Tomato Physiological

DisordersToT to FFS Staff By Mr. Allah Dad

KhanProvincial

Coordinator IPM KPK MINFAL

symptoms Physiologic Leaf Roll

Leaf roll is a physiological disorder of tomatoes that is most commonly associated with hot dry weather, but can occur in response to other stresses like fast growth, high production, and pruning. Leaf margins roll upward until they touch or overlap in an almost tube like fashion. Affected leaves are firm and leathery to the touch. This disorder is believed to be a strategy to conserve moisture. Lower leaves are commonly affected first. Once leaves roll, they will not unroll even if weather conditions become cool and wet. In severe conditions the entire plant may exhibit leaf roll. Leaf roll does not noticeably reduce plant growth or yield. Some varieties exhibit leaf roll more easily than others. Leaf roll is very common in tomatoes grown in hoop houses.

Physiologic leaf roll

Symptoms

Plants fail to set fruit. Cause: Extremes in temperature and dry conditions may result in poor pollination and cause the flowers to drop from the plant without setting fruit. Blossom drop on tomatoes occurs when night temperatures are below 55 F or above 75 F. Control: Water the plants deeply once a week during dry weather. Fruit set should increase when temperatures moderate. Hormone sprays, such as "Blossom Set", may prevent some blossom drop due to low temperatures. However, the resulting fruit are often misshapen. Hormone sprays do not prevent blossom drop due to high temperatures

Blossom Drop

Symptoms Blossom end rot,

Blossom-end rot is one of the most common tomato disorders seen in Minnesota. Affected fruit have a tan to black flattened spot at the blossom end of the fruit. Secondary fungi and bacteria can enter the blossom end rot area, resulting in further decay of the fruit. Blossom end rot can appear on fruit in any stage of development, but it is most common when fruit are one-third to one-half grown. The first fruit produced by the plant are often most severely affected. Fruit that develop later in the season on the same plant can be unaffected.

Blossom-end rot

Blossom end rot

In tomatoes and peppers, blossom end rot produces a symptom of a black, concave lesion which looks at first sight like a fungal disease.

It is caused by an imbalance between potassium and calcium in the soil or compost.

It occurs most often when the soil or compost is allowed to dry out while the fruits are swelling.

It is most common when plants are raised in grow bags, where they have a small, shallow root run that dries out easily.

Although there is no cure for blossom end rot once the symptoms begin to appear, the obvious recommendation is that fruiting crops should never be allowed to have dry roots.

Symptoms

The outer wall of the fruit is normal, but the tomato is hollow inside. One of the seed cavities is usually empty. Cause: Extreme high or low temperatures, excessive nitrogen fertilization, and heavy rains may interfere with normal pollination, resulting in puffy fruit. Puffiness occurs most frequently on early fruit. Control: No effective controls. Puffiness should decline later in the summer

Puffiness

Symptoms Sunscald,

Sunscald, H. Schwartz, Colorado State UniversityCopyright info

Sunscald occurs on tomato fruit that have been exposed to too much sun. This is common in plants that are suffering leaf loss from a leaf spot disease or insect feeding, but can also occur on plants that are over pruned or on fruit that are otherwise exposed to the sun.

Sunscald results in a pale yellow to white spot on the side of the fruit facing the sun. This area may become a flattened, grayish-white spot. The surface may dry out to a paper like texture. Sunscald spots are frequently invaded by decay-causing fungi and bacteria that further rot the fruit.

The best way to avoid sunscald is to maintain a healthy tomato plant through management of insect and disease pests that defoliate tomatoes.

Sunscald

Symptoms Growth crack

Growth crack, M. Grabowski Growth cracks result from extremely rapid

fruit growth. This may be brought on by periods of abundant rain and high temperatures, or can occur when water is suddenly available to the plant through rain or irrigation after a period of drought. Cracks may radiate from the stem end of the fruit or may encircle the fruit. Cracks are often invaded by secondary fungi and bacteria that further rot the fruit.

Maintaining even moisture by watering regularly and mulching the soil around the tomato plant can help reduce growth cracks. Varieties differ in susceptibility to cracking, and variety descriptions may be helpful in choosing a plant less likely to crack.

Growth cracks

Symptoms Catface

Catface is a condition involving malformation and scarring of fruits, particularly at the blossom end. Affected fruit are often somewhat flat with a corky brown scar covering the base of the fruit. Catfaced fruit can have cavities extending deep into the flesh.

