Extremes of temperature and water supply are the most common causes
Other causes are chemical substances in the soil, water, and air; transplant shock; and mechanical injuries
Often weaken the plant
Enabling living agents such as fungi, bacteria, viruses, nematodes, and insects to attack and injure or kill the tree
May resemble those produced by insects or fungi
If no signs of these organisms are present, the plant may have been affected by an abiotic agent
Nutritional Deficiencies- Older Leaves First
Restricted growth tops and roots - especially lateral shoots
Spindly with chlorosis of entire plant to a light green
Yellowing of older leaves which proceeds toward younger leaves
Older leaves defoliate early
Nitrogen Deficiency in Greenhouse Crops
Older leaves uniformly chlorotic
Older leaves become necrotic
Purple to red discoloration may develop in older leaves as they turn chlorotic in some species such as begonia, marigold, and pansy.
Exceptionally dark green
Often red or purple colors appearing
lower leaves yellow.
purpling of petioles and the veins on underside of younger leaves
Younger leaves may be yellowish green with purple veins with N deficiency and darker green with P deficiency
Otherwise, N and P deficiencies are very much alike.
Phosphorus Deficiency in Greenhouse Crops
Roots become longer than normal when the deficiency is moderate
Foliage plants: older leaves may lose their sheen, becoming dull green followed by red, yellow, and blue pigments showing through the green particularly on the undersides of the leaves along the veins
These symptoms spread across the leaf
Older leaves abscise if possible, otherwise necrosis develops from the tip towards the base.
Pale brown to black leaf scorch
preceded by irregular marginal or interveinal chlorosis
Margins of older leaves become chlorotic followed by an immediate necrosis
Similar necrotic spots may form across the blades of older leaves but more so towards the margin
Soon the older leaves become totally necrotic
Some foliage plants will develop oily spots on the undersides of older leaves, that then become necrotic.
persistent green margin of leaf
brown necrotic areas
Appearance of brilliant orange, red or purple tints
Magnesium Deficiency in Greenhouse Crops
In several species pink, red, or purple pigmentation will develop in the older leaves follow
Foliage plants with pinnately (netted) veined leaves: Bronze-yellow chlorosis begins at the upper margin of older leaves progressing downward along the veins leaving a green v-shape pattern at the top of the leaf
As chlorosis progresses down the leaf a green v-shape of tissue remains at the bottom
Eventually the tip and then the base become chlorotic. Necrosis follows chlorosis in the same pattern
Nutritional Deficiencies – Younger Leaves First
Uniform chlorosis of younger leaves
veins remain darker green
Iron Deficiency in Greenhouse Crops
Interveinal chlorosis of young leaves
Young leaves of seedlings sometimes develop general rather than interveinal chlorosis
In late stages, the leaf blade may loose nearly all pigment taking on a white appearance .
Terminal buds die
distortion and necrosis of young leaves
die back at tips and margins
Root tips gelatinous and swollen.
Calcium Deficiency in Greenhouse Crops
Young leaves may develop variable patterns of chlorosis and distortion such as dwarfing, strap-like shape, or crinkling
The edges of leaves may become necrotic
Shoots stop growing
Petals or flower stems may collapse
Roots are short, thickened, and branched
Foliage plants: in addition to the above, the older leaves may become thick and brittle
Young leaves light green-yellow at base
die back of terminal bud
leaves misshapen, thick, brittle and small
Cracks and splits occur in petioles and stems
Root tips enlarged
Boron Deficiency in Greenhouse crops
Incomplete formation of flower parts such as fewer petals, small petals, sudden wilting or collapse of petals, and notches of tissue missing in flower stems, leaf petioles, or stems
Death of the bud
Short internodes, crinkling of young leaves, corking of young leaves, stems, and buds, thickening of young leaves
Chlorosis of young leaves but not in any definite pattern
Roots short and thick with eventual death of root tips.
Additional symptoms in foliage plants can include brittle stems and leaves, necrotic spots (black and sunken) on stems just below nodes
nodal roots on vine plants may become thick and short and abscise, and vines may become highly curled at the nodes .
Decreased leaf size
pale green-yellow leaves
Leaf veins become chlorotic.
Sulfur Deficiency in Greenhouse Crops
Foliage over the entire plant becomes uniformly chlorotic
Sometimes the symptoms tend to be more pronounced toward the top of the plant
While symptoms on the individual leaf look like those of nitrogen deficiency, it is easy to distinguish sulfur deficiency from nitrogen deficiency because nitrogen deficiency begins in the lowest leaves.
Young leaves permanently wilted
Leaves rolled or curled
Emerging leaves often trapped in subtended leaves
Pollen cells often sterile
Copper Deficiency in Greenhouse Crops
Young leaves develop interveinal chlorosis
however, the tips and lobes of these leaves may remain green
Next, the youngest fully expanded leaves rapidly become necrotic
The sudden death of these leaves resembles desiccation
Chlorosis often interveinal
produces a bold pattern of dark green major veins
Unlike iron, necrotic spotting or lesions appear on affected leaves
These may be brown to black
Manganese Deficiency in Greenhouse Crops
Interveinal chlorosis of young leaves sometimes followed by the formation of tan spots in the chlorotic areas between the veins.
yellow-ivory interveinal areas
extreme rosetting of terminal and lateral shoots in woody species
In some cases necrotic spots appear on affected leaves.
