NEW
Font size
WorksheetsMIDTERM EXAMINATION
Total questions: 50
Worksheet time: 55mins
Sedges, distinguished from their triangular stems, are members of what family?
Cyperaceae
Mimosaceae
Pontederiaceae
Asteracea
Which of the following is UNTRUE about weeds?
They have rapid vegetative growth.
They have the ability to survive and adapt to adverse conditions.
They are less adapted to crop competition.
They are prolific and produce abundant seeds.
This refers to the seed bank where weed seeds are deposited:
soil
water
field
all of the choices are correct
The most competitive stage of the weed plant is:
mature stage
juvenile stage
seedling stage
declining stage
Of the following statements below, which does NOT best describe the seedling stage of weeds?
It is the most competitive stage in most species.
It is most sensitive to environmental influences.
It is the most tolerant stage to herbicide action.
It is the most vulnerable and the most practical stage for control.
Weeds with rounded hollow stems and fibrous root system
sedges
grasses
braodleavesbroadleaves
annual
The following are vegetative propagules except…
seeds
tubers
rhizome
off-shoots
The phenomenon when weed seeds fail to germinate even under favorable conditions
quiescence
dormancy
viability
longevity
Weeds with triangular stems and parallel leaf venation
sedges
broadleaves
grasses
annuals
Grassy weeds (Poaceae) look similar to sedges except that their stem called culm is:
Triangular
Cylindrical
Polyhedral
shapeless
Weeds having expanded leaves with netted venation
sedges
broadleaves
grasses
annuals
A post-emergence herbicide is applied
After land preparation
Before land preparation
After the weeds or crops have emerged
All of the above
Which among the following weed species is a sedge?
Ageratum conyzoides
Cyperus iria
Paspalum conjugatum
Sphenoclea zeylanica
Broadleaf weeds are those with expanded leaf blades that include the following EXCEPT:
Pistia stratiotes
Monochoria vaginalis
Eichinocloa colona
Amaranthus spinosus
Beneficial effect of weeds are the following EXCEPT:
soil binders
indicators of growing conditions in the field
Supporting natural enemies of pests
Alternative host for pests
A weed that propagate not only through seeds, but also by the underground stem, roots, tubers etc., and grows from year to year.
Annual weed
Dicot weeds
Monocot weed
Perennial weed
The study of weeds and their control
weed evaluation
weed control
weed science
population management
Chemicals that are used to kill weeds
weedicides
. insecticides
fungicides
herbicides
Weeds that originate from other areas and are introduced to the area where they are found
endemic
native
local
exotic
The author defined weeds as “a plant growing where it is not wanted”.
Humburg
Harper
Emerson
Tull
Sedges, grasses and broadleaves belong to this classification:
body texture
growth habit
habitat
gross morphology
In crop production, the primary reason why a weed is considered as a pest is:
it is able to harbor organisms
it produces seeds and other vegetative propagules
it annoys human requisites
it is able to significantly lower the quantity and quality of products
The period or stage in the life cycle of crops where the presence of weeds could affect the yield of the crop is:
critical density of weed competition
critical threshold level
critical threshold density
critical period of competition
Like any other plant, the germination of weeds is affected by a group of environmental factors:
water, oxygen, temperature
water, oxygen, light, temperature
water, oxygen, carbon dioxide
water, light, temperature, carbon dioxide
A method where one can still harvest profitable crops in spite of the presence of weeds.
weed competition
weed prevention
weed control
weed eradication
Weed seed imbibition involves the absorption of:
oxygen
nitrogen
water
light
Weeds that are persistent, highly competitive, and difficult to control and reduce crop yield even at low density.
perennial
indigenous
annuals
noxious
A deliberate use of a weed’s natural enemies to suppress the growth or reduce the population of the weed.
Chemical method
Preventive method
Biological method
Cultural method
The weeds cause ailment to livestock resulting in death and cause great loss.
exotic
poisonous
indigenous
parasitic
The ability of the seed to germinate even after prolonged dormancy.
quiescence
dormancy
viability
longevity
This is described as the struggle between two or more plants for a limited resource
allelopathy
interference
dispersal
competition
The effects of one plant on another plant due to the chemicals that it releases
allelopathy
interference
dispersal
competition
The predominance of weed species in the field is largely due to all of the following reasons except one:
their ability to get dormant when exposed to unfavorable conditions, thus they escape control measures
they survive better than cultivated plants due to built-in mechanism for adaptation
high capacity for reproduction and efficient mechanism for adaptation and competition.
they have slow vegetative growth
An environmental factor that is optional in the germination of crop seeds but very important in the germination of most weed seeds
moisture
light
temperature
oxygen
The ability of weed seeds to become dormant when exposed to unfavorable conditions is a mechanism for __________.
reproduction
adaptation
germination
competition
Weeds and crops have similar requirements that is why weeds are characterized as
Competitive
Persistent
Reproductive
Pernicious
Weeds that reproduce mainly through seeds, and grow within a year.
biennial
creeping perennials
simple perennials
annuals
This is considered the first sign of weed growth.
Emergence of root
Emergence of the shoot
water imbibition
seed dispersal
Perennial weeds are more difficult to control than annuals because
They have deeper root penetration.
They produce more shoots.
They have numerous underground vegetative propagules that may exhibit dormancy.
They produce allelochemical.
Type of herbicide whose phytotoxic effects are manifested at the sites on the plants where the spray droplets are deposited.
Pre-emergence herbicides
translocated herbicides
contact herbicides
systemic herbicides
Type of herbicide that is applied after the crop is planted but before the emergence of weeds or crop.
Pre-emergence herbicides
pre-plant herbicides
post-emergence herbicides
systemic herbicides
Characteristics of weeds:
(1). Weeds have rapid vegetative growth.
(2). Most weeds are very prolific and produce abundant seeds
Statement 1 and 2 are true
Statement 1 is true, Statement 2 is false
Statement 1 and 2 are false
Statement 1 is false, Statement 2 is true
The following are means by which weeds are dispersed from one area to another, except..
wind
animals
water
fire
The most practical stage for controlling weeds especially when using herbicides is during their seedling stage because:
It is the stage where damage against crops is becoming apparent.
It is the most competitive stage for growth resources.
It is the stage where leaves are succulent and still lack cutin or waxes and the roots have thin epidermal walls.
It is the most destructive stage.
(1) The main purpose of weed management is to reduce weed population to levels that will not significantly reduce crop yield.
(2) Presence of weeds in a crop does not necessarily lead to significant reduction in yield.
Statement 1 and 2 are true
Statement 1 is true, Statement 2 is false
Statement 1 and 2 are false
Statement 1 is false, Statement 2 is true
The scientific name of cogon is:
Leptochloa chinensis
Ischaemum rugosum
Echinochloa colona
Imperata cylindrica
The scientific name of tropic ageratum (bangbangsit) is:
Ipomoea triloba
Euphorbia hirta
Cleome rutidosperma
Ageratum conyzoides
The scientific name of beggarstick is:
Ipomoea triloba
Euphorbia hirta
Cleome rutidosperma
Bidens pilosa
The scientific name of tawa-tawa (garden spurge) is:
Leptochloa chinensis
Ischaemum rugosum
Echinochloa colona
Euphorbia hirta
The scientific name of jungle grass is:
Leptochloa chinensis
Ischaemum rugosum
Echinochloa colona
Cynodon dactylon
