Download Topic 6 - CTK Science


From the point of view from a farmer or
forester, a pest is any organism that is
causing plants to die or produce less.
› Fungi
› Weeds
› Insects
› Birds
In natural ecosystems organisms have parasites,
predators, or competing plants to keep their numbers
normal.
 The pests that cause the most damage are insects,
fungi and weedy plants.

› Thieves that steal water, nutrients & lights, from other plants.
› Bacteria and fungi cause infections destroying all or part of
the plant.
Occurs when pollution washes into water (or other
places)
 Pollution gets absorbed into small animals like Plankton.
 Small animals like fry (baby fish) eat the plankton, and
absorb the pollution into their bodies.
 Large fish eat many small fish and absorb all their
pollution into their bodies.

Some of the chemicals wash of plants and leave
residues in the soil.
 Some pesticides can leave residue in the soil for
decades, for example, DDT.
 Toxic residues have turned up in arctic ice.





As pesticides are being over
used, some species of pests
have evolved or adapted to
become resistant to them.
These young survive passing
on their genes to the next
generation making the specie
completely resistant to the
pesticide.
Only way to control them is to
up the dosage or find a new
way to kill them.
Chemical Warfare
Resistant Species
Number of Resistant Species
Number of Resistant Species
426
305
220
172
155
25
28
1954
1957
12
1943
1960
1967
1971
1975
1980
Grown without any human made chemicals fertilizers or
pesticides.
 Use manure and compost to fertilize the soils.
 Use natural methods like: tilling, crop rotations,
mulching, companion plating crops )crops with others
that discourage insects) or hand pick pests.
 In Fact: Organic

Grow good quality seeds
 Removing weeds before seeds mature by tillage or
mowing.
 Cutting weeds along property edges.
 Cleaning equipment so it doesn’t transfer weeds to
other crops.
 Grow a variety of crops (biodiversity)

Using one organism to eat or kill another.
 Bacterium Bacillus thuringienis (Bt) produces a toxin that
kills certain insects, but is harmless to humans.
 Ladybugs to control aphids.

Invasive Plants
 Biological Controls
 Pine Beetles

Canola is popular with fungi, insects and weeds.
 COMPLETE the WANTED POSTER
