PLANT PROTECTION

A. Pests

The major insect pests of the coconut palm are the rhinoceros beetle, the red palm weevil, the black headed caterpillar, the cockchafer beetle and the coreid bug. Adopt suitable remedial measures as and when required. The following table gives the major symptoms and control measures.

VII. Mealy Bugs and Scale Insects

Symptoms

During summer months mealy bugs cause damage to spindle leaves, spathes and bunches and the scale insects make encrustations on the foliage. 
The infested turn yellow and finally dry up.

Control measures

Two rounds of spray with 0.1% Fenthion or 0.05% Monocrotophos. 
In the case of scale insects spraying with dimethoate or monocrotophos 0.05% is efficacious.

VIII. Termites

Symptoms

It is estimated that nearly 20% of the coconut seedlings are damaged by termites particularly in laterite soil. 

Control measures

Adoption of field sanitation by disposal of organic matter in nursery soil and covering germinating nuts with a layer of river sand.
Drench the nursery with 0.05% chlorpyriphos twice at 20-25 days interval 
Swab the affected trunk with the same chemical.

IX. White Grub

(Leucopholis coneophora Burm.) (Melolonthinae: Coleoptera)

Symptoms

The white grubs are mostly found in sandy loam tracts of Kerala and Karnataka. It damage the roots. In seedling, it tunnels in to the bole and collar region. 
It has an annual life cycle with a grub period of 8 months. Peak grub population is observed from Sept. to Oct. Adult beetles emerge out of the soil after pre- monsoon showers in May-June during sunset hours. 

Control measures

Plouging and digging of soil during pre and post monsoon period will expose the insect for predation. 
Collection and destruction of the adult beetles during May-June. 
Setting up light traps to attract adult beetles. 
Application of phorate 10G @ 100g per palm should be mixed and raked in the top 15cm soil in May-June and Sept.-Oct. is recommended in coastal and Malanad areas. Irrigation is necessary after the pesticide application.

X. Eriophid Mite of Coconut

Symptoms

The Eriophid Mite (Aceria guerreronis (Keifer) (Acarina: Eriophyidae) which was a minor pest of coconut in India has become a major pest on coconut recently. 

The attack of this mite was first recorded in 1965 in guerrero, Mexico. Later it was reported from Ivory cost, Brazil, Costa Rica etc. The first Indian report of this pest is from Ernakulam District of Kerala during 1998. The sporadic occurrence of this pest is reported from almost all the 14 districts of Kerala, Tamil Nadu, Karnataka, Andhra Pradesh and Kalpeni Island of Lakshadweep. As per the recent survey conducted in Kerala (13th -18th December 1999) about 589 lakh bearing palms are affected. This accounts for about 42% of the total yielding palm population and the estimated crop loss is in the tune of 21.8%. A roving team to study the intensity of infestation has identified its occurrence from all the South Indian States and Union Territory of Lakshadweep. 

The mites are very minute in size and are not visible by naked eye. The size of this measures to 200-250 microns in length and 20-30 microns in width. The life cycle of this mite is completed in 10-12 days. It remains underneath the periyanth (cap) and cause injury by feeding on the soft paranchymatic tissues. Though the mites are microscopic their damage is enormous and hundreds of mites could be seen in each infested button and tender nut. Visible symptoms are brown discoloration noticed in patches of the husk. In case of severe attack the button sheds, resulting in very poor setting percentage. In other cases the nuts are deformed and undersized with poor development of kernel and husk.

The mites spread through wind and its multiplication is at a high rate. Though this pest was noticed only in a limited area during 1998 it has become a major pest of coconut in India.

Control measures

Being a micro pest inhabiting under the periyanth, the control measurers at field level are not easy. However by adopting the following integrated plant protection measurers the mite population could be reduced considerably.

1. Adoption of phytosanitary measures in coconut gardens such as cleaning the crown of the palm, keeping the plantation clean and burning of all immature nuts fallen due to mite infestation. 

2. Spraying biopesticides on the bunches
   a) 2% neem oil - garlic emulsion (20ml neem oil + 20g garlic + 5g bar soap in 1 litre water). Emulsion has to be prepared on the same day of application itself.
   b) Other neem based pesticides at 0.004% (Azadirachtin). If the pesticide formulation contains 1% Azadirachtin, 4ml has to be used in 1 litre water.
   Wherever spraying is difficult root feeding may be resorted to with Azadirachtin 5% formulation (7.5ml+7.5ml water) or Azadirachtin 1% formulation (10ml + 10ml water). 

3. Spraying has to be done 3 times a year - December-February, April-June and September-October. While spraying, ensure that the spray fluid falls over the perianth region especially on button and tender nuts. On an average 1-1.5 litre spray fluid is required per palm. Care should be taken to harvest mature bunches before spraying.

4. Following palm health care practices also may be adopted.

   1. Recycling of biomass generated within the coconut system by vermi compost method or by using lignin degrading fungus.

   2. Raising of green manure crops in the coconut basins (like sunhemp, cowpea, calapagonium etc.) and incorporation into the soil in the basin itself, these act as mulch during summer and slowly decompose and provide nutrients when incorporated to soil.

   3. Application of recommended dosages of fertilizers, in two split doses, as per the package of practices prevailing in the respective states.

   4. Recommended level of irrigation during summer months i.e. 250-500 litres of water per tree per week (based on evapotranspiration in the given area).

   5. Soil moisture conservation by following methods.

      1. Burial of coconut husk in the basin.

      2. Mulching the basins (2m radius) with coconut leaves/green manure / green leaf manure.

      3. Mulching with coir pith wherever available (2m radius).

Video film on Integrated management of coconut Eriophyid Mite

XI. Slug Caterpillar

(Leucopholis coneophora Burm.) (Melolonthinae: Coleoptera)

Symptoms

The white grubs are mostly found in sandy loam tracts of Kerala and Karnataka. It damage the roots. In seedling, it tunnels in to the bole and collar region. 
It has an annual life cycle with a grub period of 8 months. Peak grub population is observed from Sept. to Oct. Adult beetles emerge out of the soil after pre- monsoon showers in May-June during sunset hours. 

Control measures

Plouging and digging of soil during pre and post monsoon period will expose the insect for predation. 
Collection and destruction of the adult beetles during May-June. 
Setting up light traps to attract adult beetles. 
Application of phorate 10G @ 100g per palm should be mixed and raked in the top 15cm soil in May-June and Sept.-Oct. is recommended in coastal and Malanad areas. Irrigation is necessary after the pesticide application.

For details regarding Diseases of Coconut click here: Diseases

For more details please contact us: 

E-mail: cdbkochi@dataone.in