738 Invasive Stink Bugs and Related Species (Pentatomoidea)
or reducing pest damage. Therefore, use of cultural controls requires an intimate understanding of both
the pest and the crop. Cultural controls that are widely adopted generally are consistent with agricultural
recommendations for other purposes. The cost of implementing cultural controls depends on how closely
the control strategy aligns with recommended agricultural practices. The following sections cover the
primary cultural controls used in agriculture.
16.3.1.1.1 Crop Rotation or Fallowing
Crop rotation is a designed sequence of crops grown on a piece of land. The length of a rotation can
be as short as two years or as long as 10 or more years, especially when a multi-year crop like alfalfa
(Medicago sativa L.) is included in the rotation. Rotations can have benefits for soil fertility, disease
management, and weed control in addition to insect management. The principle behind crop rotation
for insect management is removing a requisite for insect development. This is most effective for pests
with a narrow host range, those with a long generation time, and those that overwinter locally. One of
the most widely adopted uses of crop rotation for insect control is rotating between corn (Zea mays
L.) and soybean (Glycine max Merrill) in the American Midwest. Western corn rootworm (Diabrotica
virgifera virgifera LeConte) only has one generation per year, larvae can only develop on corn roots,
and eggs are the overwintering stage (Levine and Oloumi-Sadeghi 1991). By rotating between corn and
soybean, corn rootworm eggs are laid in corn fields in the fall, but when the eggs hatch the following
spring, the field now has soybean; this effectively starves the corn rootworm larvae with no damage to
soybean roots.
Fallowing is similar to crop rotation except that a period of no plants is included in the sequence.
Fallowing is normally practiced in arid climates to try and accumulate enough ground water to grow a
crop. From a pest management perspective, it is the same as crop rotation because the habitat does not
have a suitable host for a period of time, causing the insects to leave or die.
16.3.1.1.2 Sanitation or Clean Culture
Sanitation or clean culture involves practices that remove infested crop material or potential host habitat
from the area. The principle of sanitation for pest control is to create adverse conditions for pest survival.
Many pests survive between crops by feeding on culls, volunteer plants, and crop residue. By remov-
ing these pest havens through sanitation, surviving populations are reduced, thereby reducing the pest
population in the subsequent crop. Examples where sanitation is a critical pest management component
include controlling bark beetles (Curculionidae: Scolytinae) by debarking infested logs and burning or
chipping the infested bark (Wermelinger 2004) and shredding cotton (Gossypium spp.) stalks at the end
of the growing season to control the boll weevil (Anthonomus grandis grandis) (Summy et al. 1986). In
both cases, the cultural control prevents the insects from completing their generation, thereby reducing
the size of the next generation.
Sanitation also includes removing alternative crop hosts found on the periphery of fields. Johnsongrass
[Sorghum halepense (L.)] and other wild sorghum species are key hosts for sorghum midge [Contarinia
sorghicola (Coquillett)]. Reduction of Johnsongrass in the vicinity of sorghum [Sorghum bicolor ( L .)]
fields removes an early-season host of sorghum midge, reducing the size of the population available to
infest sorghum later in the year (Young and Teetes 1977).
16.3.1.1.3 Tillage
Tillage is a common agricultural practice with many purposes. Weed control, incorporation of plant
nutrients, and seedbed preparation are common reasons for tilling the soil. In addition to these benefits,
some pests can be controlled effectively with tillage. Tillage can change the microclimate of soil-living
insects, or it can disturb their habitat. European corn borer [Ostrinia nubilalis (Hübner)] is one of several
corn borers that overwinter in the base of corn stalks. Mowing and tillage breaks apart their overwin-
tering home, increasing mortality from predation and desiccation (Umeozor et al. 1985). Other insects
such as corn earworm [Helicoverpa zea (Boddie)] overwinter as pupae in the soil. Tillage can either bury
them so deeply that the moths cannot reach the surface, or expose them to the surface so they are eaten
by predators or dessicate and die (Roach 1981).