Introduction

Although poisoning by DEET (active ingredient of the most common commercial repellents) and D-limonene are rare events, it is known that these two substances may be toxic. The absorption of high concentrations of DEET (N, N-diethyl-m-toluamide) can have neurotoxic effect and even be lethal (1,2,3,4,5). D-limonene, if ingested in high concentrations may also cause death (6). Therefore, we conducted a simple test to compare the effect of the two substances on beans development (Phaseolus vulgaris, Fabaceae).

Methods

In order to reduce fungal contamination, water and cotton used in the experiment were sterilized by autoclaving. Beans seeds were immersed in 2.7% hypochlorite and then in 70% ethanol (5 minutes for each solution). The seeds were divided into 5 groups (corresponding to five different treatments), each containing 16 individuals. Each seed was placed on a piece of cotton inside a plastic cup. The groups were placed on a bench in order to receive the same illumination.

All seeds initially received 2 mL of water. Treatments were initiated after 24 hours. The following treatments were administered every 24 hours:

Analysis of results

Beans development At the end of the experiment, all individuals in each group were measured, as seen below: There was a significant difference between the growth of limonene and control groups compared to the group receiving DEET.