Transcript Tomato plants fail to produce fruit when pollination does not occur

Tomato plants fail to produce fruit
when pollination does not occur
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Night temperatures above 70 degrees or below 50 degrees.
Day temp. above 90 degrees combined with low humidity and/or drought.
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Hot drying winds can add to the problem.
High humidity creates sticky pollen which does not transfer well.
Dry soil can cause blossoms to dry up and drop.
Too much N fertilizer produces leafy growth at the expense of flowers / fruits.
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(vegetative growth vs. reproductive / fruit growth)
Cold soils at planting time can stunt growth and delay or eliminate flowering.
Insufficient light. Tomatoes require at least 8 hours of direct sunlight per day.
Viral disease can affect flowering and fruit set (curly top, mosaic viruses, etc.)
Lack of air circulation can inhibit the movement of pollen to the flower pistils
Factors affecting tomatoes from ripening
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Temperatures below 50 degrees or above 90 degrees
Compacted soil and overly wet soil inhibit the root system which restricts
fruit ripening.
Low potassium (potash) levels inhibit proper fruit growth and maturity;
however, too much potassium can reduce the absorption of calcium and
magnesium
Tomato Problems
Splitting/Cracking
• Symptoms / ID Presence:
– Radial: cracks run from the stem end to the blossom end
– Concentric: cracks form circular pattern around the stem
• Possible causes
– Rapid growth rate (at close to maturity stage) makes them
susceptible (fruit swell with moisture until the skin cannot
stretch anymore)
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Wide fluctuations in temperature
Wide fluctuations of rain and/or watering habit
Soil temperature fluctuations
Excessive fertilizer, particularly Nitrogen
• Prevention
– Maintain even consistent soil moisture during dry periods, do
not over fertilize, water with sun-warmed tepid water, mulch
to maintain consistent soil temps. and select varieties that
are crack-resistant (generally hybrids with thick skin/walls
Tomato Problems
Early Blight
• Symptoms / ID Presence:
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Large dark brown to black leaf spots with concentric rings that develop in
the spot forming a bull’s eye.
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The leaf area around each target spot turns yellow, and soon the entire leaf turns
yellow and drops
Early blight fungus also infects stems and may produce stem cankers.
It occasionally attacks the fruit, producing large sunken black target spots on the
stem end of the fruit
Infestation during the tomato flowering stage causes the blossoms to drop
• Possible causes
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Early blight can develop quite rapidly in mid to late season and is more
severe when plants are stressed by poor nutrition, drought, warm humid
weather with heavy dews or rain or other pests
Over crowded plants that cause poor air flow among the plants
Too much moisture during cool and warm weather
• Prevention / What to do
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Rotate nightshade family, adequate spacing between plants to promote
good air circulation, select resistant varieties, don’t use overhead watering,
maintain optimum fertility levels – N, P deficiency can increase EB
susceptibility, destroy diseased plants, disinfect tools, stakes, cages, etc.,
mulch to prevent soil pathogens from splashing up on leaves, add lots of
organic matter to soil, use a fungicide: Serenade Max™ (Bacillus subtilis),
Garlic, neem oils and seaweed extract have shown some effectiveness
Tomato Problems
Septoria Leaf Spot
• Symptoms / ID Presence:
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Spots are circular, about 1/16 to 1/4 inch in diameter with dark brown
margins and tan to gray centers with small black fruiting structures
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The presence of fruiting bodies of the fungus, visible as tiny black specks in the centers of the spots,
confirms Septoria leaf spot.
