Mangoes in India . . . . .

DISEASES: Powdery mildew, Anthracnose, Die back , Phoma blight , Bacterial canker, Red rust , Sooty mould Postharvest Diseases
: Hopper, Mealy bug , Inflorescence midge, Fruitfly, Scale insects, Shoot borer, Bark-eating caterpillar, Stem borer, Shoot gall psylla, Leaf webber, Stone weevil
DISORDERS: Mango malformation, Biennial bearing, Fruit drop, Black tip, Clustering disorder in mango (‘Jhumka’)                                                                                                                            | Home |Mango Site |

Mango suffers from several diseases at all stages of its life. All the parts of the plant, namely, trunk, branch, twig, leaf, petiole, flower and fruit are attacked by a number of pathogens including fungi, bacteria and algae. They cause several kinds of rot, die back, anthracnose, scab, necrosis, blotch, spots, mildew, etc. Some of these diseases like powdery mildew are of great economic importance as they cause heavy losses in mango production. Major diseases of mango and their control measures are discussed below.
a) Powdery mildew (Oidium mangiferae Berthet) : Powdery mildew is one of the most serious diseases of mango affecting almost all the varieties, It occurs up to latitude of 40o North and South of the equator. It may persist for longer period at an elevation of 600-1200 meters, in many African countries, south of the Sahara, the middle East, Southern Asia and America : from the Southern United States to Peru and Brazil.
The disease is reported to cause approximately 20 per cent crop loss in Maharashtra state alone. Sometimes, as high as 70-80 per cent crop loss has been recorded on individual plant basis.
The characteristic symptom of the disease is the white superficial powdery fungal growth on leaves, stalks of panicles, flowers and young fruits. The affected flowers and fruits drop pre-maturely reducing the crop load considerably or might even preven the fruit set. Rains or mists accompanied by cooler nights during flowering are congenial for the disease spread. The fungus parasitizes young tissues of all parts of the inflorescence, leaves and fruits.
Control : Following three sprays of fungicides at 15 days interval recommended for effective control of the disease :
b) Anthracnose (Colletotrichum state of Glomerella cingulata Ston, Spaull and Schrenk) : The anthracnose disease is of widespread occurrence. The disease causes serious losses to young shoots, flowers and fruits under favourable climatic conditions of high humidity, frequent rains and a temperature of 24-32oC. It is also affects fruits during storage. The disease produces leaf spot, blossom blight, withertip, twig blight and fruit rot symptoms. Tender shoots and foliage are easily affected which ultimately cause ‘die back’ of young branches. Older twigs may also be infected through wounds which in severe cases may be fatal.
Depending on the prevailing weather conditions blossom blight may vary in severity from slight to a heavy infection of the panicles. Black spots develop on panicles as well as on fruits. Severe infection destroys the entire inflorescence resulting in no setting of fruits. Young infected fruits develop black spots, shrivel and drop off. Fruits infected at mature stage carry the fungus into storage and cause considerable loss during storage, transit and marketing. The fungus perpetuates on twigs and leaves of mango or other hosts. Varietal differences in susceptibility have been noted in India. In Kerala, maximum damage was observed on Neelum, whereas variety Edward was reported to be resistant. Since the fungus has a long saprophytic survival ability on dead twigs, the diseased twigs should be pruned and burnt along with fallen leaves for reducing the inoculum potential.
Control: Trees may be sprayed twice with Bavistin (0.1%) at 15 days interval during flowering to control blossom infection. Spraying of copper fungicides (0.3%) is recommended for the control of foliar infection.
c) Die back (Botryodiplodia theobromae Pat.) : Die back is one of the serious diseases of mango. The disease is prevalent in Rajasthan, Delhi, Tamil Nadu, Punjab, Haryana, Orissa, Gujrat, Maharashtra and Uttar Pradesh. The disease on the tree may be noticed at any time of the year but it is most conspicuous during Oct.-Nov. The disease is characterized by drying of twigs and branches followed by complete defoliation, which gives the tree an appearance of scorching by fire. The onset of die back becomes evident by discolouration and darkening of the bark. The dark area advances and young green twigs start withering first at the base and then extending outwards along the veins of leaf edges. The affected leaf turns brown and its margins roll upwards. At this stage, the twig or branch dies, shrivels and falls. This may be accompanied by exudation of gum. In old branches, brown streaking of vascular tissue is seen on splitting it longitudinally. The areas of cambium and phloem show brown discolouration and yellow gum like substance is found in some of the cells.
