Species diversity of grasshoppers in Kamrup district of Assam and their management by aqueous extracts of <i>Azadirachta indica</i> A. Juss and <i>Aegle marmelos</i> L.

Abstract

Grasshoppers pose a significant threat to agricultural productivity worldwide, causing substantial damage to various crops such as cereals, legumes, orchards, vegetables, grasslands, and forest plantations. This research aimed to study the species diversity of grasshoppers in five selected paddy field locations of Kamrup district, Assam, and assess the efficacy of aqueous extracts from the leaves of Azadirachta indica A. Juss (neem) and Aegle marmelos L. (bael) for controlling the most common grasshopper species, Acrida exaltata, found in the study locations. A total of 36 species of grasshoppers were collected and identified, out of which Acrididae was the most predominant grasshopper family, constituting 77.78% of the total collected species. The experimental results demonstrated abnormal changes in behaviour, including slower movement and increased inactivity among the aqueous extracts treated insects. Both the treated groups showed morphological and behavioural change with the more prominent effects observed from the neem-treated group. Haemolymph analysis revealed the presence of severe deformities in both treated groups, such as the spindle-shaped formation of cells, nuclear membrane disintegration, cell fusion and stacking, cytoplasmic vacuole formation, and cytoplasm degeneration. These findings demonstrate the pesticidal potential of neem and bael extracts against the Acrida exaltata grasshopper species, following its toxic impact on haematological, physiological, and morphological behaviour, suggesting the need for further research on their use as effective and environmentally friendly control measures against grasshopper pest infestations in densely vegetated and paddy fields in the region.