Transcript Plant-Disorders-Nutritional-and-Environmental - Mid

Nutritional & Environmental
Disorders
Floriculture
Iron Deficiency
Symptoms:
Iron-deficient plants are yellow and stunted, with the symptoms expressed on
the young leaves first. Affected leaves have interveinal chlorosis, with the leaf
lamina at first appearing to be a "healthy" yellow.
Control:
Conduct soil and/or foliar nutrient analysis to confirm that the problem is
nutritional. Follow recommended practices for fertility using a balanced fertilizer.
High pH soils often induce iron deficiency by holding iron in an insoluble form.
Powdered sulfur applications may be used on limited areas to lower pH. A number
of chelated iron compounds are available for spray application.
Magnesium Deficiency
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Magnesium deficiency is generally a pale green color that is
very pronounced in the old or lower leaves. The leaf
margins may curve upward and may turn red brown to
purple in color in some plants.
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Adding Epsom salts or crushed limestone to the soil can
rectify magnesium deficiencies
Nitrogen Deficiency
The most common plants affected by nitrogen deficiency
include fruit trees, vegetable plants and broad-leafed
evergreens, although any plant can become nitrogen
deficient.
Checking for deficiency:
Check the color of the leaves. The older leaves, which are generally at
the bottom of the plant, will first turn yellowish-green and then
possibly yellow, red or purple. The newer growth, generally near the top,
will show signs of being deficient in nitrogen by turning slightly yellowishgreen as well
Phosphorus Deficiency
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A phosphorus deficiency in your plants will cause stunted growth and
prevent them from producing fruit as expected, yet it is often overlooked or
misdiagnosed as a nitrogen deficiency or simply as poor soil.
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Stunted growth. Plants suffering may be stunted and short in stature. May
appear healthy and look like much younger plants.
Overwatering Damage
-Leaves are becoming yellow.
-Leaves becoming dark or black in color.
-A fuzzy mildew substance is seen on the plant.
-Plant is not growing.
-Plant appears to not perk up when watered.
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Check that the drainage is adequate. Standing water will rot the roots of
even a moisture loving plant. Water only the root area. Wait for signs that
your plant need watering instead of watering on a set schedule.
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Decrease the amount of water given to the plant. Let the soil dry out to
normal levels. Begin an appropriate watering schedule based on the plant's
needs. Use the soil moisture as a guide to determine when to water.
Drought Stress
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Drought symptoms can be very confusing, and can vary with different types
of plants. Woody plants under drought stress can have many symptoms
including yellowing, wilting leaves that develop early fall color and burning
or scorching on edges of leaves. Plants may drop some or all of their
leaves and appear dead.
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Increase Watering the plant and check for adequate soil to correct problem
Excessive Soluable Salt Damage
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Salts are naturally found in fertilizers, potting mixes, and even tap water. Over time,
they can build up and leave crusty white deposits on the soil surface or on the pots.
But more importantly, excess salts can create toxic conditions in the soil, damaging
roots, causing the leaf tips to turn brown, or even causing the plant to die.
Prevent salt build-up by drenching your plants periodically. Take the plants to
the sink or bathtub and add water to the potting mix until it comes out the
bottom of the pot. This will help leach some of the salts from the potting mix.
Or you can repot your plants in fresh potting mix.
Excessive Light
• Here are some signs that a plant is getting too
much sun:
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Flower petals dry out.
Leaf edges look burnt or dried.
Flower color looks faded or washed out.
The entire plant starts to weaken and droop.
Inadequate Light
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And here are signs that a plant isn't getting enough light:
Growth is sparse.
Stems are lanky and spindly.
The distance between leaves, where they're attached to
the stems, is especially wide.
• You see fewer flower buds and, thus, fewer flowers.
• The entire plant leans toward the light sources.
Ethylene Damage
How to prevent ethylene damage
The proper maintenance and use of heating units is the best way to prevent ethylene
damage in the greenhouse.
Adequate ventilation is also needed so that the heaters have enough oxygen for complete
combustion to reduce the production of these byproducts.
Use electric carts or bicycles rather than modes of transportation that utilize gasoline or propane
Clean up all dying and damaged plant materials
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Short duration exposures at high concentrations result in flower and leaf abscission, chlorosis, and
downward bent leaves that look wilted, Longer-term exposure to high concentrations of ethylene can
result in stunted growth, deformed or chlorotic leaves, delayed flowering and plant death
Improper Temperature
Mechanical Damage