Anthracnose of mango

Host: Mango (Mangifera indica L.)
Pathogen: Colletotrichum gloeosporioides Penz.

Distribution

Anthracnose of mango is distributed throughout the tropical and subtropical countries of the world. The disease is reported from Australia, Asia, Europe, Africa, the Caribbean, North, Central and South America. In India the disease is prevalent in the mango growing states.

Symptoms

Symptoms of the disease occur on leaves (spots), petioles, branches (blight), inflorescence (panicles) and fruits (rot). Infected leaves show tan to dark brown colored spots at the margins. In young bronze and pale green leaves semi-circular lesions appear. The lesion eventually drop-out of the leaves. In old leaves spots appear as charcoal and leaves become curled.
Anthracnose of mango
Mango leaves showing anthracnose disease
Infected fruits develop dark-brown to black spots, which grow larger and coalesce. These spots may penetrate deeper into the fruit tissues and cause rotting. Premature dropping of fruit may occur. The symptoms on the infected green fruit are not visible until the ripening. A peculiar symptom of the disease is the several linear necrotic black colored regions (tear-stain), which are marked by the cracking of epidermis, giving alligator skin appearance.
The disease is favored by the wet, humid and warm weather conditions.

Pathogen

Anthracnose of mango is caused by the ubiquitous fungus Colletotrichum gloeosporioides Penz and Sacc. Its perfect stage (telomorph) is Glomerella cingulata var minor. This pathogen is also responsible for the "anthracnoses" on the tropical fruits including, chili, papaya, banana, coffee, etc. The pathogen multiply by producing numerous spores (conidia), which on splashing by rain or through irrigation water reach the healthy area and spread the infection. Conidia formation is favored by wet, humid and warm weather conditions making disease devastating.
Infected areas of the leaves are attacked by a number of secondary pathogens including, Fusarium, alternaria, curvularia, etc.

Management

Anthracnose of mango is of very common occurrence in areas of wet and warm environments. It becomes devastating in the areas of high rainfall, where it is very hard to control. Integration of cultural practices, biological control and use of fungicides reduce the infection.
  • Pruning and field-sanitation is necessary. In order to reduce the humidity, prune the branches every year to allow air passage through the branches and remove any debris found in the vicinity.
  • Infected branches should be removed and burnt.
  • Foliar anthracnose can be controlled by spraying 1.0 % Bordeaux Mixture or 0.1 % Carbendazim (50WP) every 14-20 days.
  • Above fungicide should be sprayed 4-5 times since the first appearance of panicle up to the development of fruits.
  • Post-harvest rotting of fruit can be controlled by dipping into the carbendazim or in hot water (52 °C) for 5 minutes.

Mango malfomration

Host: Mango (Mangifera indica L.)
Pathogen: Fusarium subglutinans Wollenw. & Reinking

Distribution

Mango malformation disease was first reported by Marries from Darbhanga district of Bihar, India. Since then, it is of common occurrence in the tropical and subtropical countries of the world including India, Pakistan, Bangladesh, Myanmar, Philippines, Malaysia, Oman, Sudan, Egypt, America, Cuba, Mexico, Brazil (Kumar et al., 2011). In India, it causes heavy economic loss in all the mango growing states. The disease causes 50 to 60 % loss in yield (Kumar et al., 2011).

Symptoms

Mango malformation Mango malformation
'Bunchy top' branch of mango tree Malformed branches of mango

Mango malformation disease affects saplings in nurseries as well as mango trees. In mango trees, both vegetative as well as floral meristems are affected. Affected young sapling produces small scaly leaves with ‘bunchy top’ appearance of the apex. This causes loss in apical dominance and plantlets remain stunted.

Mango malformation Mango malformation
Malformed inflorescence of mango  Diseases plant (upper), After treatment (lower)
In big trees excessive branches of limited growth arise. These branches are with short and swollen internodes giving ‘witches' broom’ appearance. Malformation ceases the growth of vegetative branches.
Floral malformation affects the panicles (inflorescences). The branches of the panicles become short, thickened and hypertrophied. Flowers in infected panicles are numerous and remain unopened. These are compact and crowded. Malformed panicle dries up in black mass and persists for a long time.


Pathogen

Mango malformation disease is caused by Fusarium moniliforme var. subglutinans (Syn. Fusarium subglutinans). It is anamorph of Gibberella fujikuroi var. subglutinans.

Control measures

  • Disease-free saplings should be planted.
  • The diseased plants should be destroyed.
  • If disease appears in the branch, the branch should be pruned 10-15 cm below the infection.
  • Mango malformation disease can be controlled by the spray of systemic fungicide, Carbendazim (0.1%).
  • Spray of 0.2 % Captafol also controls the disease, but because of being highly toxic to fishes and other aquatic organisms, it is no longer approved in several countries (NCBI, CID=17038).

References

  • Kumar, P., Misra, A.K. and Modi, D.R., 2011. Current status of mango malformation in India. Asian Journal of Plant Sciences, 10(1), p.1.
  • National Center for Biotechnology Information. PubChem Database. Captafol, CID=17038, https://pubchem.ncbi.nlm.nih.gov/compound/Captafol (accessed on Apr. 17, 2020).


