Term
| causal agent of fire blight |
|
Definition
|
|
Term
| physical characteristics of Erwinia amylovora |
|
Definition
-rod-shaped bacteria
-peritrichous flagella |
|
|
Term
|
Definition
| flagella spread around the bacteria |
|
|
Term
| closely related to Erwinia amylovora |
|
Definition
-Erwinia carotovora
-Erwinia tracheiphila |
|
|
Term
|
Definition
| causal agent of fire blight |
|
|
Term
| Host range of Erwinia amylovora |
|
Definition
1. Pear
2. Other pome fruits (esp. apple, quince)
3. Stone fruits - less disease
4. All other members of Rosaceae - varying
disease levels
– several important ornamental hosts
***Absolute number 1 most important limitation on pear production east of the Mississippi |
|
|
Term
| can Erwinia amylovora be avoided in the East? |
|
Definition
|
|
Term
| distribution of Erwinia amylovora |
|
Definition
| Throughout the world - warm humid regions |
|
|
Term
| severity of Erwinia amylovora |
|
Definition
-The disease can completely eliminate pear
production
-Can be almost as disastrous with very susceptible apple varieties |
|
|
Term
| Are apples in the grocery store resistant to Erwinia amlovora |
|
Definition
| Most apples in grocery store are resistant to Erwinia amylovora |
|
|
Term
|
Definition
|
|
Term
| symptoms of fire blight caused by Erwinia amylovora |
|
Definition
1. Blossoms, twigs, leaves, fruit, and limbs are affected
2. Starts at the tips of branches or fruit spurs
3. Moves downward toward the larger limbs -girdles and kills main stem
4. Flowers and leaves turn brown - then black (coal black; very very diagnostic)
5. Appear to be scorched by fire (thus the name ‘Fire blight’)
6. Stems turn brown to black - later shrivel -slows down here
7. Larger limbs - cankers
8. Cankers - sunken with definite margins
9. Fruit blackens - develop into soft rot |
|
|
Term
| signs of Erwinia amylovora |
|
Definition
Drops of bacterial ooze
come out of infected tissue
appear on surface in moist, warm weather |
|
|
Term
|
Definition
| blossom blight phase of Erwinia amylovora |
|
|
Term
| blossom blight phase of Erwinia amylovora |
|
Definition
|
|
Term
|
Definition
| shepherd's crook or hook caused by Erwinia amylovora |
|
|
Term
| shepherd's crook or hook caused by Erwinia amylovora |
|
Definition
|
|
Term
|
Definition
| blackening caused by Erwinia amylovora |
|
|
Term
| blackening caused by Erwinia amylovora |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
| sunken canker caused by Erwinia amylovora |
|
|
Term
| sunken canker caused by Erwinia amylovora |
|
Definition
|
|
Term
|
Definition
| what Erwinia amylovora does to apple |
|
|
Term
| what Erwinia amylovora does to apple |
|
Definition
|
|
Term
|
Definition
| close up of bacterial ooze |
|
|
Term
| Why is bacterial ooze attractive to insects? |
|
Definition
|
|
Term
| disease cycle of Erwinia amylovora |
|
Definition
1: survival
2: primary inoculum
3: dissemination
4: inoculation
5: penetration
6: infection and invasion
7: reproduction
8: secondary cycles |
|
|
Term
| survival phase of Erwinia amylovora |
|
Definition
| bacterial cells inside the edge of cankers on limbs |
|
|
Term
| primary inoculum of Erwinia amylovora |
|
Definition
| bacterial ooze formed on the canker surfaces from rising sap |
|
|
Term
| When does Erwinia amylovora cause bacterial ooze? |
|
Definition
| early spring when trees are blooming |
|
|
Term
| dissemination phase of Erwinia amylovora |
|
Definition
a. Insects attracted to ooze -> blossoms
(no specific insect vectors, but bees are
very effective)
b. Bacteria/ooze splashed by rain |
|
|
Term
| inoculation phase of Erwinia amylovora |
|
Definition
nectaries in blossoms
-natural openings |
|
|
Term
| penetration phase of Erwinia amylovora |
|
Definition
-through openings in nectaries - at the base of flower (indirect)
-bacteria grow and divide several days in the nectar
-then move through floral parts into fruit spur |
|
|
Term
| infection and invasion phase of Erwinia amylovora |
|
Definition
-bacteria multiply, secrete enzymes, move intercellularly
-causes the plant cells to separate and die
-twigs and stems - bacteria move through the phloem
-invasion can be rapid in succulent, susceptible tissue
-not much for it to infect until there's fruit on tree |
|
|
Term
| How fast can a bacterial infection spread in a plant? |
|
Definition
|
|
Term
| reproduction phase of Erwinia amylovora |
|
Definition
-Bacterial ooze formed on all infected tissues during wet, warm weather
-insects attracted to this ooze
-will kill tree
-reduces production |
|
|
Term
| secondary cycles of Erwinia amylovora |
|
Definition
-same as the primary cycle except for the source of inoculum
-bacteria from blighted blossoms, leaves, or twigs
-carried by insects to other blossoms |
|
|
Term
| primary means of dissemination for secondary cycles of Erwinia amylovora |
|
Definition
|
|
Term
| ideal conditions for Erwinia amylovora |
|
Definition
-favored by wet and warm weather
-rapid, succulent growth of trees |
|
|
Term
| methods of control for Erwinia amylovora |
|
Definition
1: sanitation
2: cultural methods
3: chemical sprays |
|
|
Term
| methods of sanitation to control Erwinia amylovora |
|
Definition
a. Summer pruning to remove blighted limbs (cut 4 inches below visible symptoms, because bacteria will have already moved that far)
-just like amputating gangrene
b. Winter pruning to remove cankers
c. Disinfection of pruning tools between every single cut (or else (a) and (b) only make the disease WORSE) |
|
|
Term
| controlling Erwinia amylovora using cultural methods |
|
Definition
a. prevent succulent growth
b. plant pears somewhere else – more arid climate!
(‘b’ is actually the only widely-practiced control method for fire blight of pears…) |
|
|
Term
| Are any pears resistant to Erwinia amylovora? |
|
Definition
| some are, but not accepted by the American public |
|
|
Term
| controlling Erwinia amylovora using chemical sprays |
|
Definition
a. copper compounds
b. streptomycin
applied several times during bloom
Insect control ??? - not during bloom |
|
|
Term
| causal agent of crown gall |
|
Definition
| Agrobacterium tumefaciens |
|
|
Term
|
Definition
| hypertrophy, hyperplasia - on stems, roots |
|
|
Term
| physical characteristics of Agrobacterium tumefaciens |
|
Definition
-rod-shaped
-few peritrichous flagella |
|
|
Term
| virulent and avirulent strains determined by... |
|
Definition
|
|
Term
|
Definition
| small circular DNA in bacteria |
|
|
Term
| Where did plasmids come from? |
|
Definition
| one theory says they came from captured viruses |
|
|
Term
| what Agrobacterium tumefaciens does to plant cells |
|
Definition
| makes them bigger and makes them divide more rapidly |
|
|
Term
| diagnosis of Agrobacterium tumefaciens by... |
|
Definition
|
|
Term
| Agrobacterium tumefaciens abundant in... |
|
Definition
|
|
Term
| Is Agrobacterium tumefaciens a saprophyte? |
|
Definition
| excellent facultative saprophyte |
|
|
Term
| distribution of Agrobacterium tumefaciens |
|
Definition
| worldwide, common soil inhabitant |
|
|
Term
| host range of Agrobacterium tumefaciens |
|
Definition
-many woody and herbaceous hosts - >200 genera (only dicots!)
