatching is far worse since the fogging etc began – and if insectivorous birds like flycatchers and warblers arrive, they tend to occur only for a day or two. Numbers of nesting Barn Swallows – which were very common along the narrow village streets have fallen. This is not unique to Cheung Chau.Kowloon Park, say, was a hotspot for migratory birds. But it is just a shadow of the past. Feral cats and damage to vegetation don’t help, but pesticides again likely play a role. Doesn’t have to be this way: there’s a private estate garden in Kowloon that’s a curious magnet for insect eating migratory birds, and some stay for weeks. Uses trapping versus mosquitoes… … – which I believe is significant. Not poisoning the environment.
Disease Control Needed if No Disease Present???
I was keenly aware of the dengue fever outbreak on Cheung Chau – living just tens of metres from a place where two people caught dengue [they had a lot of pots etc with water in their garden, which I suspected was significant]. Yet soon, the dengue was eradicated.It would take a further introduction, by a human, for it to reappear.Never mind this fact: over zealous mosquito control became normalised, with fogging, spraying and so forth just happening time after time, poisoning the environment, wiping out many non target species, depleting the ecosystems simply through force of habit.
Insecticides can persist for weeks
Importantly, you write:
The active ingredients break down in hours when come into contact with air under sunlight. Adverse effect to non-target animals / wildlife should be minimal.”
Where do you get this information? Have you done any testing, studies? I know of cypermethrin being sprayed, including in fogging.Googling reveals a wealth of research including cypermethrin persistence, accumulation, and impacts on non target species – including mammals. Here, if FEHD was truly concerned about biodiversity, you should know much of this information already. Your assertion without substantiation indicates a lack of concern; and a troubling lack of basic scientific knowledge in FEHD. It should not be for me to inform you of some of this research, yet I do so.
Cypermethrin persistence and potential for accumulation
From a paper looking mainly at fish://Cypermethrin (CYP) is a chemical of emerging concern which has persistent and bioaccumulating impacts as it can be found extensively in freshwater ecosystem and agricultural products.// https://www.sciencedirect.com/science/article/abs/pii/S0045653524009895 A new paper, looking at hedgehogs – ie terrestrial mammals://the common assumption that pyrethroids dissipate rapidly in terrestrial environments is not universally valid. Instead, this study shows that both cypermethrin and its metabolite 3-PBA can persist in shaded soils, prey items, and lipid-rich tissues, resulting in sustained exposure within a soil-driven food web. This underscores the need for ecological risk assessments// https://www.sciencedirect.com/science/article/abs/pii/S0045653526000706– I’ll note here my belief you have conducted no such risk assessments. Seem to remember being told you use cypermethrin as manufacturer recommends; which to me is like smoking cigarettes as advised by tobacco companies.
Cypermethrin persistence and toxicity
//The laboratory aerobic soil DT50 values ranged from 2.4 to 58.3 days which resulted in an 80th percentile DT50 of 25.0 days (n = 8, non-normalised), indicating cypermethrin is moderately persistent under aerobic conditions in the soil environment in accordance with the EPA’s risk assessment methodology (DT50 < 30 days). Cypermethrin is also considered moderately persistent under anaerobic conditions, with a DT50 of 46 days (n = 1). Photolysis is considered to contribute to degradation of cypermethrin in soil, but degradation rates were not significantly faster under irradiated conditions (arithmetic mean DT50 of 36.8 days, n = 2), than under dark conditions (arithmetic mean DT50 of 47.8 days, n = 2).//- a lot of jargon here; but in all cases cypermethrin was lasting way longer than hours; and it maybe didn’t matter if there was sunlight.//Cypermethrin displayed signs of acute toxicity to birds, the severity of which appears to depend on the species.////The EPA propose that active ingredient cypermethin is classified as hazardous to terrestrial invertebrates// Above in a long report from NZ EPA. https://www.epa.govt.nz/assets/Uploads/Documents/Hazardous-Substances/Synthetic-Pyrethroids-consultation/APP203936-Draft-Hazard-classification-and-endpoint-memo-Cypermethrin.pdf?vid=2What is the equivalent document on cypermethrin in Hong Kong? Cypermethrin is known to kill bees. Also://while sublethal effects were slightly noticeable from behavioural responses, underlying biochemical responses were significantly impaired even at low concentrations of the pesticide.// – https://www.sciencedirect.com/science/article/pii/S2666765721000454 – so impacts of pesticide can be significant, even if insects are not killed. Killing insects can reduce insectivorous birds’ breeding success: //the negative effects of cypermethrin spraying on breeding success of the blue tit in both treated plots are due to indirect effects (shortage in prey availability)// https://academic.oup.com/etc/article-abstract/11/9/1271/7861475?redirectedFrom=fulltext
FEHD’s “Invisible” Eco-friendly Methods
I’ve been told before that FEHD would employ more eco-friendly methods. But apart from using bti toxin, I have never noticed them here! bti toxin seems promising. But I’ve seen it squirted on dry ground and vegetation; the contractors’ staff evidently not knowing or caring it is only effective versus larvae, ie in water where mosquitoes breed. Other methods as mentioned are lacking. No increase in trapping, which is only for sampling mosquitoes.- again, shows lack of concern for biodiversity.
