FARMER'S NOTEBOOK
Integrated management of areca nut pests
By Our Agriculture Correspondent
An areca palm infested with `white' grubs (left). `Spindle bug' can cause severe damage to the un-opened spindle leaf (right).
SCIENTISTS AT the Central Plantation Crops Research Institute's (CPCRI's) Regional Station at Vittal, Karnataka, have come out with an integrated package of practices to effectively manage the pests of areca nut in the areca-cocoa cropping system and make areca nut-cocoa cultivation more remunerative to the growers.
They have found that cocoa trees are not common or alternate hosts of the economically important pests of areca palms.
Areca pests
"Sucking insects, root-feeding insect and a caterpillar, which damages the inflorescence are important pests of areca palm. The sap-sucking bug, Carvalhoia arecae, commonly known as `spindle bug', damages the unopened spindle leaf. The damage is more severe in young exposed plantations, and it is manifested as blackish brown linear lesions on the spindle leaf. As this insect completes its life cycle within a month, an insecticide treatment is needed for young plantations with continued attack.
A fine spray to the spindle leaf alone in the morning hours (before the day temperature rises) with dimethoate (at 0.05 per cent concentration) will reduce the population of these bugs," says Dr. Mariamma Daniel, Senior Scientist at CPCRI's Regional Station at Vittal.
Root infestation
Root grubs or `white' grubs are the larval stages of chafer beetles. Mainly, two species of Leucopholis beetles are found infesting the roots of areca palm.
This insect is more localised in distribution, and its infestations are noticed in parts of Dakshina Kannada, Uttara Kannada, Chickmagalur, Kozhikode and Wynadu districts. The annual life cycle of this insect gives it a perennial existence.
Its grubs feed on the roots. The external symptoms are reflected on the palms after two to three years of infestation.
Disease symptoms
Tapering of stem, yellowing and drooping leaves and reduction in the number of spadices produced are observed in the plantation within a year of its attack. Integrated pest management techniques are to be followed to reduce the population of this insect in a locality. Management measures must be intense and should be adopted in all affected plantations in a locality or village.
Collection and destruction of adult beetles during the emergence time, which occurs after the pre-monsoon showers in May and June, will prove to be rewarding, according to Mariamma Daniel.
Cultural practices
Digging and forking of the soil before and after the monsoon will help in eliminating the various developmental stages of the beetle. Addition of organic amendments and anti-feedants such as neem and pongamia oilcake will give good results.
Soil checking
In severely infected gardens, the soil should be suitably drenched with eco-friendly insecticides to ward off the pest. The palms will recover within a few years, and soil checking must be continued even after the recovery of the palms.
Inflorescence caterpillar attack is mainly observed in Dakshina Kannada and Shimoga districts. The mechanical damage caused by slugs' feeding on the spathe covering is a pre-disposing factor for the incidence of this pest.
Mechanical removal of slugs and destruction of affected inflorescences in a plantation will help in the reduction of its incidence, according to the scientists.
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