-mainly on stone, pome fruits, ornamentals |
|
|
Term
| When can a plant become infected with Agrobacterium tumefaciens? |
|
Definition
|
|
Term
| negative economic effects of Agrobacterium tumefaciens |
|
Definition
-nursery plants worthless with
-may lose valuable mature ornamental plants at any ag |
|
|
Term
| positive economic effects of Agrobacterium tumefaciens |
|
Definition
-vector for plant genetic transformation, genetic
-unlimited economic potential $$$$$ |
|
|
Term
| symptoms of Agrobacterium tumefaciens |
|
Definition
-disorganized, amorphous galls
-just below soil line - on crown
-malignant tumor |
|
|
Term
| why galls caused by Agrobacterium tumefaciens are usually on crown |
|
Definition
| because Agrobacterium tumefaciens is abundant in soil and there's many many ways plants can get wounded at crown |
|
|
Term
|
Definition
-will spread
-won't stop dividing |
|
|
Term
| Is Agrobacterium tumefaciens useful regarding human cancer? |
|
Definition
|
|
Term
| some good things Agrobacterium tumefaciens has led to |
|
Definition
| some drug discoveries and being able to GMO plants |
|
|
Term
|
Definition
|
|
Term
| behavior of galls in plants |
|
Definition
-Galls, once begun, will not stop growing
-Does not depend on continued presence of bacterium
-Secondary galls may form – ***not associated with presence of bacteria
-Eventually causes stunted growth, death |
|
|
Term
| Does Agrobacterium tumefaciens have to be present for secondary galls to form? |
|
Definition
|
|
Term
| disease cycle of Agrobacterium tumefaciens |
|
Definition
1: overwinter
2: penetration
3: infection, invasion |
|
|
Term
| overwinter phase of Agrobacterium tumefaciens |
|
Definition
-bacterial cells - infested soils
--excellent saprophyte, mainly on host tissue
-rain-splash dissemination from ground to lower parts of plant |
|
|
Term
| penetration phase of Agrobacterium tumefaciens |
|
Definition
| -Bacterium enters roots, stems- requires recent wounds near ground |
|
|
Term
| penetration phase of Agrobacterium tumefaciens is caused by... |
|
Definition
-cultural practices - lawnmower
-insect feeding |
|
|
Term
| infection, invasion phase of Agrobacterium tumefaciens |
|
Definition
a. bacterium degrades pectins, occupies intercellular spaces
b. bacterium grows, divides
c. stimulates surrounding plant cells to divide, enlarge
d. gall visible 10-14 days
e. plant cell division, enlargement continues (up to 1 ft. diameter)
f. crushes xylem elements – reduces water flow 80%
g. galls become woody, stop enlarging
h. turn brown - black, decay
i. bacteria fall to soil on decaying gall tissue |
|
|
Term
| what you can do on plate with gall tissue |
|
Definition
| grow it on media without Agrobacterium tumefaciens present |
|
|
Term
| how secondary galls are formed |
|
Definition
1. tumor cells dislodge
2. move through vascular system
3. initiate secondary galls in upper part of plant
4. no bacteria present in secondary galls |
|
|
Term
| ways to control Agrobacterium tumefaciens |
|
Definition
1: Inspection, certification of nursery stock
2: Rotation
3: Cultural practices
4: Chemical
5: Biological control |
|
|
Term
| using rotation to control Agrobacterium tumefaciens |
|
Definition
| plant nonhosts for several years - corn, small grain crops |
|
|
Term
| using cultural practices to control Agrobacterium tumefaciens |
|
Definition
| reduce wounding during cultivation, mowing |
|
|
Term
| chemical means of controlling Agrobacterium tumefaciens |
|
Definition
insect control – reduces wounds
a. soil insecticides – rootworms
b. shoot insecticides – cutworms, stem feeders |
|
|
Term
|
Definition
-soil insecticides – rootworms
-shoot insecticides – cutworms, stem feeders |
|
|
Term
| using biological control to control Agrobacterium tumefaciens |
|
Definition
Agrobacterium radiobacter strain 84
-antagonistic to A. tumefaciens
-coat seeds, dip seedlings, nursery stock
-inhabits rhizoplane, inhibits pathogen
-Galltrol-A, Nogall, Diegall, and Norbac 84C |
|
|
Term
| crown gall tumors similar to this in humans |
|
Definition
|
|
Term
| how Agrobacterium tumefaciens modifies genome of host |
|
Definition
1. introduces strip of DNA from Ti-plasmid (Tumor inducing)
2. plasmid DNA is transferred to nucleus and incorporated into host DNA
3. genes on Ti-plasmid are switched on activated
4. bacterium not needed after incorporation of Ti-plasmid |
|
|
Term
| how Agrobacterium tumefaciens is a natural genetic engineer |
|
Definition
1. sense genes in bacteria detect wounded plant tissue (leakage of cell contents, sugars)
2. bacteria transports Ti DNA across cellular membrane to cell membrane of nearby healthy plant cells
3. plant cell actively transports bacterial package across plant cell membrane
4. existing plant cell mechanisms transport Ti factor across cell into nucleus
5. Ti factor is incorporated into host genome becomes part of the chromosome
6. genes on the Ti-factor are switched on by a construct that is a part of the plasmid
***self activating genetic insert
7. genes expressed:
-IAA, auxins, cytokinins enzymes -> regulate plant growth
-opines -> carbon energy source
***gall is uncontrollable, rapidly growing opine factory
8. opines can only be used as an energy source by A. tumefaciens with Ti-plasmid
-very specific coevolved system
-controlled by plasmid |
|
|
Term
| now possible to use Agrobacterium tumefaciens to do this |
|
Definition
1. remove Ti-plasmid from A. tumefasciens
2. strip away interior contents of plasmid – leave flanking regions that are responsible for movement, uptake, incorporation, activation of genes
3. incorporate new genes into the plasmid construct
4. put plasmid back in A. tumefaciens
5. infect plant
-new genes introduced and activated in host plant
***basis of genetic engineering in plants |
|
|
Term
|
Definition
| device used to shoot construct directly into plant cell – removes Agrobacterium tumefaciens from system |
|
|
Term
|
