FORESTRY PESTICIDE TEST
QUESTIONS AND ANSWERS
Therapy - Answer-destruction of a disease that has become established
Resistant varieties - Answer-use of resistant varieties is understood by most producers.
We should keep in mind that resistance does not imply immunity
Escape - Answer-avoidance of the disease by following practices that do not favor the
disease development
Protection - Answer-usually implies the use of protective chemical which prevents the
pathogen from attacking the host plant
Factor that affect herbicidal activity - Answer-Soil, environmental, plant species, and
varieties within the species
Soil factors - Answer-Physical conditions are soil composition such as sand, silt, clay,
and organic matter content, moisture air relationship and soil temperature. Chemical
properties are pH, cation exchange capacity and kind of clay. Microbial properties are
the kind and amount of microorganisms plus the microbial environment
Environmental factors - Answer-Soil moisture, humidity, air temperature, and sunlight
Factors affecting herbicide selectivity include - Answer-morphological, absorption,
translocation, and physiological
Morphological - Answer-type, shape, and position of leaf affects retention and
penetration of herbicide
Absorption - Answer-Herbicide must enter the plant
Translocation - Answer-translocation within the plant involves movement through the
phloem, through the xylem, and through the intercellular spaces
Physiological - Answer-selectivity among plants is often not well understood
Types of herbicides - Answer-contact, translocated/growth regulators, and residual
Contact - Answer-chemical agents that kill plant parts covered by the chemical
Selective contact - Answer-kill or stunt some plants with little or not injury to others
Non-selective contact - Answer-toxic to all plants
, Translocated/growth regulators - Answer-are absorbed by either the roots or above
ground parts and move, or are translocated, through the plant systems
Residual - Answer-chemical which provides weed control for a period of time by the
application of a soil-applied herbicide
Factors affecting herbicidal persistence - Answer-volatility, photo-decomposition,
absorption, leaching, plant uptake, microbial decomposition, chemical decomposition
Volatility - Answer-the rate of breakdown is determined by vapor pressure of the
chemical and the change due to temperature
Photo-decomposition - Answer-breakdown of the herbicide by sunlight
absorption - Answer-the process whereby the herbicide is bond to the surface of clay or
organic matter particles
Leaching - Answer-this occurs when a herbicide is dissolved in water and moves
through the soil profile
Plant uptake - Answer-absorption of the herbicide by certain plants reduces the amount
of material in the soil solution
Microbial decomposition - Answer-occurs when the soil microorganisms utilize the
herbicide as a source of food or when herbicides are decomposed incidental to other
action by soil nucroorganisms
Timber stand improvement - Answer-selective removal of undesirable trees to improve
growing conditions for desirable trees
Chemical precommercial thinning - Answer-removing all excess trees in a young forest
by applying chemicals to individual trees.
Preharvest drying of softwood timber - Answer-the treatment of trees with chemicals to
allow timber to season before cutting. May loosen bark and control insects and
diseases. Herbicides registered for conifer thinning may be used for this practice.
Dormant spray - Answer-applying before buds open in the spring or after trees go
dormant in the fall.
Early foliage spray - Answer-application while new growth is elongating rapidly after the
first leaves are fully expanded
Summer foliage spray - Answer-application in late summer to early fall. Generally used
with readily translocated herbicides
QUESTIONS AND ANSWERS
Therapy - Answer-destruction of a disease that has become established
Resistant varieties - Answer-use of resistant varieties is understood by most producers.
We should keep in mind that resistance does not imply immunity
Escape - Answer-avoidance of the disease by following practices that do not favor the
disease development
Protection - Answer-usually implies the use of protective chemical which prevents the
pathogen from attacking the host plant
Factor that affect herbicidal activity - Answer-Soil, environmental, plant species, and
varieties within the species
Soil factors - Answer-Physical conditions are soil composition such as sand, silt, clay,
and organic matter content, moisture air relationship and soil temperature. Chemical
properties are pH, cation exchange capacity and kind of clay. Microbial properties are
the kind and amount of microorganisms plus the microbial environment
Environmental factors - Answer-Soil moisture, humidity, air temperature, and sunlight
Factors affecting herbicide selectivity include - Answer-morphological, absorption,
translocation, and physiological
Morphological - Answer-type, shape, and position of leaf affects retention and
penetration of herbicide
Absorption - Answer-Herbicide must enter the plant
Translocation - Answer-translocation within the plant involves movement through the
phloem, through the xylem, and through the intercellular spaces
Physiological - Answer-selectivity among plants is often not well understood
Types of herbicides - Answer-contact, translocated/growth regulators, and residual
Contact - Answer-chemical agents that kill plant parts covered by the chemical
Selective contact - Answer-kill or stunt some plants with little or not injury to others
Non-selective contact - Answer-toxic to all plants
, Translocated/growth regulators - Answer-are absorbed by either the roots or above
ground parts and move, or are translocated, through the plant systems
Residual - Answer-chemical which provides weed control for a period of time by the
application of a soil-applied herbicide
Factors affecting herbicidal persistence - Answer-volatility, photo-decomposition,
absorption, leaching, plant uptake, microbial decomposition, chemical decomposition
Volatility - Answer-the rate of breakdown is determined by vapor pressure of the
chemical and the change due to temperature
Photo-decomposition - Answer-breakdown of the herbicide by sunlight
absorption - Answer-the process whereby the herbicide is bond to the surface of clay or
organic matter particles
Leaching - Answer-this occurs when a herbicide is dissolved in water and moves
through the soil profile
Plant uptake - Answer-absorption of the herbicide by certain plants reduces the amount
of material in the soil solution
Microbial decomposition - Answer-occurs when the soil microorganisms utilize the
herbicide as a source of food or when herbicides are decomposed incidental to other
action by soil nucroorganisms
Timber stand improvement - Answer-selective removal of undesirable trees to improve
growing conditions for desirable trees
Chemical precommercial thinning - Answer-removing all excess trees in a young forest
by applying chemicals to individual trees.
Preharvest drying of softwood timber - Answer-the treatment of trees with chemicals to
allow timber to season before cutting. May loosen bark and control insects and
diseases. Herbicides registered for conifer thinning may be used for this practice.
Dormant spray - Answer-applying before buds open in the spring or after trees go
dormant in the fall.
Early foliage spray - Answer-application while new growth is elongating rapidly after the
first leaves are fully expanded
Summer foliage spray - Answer-application in late summer to early fall. Generally used
with readily translocated herbicides
