Most Destructive Pest ‘Red Palm Weevil’ Strikes Coconut Palms in Mangaluru?

Most Destructive Pest ‘Red Palm Weevil’ Strikes Coconut Palms in Mangaluru?

Most Destructive Pest ‘Red Palm Weevil’ aka ‘Rhynchophorus ferrugineus’ strikes Coconut Palms in Mangaluru?

Mangaluru: Team Mangalorean received a call from K Krishnappa, a resident of a Housing Colony-Bondel, and an active environmentalist, who said, “I have never seen anything like this before. I have lost two coconut trees due to this peculiar kind of pest/worm which has destroyed my coconut trees. I have informed the officials at the Krishi Vigyan Kendra (KVK), Kankanady, Mangaluru, and they have agreed to come and inspect my place. It would be great if this is also highlighted in Mangalorean.com so that others would take precautions on their coconut trees”. Team Mangalorean agreed and here is what we learned from the officials of Krishi Vigyan Kendra. Krishnappa’s red palm weevil infested plot was visited by Rashmi.S, Subject Matter Specialist (SMS) -Plant protection) and Patil. R. S, SMS (Horticulture) from KVK, Mangaluru.

As per the recent survey by UN, it has stated that Red palm weevil is ‘global threat’ after spreading to 60 countries. Agricultural ministers have agreed on a plan to fight the red palm weevil which ravages coconut, date and oil palms, describing it as “a global threat”. The strategy includes greater involvement of farmers in combating the weevil, improved pest monitoring and a proposed ban on the import of palms larger than 6cm wide from infested countries.

                  LARVA                                                          ADULT

In some countries, farmers have already set up smartphone messaging app groups to share information and alerts, the U.N. Food and Agriculture Organization (FAO) said. The red weevil, which has few natural enemies, has spread to more than 60 countries from the Caribbean to southern Europe, according to the FAO which hosted a meeting of scientists, pest control experts, farmer representatives and government officials in Rome last month. An adult female can lay around 200-300 eggs in a palm and the resulting larvae munch their way through the tissue, destroying the tree from the inside.

The weevil, which has spread rapidly through the Middle East and North Africa in the last three decades, causes economic losses in the millions of dollars annually through lost production and pest control. It attacks 40 palm species, the most affected being the coconut palm, date palm and the tall ornamental Canary Island date palm. The FAO said measures to combat the pest should include training farmers, introducing regular inspections, using pheromone traps, tracking infestations, removing heavily infested trees and tightening quarantine controls. Farmers can regularly inspect trees to detect pests in the early stage of attack when a tree can still be saved, and carry out trapping and spraying.

Rashmi, giving elaborate details to Team Mangalorean on this ‘Red Palm Weevil’ stated- “The pest is distributed in India, Pakistan, Bangladesh, Sri Lanka, Malaysia, the Philippines and New Guinea. It’s one of the most destructive pests of coconut palm in Maharashtra, Assam, Kerala, Tamil Nadu, Karnataka, Andhra Pradesh and Orissa. It is also found on date palms. Mangaluru has not seen this pest for a while, but many parts of South Karnataka had coconut palms infected by these pests.”

“This weevil is reddish brown in colour, cylindrical, is having six dark spots on thorax with a long curved snout. The male has a tuft of hairs on the dorsal surface of the snout, whereas the female is without it. This weevil usually infests palms younger than twenty years. While the adult causes some damage through feeding, it is the burrowing of the larva into the heart of the palm that can cause the greatest mortality of trees. The adult female lays approximately two hundred eggs on new growth in the crown of the palm. They lay eggs in holes they produced while searching for food, or take advantage of the cracks or wounds in a recently cut palm.”

“At oviposition (to deposit or lay eggs, especially by means of an ovipositor), females bend upward and the tarsi are anchored to the tissue with the spines of the third pair of legs to push the ovipositor into the tough palm tissue. After laying, the female protects and secures the eggs with a secretion that rapidly hardens around the eggs. On average, females produce 210 eggs per clutch, most of which hatch over a period of 3 days. The eggs are white, cylindrical, glossy, oval shaped, and measure 1 to 2.5 mm. The back of these eggs possesses special ‘gill cover’ structures that provide the developing insect with oxygen. The egg hatches into a white, legless larva. The larva will feed on the soft fibers and terminal buds, tunnelling through the internal tissue of the tree for about a month. The larvae can occasionally grow to a length of six to seven centimeters. At pupation, the larva will leave the tree and form a cocoon built of dry palm fibers in leaf litter at the base of the tree. The total life cycle takes about 7–10 weeks”.

“Symptoms of infestation: The infestation of the pest can result in yellowing and wilting of palms that may lead to the death of the affected plant. The crown wilts first, and lower leaves will follow, due to damage to vascular tissue. Major symptoms such as crown loss or leaf wilt are usually only visible long after the palm has become infested. Secondary infections of opportunistic bacteria and fungi may occur within damaged tissues, accelerating the decline. By the time these external symptoms are observed, the damage is usually sufficient to kill the tree, and the infestation may have been present for six months or longer. In high-density infestations, sounds of the larvae burrowing and chewing can be heard by placing one’s ear to the trunk of the palm. Recent research has been conducted using electronic listening devices or dogs trained to recognise the scent of weevils or palm decay to detect infestations at low densities earlier in the process”.

Control measures:

– Practice clean cultivation by cutting and removing palms already damaged and the decaying stumps in the garden. Such palms should be split open and the different stages of pest inside burned off.

– Avoid injury to the trunk as the pest lay eggs in these wounds. While cutting leaves, retain at least 1m of the petiole.

– Use pheromone trap for attracting weevils and kill the collected ones.

– Fill the crown and the axils of top most three leaves with a mixture of fine sand and neem seed powder or neem seed kernel powder (2:1) once in three months to prevent the attack of rhinoceros beetle damage in which the red palm weevil lays eggs.

– Spray Neem oil or Chlorpyrifos 20 EC or Quinalphos 25 EC @ 2ml per liter of water. Plug the holes in damaged region and pour the insecticide suspension into a slanting hole made above the damaged portion using a funnel. Then plug this hole also. If needed repeat after one week.

If you need more information you can call: Miss Rashmi at 9008434151 or Office at 0824-2431872; Email: kvkdk@rediffmail.com