Definition
|
|
Term
| Uses for Ti-plasmid-based transgenic system |
|
Definition
-Resistance genes from another plant
-Insecticidal compounds – genes from Bacillus thuringiensis etc. to produce toxins - Bt® crops
-Herbicide resistance - Roundup Ready® crops
-Completely artificial genetic constructs – virus resistance – papaya ringspot
-(can’t sell GMO’s in numerous countries) |
|
|
Term
|
Definition
|
|
Term
| how Agrobacterium tumefaciens destroys pectins |
|
Definition
|
|
Term
| Is Agrobacterium tumefaciens intercellular or intracellular? |
|
Definition
|
|
Term
| what Agrobacterium tumefaciens does to the surrounding plant cells |
|
Definition
| stimulates surrounding plant cells to divide, enlarge |
|
|
Term
| How long does it take for crown gall to become visible? |
|
Definition
|
|
Term
| How big can a crown gall get? |
|
Definition
|
|
Term
| what gall does to water flow |
|
Definition
-crushes xylem elements – reduces water flow 80%
-does this purely by physical force |
|
|
Term
| What happens as galls stop enlarging? |
|
Definition
-become woody
-turn brown - black, decay |
|
|
Term
| Gall completes the disease cycle by doing this after it decays. |
|
Definition
| bacteria fall to soil on decaying gall tissue |
|
|
Term
| This led to cell culture. |
|
Definition
| can culture tumor tissue on media – continues to grow without bacteria |
|
|
Term
| The ability for gall cells to continue multiplying without bacteria led to this. |
|
Definition
|
|
Term
| mandatory measure of control for Agrobacterium tumefaciens |
|
Definition
| Inspection, certification of nursery stock |
|
|
Term
| how you might wanna do rotation when trying to control Agrobacterium tumefaciens |
|
Definition
| this disease only affects dicots, so you might wanna rotate with monocots by leaving dicots out of it for 2 years |
|
|
Term
| When a plant's infected, it turns out to be more practical to... |
|
Definition
|
|
Term
| Mow when there's this around the plant for this reason. |
|
Definition
| mow when there's mulch around the plant such that you don't nick the plant |
|
|
Term
| why Agrobacterium radiobacter strain 84 works to control Agrobacterium tumefaciens |
|
Definition
| occupies same niche as tumefaciens, but doesn't carry Ti plasmid |
|
|
Term
|
Definition
|
|
Term
| What happens to the Ti-plasmid in Agrobacterium tumefaciens? |
|
Definition
| plasmid DNA is transferred to nucleus and incorporated into host DNA |
|
|
Term
| how the Ti-plasmid gets activated |
|
Definition
|
|
Term
| Agrobacterium tumefaciens attacks only wounded plant cells. What are the indicators of wounded plant cells? |
|
Definition
| leakage of cell contents, sugars |
|
|
Term
| how Agrobacterium tumefaciens causes crown gall |
|
Definition
| bacteria transports Ti DNA across cellular membrane to cell membrane of nearby healthy plant cells |
|
|
Term
| why plant cell actively transports bacterial package from Agrobacterium tumefaciens across plant cell membrane |
|
Definition
| this bacteria deceives cell into thinking it's good |
|
|
Term
| how Ti-plasmid from Agrobacterium tumefaciens gets into nucleus |
|
Definition
| existing plant cell mechanisms transport Ti factor across cell into nucleus |
|
|
Term
| Ti factor from Agrobacterium tumefaciens is incorporated into host genome and becomes part of the chromosome. What is required for this? |
|
Definition
| has to have certain construct of 5' end that cleaves into there |
|
|
Term
| The Ti-plasmid from Agrobacterium tumefaciens has how many genes? |
|
Definition
|
|
Term
| how Agrobacterium tumefaciens regulates plant growth |
|
Definition
| IAA, auxins, cytokinins enzymes |
|
|
Term
| where it became known that Agrobacterium tumefaciens had nothing to do with cancer |
|
Definition
| when it became known that Agrobacterium tumefaciens regulates plant growth using IAA, auxins, cytokinins enzymes |
|
|
Term
| the carbon energy source for Agrobacterium tumefaciens |
|
Definition
|
|
Term
| how Agrobacterium tumefaciens uses opines |
|
Definition
-very complex amino acid base energy containing molecule that only the Ti plasmid has the gene to digest
-creates uncontrollable buffet for the infecting Agrobacterium tumefaciens |
|
|
Term
| opines can only be used as an energy source by... |
|
Definition
| Agrobacterium tumefaciens with the Ti-plasmid |
|
|
Term
| depiction of how Agrobacterium tumefaciens infects plant cells |
|
Definition
|
|
Term
| The flanking regions of the Ti-plasmid are responsible for this. |
|
Definition
| movement, uptake, incorporation, activation of genes |
|
|
Term
| how monocots can be infected with Agrobacterium tumefaciens |
|
Definition
-modern gene guns used to infect monocots
-can also do this electrophoretically |
|
|
Term
| Uses for Ti-plasmid-based transgenic system |
|
Definition
-Resistance genes from another plant
-Insecticidal compounds – genes from Bacillus thuringiensis etc. to produce toxins - Bt® crops
-Herbicide resistance - Roundup Ready® crops
-Completely artificial genetic constructs – virus resistance – papaya ringspot
+(can’t sell GMO’s in numerous countries) |
|
|
Term
| the first plant to have its genome sequenced |
|
Definition
tobacco
-used Ti-construct to transfer in jellyfish luminescence genes |
|
|
Term
| the 3 genera of mollicutes |
|
Definition
| Phytoplasma, Spiroplasma, Mycoplasma |
|
|
Term
| which genera of mollicutes is not plant pathogens? |
|
Definition
|
|
Term
| this genera of mollicutes is the animal pathogen group |
|
Definition
|
|
Term
| What type of parasites are mollicutes? |
|
Definition
|
|
Term
| mollicutes discovered in... |
|
Definition
|
|
Term
| how mollicutes were discovered |
|
Definition
| Seen in phloem with EM in plants infected with 'Yellows' disease |
|
|
Term
| Diseases caused by mollicutes were previously thought to be caused by... |
|
Definition
|
|
Term
| Mollicutes can also be found inside... |
|
Definition
|
|
Term
|
Definition
