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37 Cards in this Set

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How can soil fertility be a cultural management technique?
Species able to utilize soil nutrients will have a competitive advantage, so band fertilizer instead of broadcast
What is the pH range for most crops?
6-6.5
Name the weeds and their indicators.
Low pH indicator-- red sorrel
Compaction-- goosegrass
Poor drainage-- dollarweed
Low N-- legumes
High pH-- plaintains
What are natural reasons for voids?
environmental stress (flooding, lightning, hurricanes), animals, diseases, insects, nematodes
What are management reasons for voids?
improper mowing, improper fertility, improper irrigation, lack of core cultivation, lack of thatch mgmt, lack of traffic control
What are some weed management strategies for summer grasses (crabgrass, goosegrass)?
Avoid establishment at time of grass germination
Avoid core cultivation at time of germ
Lower mowing height when grass is setting seed or collect clippings
Relieve soil compaction
Apply pre-emergence herbicide
What are some weed management strategies for winter grasses (annual bluegrass)?
Species most competitive with close mowing, high water, high N
Correct drainage, raise mowing height
Avoid cultivation at germination
Collect clippings
What are some weed management strategies for perennial weeds in turf?
Maintain dense turf through proper fertility, proper mowing, insect and disease control
Spot treat or physically remove isolated patches
Apply postemergence herbicides
What is the difference between ecological and applied biological control?
In ecological, you put it out there and they are on their own. In applied, you need a continual introduction of biocontrol agents to suppress weed population
What are some examples of biocontrol?
prickly pear cactus--moth borer
water lettuce and water hyacinth
grass carp
N. jointvetch
melaleuca- psyllid, weevil
alligatorweed- flea beetle
What is a parasite?
a species which lives in or on a larger host, feeding upon it and frequently destroying it (mistletoe, leeches)
What is a parasitoid?
an insect which is only parasitic in its immature stages and will destroy host in the process of development
What is a predator?
an animal which feeds upon other organisms (grass carp, sheep, cattle)
What is a pathogen?
a microorganism that causes disease in a target organism (mycoherbicides)
What are 5 characteristics of a good biological system?
host specific (selective) + non-important alternative host
effective
favorable host plant synchonization
prolific and thrive in widespread areas that the weed occupies
good colonizers
Where does biocontrol fit?
perennial crops, low input cropping systems
rapid control not necessary
complete control not necessary
monoculture of one target weed
natural ecosystem ideal situation
Why is there a time lag for biocontrol?
no effect early on
never a true monoculture
preference of agent
What are some methods of mechanical weed management?
hand pull, tillage, cultivation, mowing, large equipment, mulches, flooding, fire, heat
What are (dis)advantages to hand pulling?
Adv. preferred in underdeveloped countries, selective
Disadv. money (labor), time
What is mechanical weed management?
anything that employs a physical force
What are advantages of tillage?
breaks weeds apart/pulls
dessicates
exhausts food reserves
reduces seed bank
What are disadvantages of tillage?
erosion
buries weed seed
raises weed seed
damages roots
compaction
serveral operations must be performed
What 3 things can you do for conservation tillage (no-till)?
1. spray for weeds
2. plant directly into residue
3. control weeds with herbicides
What weeds do no-till and conventional tillage have come up?
no-till has perennials while conventional has small-seeded annuals
What is the primary tillage equipment?
moldboard plow
disk harrow
spring tooth harrow
planter
What is the secondary tillage equipment and what does it do?
disk harrow and field cultivator
It levels, firms, breaks up clods and leave a suitable seedbed
What does mowing do to annuals and perennials?
Annuals- kills plant, prevents seed formation
Perennial- deplete reserves--> allow grasses to become competitive
What types of mowers are there?
reel, rotary, flail, sicklebar
What types of large equipment are there?
bulldozer, chaining, roller chopping, web plow
What do you use large equipment for and what are the disadvantages?
brush and woody plant control, generally expensive and long-term
What is the purpose of mulches?
excludes light and prevent growth
What are the disadvantages of mulches?
limited to small acreage, limited to transplants or specialized seeding, poor control of nutsedge, need drip irrigation, disposal of plastic is problem, not permanent
What types of mulches are there?
organic (straw, wood chips)
inorganic (rock, gravel)
synthetic (black plastic)
What does flooding do to weeds?
shift in species
What is the opposite of flooding and what is it used for?
drawdown for aquatic weed control
What is fire used for and what are the disadvantages?
used on certain crops with a tough bark
disadv. hazard, cumbersome
What are 2 other mechanical management techniques?
heat, microwave