Red rust of mango
Algal leaf spot of mango

Host: Mango (Mangifera indica L.)
Pathogen:Cephaleuros virescens Kunze (Green alga)

Distribution

Red rust of mango occurs in all the mango growing tropical and subtropical region (between 32° N and 32° S) of the world, where temperature and humidity is favorable for the growth of pathogen, i.e., Cephaleuros (Vasconcelos et al., 2018). In India the disease has been widely reported from the states of Uttar Pradesh, Bihar and Karnataka. During 1956 the disease appeared in the form of epidemic in Tarai region. Author has observed this disease in the endemic form (during 2020) in most of the mango-gardens of the Tarai region.

Symptoms

Red rust of mango
Early grayish-green spot on mango leaf

Red rust of mango
Older leaf spot showing hole in the center

Symptoms mostly appear on the upper surface of the leaves. Initial symptoms appear as grayish-green small spots with velvety appearance. Later spots become reddish-brown in color giving rusty appearance (hence, red rust). Velvety appearance of the spots is due to the numerous unbranched filaments. As disease intensified, more than one spots coalesce to make larger spots. In older spots, the center of the spots is torn-out in the form of holes. In affected leaves photosynthetic area is decreased, which reduces the yield.

Pathogen

Cephaleuros
Filaments of Cephaleuros virescens on mango leaf

Red rust of mango is caused by a green-parasitic alga Cephaleuros virescens belonging to the family Trentepohliaceae. Vasconcelos et al. (2018) have cultured Cephaleuros virescens in Trebouxia medium and characterized molecularly. The alga has a broad host range including tea. Alga reproduces by producing red-colored, ciliated zoospores in a humid atmosphere.


Cephaleuros virescens
Cephaleuros virescens: a: surface view under stereobionocular microscope, band c: microscopic details (sp = sporangiophore, zs = zoosporangium, sc = suffultory cell and hc = head cell). bar = μm.

Epidemiology and Control measures

  • Red rust of mango is favored by close plantation, hence close plantation should be avoided.
  • Frequent rains, warm weather, poor soil drainage and stagnant air favors the growth and reproduction of Cephaleuros.
  • Trees should be properly pruned and fertilized to ensure the proper aeration and growth. All the weed should be removed from time to time.
  • Red rust of mango can be effectively controlled by spraying Bordeaux mixture (6:6:100 or 0.6-1.2 5).
  • The disease can also be controlled by Copper oxychloride (0.25 %).
  • Lichens growing on affected plants should also be removed by applying caustic soda.

References

  • Vasconcelos, C.V., Pereira, F.T., Duarte, E.A.A., de Oliveira, T.A.S., Peixoto, N. and Carvalho, D.D.C., 2018. Physiological and Molecular Characterization of Cephaleuros virescens Occurring in Mango Trees. The plant pathology journal, 34(3), p.157.


Boron deficiency in mango

Symptoms

Boron deficiency in mango
Internal necrosis on mango tip
Internal necrosis and fruit cracking are two symptoms of B deficiency in mango. The disease is prominent in the areas of high rainfall and temperature, acid and calcareous soils. ‘Dashehari’ is the most sensitive to B deficiency among other cultivars of mango (Saran and Kumar, 2011).
Internal necrosis appears initially as a dark green color area on the tip of fruits. Soon, it becomes brown with an irregular outline. In the infected area, mesocarp and seed develop necrotic tissues. Soon the necrotic mesocarpic tissues collapse and a cavity surrounded by hard tissues is formed.
Mango fruit cracking
Cracked mango fruits because of boron deficiency

Because of the abnormality in cell division and carbohydrate translocation, fruits are cracked immaturely.


Management

As B is leached in the soil, it should be applied as a foliar spray.
  • B deficiency is cured by foliar spray of borax (Sodium tetraborate decahydrate).
  • 5-10 kg borax should be sprayed in one hectare.
  • Foliar spray of 0.10 to 0.25 % solution of borax cures the disease effectively.

References

  • Saran, P.L. and Kumar, R., 2011. Boron deficiency disorders in mango (Mangifera indica): field screening, nutrient composition and amelioration by boron application. Indian Journal of Agricultural Sciences, 81(6), p.506.



Foliar gall of mango

Name of the host: Mangifera indica L.
Name of the pathogen: Mango gall midge

Symptoms

Foliar gall of mango
Galls on mango leaves

Mango midges affect mostly young developing leaves. Adult midges lay eggs on the lower surface of mango leaves in the months of March, July and October. The larvae invade the mango leaf and form smooth to rough, blister or wart-like, raised gall on the upper surface of the leaves. Depending on the midge species, more than one type of gall can occur on the same leaves. In severe infestation, few hundred such galls are formed on a single leaf. Gall formation reduces the photosynthetic area as well as larvae feed on the phloem sap inside the leaf, which reduces the yield.


Insect

gall formation in mango
Galls formed by mango midges (enlarged)

Gall formation in mango is caused by mango midges including several species of Procontarinia. Procontarinia matteiana Keiffer and Cecconi is common mango midge reported from Indian subcontinent, Indonesia, Iran, Oman, Pakistan, United Arab Emirates, South Africa, Sudan Kenya, Mauritius, Réunion. Other mango midges such as Amraemyia and Amradiplosis echinogalliperda also cause foliar gall formation in mango in Uttar Pradesh.

Control measures




See also


Content first created on 21-08-2020
last updated on 27-12-2023