-Prokaryotes - no cell wall
-No flagella
-Pleomorphic shapes |
|
|
Term
| some paleomorphic shapes of mollicutes |
|
Definition
-spherical to oval, or irregular
-tubular, filamentous helical |
|
|
Term
| Mollicutes have been found to be susceptible to ______, but not to ______ |
|
Definition
|
|
Term
| Penicillin does this to cells. |
|
Definition
|
|
Term
|
Definition
| destroys the energy pathway |
|
|
Term
| Mollicutes cause > ______ plant diseases on > ______ genera of plants |
|
Definition
|
|
Term
| some diseases caused by mollicutes |
|
Definition
-Peach X disease
-Pear decline
-Coconut lethal yellowing
-Aster yellows
-Citrus stubborn |
|
|
Term
| one disease that can't be treated with tetracycline |
|
Definition
|
|
Term
| this is probably the most common mycoplasmal disease |
|
Definition
|
|
Term
| name another mycoplasmal disease |
|
Definition
|
|
Term
| symptoms of mollicute diseases |
|
Definition
1. Gradual, uniform yellowing or reddening of leaves
2. Shortening of internodes
3. Stunting or proliferation of shoots (witches-broom)
4. Sterile flowers
5. Decreased yield
6. Rapid dieback
7. Decline, death of plant |
|
|
Term
| this mollicute symptom often seen in a disease called "phony peach" |
|
Definition
|
|
Term
| what mollicutes often do to carrots |
|
Definition
| keeps root from forming carrot |
|
|
Term
| how mollicutes move in plants |
|
Definition
-can invade xylem or phloem
-don't get stuck
-can even go thru plasmodesmata because thay have no cell walls |
|
|
Term
| general life cycle for mollicutes |
|
Definition
| -Live in phloem and in insect vectors -Reproduce by fission -Most are transmitted (vectored) by leafhoppers +Specific association – not just any insect will vector |
|
|
Term
| how mollicutes behave in insect vectors |
|
Definition
-Leafhopper feeds on infected plant
-3 hrs to 1 day feeding required to acquire (not instantaneous)
-Vector cannot transmit to healthy plant immediately
-10 to 45 day incubation required
+(temperature dependent, 30 C optimum, 10 C required)
-Mollicute must multiply and invade tissues of insect
-Must reach high concentration in salivary glands
-Insect remains infectious for rest of life
-Insect not affected by mollicute
-Can be acquired by nymphs, survives through molts to adult, but not egg transmitted |
|
|
Term
| Mollicute must do these things in insect vectors. |
|
Definition
-Mollicute must multiply and invade tissues of insect
-Must reach high concentration in salivary glands |
|
|
Term
| how insect is affected by mollicute |
|
Definition
-Insect remains infectious for rest of life
-Insect not affected by mollicute |
|
|
Term
| Can mollicutes be transmitted by eggs? |
|
Definition
|
|
Term
| Why are mollicutes hard to study? |
|
Definition
|
|
Term
| Why can't mollicutes be cultured? |
|
Definition
|
|
Term
| these techniques now used for detection and identification of mollicutes |
|
Definition
| Serological, molecular techniques |
|
|
Term
| Does soil treatment work for mollicutes? |
|
Definition
|
|
Term
| chemical means to control mollicutes |
|
Definition
-sensitive to tetracyclines
-dip entire plants in solutions
-foliar, soil applications not effective
-can inject trees -> into phloem
-temporary relief only, not cure |
|
|
Term
|
Definition
-helical-shaped mollicutes
-motile (no flagella, rotary 'screw' motion) |
|
|
Term
| causal agent of citrus stubborn disease |
|
Definition
Spiroplasma citri
spiral shaped |
|
|
Term
| distribution and host range of Spiroplasma citri |
|
Definition
-Orange and grapefruit, 20 other citrus genera
-Southwestern US, Brazil, Mediterranean countries, Australia, South Africa
-In Mediterranean and SW US considered greatest threat to orange and grapefruit production
-California alone, > 3 million trees destroyed |
|
|
Term
| Why is Florida serious about people not bringing citrus into there? |
|
Definition
| because Spiroplasma citri, the causal agent of citrus stubborn, hasn't hit there and they don't want it to |
|
|
Term
| symptoms of cutrus stubborn caused by Spiroplasma citri |
|
Definition
1. Bunchy, upright growth
2. Shortened internodes
3. Excessive shoots
4. ‘Flat top' (shortened central leader shoot)
5. Thickened bark
6. Severe overall stunt
7. Chlorotic, mottled leaves (virus misdiagnosis)
8. Winter defoliation caused by weakening
9. Flowers formed all year (sterile flowers, kinda like phony peach)
10. Fewer fruit, misshapen, thick rind, bitter flavor
11. Unpleasant odor - worthless = NO YIELD even pigs won't eat it |
|
|
Term
| one of the first indicators of citrus stubborn caused by Spiroplasma citri |
|
Definition
|
|
Term
| the most accurate way to diagnose citrus stubborn caused by Spiroplasma citri |
|
Definition
|
|
Term
| How did citrus stubborn get its name? |
|
Definition
| because the oranges wouldn't turn orange |
|
|
Term
| disease cycle of Spiroplasma citri |
|
Definition
1. overwinters
2. primary inoculum
3. dissemination
4. secondary cycles |
|
|
Term
| how Spiroplasma citri overwinters |
|
Definition
-phloem of infected trees
-inside insect vectors
seems to prefer perennials |
|
|
Term
| the primary inoculum of Spiroplasma citri |
|
Definition
|
|
Term
| how Spiroplasma citri disseminates |
|
Definition
1. Multiplies in sap and spreads throughout tree
2. Acquired by feeding leafhoppers
(feed directly from phloem with small tube – no wounding of surrounding tissues)
3. Increases in leafhoppers
4. Disseminated by leafhoppers - after incubation
5. Injected directly into phloem from salivary glands during feeding
6. Begins to multiply in sap |
|
|
Term
| how feeding leafhoppers acquire Spiroplasma citri |
|
Definition
| feed directly from phloem with small tube – no wounding of surrounding tissues |
|
|
Term
| secondary cycles of Spiroplasma citri |
|
Definition
|
|
Term
| effects of environment on Spiropla citri |
|
Definition
narrow optimum temperature range of 30-32 C (but it is only found on citrus!)
