Two years after scientists from the National Bureau of Agricultural Insect Resources (NBAIR), released a tiny parasitic wasp Anagyrus lopezi into South India’s tapioca fields, the crop that once faced near devastation from an invasive pest is now thriving again.
About Anagyrus lopezi

• Anagyrus lopezi is a tiny parasitic wasp species native to Central and South America, which has been introduced as a biological control agent against the cassava mealybug (Phenacoccus manihoti), a pest that severely affects cassava/tapioca crops.
• The female wasp lays its eggs inside the mealybug, and the developing larvae consume the pest from within, naturally reducing its population without harming other insects or crops. This parasitic control method is self-sustaining once the wasp is introduced into an area.
• Originally deployed successfully in Africa in the 1980s, where it reduced mealybug populations by 80-90%, it has also been extensively used in Southeast Asia since 2010, including large-scale releases in Thailand and South India.
• In South India, after introduction in areas like Salem, Namakkal, and Dharmapuri districts in Tamil Nadu in 2022, cassava harvests rebounded dramatically within two years to pre-outbreak levels, restoring farmers' income and reducing the need for chemical pesticides.
• The wasps have been found to spread naturally up to 30-40 kilometers from release points, controlling the pest across large areas without further human intervention. The introduction has had significant positive ecological and economic impacts by protecting a major food and industrial crop while minimizing chemical pesticide use.

Key Facts about Tapioca (Cassava)

• It is a major horticulture crop cultivated in Tamil Nadu, Kerala, and Puducherry.
• It is cultivated throughout the tropical world for its tuberous roots, from which cassava flour, breads, tapioca, a laundry starch, and an alcoholic beverage are derived. 

Climatic Conditions Required for Tapioca

• Soil: Any well-drained soil, preferably red lateritic loamy soil.
• Climate: It thrives best in a tropical, warm, humid climate
• Rainfall: Well-distributed rainfall of over 100 cm per annum.
• This crop can be cultivated upto an elevation of 1000 m.

All parts of cassava/tapioca – leaves, stem, tuber and rind – contain the compounds called cyanogenic glucosides (CNGs).

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