200
Gene R. DeFoliart
8.4. INTEGRA TED PEST AND VECTOR MANAGEMENT
The DDT and immediate post-DDT era pinpointed problems that result from
a unifactor approach to insect control using nondegradable, broad-spectrum insecticides:
1. Incorporation and concentration in food chains, hence the current insistence that new insecticides be biodegradable. An important exception
is the use of DDT as an intradomiciliary spray for malaria control, as
this presents no environmental hazard.
2. Destruction of beneficial parasites and predators by broad-spectrum insecticides, hence the desire for insecticides or other biocides of relatively
narrow target specificity. This is the aim of much current research, but
we know practically nothing about the impact of introducing an additional biocide into specific environments. Laird (1977) described how
it required 9 years to secure simply a taxonomic inventory (incomplete)
on more than 200 species of plants and animals that inhabited a small
Canadian snow-melt pool only 2 m in diameter. A counterforce here is
that insecticides of narrow specificity have smaller markets and therefore
attract less interest from manufacturers. Reduced markets have jeopardized continued supplies of such well-established insecticides as DDT
and Paris green (NAS, 1976).
3. Development of genetic resistance, hence the need to minimize the use
of anyone biocidal agent by developing approaches that integrate a
variety of methods against a target species. It can be expected that any
chemical approach will be vulnerable to the selection of resistant strains,
as were the organochlorines (DC). OC- and OP-resistant house flies,
Musca domestica, have exhibited cross-resistance to juvenoids (synthetic
analogues of juvenile hormone) (Cerf and Georghiou, 1972, 1974; Plapp
and Vinson, 1973) and direct selection by methoprene resulted in resistance levels of 80 to 400-fold in Culex (T. M. Brown and A. W. A.
Brown, 1974; Georghiou et al., 1974) and of greater than WOO-fold in
M. domestica (Georghiou et al., 1978). Cross-resistance to pyrethroids
has been reported for OC- and OP-resistant house flies (Farnham, 1973;
Farnham and Sawicki, 1976) and mosquitoes (Chadwick et al., 1977),
and a strain of Culex p. quinque/asciatus selected by d-trans permethrin
developed >4000-fold resistance to this isomer by generation FI8 along
with cross-resistance to the d-cis isomer and to various other pyrethroids
(Priester and Georghiou, 1978).
Brown (1977) described the progression of resistance in Ae. nigromaculis
in California as follows: to organochlorines by 1951, to parathion by 1960, to
Gene R. DeFoliart
8.4. INTEGRA TED PEST AND VECTOR MANAGEMENT
The DDT and immediate post-DDT era pinpointed problems that result from
a unifactor approach to insect control using nondegradable, broad-spectrum insecticides:
1. Incorporation and concentration in food chains, hence the current insistence that new insecticides be biodegradable. An important exception
is the use of DDT as an intradomiciliary spray for malaria control, as
this presents no environmental hazard.
2. Destruction of beneficial parasites and predators by broad-spectrum insecticides, hence the desire for insecticides or other biocides of relatively
narrow target specificity. This is the aim of much current research, but
we know practically nothing about the impact of introducing an additional biocide into specific environments. Laird (1977) described how
it required 9 years to secure simply a taxonomic inventory (incomplete)
on more than 200 species of plants and animals that inhabited a small
Canadian snow-melt pool only 2 m in diameter. A counterforce here is
that insecticides of narrow specificity have smaller markets and therefore
attract less interest from manufacturers. Reduced markets have jeopardized continued supplies of such well-established insecticides as DDT
and Paris green (NAS, 1976).
3. Development of genetic resistance, hence the need to minimize the use
of anyone biocidal agent by developing approaches that integrate a
variety of methods against a target species. It can be expected that any
chemical approach will be vulnerable to the selection of resistant strains,
as were the organochlorines (DC). OC- and OP-resistant house flies,
Musca domestica, have exhibited cross-resistance to juvenoids (synthetic
analogues of juvenile hormone) (Cerf and Georghiou, 1972, 1974; Plapp
and Vinson, 1973) and direct selection by methoprene resulted in resistance levels of 80 to 400-fold in Culex (T. M. Brown and A. W. A.
Brown, 1974; Georghiou et al., 1974) and of greater than WOO-fold in
M. domestica (Georghiou et al., 1978). Cross-resistance to pyrethroids
has been reported for OC- and OP-resistant house flies (Farnham, 1973;
Farnham and Sawicki, 1976) and mosquitoes (Chadwick et al., 1977),
and a strain of Culex p. quinque/asciatus selected by d-trans permethrin
developed >4000-fold resistance to this isomer by generation FI8 along
with cross-resistance to the d-cis isomer and to various other pyrethroids
(Priester and Georghiou, 1978).
Brown (1977) described the progression of resistance in Ae. nigromaculis
in California as follows: to organochlorines by 1951, to parathion by 1960, to