Tomato plants fail to produce fruit when pollination does not occur

• Night temperatures above 70 degrees or below 50 degrees.• Day temp. above 90 degrees combined with low humidity and/or drought.

– 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.

– (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

• 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)• 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:– Large dark brown to black leaf spots with concentric rings that develop in

the spot forming a bull’s eye.• 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– 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– 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:– 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• 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– Long periods of high relative humidity, temps of 60–80 degrees F, leaf wetness are

ideal conditions for development & spread of the pathogen– Pathways

• 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– 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

• Apply chlorothalonil, maneb, macozeb, or a copper-based fungicide, such as Bordeaux mixture, copper hydroxide, copper sulfate, or copper oxychloride sulfate

Tomato ProblemsPollination Issues

• Cat-facing– 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– 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– 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• Blotchy Ripening

– 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– Fruit area around/near the stem remaining hard and yellow or green and internal tissue

that is white or green• Yellow Shoulders (↑ carotene, ↓ lycopene)• Green Shoulders (↓ carotene/lycopene, excessive heat prevents chlorophyll breakdown

– Adverse weather conditions and out-of-balance soil fertility• Low potassium (K) levels, low organic matter, high pH

– ↑ K can ↓ Calcium, Magnesium, too much sulfur can burn plant roots

• Grey Wall / Internal Browning– Prolonged periods of cool, wet cloudy conditions, ↓ light levels unhealthy plants, too

much foliage, compacted soil, ↓ K in plant• 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• Ensure plants receive adequate fertilizer and regular, even watering, loose soil, grown in full sun,

good spacing and not heavily shaded

• Internal White Tissue– Triggered by high temperatures during ripening, ↓ K in plant

• 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

Ripening Disorders

Tomato Problems

• May be impossible to see damage on green fruit– After ripening, yellow rings or blotches may show,

discoloration is only on the surface and center of fruit will ripen normally

• Caused by Thrips / Some Controls– Attracts natural predators

• 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

Tomato Spotted Wilt Sunscald

• Symptoms– Sunscald appears as a yellow, hard area usually on

the shoulder of the fruit when tissue temperature rises above about 86° F• 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– fruits are suddenly exposed to excessive sunlight– Over pruning can also increase sunscald problems

especially with fruit in the upper part of the plant