Community not engaged
I see FEHD “death squads” as I think of them wandering around, spraying etc etc.But no attempt to involve the local community. Woeful publicity; the “No stagnant water, no mosquito breeding” campaign I remember from years ago has vanished. Terrible posters, unlike in Australia and more with advise on eliminating mosquito breeding places, as under plant pots etc etc. I’ve come across info on a “mosquito bucket of doom” that people can set up, very simply: just need a “bti dunk” which it seems some governments can supply. Something like this could help I think; but FEHD favours chemicals, not community relations.
A couple of mosquito bites won’t kill you!
Also it seems there is now paranoia about mosquitoes.They are native to Hong Kong, and small numbers should surely be tolerable.I used to spray myself before walking woodland paths here on Cheung Chau; no longer, as it seems FEHD’s death death death to mosquitoes approach is so effective. [and, also almost no interesting birds to see either] There could be education here, too.
Oversight?
Well, it seems to me that from your office, you have a very different impression of contractors’ squads actions to what happens in practice.I’ve mentioned squirting pesticide on bare ground, grass etc; not seeking out places with water for bti. Just force of habit, hard to change. Contractors’ squads could do better; they are aware of causing deaths to non target species. But for some reason, seems they feel obliged to continue with the death death death by poisoning policy.
Long way to go
Most of the above is not new; just echoes previous emails to FEHD, and answers from you can be much the same too. I’d love to see a rebound in Cheung Chau wildlife; great if Kowloon Park, for instance, again became a top place to look for songbird migrants. But it would take changes; including towards trapping etc etc. And a bit less of a “scorched earth” approach to mosquitoes; a bit of tolerance, while keeping alert to whether there actually is a disease like dengue or the emerging chikungunya in the vicinity. Again, I hope for changes for the better; but based on experience, I expect the sorry state of affairs to continue.
Cypermethrin illegally approved by European Commission
From an article that indicates the controversial nature of cypermethrin:
the Court of Justice of the EU concluded that the European Commission acted unlawfully by re-approving cypermethrin in 2021, with major gaps in the reapproval dossier, by relying on unscientific and unrealistic risk mitigation measures for insects, and by not evaluating the long-term toxicity of at least one cypermethrin-based product. The EU Court reminded that the European Commission’s decisions must be science-based and sufficiently motivated.
….
The judgement highlights that the European Commission cannot sidestep the European Food Safety Authority (EFSA) scientific conclusions without providing strong and evidence-based justifications.
”EFSA had clearly stated that no safe use of cypermethrin could be identified under realistic conditions. However, the Commission went against that opinion by fabricating non-validated risk mitigation measures, such as an unrealistic 99% reduction in spray drift, pretending it would make the use of the substance safe. This case is unfortunately not isolated: it is a recurrent practice,” added Salomé Roynel, Policy Officer at PAN Europe.
