Mango Stone Weevil

📖 Description

Mango Stone Weevil (Sternochaetus mangiferae), also called Mango Nut Weevil or Mango Seed Weevil, is a serious quarantine pest of mango across the Indian subcontinent, particularly severe in the major mango-growing belts of Uttar Pradesh (Lucknow, Saharanpur), Andhra Pradesh (Krishna, Vijayanagaram), Telangana (Mahabubnagar, Rangareddy), Karnataka (Kolar, Bengaluru Rural), Tamil Nadu (Krishnagiri, Dharmapuri), Maharashtra (Ratnagiri, Konkan), Gujarat (Junagadh, Amreli), Bihar (Darbhanga, Muzaffarpur) and West Bengal (Malda, Murshidabad) where India is the world’s largest producer of mango (over 2.5 million hectares cultivated, producing over 20 million tonnes annually). The pest is particularly damaging because (a) the grubs feed inside the mango stone (seed) — the most protected plant part, completely destroying seed viability, (b) infested fruits show no external symptoms until cut open, making detection difficult and allowing the pest to enter the marketing chain undetected, (c) infested fruits develop off-flavour and reduced shelf life from secondary infection, (d) the pest is a major quarantine concern — many countries (USA, Australia, Japan, EU) prohibit import of mangoes from regions where this pest is established, severely limiting export opportunities, and (e) once a grub is inside the stone, no insecticide can reach it — control must focus on preventing egg-laying on young fruits. The pest is most severe in older orchards (over 15 years old) and in orchards with poor sanitation (where fallen fruits accumulate). IPM with weekly collection and destruction of fallen fruits (the single most effective control — kills larvae and pupae inside and breaks the lifecycle), winter raking and burning of soil debris under trees (kills overwintering adults), light trap monitoring of nocturnal adults, systemic insecticide sprays at marble stage (the only time when contact chemical control can work — the systemic insecticide reaches the egg-laying site before the grub enters the stone), fruit bagging for high-value fruits, and need-based insecticide rotation provides effective and sustainable control. The pest is a particular concern for export-oriented mango growers (India exports mangoes to USA, EU, Japan, UAE and other markets — but many of these markets prohibit import from regions where this pest is established, severely limiting export opportunities from infested areas).