Internal; seen only upon dissection of diseased plant portion and examination under the microscope.

Malformations and other changes visible to the naked eye.

General Classification of Symptoms

Pre-necrotic "near death"; changes before actual death of protoplast or cell; involves protoplasmic disorganization and degeneration

Involve death and protoplast, cell or tissue

Inhibition/failure in the differentiation or development of some aspect of plant growth

Excessive multiplication, enlargement or overdevelopment of plant organs including abnormal prolonged retention of green color.

- premature falling of leaves, fruits or flowers due to early laying down of the abscission layer

-flow of plant sap from wounds.

Sudden death of young buds, inflorescence or the young fruits.

extensive, usually sudden, death of host tissue.

-large, irregular spots on leaves or fruits with necrotic injury of epidermal cells.

often sunken necrotic area with cracked border that may appear in leaves, fruits, stems and branches

- overgrowth of tissue formed in response to injury in an effort of the plant to heal the wound.

-yellowing cause by some factor other than light, such as infection by a virus or a mycoplasma.

- abnormal bending/leaf curling caused by over-growth on one side of leaf or localized growth in certain portions

-drying backward from the tip of twigs or branches.

rotting of seedlings prior to emergence or rotting of seedling stems at an area just above the soil line.

- yellowing of normally green tissues caused by inadequate light.

- yellowing of normally green tissues caused by inadequate light.

- clustering of roots, flowers, fruits or twigs around a common focus.

-oozing out of viscid gum from wounds in bark

-due to the infectious agent often leads to death of the plant unless controlled in time.

- extremely tiny spots on leaves, fruits, stems, etc

-presence (leaves) of variegated patterns of green and a yellow shades with sharply defined borders

- infected fruit is converted to a hard, dry shriveled mummy.

metamorphosis of sepals, petals, stamens, or carpels into leaf-like structures.

- variegation is less defined than mosaic and boundaries of light and dark variegated areas are more defused

-define depressions/pits found on surface of fruits, tubers and other fleshy organs resulting in a pocked appearance.

- disintegration and decomposition of host tissue

-shortening of the internodes of shoots and stems forming a crowding of the foliage in a rosette

-superficial brownish roughening of the skin of fruits, tubers or other fleshy organs due to suberization of sub and epidermal tissues following injury to epidermis.

-abnormal swelling of the bark above wounds due to the accumulation of food materials

perforated appearance of a leaf as the dead areas of local lesions drop out.

-slightly raised, rough, ulcer-like lesions due to epidermal and cortical tissue overgrowth with rupturing and suberization of cell walls.

-cupping or pocketing of leaf parts, due to underdevelopment of veins of leaf margins.

-localized necrotic area also referred to as a lesion, circular, angular or irregularly shaped.

- leaf veins are translucent or pale while the rest of the leaf is its normal color.

long, narrow necrotic lesions on leaves or stems.

-development of chlorophyll in tissues or organs where it is normally absent.

injury when temperatures is below 0°C

low temperatures slightly above freezing

Injury caused by too high temperature

Injury of too low temp

- tissues a light-colored and blistered, due to prolonged exposure to high temperature and bright sunlight.

yellow or brown discoloration in the vascular system.

-slightly raised, rough, ulcer-like lesions due to epidermal and cortical tissue overgrowth with rupturing and suberization of cell walls.