Efficiency of monoterpene compounds for control of rice pest Pomacea canaliculata

Abstract

Pomacea canaliculata (golden apple snail) is one of the most destructive and invasive rice pests in Southeast Asia and Thailand. This work focused on the molluscicidal efficiency of thymol, eucalyptol, and linalool against P. canaliculata under laboratory conditions. All essential oils made the snail motionless, closed its operculum shell, turned the soft body at the spire reddish and typically caused death within 24 hr. The toxicity levels of P. canaliculata after being exposed to the three essential oil compounds were significantly (p < 0.05) different at both 24 hr and 48 hr, with thymol being the most effective control (dose required for 50% mortality after 24 hr = 20.7 mg/L). Snails treated with thymol seemed to relax before death, with some typically recovering within 48 hr. The percentage of egg hatching in the treatment group (28.89-48.84%) was significantly (p < 0.005) reduced compared to the control (87-88%), with thymol being the most effective inhibitor (percentage of egg hatching = 28.89%). Glutathione-s-transferase (GST) and acetylcholinesterase (AChE) activities were reduced after snails were exposed to all three compounds (p < 0.05; correlation factor approximately1.25-1.50-fold and 1.64-2.14-fold for GST and AChE, respectively). However, carboxylesterase reduced only linalool and thymol. The findings indicated that all three essential oil compounds were viable alternatives to chemicals for controlling P. canaliculata.

Chemical Profile, Bioactivity, and Biosafety Evaluations of Essential Oils and Main Terpenes of Two Plant Species against Trogoderma granarium

“…Herein, the monoterpenes in the EOs were potent insecticides. As previously established, the bioactivities of the EOs against insects might be correlated with their contents of monoterpenes with proven insecticidal bioactivities, such as eugenol, carvacrol, thymol, p-cymene, γ-terpinene, 1,8 cineol, terpinene-4-ol and carvone [6,10,26,47,48]. Among the monoterpenes in the thyme EO studied in the present study, carvacrol and thymol showed pronounced bioactivities against T. granarium.…”

“…Among the monoterpenes in the thyme EO studied in the present study, carvacrol and thymol showed pronounced bioactivities against T. granarium. These monoterpenes have received special attention in EO research, and they have been widely evaluated as pesticides against many pests, including those that infest stored grains [13,16,[47][48][49][50][51][52][53]. The insecticidal properties of carvacrol and thymol correlated with their abilities to cause disorganization in bio-membranes, leading to the loss of permeability [49].…”