Fumigation of fruits and vegetables during quarantine and pre-shipment (QPS) treatment should be effective with a shorter fumigation time to minimize phytotoxicity. In this research study, a shorter fumigation time, 2 hours exposure which is shorter than that of the current commercial fumigation procedures using a lower dose of ethyl formate (EF) mixed with phosphine (PH3) on strawberry was investigated. The reciprocal effect between EF and PH3 against nymphs and adult Myzus persicae (Sulzer) and Tetranychus urticae (Koch) was evaluated. In addition, L(Ct)50 and L(Ct)99 of EF only and EF mixed with PH3 were analyzed at 5°C and 20°C. The synergistic ratio (SR) of L(Ct)50 and L(Ct)99 for the nymph and adult stages of M. persicae were >1.0, which indicated a synergistic effect between EF and PH3. However, the SR values of L(Ct)50 and L(Ct)99 of the nymph and adult stages of T. urticae were ≤1.0 indicating that there was no synergistic effect between the two fumigants against T. urticae. Our results showed that the reciprocal effect between EF and PH3 has different effects on M. persicae and T. urticae. This could be attributed to the biological and physical differences between the class Arachnida and Insecta. The synergistic effect between EF and PH3 against M. persicae within a shorter exposure period and without phytotoxicity on fruits and vegetables will significantly benefit the horticultural industry.

This study investigated the fumigant activity of phosphine (PH3) on 2 kinds of mealybug (Pseudococcus longispinus and P. orchidicola (Hemiptera: Pseudococcidae)) adults and nymphs. All of the two mealybugs adults showed higher LCT99 values than nymphs, and P. longispinus showed higher tolerance than P. orchidicola in a 12 L desiccator. The absorption of phosphine on 13 nursery plants showed 12.2~41.5% difference depending on the plant. All of the mealybugs treated with phosphine 2 mg/L in 0.5 m3 fumigation chamber for 4 h showed 100% fumigant activity, except P. longispinus adult (approximately 90% at bottom part). However, when the exposure time was increased to 24 h, all of them showed 100% mortality. In the treatment of 10 m3 container, the 24 h treatment of phosphine showed 100% mortality to P. longispinus and P. orchidicola adults and nymphs. In all the experiments, no phytotoxicity of phosphine observed on 13 plants until 1 month after treatment.

A combination using phosphine (PH3) and ethyl formate (EF) was performed to compensate for the disadventages (long exposure time and phytotoxicity) of a single substance. P. longisipinus was more susceptible to mixed phosphine and ethyl formate than P. orchidicola in 12 L dessicator. Mortality of mixed treatment was higher than aggregated mortalities that treated individually, so it indicated to have a synergic effect on each other. Ethyl formate was showed higher adsorption rate than phosphine on imported nursery plants and showed differences depending on the plant. P. longispinus and P. orchidicola was showed 100% mortality when phosphine and ethyl formate was treated as 1 g/m3 and 30 g/m3 for 4 hour in 0.5 m3 fumigation chamber and in 10 m3 container. Phytotoxicity was evaluated to mixture of phosphine and ethyl formate at 1 month after treatment.

The nematode Bursaphelenchus xylophilus and its vector insect Monochamus alternatus are major quarantine pests of timber products in Korea. Due to the phaseout of methyl bromide as a fumigant for plant quarantine and pre-shipment treatments, the need for an alternative fumigant is essential. Based on preliminary studies on the efficacy of ethanedinitrile (C2N2) to these two pests, three quarantine trials on logs covered with PVC-tarpaulins were conducted at three dosages and three temperatures potential for inhalation exposure was assessed by monitoring atmospheric levels of C2N2 in relation to the threshold limit value (TLV, 10 ppm, v/v). Concentration × time products (Ct) of 398.6, 547.2 and 595.9 g h m-3 were obtained for each quarantine trial. A 100% mortality of B. xylophilus and M. alternatus larvae at 23±4°C and 10±4°C occurred with a load factor of pine logs of 46% and at 3±1°C with a load factor of 30%. During all fumigant procedures, atmospheric levels of C2N2 20m downwind from the PVC tarpaulin were below the TLV. During aeration, levels 10 m and 5 m downwind were below the TLV after a maximum of 0.4 h and 1 h, respectively. For the purpose of an emergent quarantine or phytosanitary treatment, specific doses of C2N2 at the temperatures that occurred during fumigation could control B. xylophilus and M. alternatus larvae without significant inhalation risk to workers.

