Cassava (Manihot esculenta Crantz) - A future crop for harvesting insecticidal molecules against pests of horticultural crops
C.A. Jayaprakas, Sreerag, R.S., Ragesh, G., Jithu U Krishnan, Ajesh
ICAR-Central Tuber Crops Research Institute, India
Abstract: Synthetic pesticides have played a pivotal role in the modern agriculture; nevertheless, injudicious use of agro-chemicals created instability to ecosystem and environment. Undesirable effect of pesticide has created miseries to living beings; hence there has been a global drive to search for solution to replace synthetic pesticides with apposite alternatives in pest management strategies. Cassava, Manihot esculetna (Crantz), an important cyanogenic edible crop is cultivated extensively in tropical and subtropical countries for its tubers as food, feed and industrial products; but its leaves and tuber rinds are underutilised. In the present investigation, the insecticidal molecules were mechanically isolated from the cassava bio-waste in aqueous medium and formulated potent biopesticides against internationally important insect pests of horticultural crops.
Pseudostem weevil (Odoiporus longicollis Oliver), a monophagous pest of banana and plantain causes’ heavy damage to the crop. Farmers’ practice like injection of very toxic synthetic insecticides into banana pseudostem for the management of weevil is highly discouraged owing to health issues. In this context, the insecticidal molecules isolated from cassava leaves received commendable appreciation as the most befitting alternative to manage pseudostem weevil. A specialized applicator has also been developed for its trunk injection. Two more formulations developed were proved effective against sucking pests like mealybugs, aphids and thrips of common crops. Mealy substance covered over the mealybug acts like a shield to protect it from the penetration of insecticide. Ultra-structure and chemical composition of the mealy substance were studied and an appropriate bio formulation was developed to dissolve the mealy substance. A separate bio formulation was also made against aphids. Commonly used chemical insecticides were used to compare the efficacy of the bio formulations. Commercial scale production of the cassava based bio formulations was facilitated by the installation of an extraction plant.