ARECANUT

Diseases

Koleroga (Mahali or fruit rot) (Phytophthora palmivora)

Spray Bordeaux mixture 1% on all bunches three times in a year, one just before the onset of southwest monsoon and the rest at 40 days intervals. If monsoon season is prolonged give a third spray. Use rosin soda adhesive to ensure tenacity of the spray deposit on treated substrate. Remove and burn all fallen and infected nuts.

Bud rot (Phytophthora palmivora)

Remove and destroy affected spindle and leaves. In early stages of infection, scoop out affected rotten tissues by making longitudinal side splits and apply Bordeaux paste on the exposed healthy tissues or drench crown with 1% Bordeaux mixture.

Basal stem rot (Anabe) (Ganoderma lucidum)

1. Isolate affected palms by digging trenches 60 cm deep and 30 cm wide around, one metre away from the base and drench with captan (0.3%), calixin (0.1%) or copper oxychloride (0.3%)
2. Remove and destroy all severely affected palms and stumps of dead palms.
3. Drench the soil with 1% Bordeaux mixture before planting healthy seedlings.
4. Discourage growing of collateral hosts of fungus such as Delonix regia and Pongamia glabra in the vicinity of gardens.
5. Apply 2 kg neem cake per palm.
6. Avoid flood irrigation and water flowing from infected palms to healthy palms.

Yellow leaf disease

Maintain the garden properly to keep affected palms in a healthy condition by adopting recommended manurial, cultural, plant protection and other management practices. Improve drainage conditions in the garden.

Disease management

1. Apply the recommended dose of fertilizers.
2. In addition to the above, apply 160 g of rock phosphate per palm in the affected garden.
3. Apply organic manure @ 12 kg each of compost and green leaves per palm per year.
4. Provide irrigation during summer months
5. Avoid water stagnation in the garden by providing drainage facilities.
6. Grow cover crops in the garden.
7. When only a few palms are affected in a garden, remove them to prevent further spread of the disease.
8. Adopt need based plant protection measures against pests and diseases.

Band disease

Improve soil conditions by loosening hard soil strata, if present, by providing good drainage. Adopt adequate control measures against spindle bug, mealy bugs, scales and mites. Where the results of the above treatments are not found satisfactory, apply powdered mixture of copper sulphate and lime in equal quantities @ 225 g/palm twice a year at the base of affected palms. Application of borax @ 25 g/palm has been found to have an ameliorative effect.

Collar rot of seedlings

Improve drainage conditions in nursery beds and gardens. Drench spindle and base of seedlings with 1% Bordeaux mixture in disease affected nursery or garden.

Dieback of inflorescence

Remove affected inflorescence immediately. Spray zineb (4 g in 1 litre of water) or mancozeb (3 g/l) twice, once just after female flowers are set and again 15-28 days later. Aureofungin sol at 50 ppm concentration is also effective in controlling the disease.

Stem bleeding

Palms in the age group of 10-15 years are more prone to this disease. Symptoms appear on the basal portion of the stem as small discoloured depression. Later, these spots coalesce and cracks develop on the stem leading to disintegration of the fibrous tissues inside. With the progress of the disease, a brown exudate oozes out from these cracks. High water table predisposes the palm to this disease.

Improvement of drainage and root feeding of 125 ml tridemorph (1.5%) is suggested as control measure against this disease.

Sun scorch

Protect palms from southwest sun by wrapping stems with areca sheath or white-wash the exposed portion. Provide reinforcement to palms showing stem fissures. Grow tall, quick growing trees on southern and western sides of garden.

Nut splitting

This can be considered as a physiological disorder than a disease. Palms in the age group of 10-25 years are more susceptible. Symptoms are premature yellowing of the nuts when they are half to three-fourth mature. Later splits develop at the tips, which extend longitudinally exposing the kernel. Sometimes kernel also show splitting and malformation. Rarely the kernel inside may exhibit splitting without visual symptoms on the husk, resulting in nut fall. Hyper nutrition or sudden flush of water after a period of drought or insufficient moisture in the soil is the probable cause (s) of the disease.

Improvement of drainage in ill drained gardens and spraying of borax @ 2 g/litre of water are found effective in reducing the disease incidence.

Koleroga

Koleroga is a major disease of arecanut causing serious losses. The pathogen is a fungus Phytophthora palmivora. Spraying the bunches with 1% Bordeaux mixture before monsoon followed by another spray after 45 days is effective in preventing the disease. Covering the bunches with polythene bags is an effective alternate method of control.

Last updated: 22-05-2008