Control : (i) Prune the diseased twigs and spray with copper oxychloride (0.3%) on infected trees. Pruning should be done in such a way that the twigs are removed 2-3 inches below the affected portion. (ii) In small plants, pruning of twigs is followed by pasting of copper oxychloride.
d) Phoma blight (Phoma glomerata (Cords) Woll. Hochapf)
Phoma blight, a new disease of mango, was first reported at Central Mango Research Station, Lucknow. The disease was later detected in mango growing belt around Lucknow region. It is now gaining economic importance.
The symptoms of the disease are noticeable only on old leaves. Initially, the lesions are angular, minute, irregular, yellow to light brown, scattered over leaf lamina. As the lesions enlarge, their colour changes from brown to cinnamon and they become almost irregular. Fully developed spots are characterized by dark margins and dull grey necrotic centres. In case of severe infection such spots coalesce forming patches measuring 3.5-13 cm in size, resulting in complete withering and defoliation of infected leaves.
Control : The disease could be kept under control by spray of copper oxychloride (0.3%) just after the appearance of the disease and subsequent sprays at 20 day intervals.
e) Bacterial canker (Xanthomonas campestris pv. mangiferaeindicae) : Canker disease of mango, caused by a bacterium,  is prevalent in Andhra Pradesh, Maharashtra, Karnataka, Kerala, Tamil Nadu, U.P., Bihar, Delhi, Haryana, Madhya Pradesh and probably in several other mango growing areas. Besides being pathogenic on several varieties of mango, the organism is capable of infecting wild mango, cashew nut and weeds as well. The disease causes fruit drop (10-70%), yield loss (10-85%) and storage rot (5-100%). Many commercial cultivars of mango including Langra, Dashehari, Amrapali, Mallika, and Totapuri are susceptible to this disease.
The disease is found on leaves, petioles, twigs, branches and fruits, initially producing water-soaked lesions and later turning into typical cankers. The disease first appears as minute water-soaked irregular lesions on any part of leaf or leaf lamina. The lesions are light yellow in colour but with age, enlarge and turn dark brown to black. They become angular, cankerous and raised, and are surrounded by chlorotic halos. Several lesions coalesce to form irregular necrotic cankerous patches. In severe infections the leaves turn yellow and drop off. Cankerous lesions appear on petioles, twigs and young fruits. The water soaked lesions also develop on fruits which later turn dark brown to black. They often burst open, releasing a highly contagious gummy ooze containg bacterial cells. The fresh lesions on branches and twigs are water soaked which later become raised and dark brown in colour with longitudinal cracks but without any ooze.
Control :
Precautions: Do not wait for appearance of the disease. The key to success for full control is to start application of fungicides before the infection has established.
f) Red rust ( Cephaleuros virescens Kunze) : Red rust disease, caused by an alga, has been observed in mango growing areas. The algal attack causes reduction in photosynthetic activity and defoliation of leaves thereby lowering vitality of the host plant.
The disease can easily be recognized by the rusty red spots mainly on leaves and sometimes on petioles and bark of young twigs and is epiphytic in nature. The spots are greenish grey in colour and velvety in texture. Later, they turn reddish brown. The circular and slightly elevated spots sometimes coalesce to form larger and irregular spots.
The disease is more common in closely planted orchards. Fruiting bodies of the alga are formed in humid atmosphere. The zoospores formed by the sporangia initiate fresh infections. Stem entry is achieved by way of cracks. The affected areas crack and scale off. In severe infection the bark becomes thickened, twigs get enlarged but remain stunted and the foliage becomes sparse and finally dries up.
a) Mango malformation : Malformation is widely prevalent in northern India, particularly in the states of Punjab, Delhi and western U.P. where more than 50 per cent of the trees suffer from this malady. The malformed panicles remain unproductive and are characterised by a compact mass of male flowers, greenish in colour and stunted in growth. The main and secondary rachis are thick and short and bear flowers with relatively larger bracts, sepals and petals as compared to normal flowers. The malformed panicles remain intact on the trees for a considerable period. Though research efforto made hitherts have not been able to ascertain its etiology, the complexity of the disorder is attributed cultural practices, nutritional, to many factors like, mites, fungal, viral, etc. hormonal imbalance. The exact cause and control of the malady is yet to be established. However, some remedial measures are recommended as follows :
        • Pruning of shoots bearing malformed panicles
        • Deblossoming of early emerged / infested panicles.
