Physiological disorders of Tomato
1. Blossom-end rot in Tomato
This disorder of tomato that can appear on fruits at any time in their development, but most commonly appears when fruits are one-third to one-half grown. The initial symptoms are water-soaked spots on the blossom end of the fruit.
These spots later enlarge and become black. Secondary infection by other decay causing organisms usually follows. The cause of this disorder is considered to be calcium deficiency in the developing fruit. Extreme fluctuations in moisture, root pruning and excessive nitrogen fertilization can also result in blossom end rot.
Management: Avoid excessive application of Nitrogen particularly in ammonium form. Application of lime or calcium based fertilizers (eg. Calcium Ammonium Nitrate) as basal dose is commonly used to control this physiological disorder. Foliar spray of Calcium chloride (3 g/litre of water) also controls this disorder.
2. Catface in Tomato
Catface is a condition involving malformation and scarring of fruits,particularly at blossom ends. Affected fruits are puckered with swollen protuberances and can have cavities extending deep into the flesh. Generally, any disturbance to flowers can lead to abnormally shaped fruits.
Extreme heat, drought, low temperature, and contact with hormone-type herbicide sprays may cause flower injury.
Management: Delayed pruning, balancing the internal nutrient, regulating temperature, the assimilation rate, and the endogenous growth regulators can control catfacing.
3. Puffiness in Tomato
As the name implies, fruit suffering from puffiness appear somewhat bloated and angular. When cut, cavities may be present that lack the normal "gel" and the fruit as a whole isn't as dense.
Puffiness results from incomplete pollination, fertilization, or seed development often as a result of cool temperatures that negatively impact fertilization. Similar to growth cracking, high nitrogen and low potassium can also lead to puffiness. Some tomato cultivars are more susceptible to this disorder than others.
4. Sunscald in Tomato
Tomato fruits nearing maturity when exposed to the sun are prone to scald. The tissue has blistered water-soaked appearance. Rapid desiccation leads to sunken area which usually has white or grey colour in green fruit or yellowish in red fruits.
In india this is a serious problem in the month of may and june, will expose fruits to sunlight and increase chances for sunscald.
Management: Maintaining a continuous disease control program will lessen chances of foliage loss. Covering exposed fruits with straw, if plants are not staked reduce the incidence of sunscald.
5. Cracking in Tomato
Cracks results from extremely rapid fruit growth brought on by periods of abundant rain and high temperatures, especially when these conditions take place following periods of stress. Cracks of varying depth radiate from the stem end of the fruit, blemishing the fruit and providing an entrance for decay-causing organisms.
It is common during rainy season when temperature is high, especially when rain follows long dry spell. Radial cracking is more likely to develop in full ripe fruit than in mature green. Fruits exposed to sun develop more concentric cracking than those, which are covered with foliage.
Management: Picking of the fruits before the full ripe stages reduces the incidence of radial cracking, soil application of borax at the 10-15 kg/ha. Or 0.25 per cent at the fruiting stages reduces its incidence.
6. Blotchy Ripening (BR) in Tomato
In this case greenish yellow and whitish patches appear on ripened fruit, particular on the stem end portion sometimes white or brown tissues are present in blotched area. These disorders mainly due to imbalance of nitrogen and potasic nutrient in soil, water deficiency in the excessive transpiration.
Management:- Application of balancing nitrogenand potasic fertilizer in soil.
7. Browning in Tomato:
In early stage, the water soaked areas appear on the stem and curd surface. As the plant grows, the stem becomes hollow with water soaked tissue covering the internal walls of the cavity.
In advanced stage of deficiency, brown or pink coloured areas are seen on curd surface and therefore, it is also called brown rot or red rot or browning of the curd.
Sometimes the stem may become hollow even without brown areas on the curd. The affected curds are bitter in taste. Its mainly due to boron deficiency.
Control: The deficiency of boron may be corrected by applying borax. The quantity of borax 10- 15 kg /ha is sufficient.
Physiological disorders of cole vegetables.
1. Whiptail in cole crop:
In young plants the deficiency symptoms are chlorosis of leaf margins and the whole leaves may turn white. The leaf blades do not develop properly, only the midribs develop. This condition is commonly known as 'Whiptail'.
The growing point of the plant is also deformed which prevents the curd development. Whiptail disorder is caused due to deficiency of molybdenum.
Management: Lime application in acidic soils is done to increase the availability of molybdenum, soil application of Sodium Molybdate (10-15 kg/ha) effectively controls the deficiency symptoms.
2 . Buttoning in cole crop:
The development of small premature curds or buttons while the plants are young is known as buttoning. The button heads are exposed and the plants showing this condition have usually small poorly developed leaves.
Several factors like poor nitrogen supply, planting of over-age seedlings, unfavorable climatic conditions and improper time of planting are reported to cause buttoning.
Management: Adequate supply of nitrogen and moisture for rapid vegetative growth of plant is considered important for preventing the occurrence of button plants.
3. Riceyness in cole crop
When the surface of the curd is loose and has velvety appearance due to elongation of pedicel and formation of small white flower buds at the curding stage, such curds are called ricey.
Apart from fluctuating and unfavourable temperature, heavy application of N and high humidity may cause riceyness.
Management: Selection of proper varieties for a particular time of cultivation, optimum application of nitrogenous fertilizer and planting of resistant and tolerant varieties help minimize this condition.
4. Blindness in cole crop
During the early stage of plant growth, damage to growing point by insects, low temperature or frost causes blindness. Plants grow without terminal bud and fail to form any curd. The leaves of blind plants become thicker and leathery owing to accumulation of carbohydrates.
Management: Damage of growing point by insects may be avoided by proper spraying of insecticides.
5. Chlorosis in cole crop
Chlorosis shows an interveinal, yellow mottling of lower older leaves. Since cauliflower has a high magnesium requirement, its deficiency cause chlorosis when grown on high acidic soil.
Management:This can be corrected by applying magnesium oxide @ 300kg/ha. Liming soil and use of chemical fertilizer containing soluble magnesium also keeps this in control.
6. Hollow stem in cole crop
In heavy fertilized soils, particularly with nitrogen, rapidly growing plants of cauliflower develop hollow stem and curd.
Management: It may be corrected by close spacing and optimum use of nitrogenous fertilizers. and borax @ 15-20kg/ha.
7 . Frost Injury in cole crop
Leaves of young seedling turns yellowish-white on both surface, petioles become flaccid and white. Fully grown curds are more sensitive to frost than smaller one.
In cabbage the younger leaves mainly sensitive, as the center of the head turns brown while outwardly the head appears healthy.
Control: It can be minimized by irrigating on the field on anticipating the danger of frost and by raising the field temperature by creating smoke.
8. Fuzziness in cole crop
Fuzziness appears as flower pedicels of velvety curds elongate. It may be hereditary or non-hereditary.
Cultivation in abnormal times encourages fuzziness. Sowing at normal time minimizes fuzziness.
9. Leafy curds in cole crop
Development of small green leaves (bracts) inside the segments of the curd makes them leafy. Prevalence of high temperature especially after curd initiation or fluctuation in temperature at curding stage aggravates leafy curds.
Selection of proper varieties may help reduce it.
Vijay Kumar Suryawanshi
(M.Sc. (Ag.) Horticulture), IGKV, Raipur (C.G)
Rural Agriculture Extension Officer, Agriculture Department, District Bilaspur (C.G.) 495001