Insect apocalypse: Call to restrict pesticide ‘more toxic than DDT’
Tim Baylars 7/1/24. https://www.brisbanetimes.com.au/national/insect-apocalypse-call-to-restrict-pesticide-more-toxic-than-ddt-20230630-p5dknk.html
Noticed fewer moths fluttering around outside lights in the evening or that butterflies seem less frequent visitors? Or that your car’s windscreen remains clearer of the haze of dead flies after a long journey than it used to? Part of the problem appears to point towards the use of a range of pesticides called neonicotinoids which Australian authorities are accused of being slow to regulate.
Ecologist Francisco Sanchez-Bayo from environmental sciences at Sydney University pulled together 100 long-term studies of the global fortunes of insects. He concluded that worldwide an average 37 per cent of species were declining, while populations of 18 per cent were increasing – those were agricultural herbivores and nuisance pests. Aquatic insect communities like mayflies, midges and sedges were even worse off: 42 per cent of species were declining and 29 per cent increasing.
The review threw up some interesting highlights. In northern NSW (Murwillumbah, north of Byron Bay), sampled for butterflies over 23 years, the overall abundance of 21 species declined by 57 per cent due to human disturbance.
Changes among 46 butterfly species in a peripheral urban landscape near Melbourne studied since 1941 found 36 to 48 per cent of species declined since 1981.
In Denmark, a small farmland area was sampled using the “windscreen splash” method between 1997 and 2017. Overall abundance of flying insects that crashed car windscreens declined 97 per cent along a 25 -kilometre road.
Sanchez-Bayo said: “In the 1990s, when I used to go to the Macquarie Marshes [north of Dubbo] to do research, as anyone who drove for a few hours to the countryside at that time would know, you had to stop to clean the windscreen. You don’t have to do that any more.
“In the case of Melbourne, the number of butterflies declined due to urbanisation, they were common years ago, but now they are just disappearing. We are talking about global declines, in Finland, Indonesia and the Amazon, everywhere. There is massive abuse with pesticides and other chemicals, fertilisers and so on which have contaminated the environment affecting mainly aquatic insects.”
One particular branch of pesticides, the neonicotinoids (also known as neonics) are used to treat seeds before planting and are claimed to increase crop yields. Scientists are now comparing neonicotinoids with DDT, of which the devastating effects on wildlife were revealed in the 1960s.
Roger Kitching, on the conservation committee of the Australian Entomological Society, says DDT affected vertebrates, particularly birds, but now, equally, insects deserve to be a major cause for concern due to their part in the food chain.
“The substitution of the range of earlier pesticides for the current generation of neonics and others is particularly bad for insect fauna,” he said. “These pesticides are systemic, that is they act from within plants, they are persistent, water-soluble and are very general in the species they target.
“When insects decline in ecosystems there are knock-on effects because of their roles as bird food, pollination vectors, plant munchers and so on – even though neonics do not impact vertebrates directly they have measurable impacts through these food-chain effects.”
In June, US ecologist Mike Miller, who works for Wisconsin’s Department of Natural Resources, told a fly-fishing podcast that he had found neonics in randomly selected waterways throughout the state. He said a lethal dose of neonics the size of a sugar grain was enough to kill 125,000 honey bees.
“One of those little paper sachets holds between 3 -4 grams of sugar and the comparable amount of neonics is enough to kill 600 million honey bees,” he said. “Neonics are thought to be 7000 times more toxic than DDT.”
The podcast host, fly-fishing guru Tom Rosenbauer, said: “It seems like in the past 10 years or so you hear so many fly-fishers complaining that the hatches [of insects] aren’t what they used to be. There seems to have been a dramatic decline in insects since neonics became popular.”
Miller’s comments were based on a scientific paper by ecologist Dave Goulson published a decade ago, called An overview of the environmental risks posed by neonicotinoid insecticide. Goulson, now at Sussex University, said 5 grams was enough to kill half of 1.25 billion bees and leave the other half just alive [known as an LD50 dose].
“While that figure is accurate, the levels of neonics found in the environment are pretty low and a bee would have to consume several CCs [cubic centimetres] of nectar to get a lethal dose, which it might do in its lifetime, but not in a morning,” he said. “The evidence we have is that bees are probably consuming less than a lethal dose, but that doesn’t mean that we can all breathe a sigh of relief that all is well.
“There is evidence that sub-lethal doses can seriously mess up the bees in a whole bunch of different ways – reduce their fertility, their ability to navigate and their resistance to disease. If their disease-resistance is knocked out by exposure to a pesticide, and then they are exposed to a virus transmitted by the Varroa mite, then there are many people who believe it does explain why bee colonies are collapsing.
