Effects of Oleander Leaves (Nerium oleander) against Metabolism, Activity Pattern, and the Leaves Potency as Rice-Field Rat Repellent (Rattus argentiventer)

Abstract

Nerium oleander historically has been known worldwide as a poisonous plant that can be used to control pests. However, studies on the effects of oleander leaves against Rattus argentiventer as a major agricultural rodent pest are limited. This research aimed to probe the potency of oleander leaves extracted in methanol as a rice-field rat repellent. The experiments involved a choice test (T-maze arena) and a no-choice test (metabolic cage) that were analyzed by the T-test using three replications for 6 days. The results showed that the rats on the T-maze avoided consuming food and water near the oleander treatment. The same results occurred in the metabolic cage, which was indicated by a decrease in the average of food and feces, and also by an increase in the average of water and urine. Additionally, the treatment also caused a disruption in daily activity patterns, which was significantly indicated by an increase of 22.84% in average time for resting activities and a decrease in time for locomotion and nesting activities (by 9.71% and 13.13%, respectively). Overall, oleander leaves have the potential to provide a repellent effect against rice-field rats, especially in the choice test.