Zinc Deficiency in Greenhouse Crops
Young leaves are very small and internodes are short giving the stem a rosette appearance
These leaves are also chlorotic in varying patterns but tending toward interveinal
In kalanchoe, zinc deficiency can express itself as a fasciation (a flattened, highly branched stem).
Molybdenum Deficiency in Greenhouse Crops
Symptoms apply to poinsettia, the only greenhouse floral crop it is known to affect
The margins of leaves at the middle of the plant become chlorotic presenting a silhouette appearance and then quickly necrotic
Symptoms spread up and down the plant
These leaves may also become mis-shaped, resembling a half-moon pattern with some crinkling.
Molybdenum in Poinsettia
Other Abiotic Damage
Blossom End Rot
Excess sunlight to shade loving plants
Blossom End Rot
Calcium deficiency due to irregular watering
Small, wartlike, sometimes corky swellings form on the leaf tissue of many plants
late fall into early spring especially with houseplants and greenhouse crops
rust like spots on the underside of the leaves
or leaves mottled with patches of various greens
water-soaked blemishes around enlarged dark-green to black cells
Frozen tissue appears water-soaked.
An early fall or late spring frost when trees are actively growing can injure or kill succulent stem tissue, leaves, and buds. Most trees can survive this injury, but their growth rates are reduced.
Plant tree species adapted to local conditions.
Cover young trees if frost is expected.
Avoid planting in low lying areas subject to frost.
Do not use high nitrogen fertilizer late in the growing season.
Cold damage to new Spruce growth
shut down basic growth functions, and cannot draw sufficient water up into their leaves
Phenoxy Herbicide Damage
Glyphosate Herbicide Damage
Excess Sunlight to Shade Loving Plants
Strong sun and heat causes the breakdown of chlorophyll in the leaf
Damage appears as pale, bleached or faded areas
Plant is unable to take up sufficient water to meet its needs under harsh summer weather conditions.
Scorch on Spruce
Leaf margins turn yellow or brown and leaves fall prematurely.
Water during periods of hot weather to prevent injury to smaller trees.
Plant trees in locations protected from prolonged exposure to sun and wind.
When salt dissolves in water, sodium and chloride ions separate and may then harm the plants. Chloride ions are readily absorbed by the roots, transported to the leaves, and accumulate there to toxic levels. It is these toxic levels that cause the characteristic marginal leaf scorch
Salt Injury – High Soil Salts
sudden wilting, stunted growth, marginal burn on leaves (especially lower, older leaves), leaf yellowing, leaf fall, dead roots, restricted root development, and sudden or gradual death of plants
While the major effect of high soil salts are to the roots, the tops of plants may show "salt injury" while the roots are apparently unaffected - the soluble salts enter the roots and are moved through the plant vessels to the leaves where the water evaporates and gradually concentrates the salts to toxic levels
When soil soluble salts are excessively high, the roots are unable to absorb water and the plant wilts
Salt Injury - Deicing
on the south or southwest side of trees due to the heating and freezing of the bark tissue by the winter sun.
This disease occurs during late winter or early spring when the temperature is above freezing during the day and below freezing at night
During the day the tree tissues, warmed by the sun, become active
Freezing at night kills this tissue, resulting in an elongated canker usually on the southwest side of the tree
Thin barked trees such as maples are most susceptible to this type of injury.
Shade the tree or use tree wrap on younger, susceptible trees to reduce the warming of tree bark during the day.
Plant susceptible tree species at closer spacing
Sunscald on Tomato
Roots in flooded or waterlogged soils are killed by a lack of oxygen. This can occur not only to trees on obviously wet sites but also to ornamental trees planted in heavy clay soils that have poor drainage. Symptoms of oxygen deficiency closely resemble those of drought injury: reduced growth, small leaves and thin crowns, twig and branch dieback, and tree death. Trees with root damage from waterlogged soils may be affected by drought stress if the excess moisture is drained off and roots are unable to meet the demands of tree tops. Roots in waterlogged soils are susceptible to a variety of soil-borne fungal pathogens.
Plant species that are adapted to the conditions in areas subject to periodic flooding.
Prepare planting sites to allow for adequate drainage and root growth.
Winter Burn & Drying
These are common problems on conifers
Winter burn is the browning of needles caused by a rapid temperature change in winter, particularly on the south side
Rapid temperature changes often occur at sunset and sunrise or when sunlight is suddenly blocked by other trees, hills, or buildings.
Winter drying is caused by the desiccation of foliage and twigs by warm dry winds, when water conduction is restricted by frozen plant tissues or frozen ground
Reddening, browning, and, in some cases, drooping of foliage become apparent in late winter and early spring
Avoid planting ornamental conifers where sudden temperature changes may occur.
Water and mulch around the trees in the fall to help prevent the soil from completely freezing in the rooting zone.
Wrap susceptible trees in burlap during winter to reduce loss of water from the foliage.
Plant seed sources that are hardy to conditions in the local area.
Winter Burn on Norway Spruce
ID Older Leaves First
ID Younger Leaves First with Interveinal Chlorosis