“For an aquatic insect, you are not drinking the pesticide, you are bathing in it. The evidence is that anything over about 1 part per billion in a stream, which is the level which is commonly exceeded, it is enough to be impacting on aquatic insects when they are exposed to it 24/7.”
Asked if he felt Australia was behind other countries in regulating neonics, he added: “That would seem to be the case, the European regulators are pretty slow to act, but they thought the evidence was sufficiently compelling five years ago to act, and lots of other countries have followed suit in various ways. Within the developed world, Australia would appear to be at the tail end of the queue to do something about neonics. To ignore the evidence, I think, is probably foolish.
“There is a perception that we banned the really nasty pesticides years ago, we got rid of DDT and modern pesticides are better, but in some senses modern pesticides are much more dangerous because we have invented compounds that are far, far more poisonous to insect life, it means less of them has to go astray, into rivers or whatever, to do harm.
Australian scientists have also found imidacloprid (a neonicotinoid) in the catchment area of the Great Barrier Reef and the reef lagoon. Professor Michael Warne at the School of the Environment, University of Queensland in a research study of 6500 samples from 14 Great Barrier Reef catchment areas found the average concentration of imidacloprid was 0.051 µg/L (micrograms/litre) between July 2009 and June 2017. That concentration is 2.5 times higher than that found in a study of Dutch rivers, which led to an annual decrease in insectivorous bird populations of 3.5 per cent.
In a paper published a year ago, Warne wrote that within the Great Barrier Reef catchment area that imidacloprid was used to control canegrubs in sugarcane and the banana weevil borer in banana crops. He said that in a not yet published work by UQ and Department of Environment and Science suggests the risks from imidacloprid since 2017 may have stabilised or decreased, in part through education programs conducted in collaboration with some industry groups.
But he said: “There are many water samples where the concentration exceeds the proposed Australian and New Zealand water quality guideline for ecosystem protection from imidacloprid.”
Imidacloprids were restricted by the EU in 2018. In June last year, New York State moved to pass the Birds and Bees Protection Act, a first-in-the-nation bill to rein in the use of neonicotinoid pesticides. The Natural Resources Defence Council said in a statement: “Neonics are linked to massive bee and bird losses that impact food production, contaminate New York water and soil, and create human health concerns, especially with recent testing showing rising levels of neonics in 95+ per cent of pregnant women from New York and four other states.”
Pesticides use here is governed by the Australian Pesticides and Veterinary Medicines Authority (APVMA). It updated its website page on neonicotinoids in May and lists six neonics approved for agricultural use in Australia. It published a report in 2014 and then announced a review in 2019. It states three of the six neonic pesticides used here were restricted in April 2018 in the European Union to greenhouse use only.
A spokesperson for the APVMA said in a statement: “The APVMA commenced its review of neonicotinoids in 2019 to allow for the consideration of new scientific information about risks to the environment, and to ensure safety instructions on products meet contemporary standards.
“Based on the statutory timeframes, the review is due to be completed in August 2023. The APVMA anticipates publication of proposed regulatory decisions during 2024 and has assigned additional resources to chemical review activities, including the use of external scientific reviewers to progress reviews as rapidly as possible.” However, there has been no update to the statement last May.
The authority was subject of a damning independent report in July which said it was “concerning that a number of chemical reviews have been ongoing for over 20 years”. It said the APVMA appeared reluctant to take compliance and enforcement action against industry.
Recent changes to the APVMA’s staff profile following the relocation of its offices from Canberra to Armidale in 2019, “has most likely impacted corporate knowledge, workload, and work capacity. Only a small proportion of previous APVMA staff relocated”.
Sanchez-Bayo said the APVMA was way behind schedule. “We are behind in many ways and how long it will take them to come up with a final decision we don’t know,” he said. “It is under-resourced and behind the times.
“My understanding is that the APVMA does not have enough staff, they are not properly trained in these issues, there has been a lot of turnover in the last few years. They are not producing the results they are expected to produce.”
Eddie Tsyrlin, a freshwater ecologist and waterbug taxonomist, estimates that as many as to 2000 species of freshwater invertebrates could have already been lost.
“The Ecological Safety section of Safety Data Sheet [for neonics] states that ‘these chemicals are very toxic to aquatic organisms, may cause long-term adverse effects to the aquatic environment’.
“For the adequate protection of Australian fish and invertebrates, testing needs to be done on pollution-sensitive and common species of freshwater invertebrates occurring in streams as well as in still waters. These could be mayfly and stonefly nymphs and sensitive species of midges.”