Inventory of Important Insect Pests, Diseases and the Beneficial Insects in Fruits and Vegetables in West Central Bhutan

Ugyen Dorji, Kinley Dorji & Azusa Fujiie


Bhutan, an agrarian country gearing towards food self-sufficiency and food security is challenged by pests and diseases in crops. New pests emerge on old crops or known pests become adapted to new crops as a result of climatic change. These shifting in crop insectpests, pathogens and their hosts range result in outbreaks and crop losses which results in food insecurity. Pest outbreaks and crop losses can be addressed through integrated insect pests and diseases management specific to local environment. However, the comprehensive knowledge on occurrence and habitat range of beneficial and harmful organisms required for development of integrated pests and disease management is limited in the country. Therefore, we conducted the survey to monitor and inventorize the occurrence of major insect pests and diseases in fruit trees and vegetables, and their natural enemies in the west central Bhutan.

The Chinese citrus fruit fly (Bactrocera minax Enderlein), trunk borer (Anoplophora versteegi Rits.) and citrus leaf miner (Phyllocnistis citrella Stainton) were the three important insect pests of citrus while Huanglongbing was the important disease of citrus crops in the west central Bhutan. Mango fruits in the region were infested by two insect pests i.e., trunk borer (Batocera rufomaculata Dejan) and Oriental fruit fly (Bactrocera dorsalis Hendel). Grapes were infested by the leaf beetle (Scelodonta strigicollis). Insect pests of chilli were solanum fruit fly (Bactrocera latifrons Hendel) and armyworm (Mythimnia separate Walker.) while phytopthora blight (Phytopthora capcisi) was its major disease. The bean pod borer (Muruca vitrata Fabricius) and armyworm were the two major insect pests of beans in west central Bhutan. The important natural enemies observed during the study period were ladybird beetles (Coccinellidae), assassin bugs (Family: Reduviidae), parasitic wasps (Family: Braconidae), dragon flies (Order: Odonate), spiders (Order: Araneae), mantis (Family: Mantidae), hoverflies (Family: Syrphidae) and big-eyed bug (Family: Geocoridae). The first hand information from this study confirmed the occurrence of the insect pests and diseases of major fruit and vegetable crops grown in the west central Bhutan.

Keywords: Chinese citrus fruit fly, Oriental fruit fly, Trunk borers, Bean pod borer, Natural enemy

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