coevolved with citrus |
|
|
Term
| two categories of ways to control Spiroplasma citri other than chemical |
|
Definition
|
|
Term
| exclusion means by which to control Spiroplasma citri |
|
Definition
-Use spiroplasma-free scion and rootstocks
-Monitored by serology in nurseries (use serology for both sides) |
|
|
Term
| sanitation means by which to control Spiroplasma citri |
|
Definition
-Roguing - removal of infected trees
***usually too late, unless combined with routine serological monitoring of ALL trees in grove ($45.00 per tree....??)
-for this to be effective, it must be for every single tree |
|
|
Term
|
Definition
| removal of infected trees |
|
|
Term
| some characteristics of viruses |
|
Definition
-Submicroscopic
-Nonliving
-Obligate parasites
-Require wounds for penetration
-Most commonly transmitted by insects (aphids and leafhoppers)
-Systemic infections
-Stunting; mosaic |
|
|
Term
|
Definition
-active or inactive
-infective or noninfective |
|
|
Term
| Do viruses have cellular machinery? |
|
Definition
|
|
Term
| Viruses have to be placed into contact with this to invade a cell. |
|
Definition
|
|
Term
| Can viruses use destroyed cells? |
|
Definition
|
|
Term
| Insects automatically expose this, which makes it possible for a virus to infect a plant. |
|
Definition
|
|
Term
| the 2 most common symptoms of viruses |
|
Definition
-stunting
-mosaic (may go necrotic in late stages) |
|
|
Term
|
Definition
-Average width is 10-60 nm
-Average length is 20-300 nm
-Observe only with electron microscope |
|
|
Term
| the 3 types of virus shapes |
|
Definition
-enlongate
-Rhabdovirus
-spherical |
|
|
Term
|
Definition
-long and slender
-can be rigid or thread-like |
|
|
Term
|
Definition
bacillus-like (about the shape of bacteria)
they resemble bacteria |
|
|
Term
|
Definition
actually polyhedral (composed of flat pads)
most common in magazines and books |
|
|
Term
|
Definition
-Ribonucleic acid
-DNA or RNA
-Single-stranded or double-stranded
-Core nucleic acid covered with coat protein |
|
|
Term
| This gives virus some protection from the environment. |
|
Definition
| 1 molecule thick coat of protein |
|
|
Term
| the whole purpose of a virus |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
1. Mosaic, mottle
2. Stunting (virus is energy drain)
3. Growth distortions
4. Ringspots, vein banding, other patterned necrotic symptoms |
|
|
Term
| difference between mosaic and mottle |
|
Definition
| mosaic has clearly defined edges and mottle has fuzzy edges |
|
|
Term
|
Definition
|
|
Term
| growth distortions as a symptom of viruses |
|
Definition
-can be complicated or mild
-not very common with viruses |
|
|
Term
| ring spots as a symptom of viruses |
|
Definition
| ringspots aren't very common, but they're caused only by viruses |
|
|
Term
| vein banding as a symptom of viruses |
|
Definition
| light area around all the veins in a dicot leaf |
|
|
Term
| criteria by which viruses are classified |
|
Definition
| 1. Type of nucleic acids 2. Shape of particle 3. Number of discrete particles |
|
|
Term
|
Definition
multipartite virus, which means the nucleic acid of the virus is cut up and split up into parts as a matter of packaging
significant because virus has to recover all the nucleic acid |
|
|
Term
|
Definition
| same sense as mRNA, functions as mRNA in cell |
|
|
Term
| how plus sense RNA is transcribed |
|
Definition
|
|
Term
|
Definition
| opposite sense from mRNA, must have viral RNA polymerase to produce plus sense image |
|
|
Term
| how minus sense RNA is transcribed |
|
Definition
|
|
Term
| something retroviruses do |
|
Definition
| RNA -> DNA = ‘retrovirus’ uses reverse transcriptase, not polymerase. DNA then produces mRNA using normal cell processes |
|
|
Term
| how polymerase in your cells codes |
|
Definition
| won't code from the 3' end |
|
|
Term
| Do your cells have a defense against rogue DNA? |
|
Definition
|
|
Term
| regarding viruses, you can see this without an electron microscope |
|
Definition
|
|
Term
|
Definition
-replication
-translocation
-transmission
-inoculation
-survival |
|
|
Term
| the best place for viruses to be |
|
Definition
| dead host tissue (they can survive here, but can't replicate) |
|
|
Term
| Virus replication must occur in... |
|
Definition
|
|
Term
|
Definition
1. Virus particles shed their protein coats
2. RNA replication using host polymerase, nucleic acids
-Virus (+) RNA replicates to give (-) RNA
***Temporary double-stranded RNA is formed
3. RNA strands separate
4. (-) RNA then acts as a template for additional virus (+) RNA (also codes for transcriptase)
5. (+) RNA acts as template for additional coat protein subunits – forms polysome with host ribosomes
ssRNA can be used to code for more RNA, or to code for proteins – all based on natural, existing cellular processes (these viruses code for useful proteins in both directions)
6. (+) RNA, and protein coat assembled by host cell processes to form new virus particles
7. Cell to cell movement followed by systemic movement
-Virus concentration rapidly increases up to several million particles per cell |
|
|
Term
| how viruses shed their protein coats |
|
Definition
| usually degraded by cells |
|
|
Term
| the point where a virus becomes systemic |
|
Definition
| when it reaches the phloem |
|
|
Term
| Cells are connected by... |
|
Definition
|
|
Term
| depiction of how viruses manipulate RNA |
|
Definition
|
|
Term
| the only thing your DNA can do |
|
Definition
| code for messenger RNA and DNA |
|
|
Term
| takes ______ bases to make a codon, and each codon codes for ______ |
|
Definition
|
|
Term
|
Definition
| virus hijacks the mRNA and tells the polysome where to start |
|
|
Term
| what viruses do in the cell |
|
Definition
| takes advantage of processes that occur in the cell |
|
|
Term
| most important element in virus infection |
|
Definition
|
|
Term
|
Definition
1. cell to cell
2. long distance or systemic |
|
|
Term
| cell to cell translocation |
|
Definition
|
|
Term
| long distance or systemic translocation |
|
Definition
through the vascular system - almost always the phloem
***can be quite rapid |
|
|
Term
| how virus or viral nucleic acid is distributed throughout plant |
|
Definition
| In phloem, viral nucleic acid or virus is carried with the photosynthate throughout the plant. |
|
|
Term
| the 4 stages of virus transmission |
|
Definition
1. Obtaining the virus from the infected plant
2. Dissemination
3. Inoculation
4. Penetration
***wounds required for penetration |
|
|
Term
| some ways for plants to be inoculated with viruses |
|
Definition
1. insect transmission
2. aphids
3. leafhoppers
4. mechanical transmission on mouthparts of chewing insects |
|
|
Term
| most common way for plants to be infected with viruses |
|
Definition
|
|
Term
| details about virus inoculation by insect transmission |
|
Definition
1. Considerable specificity
often a particular virus is transmitted by only one species of insect
***aphids, leafhoppers, whiteflies, thrips are most important vectors of plant viruses |
|
|
Term
| details about virus inoculation by aphids |
|
Definition
-Virus carried on stylet
-Nonpersistent:
+Acquire time - < 30 sec.
+Virulent period - few min - few hrs.
