Environmental Engineering Reference
In-Depth Information
11
Pests
Pests are living organisms that interfere in some way with something we
consider important. For example, to farmers, pests may include insects
and diseases that damage their crops, weeds that compete with crops for
nutrients and water, aquatic plants that clog irrigation ditches or rodents
that feed on the grain. To homeowners, pests may include filthy cock-
roaches, annoying mosquitoes, wood-destroying termites, etc. Overall
the presence of pests in the environment is widespread and natural.
When the degree of their infestation is small, they are usually ignored,
but when their number or activity exceeds a certain tolerance level, they
are ordinarily restrained or controlled in some manner. Level of tolerance
may be very different for different people or in different situations. Some
people may consider one cockroach unacceptable, even though hundreds
would not alarm some others. Similarly, one weed in the centre of a golf
putting-green may not be acceptable, while hundreds of identical ones
growing in the rough may not even be noticed.
In turf-grass situations, the presence of pests exceeds the level of
tolerance when their number or activity disrupts quality or uniformity
of the turf. In turf-grass pest management, pests are usually separated
into major groups that include weeds, diseases and insects. Because a
large variety of different organisms infests turf-grasses in various geo-
graphical locations or in specific management situations, this chapter
discusses groups of pests and methods of their control rather than the
characteristics of individual pest species. Species-specific information on
particular pests and their control should be checked at local pest-control
bureaux or places providing similar information. In some countries,
