Acaricidal and repellent activities of Litsea cubeba (Lour.) oil and 3,7-dimethyl-2,6-octadienal against Haemaphysalis longicornis (Acari: Ixodidae)

Jun-Hwan Park,Namhyun Chung,Hoi-Seon Lee

doi:10.1186/s13765-021-00662-x

Jun-Hwan Park, Namhyun Chung + Show 1 more

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https://doi.org/10.1186/s13765-021-00662-x

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Abstract

The bioactivity of the essential oil extracted from Litsea cubeba fruits against tick vectors of severe fever with thrombocytopenia syndrome is unknown. In this study, L. cubeba oil and its main constituents, 3,7-dimethyl-2,6-octadienal and its similar structures, were evaluated for their acaricidal and repellent activities on the unfed nymphs and adults of Haemaphysalis longicornis. L. cubeba oil displayed both acaricidal and repellent activities against both life stages. Among the constituents of L. cubeba oil, only 3,7-dimethyl-2,6-octadienal exhibited both acaricidal and repellent activities against both life stages. In a repellent bioassay, 3,7-dimethyl-2,6-octadienal and L. cubeba oil at dose of 0.08 mg/cm2 provided excellent repellence (100%) against the nymphs and adults for over 60 min post-application. When the acaricidal and repellent activities of 3,7-dimethyl-2,6-octadienal and its similar structures were compared, activities of all tested derivatives were significantly less potent than those of 3,7-dimethyl-2,6-octadienal. The strong acaricidal and repellent activities of 3,7-dimethyl-2,6-octadienal in L. cubeba oil suggests that it is a promising natural candidate for developing new sustainable acaricidal and repellent agents.

Highlights

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease that is clinically characterized by thrombocytopenia, gastrointestinal symptoms, and high fever [1]
Acaricidal toxicity and chemical composition of L. cubeba oil Acaricidal toxicity of L. cubeba oil was evaluated in H. longicornis unfed nymphs and adults using the nymphal and adult immersion tests, respectively (Table 1)
Thirteen constituents were identified in L. cubeba oil including 3,7-dimethyl-2,6-ctadienal (75.88%), (+)-limonene (10.44%), eucalyptol (3.70%), α-pinene (1.55%), and-β-pinene (1.02%)

Summary

Introduction

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease that is clinically characterized by thrombocytopenia, gastrointestinal symptoms, and high fever [1]. SFTS is caused by the SFTS virus, a member of the genus Phlebovirus (family Bunyaviridae), which was first discovered in China in 2009 and subsequently found in Japan and South Korea in 2013 [1,2,3]. The hard tick Haemaphysalis longicornis (Acari: Ixodidae), which is widely distributed in Japan, China, Korea, and Oceania [1, 2], is regarded as the primary vector of the SFTS virus [1, 2]. The incidence of SFTS is low in comparison to other tick-borne diseases, it remains a serious public health issue, causing widespread public concern in South Korea due to its high mortality rate.

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