Plant part affected and symptoms |
|
Possible cause |
| Foliage ` |
|
|
Chlorosis (general) |
|
Low soil fertility
Excessively high light intensity
Excessively high temperatures |
Chlorosis (younger leaves) |
|
Inadequate supply of iron or manganese and possibly copper or zinc
Plants excluded from light for extended period phytotoxicity from pesticides |
Chlorosis (older leaves) |
|
Low nitrogen or potassium supply
High soil salinity
Over watering
Poorly aerated soil mix |
Marginal chlorosis |
|
Low magnesium and potassium supply (primarily lower leaves)
High soil salinity
Cold drifts (primarily lower leaves)
Spider mite feeding injury (primarily lower leaves)
Phytotoxicity from pesticides |
Interveinal chlorosis |
|
Deficiency of iron or manganese (upper leaves affected first)
Spider mite feeding injury
Sulfur dioxide air pollution injury
Phytotoxicity from pesticides |
Veinal chlorosis |
|
Injury from certain herbicides |
Round chlorotic spots |
|
Fungal or bacterial spots
Phytotoxicity from pesticide, fertilizer or pollutant |
Irregular, chlorotic spots |
|
Cold – water injury
Fungal or bacterial leaf spots
Virus or virus like infection
Phytotoxicity from pesticides, fertilizers, or pollutants. |
Striped, chlorotic pattern not associated specifically with veins or interveinal areas |
|
Feeding injury from spider mites, plant hoppers, leafhoppers, or trips |
Mosaic, chlorotic pattern |
|
Cold – water injury of some plants
Virus or virus like infection
Phtotoxicity from pesticides |
Sectors of leaves that appear water soaked or have a greasy color |
|
Early stages of high – temperature injury often associated with high light intensity or high temperatures which plants are subjected to when improperly handled during shipment. |
|
|
Early stages of cold injury from either low air temperatures or very cold water dropping onto foliage |
|
|
Certain foliar diseases caused bacterial or fungal pathogens |
|
|
Foliar nematodes in fleshy tissue |
|
|
Early stages of phytotoxicity from improper use of pesticides or fertilizers |
Necrosis of leaf margin or tip |
|
Nutrient deficiency: potassium (lower leaves first)
Boron excess
High soil salinity
Fluoride phytotoxicity of susceptible plants
High temperature injury
Low temperature injury
Desiccation injury
Low relative humidity, particularly indoors
Spider mite feeding injury
Foliar bacterial diseases
Phytotoxicity from pesticides or fertilizers. |
Necrotic spots or sectors within the lamina |
|
Cold – water injury
Leaf miner feeding injury
Leaf spot diseases fungal and bacterial
Foliar nematode feeding injury
Phytotoxicity from pesticides or fertilizers. |
Combination of marginal and internal necrotic areas |
|
Sun scorch
Cold injury from low air temperatures or very cold water
Foliar diseases and injury from several foliar feeding pests
Air pollution injury
Phytotoxicity from pesticides or fertilizers |
Leaves abnormally large |
|
Plants received a high level of nutrition
Plants grown under moderate to low light intensity
Stock plants not harvested frequently enough
Old specimens with large root system |
Leaves abnormally small |
|
Plants grown under low nutritional program
Lack of copper, which occurs first in new leaves and may be associated with some chlorosis
High soil Salinity
Plants grown under excessively high light intensity
Low light and low humidity. |
|
|
Container-grown plants that become root-bound Root mealy bugs or nematodes
Root diseases
Phytotoxicity from certain pesticides Tarsonemid mite injury |
Petiole (leaf stem too long |
|
Low light intensity |
Petiole very short |
|
High Light intensity |
Lamina (leaf blade long and narrow |
|
Low light intensity |
Lamina short |
|
High light intensity |
lamina very thin |
|
High nitrogen nutrition Low light intensity |
Lamina extremely thick |
|
Virus or virus like disease
Phytotoxicity form pesticide s
High light intensity
Tarsonemid mites |
Splitting of lamina along margins |
|
Mechanical injury to developing or fully expanded
leaves
Fluctuating moisture supply |
Abnormally tight rosette pattern of new foliage |
