Koleroga or Mahali is a major disease of arecanut causing serious losses. The pathogen is a fungus Phytophthora palmivora. Spraying the. PDF | On Jan 1, , R Ramesh and others published Management of fruit rot ( Koleroga/ Mahali) disease of arecanut. Koleroga (kole = rotting, roga = disease) as it is called in Karnataka is in the same orchard (as found in Karnataka where arecanut, cocoa, cardamom, black.

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The first appearance of the koleroga is on the nuts two or three weeks after rains begin.

Please enter an answer in digits: A fine spray will be needed for effective spread of spray fluid over the surface of the nuts. From Wikipedia, the free encyclopedia. Therefore, Phytophthora root rot may occur on papaya at any age joleroga poorly drained areas. Although the disease is predominant on the nuts, it occasionally attacks the crown of the palm resulting in rotting and drying.

As the intensity of rains did not come down, many farmers were not able to spray the usual first round of prophylactic solutions in the last week of May or the first week of June to prevent the disease.

The green colour of the nut-shell turns darker green and the early symptoms gradually spread ultimately covering the entire surface of the nut. During the onset of the rainy season, these structures are carried to young nuts by various agencies and germinate there upon causing primary infection. Zoospores emerge out of the sporangia in the presence of abundant light and atmospheric humidity.

Control of fruit rot or koleroga disease of arecanut (Areca catechu L.)

This is the most conspicuous and dangerous stage and is a sure sign of the disease in the plantation. Under waterlogged conditions, P. The impact of falling rain drops may splash zoospores into air in droplets.

The zoospore-containing droplets may be further dispersed by wind and become the inoculum for infecting fruit and occasionally stems of papaya in the fields. Articles koleroa ‘species’ microformats. The initial spray is to be done immediately after the onset of monsoon showers, and the second spray after an interval of 40 to 45 days.


Chemical control methods for P. Mature zoospores can be induced to germinate by treatment with 0. Favorable temperature is also a contributing factor to the severity of Phytophthora diseases because of its effect on growth and sporulation of the pathogen. In coconuts, the expected yield losses caused by P. Related Agecanut Karnataka Mangalore.

Control of fruit rot or koleroga disease of arecanut (Areca catechu L.) [1988]

Users may want to set up a specific directory and file naming scheme for storing images; otherwise, they will be saved using your system defaults. Bud rots can also be seen in papaya and coconuts aecanut with P. Infected fruit on the trees and those that have fallen to the ground should be removed to reduce the inoculum for aerial infection of fruit and stems, and infection of seedling roots in subsequent plantings.

Therefore, intermittent rains maintaining constant humidity in the atmosphere with alternating sunshine abundant light are more conducive for the rapid spread of Koleroga. Careers In Plant Pathology. Phytophthora Water mould plant koleroha and diseases Coconut palm diseases.

Retrieved 15 November Heavy rainfall and constant moist conditions of the atmosphere are the chief predisposing factors for the disease. Trees established with the virgin soil method in the replant fields produce fruit as abundantly as those growing in the first planting fields. Mobility of zoospores of P. Retrieved from ” https: Phyto-sanitary measures such as removal of all koleroya and infected bunch attached to the palm and collection and destruction of all arecanuy nuts will prove to be rewarding.

Phytophthora palmivora produces abundant sporangia on V-8 agar under continuous fluorescent light. Bipolaris incurvata Botryosphaeria cocogena Bursaphelenchus cocophilus Cadang-cadang Capnodium footii Cephaleuros virescens Corticium penicillatum Cytospora palmarum Marasmiellus cocophilus Periconiella cocoes Pestalotiopsis palmarum Phaeochoropsis mucosa Phyllosticta palmetto Phytophthora palmivora Pseudoepicoccum cocos Ramularia necator Stigmina palmivora.

Symptoms and Management Plant Pathology. The chamydospores formed in the infected fallen nuts on the soil serve as the perennating structures of the pathogen.


Prophylactic spraying with one per cent Bordeaux mixture on the bunches is needed to prevent the incidence of the disease. Covering klleroga arecanut branches with polythene bags as a prophylactic measure provides cent percent control of the disease but it is costlier than fungicide spray. Chlamydospores produced in infected papaya fruit and pure papaya juice are thick-walled.

The Hindu : Sci Tech / Agriculture : Managing fruit rot disease of areca nut

The hyphae invade inter- or intracellularly and produce sparsely distributed finger-shaped, occasionally branched haustoria in the host cells. Sporangia produced from primary infection lesions serve as the source of secondary infections during the growing season. The pathogen produces abundant sporangia on the surface of infected fruit that are further dispersed by wind-blown rain and cause outbreaks of Phytophthora fruit rot in the same and nearby orchards.

The officer said the department would compile its data on Tuesday as it has sought details on the extent of land affected from its taluk offices. Common Names of Plant Diseases. Genetic Recombination in Bacteria: Saraswathy and Nambiar stated that the systemic fungicides such as Aliette and Ridomil at 0.

Wind is required for dispersal of the inoculum once it reaches the air.

The disease appears usually 15 to 20 days after the onset of regular monsoon rains and may continue up arecanuy the end of the rainy season. Kawakamia carica Hara [2] Phytophthora arecae L. Collar rots are found on citrus, mango, and black pepper infected with P.

Although sporangia and zoospores may survive in soil for short periods, chlamydospores are the main survival structure for P. The sporangiophores are irregularly branched and are about 2.

Therefore, wind-blown rain is essential for initiation of the primary infection and the development of epidemics in papaya orchards.