– Disease spreads upward from oldest to younger leaves
• Possible causes
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Long periods of high relative humidity, temps of 60–80 degrees F, leaf
wetness are ideal conditions for development & spread of the pathogen
Pathways
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The fungus overwinters on infected tomato debris or on weeds in nightshade family
The fungus can also survive on equipment such as plant stakes and cages
Spores may be spread by windblown water, splashing rain, hands and clothing of pickers,
insects such as beetles, and cultivation equipment
• Prevention / What to do
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Remove infected leaves
Improve air circulation around the plant
Do not work around plants when they are wet
Mulch around the base of the plant, control weeds
Do not use overhead watering
Rotate nightshade family
Last resort: Use a fungicidal spray
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Apply chlorothalonil, maneb, macozeb, or a copper-based fungicide, such as Bordeaux
mixture, copper hydroxide, copper sulfate, or copper oxychloride sulfate
Tomato Problems
Pollination Issues
• Cat-facing
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Disturbance to flowers and flower buds and cold temperatures
occurring just before flowering can increase the amount cat-facing
Deformed abnormally shaped and has a corky brown scar covering
the blossom end of the fruit
Can also be caused high Nitrogen fertilizer, improper pruning, heavy
thrips infestation and exposure to herbicides
• Zippering
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Occurs when the anther of the tomato flower sticks to the
developing fruit and produces a scar as the fruit grows, extending
from the blossom end to the stem
Sometimes an open hole develops in addition to the scar
• Puffiness
– open cavities are observed between the seed gel area and the
outer wall. Fruits are also very light in relation to size
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Caused by any factor that affects fruit set, including inadequate
pollination, fertilization, or seed development
High N, low light, or rainy conditions can also cause seed set
problems as well as too low or high temperatures during fruit set
Tomato Problems
Ripening Disorders
• Blotchy Ripening
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Extreme high heat, high humidity, temperature fluctuations, low light levels during
high temperatures (potentially from dense vine coverage, or from fog or clouds during
hot weather), high nitrogen, low potassium, low boron, bacterial/fungal infections,
TMV (Tobacco Mosaic Virus), or excessive soil compaction
uneven ripening: When still green, areas of gray wall/blotchy ripening may appear gray
or brown from the outside. As fruit ripens, it will have blotchy green or yellow areas.
• Yellow / Green Shoulders
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Fruit area around/near the stem remaining hard and yellow or green
and internal tissue that is white or green
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Yellow Shoulders (↑ carotene, ↓ lycopene)
Green Shoulders (↓ carotene/lycopene, excessive heat prevents chlorophyll breakdown
Adverse weather conditions and out-of-balance soil fertility
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Low potassium (K) levels, low organic matter, high pH
– ↑ K can ↓ Calcium, Magnesium, too much sulfur can burn plant roots
• Grey Wall / Internal Browning
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Prolonged periods of cool, wet cloudy conditions, ↓ light levels unhealthy
plants, too much foliage, compacted soil, ↓ K in plant
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Fruit did not ripen properly or ripen unevenly (in green fruit)
Ripe fruit have brown or green areas on the inside of the fruit
Prevention
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Ensure plants receive adequate fertilizer and regular, even watering, loose soil, grown in
full sun, good spacing and not heavily shaded
• Internal White Tissue
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Triggered by high temperatures during ripening, ↓ K in plant
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White hard areas especially in the vascular region are present in the outer walls, fruit
may also show white tissue in cross-wall and center of fruit
Tomato Problems
Tomato Spotted Wilt
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May be impossible to see damage on green fruit
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Sunscald
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Symptoms
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After ripening, yellow rings or blotches may show,
discoloration is only on the surface and center of fruit
will ripen normally
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Caused by Thrips / Some Controls
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Attracts natural predators
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Pest-eating birds: set up bird-feeders and bird baths
lady beetles, minute pirate bugs, predatory thrips and
predatory mites: yarrow, Queen Ann's lace, coriander
and dill
Ultra-violet reflective barriers and mulches, Get rid of
Weeds (thrips are attracted to weed pollen), Blue
sticky cards, Insecticide (Radiant), Resistant varieties:
Plum Regal, BHN 640
Sunscald appears as a yellow, hard area usually on
the shoulder of the fruit when tissue temperature
rises above about 86° F
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The high tissue temperature won’t allow the red
pigment to develop nor the flesh to soften, but allows
the yellow pigments to develop
With lethal sunscald, the tissue turns white and dies.
Many times the dead tissue will turn black from fungi
that are feeding on the dead tissue and occurs when
tissue temperatures rise above 104° F
Causes
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fruits are suddenly exposed to excessive sunlight
Over pruning can also increase sunscald problems
especially with fruit in the upper part of the plant