MODUELE 4 Flashcards
“Any disturbance brought about a pathogen or an environmental factor which interferes with manufacture, translocation or utilization of food, mineral nutrients and water in such a way that the infected plant changes in appearance and yields less than a normal healthy plant of the same variety.”
Plant Disease
A dynamic interaction between an organisms and its environment which
results in abnormal physiology an often morphological or neurological
changes in the organisms
Disease
The present of physiological disorders that are generally detrimental; and b) Morphological abnormalities result from the physiological malfunctioning
Diseases
What are the Disease traingle
Environment, Pathogen and Host Plant
is any agent that causes a disease is generally referred to as
living organisms such as fungus or bacterium that causes disease.
Pathogen
an organism which depend wholly or partly on other living
organisms for its food. A parasite may be obligate or facultative.
Parasite
__ is an organisms that is restricted to subsist on
living organisms and attacks only living tissues.
Obligate parasite
___ is organisms, which has the faculty or ability
to be a parasite although it is ordinarily a saprophyte.
Facultative parasite
is organism that lives on dead or inorganic matter. A
facultative parasite has the ability to become a saprophyte but is ordinarily a parasite.
Saprophyte
refers to a plant that is attacked by a parasite.
Host
__those environmental factors that are able to cause plant
diseases.
Physiopathogen
the capacity of the pathogen to cause disease
Pathogenicity
__ is the chain of interrelated events of disease development.
Pathogenesis
a plant that is susceptible to a disease whether or not the
pathogen is parasitic
Suscept
refers to the quantitative amount of disease that can isolate of a given pathogen can cause in a given group of plants in terms of size of lesions or number of lesions
Virulence
measures the rate at which virulence is expressed by a
given pathogenic isolate
Aggressiveness
___ inherent ability of an organism to overcome in any
degree the effects of a pathogen
Disease resistance
___nthe inability to overcome the effects of a pathogen
Susceptibility
ability of plant to withstand the severe effects of the pathogen without experiencing a severe reduction in yield
Tolerance
symptoms not expressed due to unfavorable
conditio
Masked symptoms
a host that do not show symptom irrespective of
environment
Symptomless carrier
___are the expressions by the suscept or host of a pathologic condition by which a particular plant disease may be distinguished from other disease.
Symptoms
____ usually change as the disease progresses since disease is often a dynamic process. ___ may vary according to environment, the host variety, and the race of the pathogen.
Symptoms
Different type of Syptoms
Primary Syptoms, Secondary syptoms, localized ,systematic, histological and morphological syptoms
___are resultsm of the causal agent’s activities on the invaded tissues
Primary symptoms
___ the effects on the distant and uninvaded plant parts.
secondary
symptoms
___ are characterized by distinct and very limited structural changes usually in the form of the lesions.
Localized symptoms
___ on the other hand are more generalized pathological condition such as mottle, mosaic and wilting.
Systemic symptoms
___ is essentially internal, and seen only upon the
dissection of the diseased plant portion and examination under the microscope. It
is expressed as an abnormally in cell content, structure or arrangement.
histological symptom
____ are those malformations and other changes that visible to the naked eye.
Morphological syptoms
___ involved the death or protoplast, cells or tissues. Examples are spot, blight, scorch, canker and die-back.
Necrotic symptoms
___ symptoms appear when there is an inhibition or failure in the differentiation or development of some aspect of plant growth.
Examples: are stunning, mottle, mosaic, resetting and curling.
Hypoplastic symptoms
symptoms are expressed with the occurrence of excessive
multiplication, enlargement or overdevelopment may result from an increase in the size of the cells (hypertrophy) or an abnormal increase in the number of cells of hyperplasia.
Hyperplastic symptoms
___ yellowing of normally green tissues caused by inadequate light
Etiolation
___ yellowing caused by some factor other than light, such as
virus or mycoplasma.
Chlorosis
___ the presence usually on leaves of variegation pattern
Mosaic
__an, extensive, usually sudden, death of most tissue, such as leaf
Blight
___ a perforated appearance of a leaf as the dead areas of local lesion drop out
Shot hole
___ an often sunken necrotic area with cracked border that may appear in leaves, fruits, stems and branches
Canker
__ is leaf puckering as a result of different growth rates in adjoining tissue
Savoying
___ an affected fruit is converted to a hard, dry, shriveled
mummy.
Mummification
___ is when a plant is reduced in size and vigor as a result of
unfavorable environmental conditions or a wide range of pathogens or
abiotic agents.
Stunting
___ the host’s juices exude or leak out from soft-rotted portions.
Leak
__a drying backward from the tip of twigs or branches
Die-back
___ definite depressions or pits are found on the surface of fruits, tubers and other fleshy organs resulting in a pocked appearance.
Pitting
___ premature falling of leaves, fruits or flower due to the early
laying the down of the abscission layer.
Abscission
___ metamorphosis of sepals, petals, stamens or carpels into leaf- like structure
Phyllody
Phyllody
__ abnormal bending or curling of leaves caused by overgrowth of one side of the leaf or localized growth in certain portions
Curling
__ slightly raised, rough, ulcer like lesion due to the overgrowth of epidermal and cortical tissues accompanied with rapturing and suberization of cell walls.
Scab
___ rotting of seedlings prior to emergence or rotting of
seedling stems at a area just above the soil
Damping off
___ abnormal swelling of the bark above wounds due to the
accumulation of elaborated food materials
Scarcody
__an overgrowth of tissue formed in response to injury in an effort of the plant to heal the wound.
Callus
___ clustering of roots, flowers, fruits, or twigs
around a common focus
Fasciation
___ term applied to the sudden death of young buds, inflorescence or
young fruits.
Blast
___ a superficial brownish roughening of the skin or fruits, tubers or other fleshy organs usually due to the suberization of epidermal or sub- epidermal tissues following injury to epidermis.
Russeting
___ is the identification of specific plant disease through their characteristic symptoms and signs including other factors that may relate to the
disease process.
Plant Disease Diagnosis