Ethyl formate (EF), a methyl bromide alternative fumigant which is commercially used for quarantine and pre-shipment(QPS) purpose, has a potential to control various insect pests. Based on CTP (concentration × time products), we've firstly evaluated fumigation trials of EF on cucumber plants to eradicate horticultural insect pests in greenhouse. In the preliminary test, EF achieved 100% control of cotton aphid, western flower thrip and tobacco whitefly when CTP of EF was 4.4, 5.6 and 3.3 g h m-3, respectively. In 1300m3 scale cucumber greenhouse trial, EF was applied with 2g m-3 dosage for 15 hrs, and cotton aphid, western flower thrip and tobacco whitefly were completely controlled without phytotoxic symptom. EF fumigation could be suitable for greenhouse cultivation in terms of good efficacy on horticultural insect pests with labor-saving benefit than current insecticide spraying applications.

Exportation of sweet persimmon has been grown up recently, but the growth was accumulated because of quarantine and shelf life issues. Herein, we've investigated the concurrent processing of ethyl formate (EtF), a MeBr alternative quarantine fumigant, and 1-methylcyclopropene (1-MCP), an anti-ethylene compound, on sweet persimmon and suggested proper fumigation methods. An important quarantine pest, Tetranychus urticae, was inoculated on sweet persimmon, and then 70 g m-3 of ethyl formate has been fumigated for 6 h before and after 1 ppm of 1-MCP treatment for 24 h at 5°C condition. These concurrent processing showed the promise that efficacy of EtF was enough to meet quarantine guideline and shelf life of fruits was extended in terms of the hardness, surface color and sugar contents when treated fruits were stored for four weeks at 5°C.

Methyl bromide (MB) fumigation is still allowed to use in quarantine treatment on imported timbers and logs, even though IPPC(International Plant Protection Convention) was strongly recommended to reduce their use in case of existing alternatives. A newly developing MB alternative fumigant, ethanedinitrile (EDN), showed the potential in terms of better efficacy to various timber pests and penetration into the timber than MB. Herein, for suggestion of quarantine guideline in Korea, we had verified the efficacies under different temperature conditions(5, 5-15, >15℃) and monitored TLV(Threshold limited value) of EDN post-fumigation for worker safety. The 6 scheduled doses of EDN depending on types of timber pest and temperature conditions had evaluated with PVC-Tarp tent(>100m3) with 40-50% loading factors of imported logs. To control normal wood related pests such as Japanese termite (Reticulitermes speratus) and bark beetle(Cryphalus fulvus), the scheduled doses 30, 40 and 40 g/m3 for 24hr fumigations showed >99% efficacy at 5, 5-15 and >15℃, respectively. The scheduled doses 100, 120 and 150 g/m3 for 24hr fumigations was also successful to gain the proved efficacies at 5, 5-15, >15℃, respectively, for the quarantine guideline to notorious wood related pests such as Japanese pine sawyer (Monochamus alternatus) and pine wilt nematode (Bursaphelenchus xylophilus). The recommended ventilation times with atmospheric conditions at ports was > 1 and > 2 hr under the fully uncovered and partially uncovered of fumigation tent conditions, respectively.

With the increasing trend of global trades and protection of agro-ecosystem in importing and exporting countries, quarantine and pre-shipment(QPS) fumigation for perishable commodities are critical in terms of quality maintenance of fumigated commodities as well as eradicating quarantine pest. There are limited use of methyl bromide(MB) fumigation on fruits and vegetables due to not only worker safety issue at low temperature condition but phytotoxic damage to valuable commodities. We are here presented that commercial development of methyl bromide (MB) alternatives such as ethyl formate and phosphine gas formulated with carbon dioxide, that are increasing consumer and worker safety and avoiding phytotoxic damage in routine MB fumigation.

Methyl Bromide (MB) has been regulated by montreal protocol due to ozone depletion since 1992, and there is a need to develop MB alternative fumigation methods. To find out the efficacies and tolerance in developmental stages of citrus mealybugs (Planococcus citri) which frequently infested in imported pineapples, phosphine(PH3) gas was tested in different exposure times (2~24 hr) and concentrations (0.1∼2g/m3) in small desiccators at 8℃. Based on Lethal 99% concentration × time products (LCTP 99%) of PH3 gas to target developmental insect, 2g/m3 PH3 was applied for 24 hr in 300 m3 fumigation facility, which was designed in well sealed and evacuation system (5 air exchange/min). We monitored PH3 gas in fumigation facility to confirm CTP and checked PH3 gas in atmospheres in air ventiliation process after fumigations to make quarantine guideline and protocol for worker safety as well as efficacy to target pest.

