Biodegradable Insecticides in Forestry
165
Lepidoptera pests: western spruce budworm, spruce budworm, gypsy moth, and
Douglas fir tussock moth. Fenitrothion is used extensively in Canada. This
compound is registered in the United States for spruce budworm, and most of
the pounds reported were applied in Maine in 1978, but it is no longer used.
Trichlorfon is registered for gypsy moth and spruce budworm, but the formulation
for use on western spruce budworm is no longer available. Malathion is registered
for use in spray programs for both spruce budworm and western spruce budworm,
but the reproducibility of results is highly variable (Lyon et al., 1968). Acephate
is registered for many defoliators, including western spruce budworm, spruce
budworm, and gypsy moth. Mexacarbate was last used in Maine in 1975 for
control of spruce budworm and is no longer available (Graham, 1975).
7.5. INSECTICIDE EVALUA TION RESEARCH
The Forest Service's Insecticide Evaluation Research Work Unit, headquartered in Berkeley, California, is charged with developing and evaluating
safe, effective chemicals for controlling destructive forest pests. Present emphasis
is on defoliating insects previously suppressed with DDT. In setting up the unit,
the Forest Service recognized that basic and applied chemical research for insect
control had to be conducted on a broader scale and in greater depth than in the
past (Moore, 1969). DDT and other chlorinated hydrocarbon insecticides could
no longer be used on the forests in the United States. Thus, the unit was charged
with finding suitable replacements, but the chemicals had to be selective in
action, of low hazard to associated insects--especially natural enemies of the
target pests--short-lived, degradable into innocuous residues in the forest, and
generally harmless to the total environment (Lyon and Camp, 1972).
The unit's research from 1964 to 1979 emphasized four lines of investigation: screening and bioassay of candidate insecticides; chemistry, including
synthesis, residue analysis, and metabolism; research on systemic insecticides,
including time and method of application; and field testing of the most promising
insecticides indicated by laboratory studies. The Forest Management Institute
in Canada followed a similar approach.
Work on any particular insecticide began with laboratory screening and
progressed through studies on residual life, rainfastness, and toxicity to various
instars. If an insecticide was selected for further study, it was evaluated under
field conditions, sometimes starting with small, individual tree studies to simulate
the dynamics of an aerial application (Barry et ai., 1976), then progressing to
environmental safety tests to determine the environmental risks to nontarget
organisms (Shea, 1979), to small plot field trials to evaluate efficacy to the target
pest (Hard, 1979), and to pilot control projects to determine effectiveness under
operational conditions (Ciesla, 1977). Most field studies were conducted with
165
Lepidoptera pests: western spruce budworm, spruce budworm, gypsy moth, and
Douglas fir tussock moth. Fenitrothion is used extensively in Canada. This
compound is registered in the United States for spruce budworm, and most of
the pounds reported were applied in Maine in 1978, but it is no longer used.
Trichlorfon is registered for gypsy moth and spruce budworm, but the formulation
for use on western spruce budworm is no longer available. Malathion is registered
for use in spray programs for both spruce budworm and western spruce budworm,
but the reproducibility of results is highly variable (Lyon et al., 1968). Acephate
is registered for many defoliators, including western spruce budworm, spruce
budworm, and gypsy moth. Mexacarbate was last used in Maine in 1975 for
control of spruce budworm and is no longer available (Graham, 1975).
7.5. INSECTICIDE EVALUA TION RESEARCH
The Forest Service's Insecticide Evaluation Research Work Unit, headquartered in Berkeley, California, is charged with developing and evaluating
safe, effective chemicals for controlling destructive forest pests. Present emphasis
is on defoliating insects previously suppressed with DDT. In setting up the unit,
the Forest Service recognized that basic and applied chemical research for insect
control had to be conducted on a broader scale and in greater depth than in the
past (Moore, 1969). DDT and other chlorinated hydrocarbon insecticides could
no longer be used on the forests in the United States. Thus, the unit was charged
with finding suitable replacements, but the chemicals had to be selective in
action, of low hazard to associated insects--especially natural enemies of the
target pests--short-lived, degradable into innocuous residues in the forest, and
generally harmless to the total environment (Lyon and Camp, 1972).
The unit's research from 1964 to 1979 emphasized four lines of investigation: screening and bioassay of candidate insecticides; chemistry, including
synthesis, residue analysis, and metabolism; research on systemic insecticides,
including time and method of application; and field testing of the most promising
insecticides indicated by laboratory studies. The Forest Management Institute
in Canada followed a similar approach.
Work on any particular insecticide began with laboratory screening and
progressed through studies on residual life, rainfastness, and toxicity to various
instars. If an insecticide was selected for further study, it was evaluated under
field conditions, sometimes starting with small, individual tree studies to simulate
the dynamics of an aerial application (Barry et ai., 1976), then progressing to
environmental safety tests to determine the environmental risks to nontarget
organisms (Shea, 1979), to small plot field trials to evaluate efficacy to the target
pest (Hard, 1979), and to pilot control projects to determine effectiveness under
operational conditions (Ciesla, 1977). Most field studies were conducted with