Slug and snail control via nonindigenous poisonous plants
Image credit: Naturallivingideas
Darko SavicMay 12, 2021
Slugs and snail infestations are a nightmare for any gardener because they destroy the harvest. What if they could be poisoned via "trojan horse" plants that are not native to the area? The slugs wouldn't naturally avoid eating them due to lack of genetic memory and would drop in numbers shortly thereafter.
About the problem
Slugs can live for about 6 years. If necessary, their eggs can remain dormant for years until the conditions for hatching are right. Arion Vulgaris, a species that is particularly problematic in Europe can lay up to 400 eggs in a season, and the eggs hatch within 3-5 weeks. It's considered one of the top 100 worst invasive alien species in Europe.
Arion Vulgaris has not yet become established in the USA but has been suggested that the species be given top national quarantine significance. It represents a potentially serious threat as a pest that could negatively affect agriculture and natural ecosystems.
Since gardeners are trying to get rid of the slugs while at the same time not poisoning themselves via pesticides, they are primarily looking for natural solutions that don't affect the produced food and animals (pets, livstock) in any way. Some of the common methods of slug control involve:
natural predators (frogs, hedgehogs)
fence made of electric wire or copper tape
Slug control via poisonous plants (trojan horse)
Placing a bunch of plants that are poisonous to slugs (without them knowing it) in strategic locations throughout the garden seems as easy as it gets. There would be no work required after the initial planting.
While working on this idea I recently left a bunch of Marble Queen Pothos plants outside overnight. In the morning the leaves were full of slug bites. I remembered that Pothos is poisonous which is how I came up with this idea. Is Pothos not poisonous to slugs or did they fail to avoid it because the plant was unknown to them? I have yet to do an experiment where I enclose a bunch of slugs in a terrarium with nothing but Pothos and see how they survive eating it.
Regardless of what this specific experiment shows, could there be other suitable plants that the slugs would enjoy eating but are deadly to them? Tropical forrest plants are often poisonous. Some are fast growing.
Introducing such fast growing tropical species to European gardens would not present a problem because they couldn't survive winter. These plants would thrive during the gardening season and die off in the winter - leaving indigenous flora intact.
"'W. De Costa, H. Hitanayake and I. Dharmawardena, "A Physiological Investigation into the Invasive Behaviour of Some Plant Species in a Mid-Country Forest Reserve in Sri Lanka" https://web.archive.org/web/20110722145720/http://thakshana.nsf.ac.lk/pdf/JNSF26-34/JNSF29_1%262/JNSF29_1%262_35.pdf
Salt also works, but it's not the best method. Pouring salt on slugs directly causes them to die in a painful and inhumane way, pouring salt in your garden will also keep them away, but leaves you with acidified soil, which is bad for the plants. Salt is most effective indoors.
I mention salt, however, to encourage us to think of other options to create barriers around the garden which might not kill the slugs, but deter them from entering.
My grandfather's "attract-and-burn" method
JuranMay 12, 2021
It's not connected with nonindigenous poisonous plants, but my grandfather had a creative way to get rid of the snails.
He would cut the grass and make small grass piles around the crops; one every few meters. During fresh summer nights, snails would eat the crops, and during the hot summer days, snails would get into the piles to escape from the sun. At that moment, my grandfather would put gasoline on the pile and burn it to the ground, burning all the snails, too. Same as salt, it's not humane, but it worked in my grandfather's garden.