b) Biennial bearing : The term biennial, alternate or irregular bearing generally signifies the tendency of mango trees to bear a heavy crop in one year (On year) and very little or no crop in the succeeding year (Off year). Most of the commercial varieties of north India, namely, Dashehari, Langra and Chausa are biennial bearers, while south Indian varieties like Totapuri, Red Small, Neelum and Bangalora are known to be regular bearers. When a tree produces heavy crop in one season, it gets exhausted nutritionally and is unable to put forth new flush thereby failing to yield in the following season. The problem has been attributed to the causes like genetical, physiological, environmental and nutritional factors. For overcoming biennial bearing, deblossoming is recommended to reduce the crop load in the ‘On’ year such that it is balanced in in the ‘Off’ year. Proper maintenance of orchard by way of effectively controlling pests and diseases and regular cultural operations may also result in better performance of the tree every year. Soil application of Paclobutrazol (PP333) or @ 4 - 5 g per tree in the month of September resulted in early flowering with higher fruit set and yield. It may be applied every year for regular fruiting, particularly in young trees. The time of application may vary according to fruit bud differentiation.
c) Fruit drop : Despite high fruit set initially, the ultimate retention is quite low in mango. The intensity of fruit drop, varies from variety to variety. Among the commercially grown varieties, Langra is more susceptible to drop while Dashehari is the least. The fruit drop is more or less a continuous process and can be classified into three groups : (i) Pinhead drop, (ii) Post-setting drop and (iii) May-month drop. The fruit drop in first two groups are insignificant compared to the third group which affects the final yield significantly and needs more attention. Embryo abortion, climatic factors, disturbed water relation, lack of nutrition, disease, pest and hormonal imbalances are the major factors that lead to fruit drop. The foliar application of Alary (B-nine) @ 100 ppm or NAA 20 ppm at pea stage of fruit was found effective in controlling fruit drop in mango.
d) Black tip : Black tip is a serious disorder, particularly in the cultivar Dashehari. The affected fruits become unmarketable and reduce the yield to a considerable extent. The damage to the fruit gets initiated right at marble stage with a characteristic yellowing of tissues at distal end. Gradually, the colour intensifies into brown and finally black. At this stage, further growth and development of the fruit is retarded and black ring at the tip extends towards the upper part of the fruit. Black tip disorder has generally been detected in orchards located in the vicinity of brick kilns. It has been reported that the gases like carbon monoxide, sulphur dioxide and ethylene constituting the fumes of brick kiln are known to damage growing tip of fruits and give rise to the symptoms of black tip. Apart from these factors, irrigation, condition of the tree and management practices also play important role in deciding the severity of the disorder.
Planting of mango orchards in North-South direction and 5 to 6 km away from the brick kilns may reduce incidence of black tip to a greater extent.
The incidence of black tip can also be minimised by the spray of borax (1%) or other alkaline solutions like caustic (0.8%) or washing (0.5%) soda. The first spray of borax should be done positively at pea stage followed by two more sprays at 15 days interval.
e) Clustering disorder in mango (‘Jhumka’) : A fruiting disorder, locallly known as ‘Jhumka’, is characterised by the development of fruitlets in clusters at the tip of the panicles. Such fruits do not grow beyond pea or marble stage and drop down after a month or so of fruit set. These fruits do not contain seeds when they are cut open. The disorder seems to be due to lack of pollination / fertilization which may be attributed to many reasons. Among them, absence of sufficient population of pollinators in the orchards is the major reason. Surveys conducted in the mango belt of Lucknow revealed that the more problem is area in Malihabad and Dashehari is the most affected cultivar. The other reasons causing the disorder are old and overcrowding of trees, indiscriminate spraying against pests and diseases, use of synthetic pyrethroids for spraying, monoculture of Dashehari, and bad weather during flowering. Some of the remedial measures are suggested below :