Methyl bromide(MB) is a fumigant for quarantine and pre-shipment(QPS) that can eradicate target pests within short fumigation periods. However, MB, an ozone-depleting substance, is scheduled to be phased out in the second decade of this century. In contrast to MB alternatives for soil fumigation, there is no ideal alternative fumigant to MB for QPS of perishable commodities. It is important that all target insect pests are killed within a short fumigation time. The citrus mealybug(Planococcuscitri), a problematicquarantine pest from Korea, was exposed to ethyl formate and phosphine for different times and to different concentrations of EF(0.0∼33.4 mg/L) and PH3(0.25∼1.0 mg/L) in small desiccators. The eggs showed more tolerance than the nymphs and adults. To control the eggs, they were treated with a mixture of EF and PH3 for 2 and 4-hr. The egg stage showed 100% mortality with EF:PH3(25.1:0.25, 16.7:0.5, and 16.7:1.0 mg/L) at 4-hr. Treatment with a mixture of EF and PH3 for 4-hr at 8°C can control all stages of the citrus mealybug.

Aphids are common pests frequently found in imported and exported fruits and vegetables. Methyl bromide(MB), a Quarantine and Pre Shipment(QPS) fumigant, could offer eradication of aphids within short period. However, MB is limited in use because of poor gas evaporation at low temperature(<5℃) and there is phytotoxic effect or damage on quality in post-harvest vegetables and fruits even at >5℃. Two candidates of MB alternative, ethyl formate(EF) and phosphine(PH3), are used and being investig at edonvarious fruits and vegetables fumigation to replace MB. Aphids are known as quarantine pest that are hard to control when conduct short period fumigation with PH3 and low dosage of EF. In this paper, dose response assessment of EF and PH3 are presented for three different aphid pecies : cotton aphid(Aphisgossypii), green peach aphid(Myzuspersicae) and turnip aphid (Lipaphiserysimi). The LCt99% values of EF at room temp. and low temp. (5℃) were 4.42 and 4.45 g·h·m-3 for cotton aphid, 3.23 and 5.58 g·h·m-3 for turnip aphid, 3.23 and 5.58 g·h·m-3 for green peach aphid when 2-hours fumigation. PH3 showed 0% efficacy on all species when 2-hours fumigation.

Methyl bromide (MB), as a fumigant for Quarantine and Pre-Shipment(QPS) could offer eradication of target pests within shorter fumigation period and without phytotoxicity. Therefore, unlike MB alternatives for soil fumigation, there is no ideally MB alternative fumigant for QPS purpose, particularly for perishable commodities. It is critically important that within shorter fumigation time requires killing all target insect pests and without effect of quality and deliver treated fruit and vegetables to the final consumer. The citrus mealybug(Planococcuscitri), problem quarantine pest, was tested with different exposure times(2 and 4-hours) and concentrations(EF(0-200 g/m3) and PH3(10-50 g/m3)) in small desiccators for mixture tests. On sensitivity test with small desiccator, the egg stage showed 100% mortality with 200/25(EF/PH3) g/m3 and the nymph and adult stage showed 100% mortality with 10/10(EF/PH3) g/m3 on 2h. Also, the egg stage showed 100% mortality with 150/25(EF/PH3) g/m3on 4h.

The fumigant activity of phosphine (PH3) and ethyl formate (EF) was determined to all stage of Phthorimaea operculella (Zeller) under high oxygen concentration (50% and 80%). Oxygenated PH3 and EF were tested at two different temperatures (20°C and 4°C) during 7 days. Two oxygenated fumigants were treated with LC10, 30 and 50 values of single fumigant against each stage of P. operculella. At 10% inhibition of hatchability concentration value, inhibition of hatchability of P. operculella eggs was shown 20.3% and 9.2% with 50% and 80% oxygenated PH3 at 20°C at 1 day after treatment, respectively. The fumigant activity of oxygenated PH3 was increased at all stage of P. operculella except eggs both 20°C and 4°C. However, oxygenated EF was determined low fumigant efficacy to hatchability of eggs and emergence rate of pupae. The insecticidal activities of P. operculella larvae and adults were slightly increased mortality rather than single EF. In this result suggests that oxygenated phosphine is effective method for managing P. operculella. But, oxygenated EF is not effective.

We elucidate the mechanism for inducing the production of ovicidal benzyl benzoate by Japonica rice varieties to kill eggs of the whitebacked planthopper, Sogatellafurcifera(Horváth), lying in the rice plant. Even when subjected to physical damage by a needle or damage with water, the rice plant produced no benzyl benzoate. However, significant benzyl benzoate was produced when the plant was damaged with a methanol extract or homogenate of S.furcifera. The extract of the male did not induce the production of benzyl benzoate, but that of the female did. We concluded from these results that benzyl benzoate was induced by some elicitor(s) in the female of S.furcifera.