|
Injury from board mites, cyclamen mites, etc. |
Loss of sinuses or holes in new foliage of split – leaf plants |
|
Reduced light intensity, especially once the plants are placed indoors |
Leaf margins notched |
|
Mechanical injury
Injury from chewing insects
Phytotoxicity from pesticide sprays |
Translucent – tunnel pattern in foliage |
|
Leaf miner feeding injury |
Holes in foliage |
|
Mechanical injury |
|
|
Feeding injury from caterpillars, snails, or slugs / Dead areas that drop from leaf after tissue is killed by foliar pathogens
Phytotoxicity from pesticides |
Abnormally glossy leaf surface |
|
Excessive amount of plant polish or plant shine
product applied to leaf surface |
Solution dripping from edges of foliage that is otherwise dry |
|
Guttation : the loss of water from tiny holes that are present along the leaf margin Guttation occurs at night and early morning and is non injurious physiological process |
Defoliation of plant |
|
High soil salinity
Plants moved from high to low light intensity Prolonged period in shipping container without
light or gas exchange
Chilling injury
Excessive desiccation between irrigation periods
Reduced humidity
Poor soil aeration
Injurious soil insects
Foliage injury from mite feeding
Parasitic nematodes
Root rot pathogens
Air pollution, especially elevated levels of ethelene Phytotoxicity from pesticides |
Stems stunted |
|
Lack of nutrient such as boron. or crop injury from certain mites, including broad mite and cyclamen mite
Phytotoxicity from pesticides
Insufficient light in growing area
Close plant spacing |
Few lateral branches on plants that naturally branch freely |
|
Insufficient light in growing area
Close plant spacing |
Fascinated stems |
|
Genetic Variation
Virus or virus like disorders
Herbicide injury |
Basal stem rot or breakdown |
|
High soil salinity
Slow-release fertilizer placed against stems
Excessive irrigation
Poorly drained soils
Fungus gnat infestation
Fungal pathogen infection
Bacterial pathogen infection
Phytotoxicity from pesticides |
Lesions or cankers on stem |
|
Sun scald
Mechanical injury
Pest feeding injury
Fungal infection
Bacterial infection |
Foliage and / or stems wilted |
|
High soil salinity
High leaf temperature and cool soil Excessively high temperature
Insufficient water supply in soil
Low humidity
Cuttings or plants not rooted adequately Roots that developed outside of container were
severed
Root mealybugs or parasitic nematodes Reduced root size from fungal root pathogens |
Cracked leaf and / or surface |
|
Mechanical injury |
Etched or pitted leaf and / or surface |
|
Excessively high temperature
Phytotoxicity from pesticides |
Thin cork layer (tan or brown), which develops on leaves and stems as spots or streaks |
|
Thrips or false spider mite feeding injury
Certain plant pathogens
Phytotoxicity from pesticides |
Tip dieback or blight |
|
Deficiency of calcium, copper. or boron Desiccation injury
Mites such as broad mite and cyclamen mite Fungal infection
Phytotoxicity from pesticides |
Epinasty of young shoot and leaves |
|
Aphid feeding injury
Virus or virus like diseases
Phytotoxicity from pesticides, particularly some
herbicides |
Stems and leaves bent or oriented to one side |
|
A phototropic response to side lighting |
Bud and flower drop on some foliage plants with flowers |
|
Temperature extremes
Plant moisture stress
Low humidity
Reduced root system from numerous causes
Mechanical injury
Ethylene injury
Phytotoxicity from pesticides |
Stems exceedingly thing weak, wide spacing between leaves |
|
Excessive fertilizer
Inadequate light
Tight spacing of plants
Temperature too high |
Stem thicker than normal and leaf spacing usually very close |
|
High light intensity
Wide plant spacing
air turbulence |
Unusual amount of red pigment |
|
Phosphorus deficiency
Cool temperatures
Root rot pathogens
Nematodes or root mealy bugs |
Development of a new color pattern |
|
Segregation of vegetative tissues in a chimeral plant Mutation in meristematic region resulting in a Chimera |
Loss of variegation |