Catface, M. Grabowski The causes of catfacing are not definitely

known, but it is generally agreed that any disturbance to flowers or flower buds can lead to abnormally shaped fruits. Cold temperatures and contact with hormone-type herbicide sprays are commonly believed to be responsible for catface.

Catface, M. Grabowski Large fruited tomatoes are more susceptible to

catface than small fruited tomatoes. In addition some varieties are particularly prone to catface and should be avoided if catface has been a problem in the past.

Catface

Symptoms Herbicides injury

Tomatoes are very sensitive to injury from broadleaf herbicide chemicals. These are commonly used for controlling weeds like dandelions, plantain and clover in home lawns. The most common injury symptoms observed are caused by phenoxy herbicides such as 2,4-D (2,4-dichlorophenoxyacetic acid) and dicamba (substituted benzoic acid). These chemicals are growth regulator, hormone-type weed control chemicals. Tomato plants usually come in contact with the chemical through spray drift or the use of a sprayer that was previously used to apply the herbicide

Herbicide injury

Symptoms

bruising is caused when the tuber is impacted. The skin doesn’t break, but internal tissues are damaged leading to the formation of the pigment melanin, which will make the damaged area appear black, or dark to light grey. This can be anywhere on the tuber, but is more prevalent at the stolon end, and where the tuber is more curved.

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Bruising or blackspot

Symptoms

Growth dwarfed, thin and upright habit; stem and petioles rigid; leaves pale green, occasional purplish tints, older leaves yellowing.

TOMATO PLANT Nitrogen deficiency

Growth dwarfed and thin; leaflets droop, curl backward and develop strong, dull purple tints

TOMATO PLANT Phosphorus deficiency

Salt Damage Phosphorus Deficiency

Physiological Disorders

Symptoms

Death of growing point and die-back of main stem from tip; die-back of leaves, progressing from terminal leaflets and of flower and fruiting trusses

TOMATO STEM Calcium deficiency

Symptoms

Dying off of terminal leaflets and flowers; leaves purplish brown tinting.

TOMATO TRUSS Calcium deficiency

Symptoms

Dying back of trusses and "Blossom End Wilt" of distal fruitlets.

TOMATO TRUSSES — "Blossom End Rot" Calcium deficiency

Symptoms

Central intervenal chlorosis and green marginal bands

TOMATO LEAF Magnesium deficiency

Symptoms

Leaves intervenal chlorosis and necrosis; fruits show "Green Back".

TOMATO TRUSS Magnesium deficiency

Symptoms

Greenhouse view. Leaves intervenal chlorosis and necrosis.

TOMATO PLANTS Magnesium deficiency

Symptoms

Leaflets slight marginal and intervenal chlorosis followed by brown marginal scorching; scorched margins curled foward

TOMATO LEAF Potassium deficiency

Symptoms

"Blotchy Ripening"; green and yellow areas merging into red color of surface. (cf. Plate 260, mosaic fruits)

TOMATO FRUIT Potassium deficiency

Symptoms

Virus Disease. Blotchy uneven ripening, similar to "Blotchy Ripening" due to potassium deficiency but blotchy areas more sharply defined. (cf. Plate 259, potassium deficiency)

TOMATO FRUITS - Tomato "mosaic" Virus Disease

Symptoms

Tip leaves, especially basal areas of leaflets, intense chlorotic mottling; stem near tip also yellow

TOMATO FOLIAGE Iron deficiency

Symptoms

Intervenal chlorotic mottling distributed over entire surfaces of leaflets; mottled areas become necrotic

TOMATO LEAF Manganese deficiency

Symptoms

Stem and petioles, especially nodal areas, necrotic lesions; leaves wither and hang down

TOMATO SHOOT Manganese toxicity (soil acidity complex

Symptoms

Stems stiff; terminal buds die and growths die back; lateral shoots developed, giving plant flat top; leaves highly tinted purple, brown and yellow.

TOMATO SHOOT Boron deficiency

Symptoms

Fruits pitted and corky areas in skin; ripening uneven

TOMATO FRUITS Boron deficiency

Symptoms

Leaflets somewhat chlorotic, strongly incurled and die back from tips

TOMATO PLANTS Molybdenum deficiency

Symptoms

Left: healthy leaf receiving molybdenum. Right: Molybdenum deficient leaf; leaflets, incurled margins, intervenal chlorotic motting and death of tips

TOMATO LEAVES Molybdenum deficiency