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Coconut Pests and Diseases

Management of Red Weevil

Young palms between the age of 04 -15 years are highly susceptible to Red Weevil attack. Coconut growers are advised to inspect young palms in the above age category at least once a week for early detection of Red Weevil attack. Female weevils lay eggs only on fresh wounds on young palms. Therefore, it is necessary to ensure that all fresh wounds on young palms are treated with the application of Coal tar or burnt (used) engine oil.
Prevention methods
Inspect all young palms at least once a week and clean the crown and the trunk of palms by carefully removing dried fronds and other material. This facilitates early identification of pest damage. Coal tar or used engine oil should be applied on fresh wounds on trunks and petioles. Severely damaged palms, which are beyond recovery, should be cut, spilt and burnt.
Control methods
The recommended systemic insecticide is Monocrotophos 60%, 20 ml/palm.
Method of application
Inject the trunk for fully developed trunk using monocrotophos, which have fully developed trunk. Pouring of insecticide to the bud region, for young palms, which do not have fully developed trunk.
Root feeding method
Reduce the Red Weevil population by using pheromone trap. Recommend for estates more than 5 acres in extent.

Coconut Red Weevil Life Cycle
Coconut Red Weevil Life Cycle

Coconut Mite and its management

If the mite infestation is reported in few palms in an area for the first time, cut and burn all bunches in the infected palms. Apply palm/vegetable oil and Sulphur mixture.

The following mixture should be sprayed on to the crown of affected palms with a modified knapsack sprayer. The modified sprayer can be operated on the ground with an extended output tube tied on to the top end of a bamboo stick at the required height. With this sprayer two people can spray palms up to the height of 40 feet.

Palm/Vegetable oil and Sulphur mixture
Palm oil 200 ml (1 cup)t
Water 800 ml (4 cups)
Soap powder 12 g (2 table spoons)
Aqueous Sulphur 80% 5 g
(1 table spoon)
Application of this mixture once in every six months reduces the mite damage up to 90% in the coconut cultivation
Coconut Red Weevil Life Cycle
Coconut Red Weevil Life Cycle

Management of Black Beetle

Coconut seedlings after transplanting are susceptible Black Beetle damage. Growers are advised to maintain the estate sanitation within the plantation by destroying all breeding grounds of Black Beetle. In areas where Black Beetle population is high young palms should be inspected at least once in every week.
Methods of managing the Black Beetle:
Mechanical method
Beetle is removed using a pointed metal hook and treat the wound with coal tar or used engine oil.
crop sanitation
Decaying breeding grounds – decaying coconut logs and stumps should be removed and burnt.
Mulch on the manure circle should be inspected periodically and replaced with fresh materials.
Chemical methods
Apply coal tar or used engine oil on leaf axils around the bud region as a repellent
Place naphthalene balls into each of the innermost leaf axils.

Black Beetle
Black Beetle

Coconut Caterpillar and its management

Coconut Caterpillar damage should be identified well in advanced before it reaches to epidemic level. Growers are advised to be vigilant and take corrective measures early. You may contact the Coconut Development Officer (CDO) in your area for necessary advice.

  • If the infestation level is low (less than 30 palms are affected), cut 5-6 infested fronds and burn.
  • If a large number of palms are infested you may contact the CDO in your area for pest population assessment.
  • Based on the recommendation of the CDO -lab-bred parasites are available in CrI to release for the coconut lands

Black Beetle Life Cycle
Black Beetle Life Cycle

Termite damage and its control

In clay soils and clay loamy soils termite attacks to seedlings are high. Coconut growers are advised to follow the chemical treatments to control termite damage to seedlings. Bear rooted seedling could be treated before transplanting. The following diluted chemicals could be drenched around the seedlings after transplanting in the case to polybagged seedlings.
Chemical control When using seedlings that have little rooting, place the seedlings in three of the above mixes dying for three minutes.
Method of application When bear rooted seedling are used dip the seed nuts in one of the above solutions for 3 minutes prior to planting.

Insecticide Dosage
Imidacloprid 20% (Admire SL 200) 1-2 ml in one liter of water
Black Beetle Life Cycle
Black Beetle Life Cycle

Recommendations to manage Weligama Coconut Leaf Wilt Disease (WCLWD) and Coconut Leaf rot Disease (CLRD) spreading in the Southern Province of Sri Lanka

The WCLWD has been declared as an epidemic disease, by the gazette notification no. 1542/7 of 24th March 2008 under the Plant Protection Act 35 of 1999.
Currently, this disease is reported in Matara, Habaraduwa and Galle Districts.
To prevent the spread of this disease to other areas, a disease free boundary has been declared. The boundary is A17 road from Galle to Akuresse, Akuresse to Kirinda-Puhulwella through Kamburupitiya, Kirinda – Puhulwella to Walasmulla, Walasmulla to Beliatte and Beliatte to Tangalle. The boundary zone is 2km interior and 1km outside of the above road. All coconut trees, seedlings and other palm species showing disease symptoms within the boundary zone are removed.
Transportation of coconut seedlings, all plants of family Palmae (including ornamental palms) and their live plant parts (excluding de-husked coconuts and arecanuts) out of the above defined diseased areas has been prohibited.
Action has been taken to identify and remove all affected palms in Matara, Galle and Hambantota Districst

Black Beetle Life Cycle
Black Beetle Life Cycle
Black Beetle Life Cycle

Management of Plesispa Beetle

Plesispa Beetle attacks to coconut seedlings and young palms are found in coconut growing areas. Growers are advised to Spray one of the following insecticides at the given dosage.
Spray one of the following insecticides at the given dosage.
Carbosulfan 20 SC 3 ml/liter of water

Black Beetle Life Cycle

Stem bleeding disease and its control

Affected tissues should be removed with the knife up to healthy tissues and the wound should be treated with Bordeaux mixture or 1% copper fungicide available in the market. Bordeaux mixture.

Bordeaux mixture
Copper Sulphate 200 g
Quick lime 200 g
Water 25 l

Leaf Blight and its control

If disease occurs in non-fertilized lands, apply correct mixtures of fertilizer.
If disease occurs in fertilized lands, additional doses of Muriate of Potash (MOP), at six monthly intervals, when the soil is wet.

Seedlings/Young palms Adult palms Muriate of Potash (60%K2O)
Muriate of Potash (domestic) (60%K2O) 250g 500g
Kitchen Ash 5kg 10 Kg
If the disease is not corrected after the above treatments, Bordeaux mixture or any commercially available Copper fungicide could be used