Assessments were made of fumigant and contact toxicities of 6 Myrtaceae plant essential oils (EOs) and their components against spotted wing drosophila (SWD), Drosophila suzukii (Matsumura) (Diptera: Drosophilidae). Median lethal dose (LD50;mg/L) values of Leptospermum citratum EO for fumigant activity were 2.39 and 3.24 for males and females, respectively. All tested EOs except Kunzea ambigua EO exhibited effective contact toxicity. LD50(μg/fly) values for contact toxicity of manuka and kanuka were 0.60 and 0.71, respectively, for males and 1.10 and 1.23, respectively, for females. β-Triketone fractions, composed of flavesone, isoleptospermone and leptospermone, exhibited efficient activity with the LD50 values of 0.13–0.37and0.22–0.57μg/fly for males and females, respective

Twelve Lamiaceae plant essential oils (EOs) and their components were evaluated for their fumigant and contact toxicities. Inhibition of AChE by the major components of active EOs was also assessed. Strong fumigant toxicity was observed from EOs of Mentha piperita and Perilla frutescens. Menthone and menthol, and perilla aldehyde were identified as major components of the above two EOs, respectively. The LC50 (mg/L) values of M. piperita, P. frutescens, menthone, menthol and perilla aldehyde were 3.87, 2.44, 5.76, 1.88, and 0.99 against male, and 4.10, 3.31, 5.13, 1.94, and 1.15 against female, respectively. Strong contact toxicity was observed from the EOs of Satureja montana and Thymus zygis. Thymol and carvacrol were major components of these two EOs. The LD50 (μg/fly) values for contact toxicity of S. montana, T. zygis, thymol and carvacrol were 2.95, 2.93, 1.63, and 1.30 for male, and 4.59, 5.09, 2.68, and 2.60 for female, respectively. Among the five major components, perilla aldehyde showed most active inhibition activity against AChE of both sexes of SWD.

Drosophila suzukii is an economically important pest of fruit in America and Europe as well as in Asia. Sparassol (1) and methyl orsellinate (2) are produced by Sparassis cripta and S. latifolia during culture. Fumigant and contact toxicities of synthetic sparassol (1) methyl orsellinate (2) and methyl 2,4-dimethoxy-6-methylbenzoate (DMB; 3) were investigated. The possible mode of action of the compounds was pursued by assessing their inhibition activities against acetylcholinesterase (AChE) and glutathione S-transferase (GST). Little or no fumigant activity was observed from tested compounds. In contact toxicity activity, LD50 (μg/fly) values are 5.29, 1.18, 0.02 for male, and 11.14, 2.27, 0.05 for female, respectively. In enzyme inhibition assay, DMB (3) which easily synthesized from sparassol could be an alternative agent for controlling insect pest. In addition, Sparassis species could be an industrial resource of sparassol.

Rapid growth in trade of agricultural products has increased the risk of introduction of exotic pests into new area. In order to fulfill quarantine obligations, several treatments are in practice: fumigation with methyl bromide (MB), application of extreme temperatures, controlled atmospheres, and combinations of them. Although MB was most effective and widely applied for quarantine treatment, its use was banned by the Montreal Protocol. Ionizing irradiation phytosanitary treatments – gamma radiation, electron beam, and X-ray are being used as an alternative to MB currently. For applying ionizing irradiation as a quarantine treatment, there is a research protocol which should be followed, International Standards for Phytosanitary Measure 18 [ISPM #18] and Phytosanitary Treatment Regulation of Korea (Notice 2014-35). We have evaluated the effect of gamma radiation, electron beam, and X-ray on H. armigera as quarantine treatments. In this presentation, ISPM #18 and Notice 2014-35 will be talked with the example of H. armigera.

Essential oils from 22 plant species were tested for their insecticidal activities against spotted wing drosophila (SWD), Drosophila suzukii Matsumura, using fumigation and contact bioassay. Responses varied with the essential oils, their constituents and concentrations. Strong fumigation activities were observed from the essential oils of wintergreen (Gaultheria fragrantissima), croton (Croton anisatum) and star anise (Illicium verum). Strong contact activities were observed in the essential oils of oriental sweetgum (Liquidambar orientalis), cassia (Cinnamomum cassia), damask rose (Rosa damascena) and sandalwood (Santalum album). The compositions of these selected essential oils were identified using gas chromatographymass spectrophotometer. The compounds identified were tested individually for their insecticidal activities against SWD. Responses varied by doses for each compound. The results showed that natural materials are as effective as synthetic pesticides.

Essential oils or phytochemicals that are naturally synthesized by plants have received much attention as alternative pest control strategy. They are composed of highly volatile compounds which are less toxic to human but highly toxic to pests such as insects, microorganisms and nematodes. Until now, many researchers have evaluated the toxicities of essential oils and phytochemicals in Korea. Among them some of essential oils are formulated as repellents against mosquitoes. However, even such a broad research, the mode of action of essential oils is still unclear. To develop more effective and environmental friendly natural pesticides and to help understand the mode of action of essential oils, we have investigated the structureactivity relationship (SAR) between the chemical components of bio-active essential oils and nematode as well as insect pests. SAR of short-chain aliphatic compounds and ester analogues and pine wood nematode, Brusaphelenchus xylophilus; and salicylate analogues and adzuki been weevil, Callosobruchus chinensis are discussed here.