+Do not multiply inside the aphid |
|
|
Term
| details about virus inoculation by leafhoppers |
|
Definition
-Viruses persistent in leafhoppers
-Acquisition time – from 1 to several days
-Incubation period – 1 to 2 weeks
-Virulent period - rest of lives
-Leafhoppers can continue to carry the viruses for the rest of their lives and can transmit them to their young |
|
|
Term
| details about virus inoculation by mechanical transmission on mouthparts of chewing insects |
|
Definition
-not specific
-not persistent
-same as transmission by activities of man – cultivating, pruning |
|
|
Term
| survival phase of viruses |
|
Definition
-Some viruses are stable - survive for long periods outside host (>100 years)
-Other viruses are unstable - no survival time outside host
-Not "living" or "dead" - simply infective or noninfective |
|
|
Term
| some ways to control viruses |
|
Definition
1. Use of virus-free seed and propagation stock
2. Resistant cultivars
3. Eradication of diseased plants (including virus-infected weeds)
4. Control of insect vectors
5. Transgenic plants |
|
|
Term
| examples of controlling viruses by use of virus-free seed and propagation stock |
|
Definition
-regulatory agencies
-certification |
|
|
Term
| the availability of virus-resistant cultivars |
|
Definition
| few cultivars where needed most |
|
|
Term
| some info about controlling viruses by control of insect vectors |
|
Definition
-not very effective
-insect can transmit a virus to a plant before an insecticide on that plant will kill the insect |
|
|
Term
| some info about controlling viruses by transgenic plants |
|
Definition
a. introduce viral genes to plant genome interferes with viral processes
b. introduce sequences to activate ‘gene silencing’ against virus inhibits viral transcription
example: Transgenic Papaya to control ringspot virus |
|
|
Term
| Papaya has these enzymes. |
|
Definition
| enzymes that dissolve proteins |
|
|
Term
| what tobacco mosaic virus does to tobacco quality |
|
Definition
| lowers the nicotine content |
|
|
Term
| size and shape of tobacco mosaic virus |
|
Definition
| rod-shaped, long, 300 nm X 15 nm |
|
|
Term
| structure of tobacco mosaic virus |
|
Definition
| protein subunits overlapping single- stranded RNA in helical spiral |
|
|
Term
| what might help tobacco mosaic virus last 100 years |
|
Definition
-strong protein coat
-helical spiral of nucleic acid |
|
|
Term
| The most important thing you can do to get viruses off of your hands is to ______ because ______. |
|
Definition
wash with soap
it breaks those proteins |
|
|
Term
| This characteristic about tobacco mosaic virus is kinda odd for viruses. |
|
Definition
| its nucleic acid being in a helical spiral |
|
|
Term
| the hardiness of tobacco mosaic virus |
|
Definition
***thermostable - 120C, 30 min, when dried
-active virus can be found in in processed tobacco products
-large quantities in plant
-remains active in dried tissue > 100 years |
|
|
Term
| why it's important for tobacco mosaic virus to survive temperatures of 120°C |
|
Definition
| because tobacco grows in the sun |
|
|
Term
| Does tobacco mosaic virus have an effect on us? |
|
Definition
|
|
Term
| distribution and host range of tobacco mosaic virus |
|
Definition
-Worldwide distribution
-Attacks 150 genera herbaceous dicots, vegetables, flowers, and weeds
-Most serious on tobacco, tomato |
|
|
Term
| the kinds of plants are attacked by tobacco mosaic virus |
|
Definition
Attacks 150 genera herbaceous dicots, vegetables, flowers, and weeds
-no monocots |
|
|
Term
| relationship between when tobacco gets infected and amount of damage |
|
Definition
| the earlier it gets infected, the more damage |
|
|
Term
|
Definition
taking the flower off of the tobacco plant
this creates a wound and makes the plant vulnerable to infection |
|
|
Term
| the tomatoes that tend to escape tobacco mosaic virus |
|
Definition
|
|
Term
| losses on tomato caused by TMV |
|
Definition
| -5 - 25% yield loss -Depends on age of plants, environment |
|
|
Term
| symptoms of tobacco mosaic virus in tobacco |
|
Definition
-mosaic
-stunting
-thin leaves
-lower nicotine content |
|
|
Term
| this is bad news for nicotine addicts |
|
Definition
-lower nicotine content
-thin leaves |
|
|
Term
| part of tobacco that tobacco mosaic virus usually attacks |
|
Definition
-leaves
-flowers
-fruit
-usually doesn't kill |
|
|
Term
| the effect of tobacco mosaic virus on infected leaves |
|
Definition
-thin, yellow areas, with thick, raised, dark green areas - blisterlike appearance
-reduces chloroplasts in light areas
-reduces photosynthesis |
|
|
Term
| This may be most significant type of loss in tobacco. |
|
Definition
|
|
Term
| symptoms of tobacco mosaic virus in tomatoes |
|
Definition
-mosaic
-shoestringing (not in tobacco)
-reduced fruit set (opposite of tobacco)
-blemishes, browning internally on fruit |
|
|
Term
| tobacco mosaic virus may cause this in other hosts |
|
Definition
-chlorosis
-mottling
-curling |
|
|
Term
| the virus for which there was the first description of a virus |
|
Definition
|
|
Term
| additional symptoms of tobacco mosaic virus that can occur on tomato |
|
Definition
| crinkling and some mottling |
|
|
Term
| disease cycle of tobacco mosaic virus |
|
Definition
-Overwinter
-Primary inoculum
-replication
-Dissemination
-Secondary inoculum |
|
|
Term
| overwintering phase of tobacco mosaic virus |
|
Definition
TMV can be found in all 3 of these:
-in crop debris
-manufactured tobacco products
-perennial weeds |
|
|
Term
| primary inoculum phase of tobacco mosaic virus |
|
Definition
|
|
Term
| how the virus particles of tobacco mosaic virus can get into a plant |
|
Definition
-from workers hands, implements
-insects vector from weed hosts
mechanically transmitted |
|
|
Term
| how tobacco mosaic virus replicates in plant |
|
Definition
1. Virus particle is partially uncoated- exposes + ssRNA
2. ssRNA is partially translated by host ribosomes - produces viral replicase
3. Viral RNA replicase makes -ssRNA copies of +ssRNA
4. Viral RNA replicase also produces original viral +ssRNA from –ssRNA template, and sgRNA’s to code for coat proteins and movement protein
5. Movement protein necessary to move virus through plasmodesmata
6. +ssRNA and coat protein subunits are assembled to recover original viral particle |
|
|
Term
| virus goes into this cell |
|
Definition
|
|
Term
| To the plant, this is the same as mRNA |
|
Definition
|
|
Term
|
Definition
| mirror images of each other |
|
|
Term
| Replication of -ssRNA starts on this end. |
|
Definition
|
|
Term
| cell machinery locks onto the + or - sense ssRNA? |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| resistance to TMV works by... |
|
Definition
|
|
Term
| how RNA of TMV is replicated in infected cells |
|
Definition
-Viral RNA replicase makes -ssRNA copies of +ssRNA
