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Status Of Pest & Disease Outbreaks In Southeast Asia And Application Of Threats From Emerging Pests & Diseases Of Coconut

Several insects were reported as coconut pests in Asia and the Pacific region. Among these pests, rhinoceros beetle or black beetle (Oryctes rhinoceros Linnaeus), red palm weevil (Rhynchophorus ferrugineas Olivier), coconut hispine beetle (Brontispa longissima (Gestro)), coconut black headed caterpillar (Opisina arenosella Walker) and coconut scale (Aspidiotus destructor Signoret) are currently causing severe damage to coconut palms in the region. Rhinoceros beetle is native to South Asia and Southeast Asia. Management of this pest is a combination of  sanitation in plantations and surrounding areas, and biological control by using Metarhizium anisopliae, Oryctes virus and pheromone trapping. Red palm weevil outbreaks usually occur after infestation of rhinoceros beetle. Keeping the rhinoceros under control also controlos the red palm weevil. Pheromone trapping was also developed for reduction of  this pest. Coconut hispine beetle is an invasive pest occurring in Southeast Asia and the Pacific region. Biological control of  the pest is recommended by releasing two species of  pcirasitoids, Asecodes hispinarus Boucek and Tetrastichus brontispae Ferriere. Coconut black headed caterpillar is one of the key pests o f coconut in South Asia and it invaded Thailand in 2008. In 2014, coconut black headed caterpillar outbreaks were observed in several locations, such as Haiko, Dhanzho and Sanya in Hainan. This insect is native to South Asia. Management of  the pest in its native region consisted of: 1) removing and burning infested leaves; 2) biological control by releasing parasitoids such as Goniozus nephantidis (Muesebeck), Bracon brevicornis (Wesmael) and Brachymeria nephantidis Gahan; and 3) chemical control by trunk injection and applying systemic insecticides in the holes. Bacillus thruringiensis has been recommended for biological control of the black headed caterpillar occurring in young coconut orchards in Thailand. Coconut scale, Aspidiotus destructor Signoret (Hemiptera: Diaspididae) has been reported as a serious in Philippines. Predators are significant biological control agents in limiting A. destructor populations. The most common natural enemies associated with the coconut scales are the coccinellid beetles Chilocorus spp., Azya trinitatis, Cryptognatha nodiceps, Rhyzobius lophanthae and Pentilia castanea. Local parasitoids, Comperiella, Aphytis and Encarsia also p lay important roles in keeping the pest under control. Application of  insecticides could induce the infestation of the scale. Biological controls is recommended for suppression of other coconut pests, such as slug caterpillars like Parasa lepida Cramer; coconut leaf moth, Artona catoxantha Hampton and coconut leafminer, Promecotheca cumingii Baly. Three important diseases were found infesting coconuts in Southeast asia. They are Cadang-cadang, bud rot, Brown leaf spot, gray leaf spot. Cadang-cadang is viroid disease fo r  which no control measure recommends. Management of  the important diseases usually recommends farmers to remove all affected tissue, apply Bordeaux paste on cut ends and provide a protective covering till normal shoot emerges. Fungicides such as Dithane are recommended against Brown leaf spot. Gray Leaf Spot was kept under control by removal burning and spraying with 1% Bordeaux mixture, applying higher dose of  potash (25% extra) along with recommended dose ofNPK.

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