Evaluation for effect of natural products and salts on Achatina (Lissachatina) fulica Bowdich, 1822

Abstract

Abstract The mollusk Achatina fulica, commonly known as the giant African snail, is a terrestrial gastropod native to East Africa that is spreading worldwide because of its high adaptability and reproductive capacity. This invasive species causes agricultural damage, negatively affects biodiversity, and poses risks to public and veterinary health by acting as an intermediate host of nematodes such as Aelurostrongylus abstrusus and Angiostrongylus cantonensis, the latter of which are responsible for eosinophilic meningitis in humans. Conventional control methods include manual collection and the use of synthetic molluskicides such as carbamate pesticides and metaldehyde. However, environmental concerns related to these substances have encouraged the search for alternative control strategies, including natural products with molluskicidal potential. This study aimed to evaluate the effects of plant extracts, fractions, and commercial fertilizer salts on A. fulica. Bioassays were performed using niclosamide, coarse salt, fractions of Abelmoschus esculentus, and extracts of Piper nigrum through a spraying method. In addition, bait formulations were prepared using fertilizer salts with agricultural applications, including salts A (potassium chloride - KCl), B (potassium nitrate - KNO3), and C (calcium sulfate - CaSO4). The results indicate that the tested fractions of A. esculentus did not present molluskicidal activity against A. fulica. Extracts of P. nigrum resulted in 11% mortality under the conditions tested. Salts B and C were active at a concentration of 2000 mg/L in the spraying protocol, with the highest mortality rate (33.3%) observed for salt C at 50,000 mg/L. In the bait experiments, the formulations were not consumed and were buried in the substrate by the mollusks.