178
Carl E. Crisp
(Williams et ai., 1969, 1978b, 1979). Carbaryl, trichlorfon, mexacarbate, and
bioethanomethrin were further tested (Williams, 1973). Mexacarbate, trichlorfon, and carbaryl performed satisfactorily. On the basis of additional field experiments conducted in 1974 and 1978, acephate and diflubenzuron emerged as
potential candidates for a large-scale operational program. Diflubenzuron has
been issued a conditional registration for use on cotton, which may open the
way for registration for forestry use.
Large variations in results from field testing can often be attributed to spray
physics and associated field techniques. More than one field, pilot, and operational test has failed because small details in spray physics were overlooked.
The contemporary forest pesticide applications manager must take this basic
science into account in aerial applications of insecticides (Roberts, 1976). The
physical problems of pesticide application from the standpoint of equipment,
nozzle design, and performance have been reviewed with respect to forestry
applications (Akesson and Yates, 1976). Meteorological effects on the impingement of air-applied small droplets were given considerable attention (Cramer
and Boyle, 1976). Small droplets less than 50 microns in diameter are the most
effective on western budworm (Himel and Moore, 1967); other targets may
require different sizes. Techniques and equipment for evaluating viruses and
other water-soluble formulations are available (Maksymiuk and Orchard, 1974;
Sundaram, 1978).
7.7. SYSTEMIC INSECTICIDES
Systemic insecticides may offer a promising new approach to insect management. They can be classified into two fundamental groups---pbloem mobile
or xylem mobile. Many insecticides are xylem mobile, particularly if they are
soluble in water. Phloem-mobile systemic pesticides are more difficult to find,
characterize, and evaluate because they must be taken into living tissue by energydependent, enzyme-supported mechanisms (Crisp and Look, 1979).
Systemic insecticides are useful tools for managing cryptic insects, e.g.,
cone and seed insects, bark beetles, shoot tip moth larvae, and twig borers
(Lyon, 1974).
The status of systemic insecticides as related to translocation and molecular
structure has been reviewed (Crisp, 1972) as well as the relationship of systemic
insecticides to phloem transport of other xenobiotics (Crafts and Crisp, 1971).
Phloem-mobile systemic insecticides provide the most efficient means to
control cryptic insects because the toxicant can translocate with the photosynthate
(food) to the tissue where the target insect is feeding. Limitations to the application of this strategy are lack of knowledge concerning the basic
structure-activity relationships of molecular structure to phloem transport for
Carl E. Crisp
(Williams et ai., 1969, 1978b, 1979). Carbaryl, trichlorfon, mexacarbate, and
bioethanomethrin were further tested (Williams, 1973). Mexacarbate, trichlorfon, and carbaryl performed satisfactorily. On the basis of additional field experiments conducted in 1974 and 1978, acephate and diflubenzuron emerged as
potential candidates for a large-scale operational program. Diflubenzuron has
been issued a conditional registration for use on cotton, which may open the
way for registration for forestry use.
Large variations in results from field testing can often be attributed to spray
physics and associated field techniques. More than one field, pilot, and operational test has failed because small details in spray physics were overlooked.
The contemporary forest pesticide applications manager must take this basic
science into account in aerial applications of insecticides (Roberts, 1976). The
physical problems of pesticide application from the standpoint of equipment,
nozzle design, and performance have been reviewed with respect to forestry
applications (Akesson and Yates, 1976). Meteorological effects on the impingement of air-applied small droplets were given considerable attention (Cramer
and Boyle, 1976). Small droplets less than 50 microns in diameter are the most
effective on western budworm (Himel and Moore, 1967); other targets may
require different sizes. Techniques and equipment for evaluating viruses and
other water-soluble formulations are available (Maksymiuk and Orchard, 1974;
Sundaram, 1978).
7.7. SYSTEMIC INSECTICIDES
Systemic insecticides may offer a promising new approach to insect management. They can be classified into two fundamental groups---pbloem mobile
or xylem mobile. Many insecticides are xylem mobile, particularly if they are
soluble in water. Phloem-mobile systemic pesticides are more difficult to find,
characterize, and evaluate because they must be taken into living tissue by energydependent, enzyme-supported mechanisms (Crisp and Look, 1979).
Systemic insecticides are useful tools for managing cryptic insects, e.g.,
cone and seed insects, bark beetles, shoot tip moth larvae, and twig borers
(Lyon, 1974).
The status of systemic insecticides as related to translocation and molecular
structure has been reviewed (Crisp, 1972) as well as the relationship of systemic
insecticides to phloem transport of other xenobiotics (Crafts and Crisp, 1971).
Phloem-mobile systemic insecticides provide the most efficient means to
control cryptic insects because the toxicant can translocate with the photosynthate
(food) to the tissue where the target insect is feeding. Limitations to the application of this strategy are lack of knowledge concerning the basic
structure-activity relationships of molecular structure to phloem transport for