|
Excess fertilizer
Low light intensity in production or holding areas Excess photoperiod indoors
Leaf aging in some plants
Segregation of vegetative tissues in a chimeral plant |
Small, translucent artifacts from living creatures |
|
Molted skins or empty puga cases form certain insects or mites |
Whitish to darker – colored residue on surface of plant |
|
Calcium, magnesium, and sodium compounds found in some water supplies, which leave an objectional deposit on foliage
Some fertilizer materials that contribute to deposits
on the foliage
Residue from certain pesticides, particularly
we table powder formulations of a given com
pound are preferred for appearance when safe Airborne particulate material adhering to plant |
Small inanimate bodies on |
|
Fecal deposits from pests |
Brown to rusty red film on foliage |
|
High iron content in water used for overhead irrigation
Heavy false spider mite infestation |
Fine webbing on leaf or between leaflets |
|
Spider mites and a few other mite species |
| Roots |
Roots very shallow; fail to penetrate deep into the soil |
|
Excessive bottom heat
Soil kept too wet
Soil – mix texture very fine with few large pore spaces
Soil – mix compacted excessively
Soil infested with root – rotting fungi, parasitic nematodes, or other root – infesting pests |
|
|
Inadequate quantity of soil added to container at
time of potting
Soil washed out by splashing water
Excessive soil-mix shrinkage in certain mixes Poor soil aeration
Development of extensive root systems in some
species, which push the plants upward in the container |
Root system slow to develop |
|
Factors listed as causing the previous problem plus: High soil salinity
Soil temperature extremes
Plant potted too deep
Toxic components in soil mixture (e.g., certain
types of bark)
Phytotoxicity from pesticide drenches |
Portions of exposed roots eaten |
|
Snail or slug feeding damage |
Roots rots |
|
High soil salinity Soil kept too wet
Soil-mix texture very fine with few
spaces
Soil mix compacted excessively
Parasitic nematodes
Root-rot pathogens, usually fungi |
Roots develop extensively through bottom of container |
|
Plant container placed on moist medium that supports root growth
Plant left in production area or retail display too long |
Knots or swollen areas on roots |
|
Root-knot nematode injury
Tuberous roots that develop naturally on some plant |
Excessive root system tightly bound in containers |
|
Plants not sold on schedule or not stepped up top a larger container |
White or gray fuzzy masses on roots |
|
Non injurious saprophytic fungi |
Whole plant |
|
|
Tissue torn or shed |
|
Mechanical injury during growing, handling packing or shipping. |
Shrinkage of leaf, stem or root tissues |
|
High soil salinity
Injurious soil insects
Parasitic nematodes
Fungal root rots
Phytotoxicity from pesticides |
Reduced rate of growth without drastic changes in typical plant characteristics |
|
One or more essential elements in limited supply Excessive soil salinity
Soil pH extremes
Extremely low light levels, usually indoors Temperature extremes
Excessive soil moisture
Poor soil aeration
Poorly drained container
Low humidity
Seedling variation in some plants
Pot-bound root system
Presence of plant pathogens or other pests that affect the root system or vascular system
Phytotoxicity from pesticides |
| Seeds |
|
|
Seed fail to germinate |
|
Nonviable seeds
Seeds harvested prematurely
Seeds stored for excessive periods
Seeds stored at improper temperature or humidity High salinity of germination medium Germination medium dried during germination Destruction of seeds prior to emergence by rodents, insects, or plant pathogens
Insufficient time for germination Impermeable seed coat
Chemical inhibitors in seed
Germination medium temperature too low Poor soil aeration
High salinity of germination medium Fungal stem and root rot pathogens |
Seedlings Damping – off |
|
High salinity of germination medium
Fungal stem and root rot pathogens |
Some seedlings are white |
|
Genetic seedlings common to certain species |