From the methanol crude extracts of the tree of heaven (Ailanthus altissima) leaves, the antifeedant substance was isolated and bioassayed with different concentrations against diamondback moth (Plutella xylostella) larvae. The antifeeding activity was evaluated by measuring the feeding area during 24 hr after inoculation. Methanol extracts showing antifeeding activity at 5000 ppm was subsequently fractionated into hexane, chloroform, ethyl acetate and water layer. Third larvae of diamondback moth was tested to each fraction layer. Chloroform layer shows the highest antifeeding activity and the layer was purified by silica gel open column chromatography. The C22 and C23 fractions showed higher antifeeding ratio with 96 and 86%, respectively, and then these two fractions were re-isolated by ODS open column chromatography. As a result, both fractions in methanol 40% (v/v) showed antifeeding ratio over 90%. The C221 fraction showed insecticidal activity in all fraction, however, C231 fraction was showed the antifeeding activity only in C2311 fraction. The C2311 fraction judging to have antifeeding activity was re-isolated and purified by HPLC and recycling, and finally obtained the bioactive substances (C23111) with antifeeding ratio with 88%. The structure of bioactive materials isolated was confirmed by LC-mass and 1H-NMR(500 MHz), 13C-NMR(100 MHz).

This study was performed to investigate the antifeeding activity of Perilla frutescens extracts against diamondback moth, Plutella xylostella larvae and to confirm the electrophysiological responses of two sensilla (LST=lateral styloconic sensillum, MST=medial styloconic sensillum) in maxilla galea, a chemoreceptor. Crude extract of P. frutescens in methanol was showed antifeeding activity approximately 70%, and subsequently separated into four fractions - n-hexane(H), chloroform(C), ethylacetate(E), and water(W). Antifeeding activity was only showed in n-Hexane fraction around 99%. H1, H2, H3, H4, H5 were isolated from n-Hexane fraction using an open column chromatography, and the bioassay showed strongest antifeeding activity in H1 fraction. Using an oscilloscope, electrophysiological responses of two sensilla showed more seven times activity in MST. H11, H12, H13, H14 were separated from H1 fraction and antifeeding activity was showed highest in H11 fraction. H11 fraction was examined electrophysiological responses at doses of 100, 10, and 1 ppm, and MST of P. xylostella responded at a dose of 100 ppm. H11 fraction was separated using HPLC and identified using GC/MS and NMR. Finally, the structure of active compound proved to be farnesene with molecular weight of 204, and a formula of C15H24

On the development and reproduction of four major agricultural insect pests including B. tabaci, M. persicae, P. xylostella and T. urticae, electron-beam was irradiated with different doses of 30, 50, 70, and 100 Gy. The effect of electron beam was investigated with respect to the longevity, egg hatching, emergence, and fecundity. Eggs hatching of B. tabaci, P. xylostella and T. urticae were more inhibited as increased irradiation doses. Especially B. tabaci and T. urticae eggs were perfectly inhibited to hatch at a dose of 100 Gy. However, these pests showed no lethal effect on the nymph/larva, pupa, and adult stages. When irradiated on the eggs of B. tabaci, P. xylostella and T. urticae, the emergence was inhibited from nymphs/larvae to adults. Individually, B. tabaci emerged adult did not lay eggs at a dose of 70 Gy. Besides, fecundity of P. xylostella emerged adult decreased at a dose of 100 Gy. On the contrary, irradiation did not affect the longevity of P. xylostella adult. When irradiated on B. tabaci, P. xylostella, Myzus persicae and T. urticae nymphs/larvae, emergence was inhibited at doses of 70 and 100 Gy, and decreased the fecundity and inhibited the hatching of laid eggs. However, the longevity of adults did not affect

This study was performed to investigate attraction effect of six plant essential oils and to confirm their electrophysiological response against Lycorma delicatula. Among the tested oils, spearmint oil (94.1%) significantly attracted L. delicatula at a dose of 1.25㎕/cm2 by using an olfactometer. In dose response to spearmint oil, a dose of 2.5㎕/cm2 was very effective. GC-MS analysis revealed that the active components responsible for the effective attraction effect of spearmint oil were carvone (70.6%) and limonene (54.8%). Of the two active components, carvone was more significant than limonene with reference to attraction activity against L. delicatula. Analysis by GC-EAD showed, major components of spearmint oil that elicited response in L. delicatula antennae, indicating the potential role of the essential oil as attractant that determine the choice of the attraction material. In the field test, spearmint oil exhibited attraction effect up to 5 days. This effect was different in accordance with test places and treatment dose.