-Viral RNA replicase also produces original viral +ssRNA from –ssRNA template |
|
|
Term
| how TMV acquires coat proteins and movement protein |
|
Definition
uses sgRNA’s to code for coat proteins and movement protein
Movement protein necessary to move virus through plasmodesmata |
|
|
Term
| how original viral particle is recovered |
|
Definition
| +ssRNA and coat protein subunits are assembled to recover original viral particle |
|
|
Term
| why tobacco produces nicotine |
|
Definition
| because it's a very effective insecticide |
|
|
Term
| the biggest problem for dissemination of TMV |
|
Definition
|
|
Term
| insects feed from ______, which basically contains ______ and no ______ |
|
Definition
|
|
Term
| some ways tobacco mosaic virus can be disseminated |
|
Definition
-mechanical, sap-transmission
-may be by insects from weed hosts in spring
-most common, by workers due to cultural practices of tobacco
-contact with plants in seedbeds, during transplanting
-penetration through wounds
-end up with relatively few infected plants in field
-then spread by workers throughout field during each cultivation, topping, priming, harvesting
-number of infected plants doubles with each trip through the field – and there are many trips through a tobacco field |
|
|
Term
| secondary inoculum phase of tobacco mosaic virus |
|
Definition
-virus particles
-from infected plants in field |
|
|
Term
| means of controlling tobacco mosaic virus |
|
Definition
1. Sanitation
2. Resistant varieties - used extensively in tomato |
|
|
Term
| how sanitation is done to control tobacco mosaic virus |
|
Definition
-remove crop debris, weed hosts
-don't allow use of tobacco products during cultural practices
-frequently wash hands with soap |
|
|
Term
| how nematodes can get into plant cells |
|
Definition
| uses this mouth to hammer thru the plant cells and to feed |
|
|
Term
|
Definition
viroids don't have a coat of protein; just a strip of nucleic acid
subclass of viruses |
|
|
Term
| some general characteristics of nematodes |
|
Definition
-Nonsegmented roundworms
-Phylum Nematoda
+Metazoa
•Pseudocoelomates |
|
|
Term
|
Definition
| no endothelial lining in body cavity - "tube within a tube" |
|
|
Term
| some more specific details of plant nematodes |
|
Definition
1. Obligate parasites
2. Penetrate host roots directly
3. All plant pathogens have stylets
4. Soilborne pathogens
5. All life stages may overwinter
6. Dissemination is by movement of soil and water
7. Nematodes are aquatic
Move within thin film of water on surface of soil components |
|
|
Term
| the class nematodes are in |
|
Definition
|
|
Term
| nematodes that can feed on plants are this kind of parasite |
|
Definition
|
|
Term
| Are all stylet bearing nematodes plant parasitic? |
|
Definition
|
|
Term
| how nematodes penetrate host roots |
|
Definition
|
|
Term
| What life stages of nematodes may overwinter? |
|
Definition
|
|
Term
| how nematodes get disseminated |
|
Definition
| by movement of soil and water |
|
|
Term
| most of the Nematoda phylum lives here |
|
Definition
|
|
Term
| When can nematodes move thru the soil? |
|
Definition
| when there's a continuous film of water between the soil peds |
|
|
Term
| Nematodes primarily attack... |
|
Definition
|
|
Term
|
Definition
On above-ground parts of plants symptoms are typical of symptoms caused by many other root problems, such as Stunting, chlorosis, wilting, nutrient deficiencies, etc.
Except for galls, root symptoms require further diagnosis to identify nematodes as cause |
|
|
Term
| the only way to diagnose nematodes as the cause for a plant disease |
|
Definition
|
|
Term
| something growers used to do to plants, but this only made the nematode problem worse |
|
Definition
| dumping fertilizer on the plant |
|
|
Term
| distribution and importance of nematodes |
|
Definition
Found wherever plants are grown
More important in southern and tropical areas
Most important diseases on some crops in warm climates:
high value crops with limited crop rotations |
|
|
Term
| worst situation regarding nematode problems |
|
Definition
| high value crops with limited crop rotations |
|
|
Term
| Nematode uses this to feed. |
|
Definition
|
|
Term
|
Definition
|
|
Term
| cross section of nematode |
|
Definition
|
|
Term
| function of a nematode's hypodermis |
|
Definition
|
|
Term
| function of a nematode's alae |
|
Definition
| when the nematode is moving, it lays on its side, and these are like tire treds so that the nematode can push against the soil peds |
|
|
Term
|
Definition
-vermiform
-fusiform
-pyriform |
|
|
Term
|
Definition
Vermiform – threadlike "worm-shaped"
most adults,
juvenile stages of all species
probably about 80% remain vermiform their entire life |
|
|
Term
|
Definition
Fusiform - "cigar-shaped“
fatter, stubbier version of vermiform
some adults
intermediate stages of others |
|
|
Term
|
Definition
Pyriform - swollen, spherical, or flask-shaped
***only mature females of some species |
|
|
Term
| most common example of pyriform nematodes |
|
Definition
| root knot nematodes and something else |
|
|
Term
| This happens when nematode goes pyriform. |
|
Definition
back end swells up to accommodate huge ovaries for massive egg laying power
lose the body muscles and can't move afterwards
stuck to plant |
|
|
Term
| the category of nematode shape that does the most damage |
|
Definition
|
|
Term
|
Definition
Length: (0.3-4 mm)
Width: 15-35 micrometers
Diameter within the range of diameters of fungal hyphae |
|
|
Term
| Other morphological features important to identification |
|
Definition
-Stylet
-Esophagous
-Reproductive organs |
|
|
Term
|
Definition
-hardened, spear-like feeding apparatus
-Size and shape of stylet are important diagnostic characters |
|
|
Term
|
Definition
Saliva is secreted through the opening of the stylet and the plant cell contents are pumped back through the of stylet
doesn't penetrate cell, but takes things across the membrane |
|
|
Term
|
Definition
| feed inside the roots - short stylets |
|
|
Term
|
Definition
| feed outside the roots - long stylets |
|
|
Term
| Which group of nematodes gets into the phloem: endoparasites or ectoparasites? |
|
Definition
|
|
Term
| some info about the esophagus of a nematode |
|
Definition
| -Salivary glands and muscular pumping bulb in esophagus; sucks in from stylet and pushes into intestine -Shape and position determines major taxonomic divisions |
|
|
Term
| reproductive organs of nematodes |
|
Definition
Females
Ovarys - number and position Location, shape of uterus, vulva; vulva located along side or on back can be species specific
Males
Testis - number and position Location, shape of spicules, cloaca |
|
|
Term
| length of nematode life cycle |
|
Definition
-may be as short as 3-4 weeks or as long as 1 reproductive cycle per year
