What gardener doesn’t want to rid his or her garden of all those nasty summertime pests? Yet to put chemical pesticides on
plants that will ultimately grow produce the family will eat seems a bit wrong. That’s where gardeners have a break as
there are several organic pesticides for use in the garden. These natural pesticides are safe and don’t damage the soil
year after year.
Many organic pesticides come from plant sources, some of which produce pyrethrum, while others produce rotenone, ryania, or
mineral-based pesticides. Mineral pesticides include cryolite, boric acid or diatomaceous earth—all of which are designed
to kill plant-destructive insects in your garden.
Experts say that, while organic pesticides are distinctly safer than synthetic pesticides, users want to be careful when
using them. Gardeners shouldn’t use them with bare hands and they should realize that some organic pesticides can be as
toxic as their non-organic counterparts. Least toxic products will say “Caution” on the label, more toxic products will
say “Warning” and the most toxic products will say “Danger”. These words, however, are not a signal of their potential for
Some organic pesticides are minimally toxic to humans but are very toxic to animals. Ryania, for example, is highly toxic
to fish. Other organic pesticides kill even the most beneficial insects, such as the combination of pyrethrins and rotenone.
By law, all pesticides, including organic pesticides, must be used precisely according to the instructions on the label.
Read the label before using any organic pesticide.
An important group of “organic” pesticides is the biopesticide group. This unique class of pesticides involves using
biological organisms to control pests. In general this type of organic pesticide acts slower than other organic pesticides
and involves critical application times. Biopesticides reduce, rather than destroy, pest populations and they have a narrow
target range with a specific mode of action. Biopesticides have a limited shelf life as they are live organisms.
There are two general types of organic biopesticides. They include biochemical and microbial-based organic biopesticides.
Biochemical pesticides include insect pheromones, odor-based chemicals that disrupt the insect mating cycle by interfering
with the ability to find a mate. Pheromone-based traps can also be used to trap male insects, disrupting the mating cycle.
Organic microbial biopesticides include those that come from genetically-changed fungi, viruses, protozoans or bacteria.
This type of organic pesticide suppresses the pest population by secreting toxins specific to the insects, causing disease
in the pest population, interfering with the establishment of pests through competition and other modes of action.
One type of organic biopesticide is the bacterium known as Bacillus thuringiensis, a soil-based bacterium that is toxic to
several types of insect larvae but not to other things. This bacterium can be applied to plant foliage or incorporated into
the genetic material of larger crops. It is toxic to the larvae of moths and butterflies. Other varieties are toxic to
mosquitoes and black flies.
Gardening with organic pesticides is generally effective and healthier to the environment and the plants than synthetic
pesticides and make a good alternative to using harmful chemicals on your garden.