Biological Warfare - Soil: Reflections on the Basis of our Existence - page 109

Tame humans . Plant-parasitic nematodes can be a major nuisance for farmers, particularly in the
Tropics. Many attempts have been made to use nematode-trapping fungi as biological control
agents, so far with limited success. As with pet cats, which can live well on the food we put out
for them and do not need to catch mice to survive, it is difficult to get the fungi to build their
nematode-trapping apparatus in nitrogen-rich soil. Like cats, the fungi do as they please—and are
not always bothered about pleasing humans
prolonged periods in the same area. Nematophagous fungi could be highly benefi-
cial in such areas and also on organic farms, where the use of chemicals is banned.
Fungal-based treatments will hopefully go on to play an important role in treating
livestock for nematode infections in the future.
Biological warfare is a complex art. While staying in the Australian state of
Queensland, I made a habit on my morning walks on the beach of studying the
nightly trails left by foraging crabs. Regular patterns of tiny hollows interspersed
with small piles of sand revealed the crabs' nocturnal presence. The tracks quickly
wore away during the day due to human activity, only to reappear miraculously every
morning. Curiosity got the better of me and I decided to grab a torch and watch the
perpetrators at work. But even before reaching the beach I ran into problems: the
grassy fringe along the shore was covered with toads. With every step I had to con-
centrate hard not to step on a toad. I am normally rather fond of amphibians, but this
mass invasion was almost scary. Think Alfred Hitchcock's The Birds . Australians
loathe the toads and some deal with them by using them as target practice for their
swing. Others zigzag deliberately along roads at night to kill as many as they can.
This anti-toadism is the result of a failed attempt at biological pest control. The
toads were introduced from South America in 1936 to eat beetles that were ravag-
ing sugar cane plantations. The problem was that the toads discovered many other