-depends on species, host, soil temperature |
|
|
Term
| reproduction of nematodes |
|
Definition
by eggs
by amphimixis or parthenogenesis |
|
|
Term
|
Definition
| male-female sexual reproduction |
|
|
Term
|
Definition
asexual production of fertile eggs
fairly common in insects and can occur in nematodes |
|
|
Term
| why mating is difficult for nematodes |
|
Definition
| because they're in the soil |
|
|
Term
|
Definition
|
|
Term
|
Definition
| the egg is 1N but DNA 2N combination comes from polar body nuclei in the egg; i.e., the egg nucleus is "fertilized" internally by the polar nuclear body still has the option of aphimixis |
|
|
Term
|
Definition
no meiosis occurs - egg is never 1N simple vegetative reproduction
eggs within ovary form clones of the mother
good option for a parasite |
|
|
Term
| root knot uses parthenogenesis, but what helps it maintain diversity within the genome? |
|
Definition
| root knot is 5n, 7n, and 9n; helps maintain diversity within genome |
|
|
Term
| soil relationships regarding nematodes |
|
Definition
1. Type and condition of the soil is important in determining kinds and numbers of nematodes
root-knot nematodes are more of a problem in lighter sandier soils than in heavy clay soils
2. Nematodes are most abundant in the root zone
3-18 inches deep for annual crops – up to 20 feet for trees
3. Soil moisture - a thin film of water between soil particles is necessary for survival, movement |
|
|
Term
| relationships of nematodes with soil-borne fungal pathogens |
|
Definition
1. Fungal pathogens that infect through the roots cause more severe diseases when they are associated with nematodes
2. Nematode-fungus complexes are common
3. Fusarium wilt with root-knot nematodes:
a. wounds made by the nematodes make fungal penetration easier
b. presence of nematodes lowers resistance, ability of plant to compensate for the other pathogen |
|
|
Term
| nemaodes often interact with ______ to worsen disease |
|
Definition
fungi and bacteria
one of the best examples is fusarium wilt on cotton |
|
|
Term
| the way to control fusarium wilt |
|
Definition
|
|
Term
| Classification of nematode feeding habits |
|
Definition
-ectoparasites
-endoparasites |
|
|
Term
|
Definition
-sedentary
-migratory
ectoparasites have big stylet |
|
|
Term
|
Definition
| do not move about after they start feeding |
|
|
Term
|
Definition
| move about freely and do not become attached to root |
|
|
Term
|
Definition
|
|
Term
| Any given nematode fits in which category of parasites? |
|
Definition
|
|
Term
| some examples of parasitic nematodes |
|
Definition
-Pratylenchus spp. - lesion nematode
-Meloidogyne spp. - rootknot nematode
-Belonolaimus spp. - sting nematode
-Criconemella spp. - ring nematode |
|
|
Term
| the only way to study ectoparasites |
|
Definition
|
|
Term
| above ground symptoms of nematodes |
|
Definition
-stunting
-growth distortions
-yellowing
-necrosis
-wilting
-reduced yields
-poor quality |
|
|
Term
| root symptoms of nematodes |
|
Definition
-galls
-lesions
-stunting
-excessive branching
-injured root tips
-necrosis |
|
|
Term
| the tricky part of above ground symptoms of nematodes |
|
Definition
| will mimic absolutely anything that comes from impairment of the root |
|
|
Term
| once you've seen this on the roots, you just need to dig to make a diagnosis of nematodes |
|
Definition
|
|
Term
| these root symptoms are diagnostic of nematides |
|
Definition
-galls
-lesions
-stunting
-excessive branching |
|
|
Term
| how nematodes cause galls |
|
Definition
| backs up photosynthate that would normally be used for growth and causes gall |
|
|
Term
| means by which to control nematodes |
|
Definition
1. Cultural practices
2. Sanitation
3. Resistant varieties
4. Biological methods
5. Soil sterilization
6. Chemicals |
|
|
Term
| cultural practices to control nematodes |
|
Definition
a. Crop rotation
b. Keeping land fallow |
|
|
Term
|
Definition
in this case, it means nothing green
works great, but extremely expensive |
|
|
Term
| sanitation to control nematodes |
|
Definition
a. Clean machinery, implements to avoid soil movement
b. Use noninfested transplants, nursery stock |
|
|
Term
| biological methods for controlling nematodes |
|
Definition
a. Nematode-trapping fungi
b. Fungi parasitic to nematodes especially eggs (works for a short time) |
|
|
Term
| one way a fungus can control nematodes |
|
Definition
| making little lassos and constricting nematode's head |
|
|
Term
| some methods of soil sterilization to control nematodes |
|
Definition
a. Steam
b. Solarization
c. Chemical - methyl bromide (no longer on the market) |
|
|
Term
| some chemicals used to control nematodes |
|
Definition
a. Soil fumigants
Telone (1,3-dichloropropene)
b. Nonfumigant nematicides
fluensulfone (Nimitz) and oxamyl (Vydate) |
|
|
Term
| some info about Telone (1,3-dichloropropene) |
|
Definition
last one on the market; EPA tried to take it off the market; developed as a weapon during WW2
won't kill anything but nematodes, and kills 90% at best; last 5-6 yrs on perennials |
|
|
Term
| some info about fluensulfone (Nimitz) |
|
Definition
-marketed last year
-mammalian safe
-very erratic
-could be safe nematicide |
|
|
Term
| causal agent of bacterial wilt of tomato |
|
Definition
|
|
Term
| Where in plants do bacteria localize? |
|
Definition
|
|
Term
|
Definition
-rapid death of cells in the local region surrounding an infection
-plant uses this to prevent the spread of microbial pathogens |
|
|
Term
| immunological methods for detecting virus in plants |
|
Definition
-Rely on specific antibody-antigen binding interactions
-Enzyme-Linked Immunosorbent Assay (ELISA)
-ELISA-based rapid test kits: minimal equipment, technique expertise, small amount of tissue, rapid |
|
|
Term
| appearacne of virulent bacterial colonies |
|
Definition
| Raspberry red/ reddish purple colonies with distinct cream margins |
|
|
Term
| appearance of avirulent bacterial comonies |
|
Definition
|
|
Term
| some things nematodes lack compared with other animals |
|
Definition
-circulatory and respiritory systems
-skeletons |
|
|
Term
| parts of a nematode's body |
|
Definition
•Digestive organs
•Reproductive organs
•Excretory structures
•Muscles
•Nerves
•Cuticle |
|
|
Term
| identifying characteristics of a nematode's digestive system |
|
Definition
-Stylet (penetrating; secreting)
-Esophagus and intestin |
|
|
Term
| identifying characteristics of a nematode's reproductive system |
|
Definition
-Male (testes, spicules)
-Female (ovaries, vulva) |
|
|
Term
|
Definition
Eggs– hatch into juveniles
Juveniles
–4 stages, each terminated by a molt
–2nd stage is usually infective, parasitic stage (J2s)
Adults– emerge as males or females after final molt |
|
|
Term
| feeding habits of nematodes |
|
Definition
•endoparasitic; ectoparasitic; semi-endoparasitic
•sedentary; migratory |
|
|
