26 | New Scientist | 24 August 2019
Editor’s pick
We need to talk about
natural pesticides in food
Letters, 3 August
From Anthony Trewavas,
Penicuik, Midlothian, UK
Cathy Cook suggests reasons to
prefer organic food other than its
alleged nutritional superiority, and
mentions pesticide residues. All
fruit and vegetables contain large
numbers of naturally occurring
pesticides. These are the result of
an arms race with insect herbivores.
If we tested for these, we
would find that they are just as
nasty as synthetic pesticides, but
present in food in higher amounts.
However, they don’t affect us when
we consume them because their
concentration is only effective
against insects, not anything large.
The real problem with organic
farming is low yield. You need much
more land to obtain similar yields
to other forms of farming. I think
we should be returning farmland
to nature, not increasing its area.Remember the carbon
footprint of kitchen kit
3 August, p 24
From Wiebina Heesterman,
Birmingham, UK
According to James Wong, a US
study of the food system’s carbon
footprint says kitchen appliances
generate nearly seven times as
many emissions as food transport.
Pointing out that eating vegan
food benefits the climate is now
common, but the burden of meal
preparation is rarely mentioned.
Recipes are full of instructions to
blitz this and blend that – who has
heard of a hand whisk these days?The importance of being
earnest about urban parks
20 July, p 24
From Rachel Mckeown,
Aberfan, Mid Glamorgan, UK
Graham Lawton praises London’s
self-declared status as a National
Park City. Born and raised in the
South Wales valleys, I have alwaysfelt the lure of green spaces.
Lawton made me realise that
I associate London as strongly
with birdwatching and strolling
around Hyde Park as I do with its
landmarks. Breaking up the urban
landscape isn’t just beneficial for
the environment, it also offers city
dwellers the opportunity to step
away from the hustle and bustle to
connect with nature, with all the
health and well-being implications
New Scientist has previously
reported (22 June, p 18).From Anders Jansson,
Helsinki, Finland
Lawton praises London as the
world’s first National Park City.
In Finland, we have nine National
Urban Parks, created under the
Land Use and Building Act of 1999.
At present, Helsinki is in the long
and tedious process of trying
to decide whether to join places
such as Turku, Forssa and Kuopio.From Ben Haller,
Ithaca, New York, US
I was shocked by Lawton’s claim
that the artificiality of ecosystems
dominated by invasive species
doesn’t matter. He notes that
Hawaii is now a hotchpotch ofmostly invasive and introduced
species. That’s true – and the harm
caused is incalculable. More than
half of honeycreepers, a group of
bird species endemic to Hawaii,
have gone extinct since humans
reached the islands and almost
all the rest are now threatened.
More than 100 species of
Hawaiian plants are already
extinct and hundreds more are
vulnerable. Lawton claims most
invasive species don’t pose a
threat to native biodiversity.
Most don’t, but the ones that
do cause immense damage.Taking care of the willow
seeds that we collect
Letters, 13 July
From Ian Willey, Fieldwork
officer, Royal Botanic Gardens
Millennium Seed Bank,
Wakehurst, West Sussex, UK
Vijay Koul’s experience makes
him concerned about the viability
of willow seeds. Indeed, they
are generally very short-lived
in natural situations. For several
years, we have been developing
a protocol for long-term storage
of Salicaceae species at the
Millennium Seed Bank. Thisprocedure addresses all stages,
from seed collection in “Hundred
Acre Wood” in Sussex and
elsewhere (25 May, p 13) to storage
conditions and monitoring,
with the aim of maximising
the longevity of the collections.
Importantly, we receive the
seeds within three to four days
of collection and place them into
long-term storage within 14 days
of arrival. This ensures the initial
viability of the collection is as high
as possible at the time of banking.
We also do germination tests
on the seeds, both on arrival at
the bank and after storage at -20°C
and at -186°C. We will monitor
the viability of each collection
of seeds in the long-term. Our
initial results are promising, with
successful germination occurring
after storage for two to three years.I suggest it’s better to rebut
errors than retract them
27 July, p 14
From Scott McNeil,
Banstead, Surrey, UK
Astrophysicist Ken Rice and
climate scientist Gavin Schmidt
are calling for a paper in Scientific
Reports to be withdrawn. It claimsViews You r le t te r s