Environmental Engineering Reference
In-Depth Information
Insects floating
on the surface
Cylinder filled
with water
Insects in
the soil
Fig. 11.11. A floatation technique is used to sample arthropods, especially
chinch-bugs.
white grubs. A square area of sod (25
25 cm) should be cut to a depth
1-2 cm below the root zone and lifted up. The roots and soil beneath
should be inspected for presence of grubs before being replaced.
Methods of insect control
Cultural practices such as proper mowing height, fertilization, soil aer-
ation and watering do not prevent infestation but can help the turf to
resist higher pest populations without serious damage. Some insect-
resistant varieties of turf-grasses have been released and are available
on the market. Among warm-season species, for example, development
of a chinch-bug-resistant variety of St Augustine grass was a significant
breakthrough in management of this particular insect.
Chemical controls, however, are usually the most reliable means of
controlling properly identified insects and, even if they cannot eliminate
all of the insects, may reduce their numbers to a manageable level. The
timing of insecticide application is one of the most critical aspects of pest
control. Insects are more susceptible to chemicals at some stages of life
than at others. Ordinarily, the resting stages, such as eggs and pupae, are
unaffected, whereas active stages such as larvae, nymphs and sometimes
adults are susceptible to chemicals. The manager's goal is to apply
chemicals at the time of peak susceptibility. Placement of the insecticide
