Chlorosis in a plant is usually the result of insufficient iron
or magnesium in and is often caused by soil pH issues or soil
compaction problems that have damaged the root system. This
causes the plant to be unable to manufacture carbohydrates
during photosynthesis. This instills a general weakness
in the plant. Fruit production, growth, and other processes
are also negatively affected. If the gardener simply adds
these nutrients to the plant, the symptoms may decrease or
disappear, but if the soil or other condition is not remedied, the
malnutrition and its symptoms will return. Overwatering or
poorly draining soil will initiate these same issues. This wet
soil inhibits respiration, so adding nutrients will not help.
To make an accurate and complete diagnosis of what ails
a plant, these issues, both biological and abiotic, need to
be discovered and addressed in order to achieve successful
remediation of the problem.
WHAT TYPES OF ISSUES CAUSE ABIOTIC DISEASE?
Soil pH is a big cause of abiotic disease, and nutrient uptakes
are severely affected by high soil pH. Iron and manganese will
not be taken up in significant amounts by root systems in the
presence of a pH over 7.8. Even nitrogen uptake is reduced to
half from a pH over 8.0.
It is true that various nutrient extremes or imbalances will
initiate disease symptoms in a plant, so improper soil pH is a
definite culprit. One way to address this problem is by utiliz-
ing chelated nutrients. The coating of any nutrient in this way
affords the proper ion exchange to occur, and the plant will
uptake that nutrient. This, of course, is not the case with other
pH sensitive nutrients that may not be chelated. Adjusting and
maintaining soil pH is a superior solution.
Air pollutants are another cause. If stomata become
damaged by smoke and dirt, gas exchange, including
absorption of CO 2 , is restricted. This, in turn, affects vigor and
production. Drifting herbicides will often baffle gardeners.
Sometimes, a neighbor or hired landscaper sprayed weed
killer which was carried by the wind to nearby gardens.
Regardless of who applied the herbicide, any plant affected
by it will suffer damage and decline or die.
Proper irrigation means applying adequate water at the
proper interval. Irrigation is not as easy to get right as some
growers may think. The symptoms for drought and flooding
appear to be very similar. Yellowing leaves can be caused
by either of these. Flagging or wilting is caused by lack of
adequate moisture within the plant. Too much water in the soil
can cause the root system to shut down and not take up mois-
ture, resulting in the same wilting appearance or symptom.
Leaf scorch can be caused by biological disease, though it can
also be caused by heat or radiation extremes. The best way to
diagnose scorching is to identify the plant and review what
biological scorch typically looks like. Discover how prone to this
disease the species is. Some plants can withstand sustained
heat and radiation without scorching while others cannot.
“
Some plants
can withstand
sustained heat
and radiation
without
scorching while
others cannot.”
Abiotic disease is a common enemy of the gardener and its cure
is usually not immediately obvious. First, a proper diagnosis
of what has caused the plant decline is needed. Often, this
diagnosis will include multiple causes. To jump at the first
apparent culprit will likely lead to a recurring complication
or perhaps not even a temporary remedy. As with so many
things in horticulture and agriculture; these are sciences where
patience and research will pay handsome dividends.
For additional tips on identifying and
controlling abiotic disease and to review
the reference information and pages for
this article, scan the QR code.
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