| Identify the symptoms. |
- Are the leaves yellow or browning?
Is it worse on the leaf edges or in the middle of the leaf?
- Are older or younger leaves
showing symptoms?
- Are there spots on leaves
and stems? Are these spots of a uniform size or are they
of many different shapes and sizes?
- Is only the upper of lower
surface of leaves showing symptoms or both tops and bottoms?
- Are plants wilting
|
| Determine if there
is a pattern to the symptoms. |
- Do all the plants show symptoms
or is it crop specific, i.e. only the tomatoes and not the
beans?
- Does the problem seem worse
on the garden's edge or is it uniform throughout?
- Do the affected plants sit
above a low spot, poor drainage area, or an area with obviously
compacted soil? Does the pattern correlate with current field
operations?
|
| Trace the problem's
history. |
- When were symptoms first
noticed?
- What rates of fertilizer
and lime were used?
- What pesticides and/or
herbicides were used?
- What were the weather
conditions like before you noticed the problems -- cool
or warm, wet or dry, windy, cloudy, sunny?
|
| Examine the plant carefully
to determine if the problem seems to be caused by insects,
diseases or management practices. |
- Insects: Look
for their presence or feeding signs on leaves, stems and
roots. Sometimes it's easier to find insects early in the
morning or toward evening.
- Disease: Look
for dead areas on roots, leaves, stems and flowers. Are
the plants wilting even though soil moisture is plentiful?
Are the leaves spotted or yellowed? Are there any signs
of bacterial or fungal growth (soft rots, mildew, spores,
etc.)? Look for virus symptoms the plants stunted
or do they have obvious growth malformations? Are all the
plants showing symptoms, or are just a few scattered around
the field?
|
| Could there be nutritional
problems? The table at the right is a list of characteristic
deficiency symptoms for the major and minor nutrients. |
| Nutrient |
Symptoms |
| Nitrogen |
Light green or yellow older
foliage. |
| Phosphorus |
Stunted plants and purplish
leaves. |
| Potassium |
Brown leaf margins and
leaf curling. |
| Calcium |
Stunted plants, stubby
roots. (Causes blossom end rot of tomatoes, tip burn of
cabbage, brownheart of escarole, celery blackheart, carrot
cavity spot).) |
| Magnesium |
Yellowing between veins
of older leaves. |
| Sulfur |
Yellowing of hew leaves,
stunted plants. |
| Boron |
Growing points die back
and leaves are distorted. |
| Copper |
Yellowing of leaves which
become thin and elongated, causes soft onion bulb with
thin scales. |
| Iron |
Light green or yellow foliage
on youngest leaves. |
| Zinc |
Rust-colored spots on seed
leaves of beans, green and yellow striping of corn, yellowing
of beet leaves. |
| Manganese |
Mottled yellow area appearing
on younger leaves first. In beets, foliage becomes deeply
red. |
| Molybdenum |
Distorted, narrow leaves,
some yellowing of older leaves; whiptail leaf symptoms
in cauliflower. |
|
| Could
there be a nutrient toxicity? |
- Soluble salt injury may be
seen as wilting of the plant even when soil is wet.
- Burning on leaf edges could
be a sign of chlorine damage -- are symptoms worse near a
pool?
- Have wood ashes been applied
to the garden? Using more than 5 pounds per 100 square feet
can dramatically increase soil pH which can result in both
nutritional deficiencies and toxicities.
|
| Could soil problems
be to blame? |
- Soil problems such as compaction
and poor drainage can severely stunt plants.
- Are gutter emptying water
into the garden keeping the soil too wet?
|
| Could pesticide injury
be at fault? |
- Were any insecticides or fungicides
applied. Remember, copper and sulfur fungicides can burn
plants if applied in hot weather.
- Broadleaf weed killers applied
to lawns can cause abnormal growth or even kill many garden
plants nearby. Tomatoes are especially sensitive. Beware
of using a lawn clipping mulch which may have residual herbicide.
|
| Could the damage be
caused by environmental conditions? |
- Have temperatures been excessively
high or low? Plants that die practically overnight may have
been touched by frost.
- Has it been very dry or wet
for extended periods?
- Have strong winds caused the
damage?
- Don't overlook air pollution.
Ozon levels may rise as hot, humid weather settles in for
long stretches. Look for irregularly shaped spots which may
look similar to feeding of mites and certain leafhoppers.
Ozone flecks are usually concentrated in specific areas of
the leaf, while feeding damage from insects is spread uniformly
across the leaf
|
| |
| For more gardening resources
visit: Gardening |
| Cornell Gardening
Resources Web Site |
| |
| Do you have tomato questions?
Try these links: |
| Try our searchable database of tomato questions and answers |
| What's wrong with my tomatoes? |
| Watering tomatoes drip by drip |
| |
