Other fungus species have been aptly named Lethal Lollipops. These have a ball-like structure covered with a sticky substance on which the nematode is caught like a fly on sticky flypaper.
These various fungi exist in all soils high in organic matter. They tend to die out, however, if moisture content of soil fluctuates up and down; they prefer a uniformly moist home. Their action against nematodes comes under the heading of biological control.
I have discussed with several nematologists the possibility of controlling nematodes by encouraging the ring and lollipop fungi. The consensus is that while these fungi are useful in keeping down the population, they tend to be self-limiting, since when the population is reduced only partially, the fungi tend to die out. Apparently, they depend upon nematodes' bungling into their traps, and if not enough victims are around, they starve.
There are predatory nematodes too; they feed on their plant-eating nematode relatives, but cannot multiply to a point where they will effect full control. In other words, with nature's help, science is fighting a holding battle while working toward a total solution.
Modern chemicals have given the gardener some highly potent weapons 'or his endless campaign against injurious soil-inhabiting insects and various other creatures. However, there is another side to the coin: these hemicals have harmful effects if misused. Where possible, natural (bio-ogical) control measures should be employed in partnership with chemical varfare. The discussion of controls for specific enemies gives greatest emphasis to nematodes, for they pose a grave and too-little-understood hreat to almost all kinds of plants in all parts of the country.