Acaricidal Activity and Synergistic Effect of Thyme Oil Constituents against Carmine Spider Mite (Tetranychus Cinnabarinus (Boisduval))

Abstract

Studies examining the use of essential oils as replacements for synthetic insecticides require an understanding of the contribution of each constituent present, interactions among these components, and how they relate to overall toxicity. In the present study, the chemical composition of commercial thyme oil was identified by gas chromatography-mass spectrometry. Thyme oil and blends of its major constituents were tested for their acaricidal activitities against carmine spider mites (Tetranychus cinnabarinus (Boisduval)) using a slide-dip bioassay. Natural thyme oil showed greater toxicity than any single constituent or blend of constituents. Thymol was the most abundant component (34.4%), and also possessed the strongest acaricidal activity compared with other single constituents. When tested individually, four constituents (linalool, terpinene, p-cymene and carvacrol) also had activity, while α-pinene, benzoic acid and ethyl gallate had almost no activity. The toxicity of blends of selected constituents indicated a synergistic effect among the putatively active and inactive constituents, with the presence of all constituents necessary to reach the highest toxicity. The results indicated that thyme oil and some of its major constituents have the potential to be developed into botanical acaricides.

Synergistic terpene combinations as larvicides against the dengue vector Aedes aegypti Linn.

“…Hence, the joint actions of distinct binary mixtures of four terpenes were measured and ascertained the kinds of relations among them. According to Wu et al () and Abbassy et al () a CTF of +20 or more points to synergism, a value of −20 or less denotes antagonism, and values amid +20 and −20 mean an additive effect. Our study has shown that all the six binary combinations of four monoterpenes γ‐terpinene, R‐(+)‐limonene, carvacrol, and trans ‐anethole were exhibiting synergistic activity as the CTF was found to be > +20.…”

“…Hence, it is essential to know the type of chemical constituents contained in the EOs and their manner of action and their ratios and their mutual interactions (Pavela, ). The studies on the synergistic effect of the terpenes will be useful in two ways (Wu et al, ). First, this draw attention to the fact that the application of EOs as such as insect control agents will be more efficient than isolating the components for the same purpose and development of resistance can be curtailed by using the whole EO as such than purifying or chemical synthesis of their major constituents.…”

“…Hence, the joint actions of distinct binary mixtures of four terpenes were measured and ascertained the kinds of relations among them. According to Wu et al (2017) The presence of terpenes present in various proportions contributes towards the biological efficacy of EOs (Dias & Moraes, 2014).…”

“…Hence, it is essential to know the type of chemical constituents contained in the EOs and their manner of action and their ratios and their mutual interactions (Pavela, 2014). The studies on the synergistic effect of the terpenes will be useful in two ways (Wu et al, 2017).…”

A homoisoflavonoid and a fatty acid in common purslane (Portulaca oleracea L.) synergistically inhibit growth of Spodoptera litura larvae

“…This is an issue of social concern. Some studies found that essential oils had a more pronounced effect on pests compared with the effect of their major chemical component alone, because the oils showed antagonistic, additive, or synergistic effects in pest control . In this study, the effect between aliphatic acid and homoisoflavonoid destroyed the mid‐gut of S. litura more easily than other compounds singly (Fig.…”