370 CHAPTER 14 Agriculture and Food Resources
- Pesticides can effectively control disease-carrying organisms
and crop pests. - Pesticide use leads to several problems: Pests develop
genetic resistance, an inherited characteristic that decreases
the effect of a given agent (such as a pesticide) on an
organism; ecosystem imbalances occur when pesticides
affect species other than the intended pests; and some
pesticides exhibit persistence, degrading very slowly.
Bioaccumulation is the buildup of a persistent pesticide in
an organism’s body. Biological magnification is the increased
concentration of pesticides in organisms at higher levels in
food webs. Pesticides also show mobility, moving to places
other than where they were applied.- Alternatives to pesticides include biological controls,
which use disease organisms, parasites, or predators
to control pests. Pheromones, produced by animals
to stimulate a response in other members of the same
species, attract and trap pest species. Integrated pest
management is a combination of pest control methods
that keep a pest population small enough to prevent
substantial economic loss.
Key Terms
broad-spectrum pesticide 364
degradation (of land) 358
economic development 352
food insecurity 350
genetic engineering 362
genetic resistance 365
germplasm 356
habitat fragmentation 358
industrialized agriculture 353
overnutrition 350pesticide 358
subsistence agriculture 354
sustainable agriculture 360
undernutrition 350What is happening in this picture?
This trap, which was placed in the middle of
a pea crop, contains a pheromone to attract
pea moth males. Note the dead males in the
trap.
What would be some advantages and
disadvantages of pheromone traps?
What would be the more conventional
method for getting rid of these moth
pests?
Pheromone traps are one tool of integrated
pest management. What other tools must
also be employed by farmers using this
approach?
How does this approach fit into the
practice of sustainable agriculture?
Why isn’t IPM in widespread use by
farmers?
Nigel Cattlin/Alamy