The fumigation toxicity of carbonyl sulfide to T. castaneum as a storage grain pest was evaluated. Carbonyl sulfide (COS) is registered in Australia for microorganism present in soil, root and fertilizer. the fumigation activity of carbonyl sulfide was investigated in 12 L desiccator for 24 h exposure to eggs, larvae, pupae, adults of T. castaneum. Eggs and pupae were showed 87.3% and 95.6% mortality for 25 mg/L of COS, respectively. Larvae and adults were investigated with 80.0% and 100.0% mortality at 15 mg/L treatment, respectively. Therefore, the eggs of T. castaneum showed the highest tolerance to COS.

The fumigation activity of phosphine (PH3) to T. castaneum as a storage grain pest was evaluated. The lethal concentration time (LCT) value of each developmental stage (egg, early larva, late larva, pupa and adult) of T. castaneum was analyzed in 12 L desiccator. At the T. castaneum larva stages, exposure for 4 h showed low LCT value, especially in early stage larvae (LCT99 = 0.32 mg·h/L) which is very high susceptibility to PH3. However, T. castaneum eggs were observed very high tolerance to PH3 at LCT99 77.47 mg·h/L. Therefore, the fumigant activity of PH3 against T. castaneum can be found to be significantly different depending on developmental stage.

The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), is one of the most important pest species, because it devastates many horticultural and ornamental crops and fruit trees. The resistance ratios calculated for the LC50 value in acequinocyl- and pyridaben-resistant strain was 4,237- and 5,555-fold higher than that of the susceptible strain, respectively. The objective of this study was to evaluate the cross-resistance to several acaricides and to identify the mechanisms associated with acequinocyl- and pyridaben-resistant strain of T. urticae.

Mosquitoes are the most important medical species by transmitting some of deadly infectious diseases to human. Established vector control methods involving the elimination of larval habitats, the use of physical barriers, or those involving insecticides are not sufficient to maintain the populations of these species below the epidemic risk threshold. The sterile insect technique (SIT) is a species-specific, non-polluting and environmentally benevolent method of insect control. This technique involves the release of massive numbers of artificially-reared sterile male insects that, due to their abundance, outcompete fertile wild males for mating opportunities with wild female insects. In this study we discuss optimization of the sterilization process and present a simple model and procedure for determining the optimum dose.

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.

Whitefly (Hemiptera: Aleyrodidae) pests, including the tobacco whitefly, Bemisia tabaci, and the greenhouse whitefly, Trialeurodes vaporariorum, are economically important in agriculture. With the annual growth of the domestic fresh fruit export market, various quarantine treatment methods are being used to export strawberries of better quality. The objective of the present study was to evaluate the effects of gamma rays on the development and reproductive sterility of B. tabaci and T. vaporariorum. In both species, the eggs were completely inhibited from hatching at 50 Gy, and the emergence of 3rd instar nymphs was completely suppressed at 150 Gy. Some adult B. tabaci and T. vaporariorum spawning occurred at 100 Gy and 70 Gy, respectively; however, at these irradiation levels, F1 hatchability was completely inhibited. Dosimetry results showed that the penetrating power of gamma ray in the strawberry-filled box was the lowest at the mid-box position. Therefore, B. tabaci and T. vaporariorum were placed in the middle of the strawberry-filled box and irradiated. A gamma-ray irradiation of 100 Gy suppressed the development and reproduction of eggs and adults in both B. tabaci and T. vaporariorum. However, the development of 3rd instar nymphs was inhibited at 300 Gy for B. tabaci and 200 Gy for T. vaporariorum. Our data suggest that at least 300 Gy should be used for the control of these two types of whitefly for strawberry export.

Acaricidal activities of 63 commecial pesticides against the longhorned tick, H. logicornis were investigated. Twenty-two pesticides (4 cabamates, 5 organophophates, 9 pyrethroids, 1 octopamine receptor agonists, 1 diamides, and 1 unknown) against adults H. logicornis showed >80% mortalities after 72 h of treatment. The residual effect of 22 pesticides was investigated at 1, 2, 3, 7, and 10 day intervals on grass for H. logicornis adults and nymphs. Eight and twenty pesticides in H. logicornis adults and nymphs showed >80% acaricidal activity at 3 days after the treatment, respectively. 7 days after the treatment, H. logicornis adults showed <60% acaricidal activity in all pesticides, but 7 pesticides (benfuracarb, gamma cyhalothrin, cypermethrin, lammda cyhalothrin, fenvalerate, cyantraniliprole, fluxametamide) showed >80% acaricidal activity in nymphs. all pesticides exhibited <60% acaricidal activity after 10 days of treatment both adults and mymphs, except benfuracarb showed 96.7% mortality in H. logicornis nymph.

This study investigated number of eggs, hatch rate, toxicities and LT (lethal time) values of Culex pipiens and Aedes albopictus using Aquatain™(Aqua mosquito film). Aquatain™ is a covering agent applied on the surface of water for the control of larva and pupa of mosquito. It forms molecule layer on the surface of the water to lower the surface tension of the water, to prevent flooding of the larva of the mosquito larvae, or to suffocate by obstructing breathing. Cx. pipiens and Ae. albopictus larvae observed 99.9% and 1% larvicidal effect after 24h, respectively. However, both mosquito pupae were showed 100% mortality after 24 h. The AMF™ was treated with three doses (0.5, 1, 2 folds) to observe the LT value in larvae and pupae stages of Cx. pipiens and Ae. albopictus. The LT values of Ae. albopictus pupa was similar regardless of dose, but the LT value of Cx. pipiens pupa decreased as the dose increased. However, Ae. albopictus larvae showed 18.6 folds longer LT90 time than Cx. pipiens larvae. Both species mosquito showed statistically significant differences in the number of eggs laid and hatch rate at recommended dose. Therefore, Aquatain AMF™ may be used to control mosquitoes, although the activity varies depending on the species of mosquito.

The two-spotted spider mite, Tetranychus urticae, is a worldwide agricultural pest that invades a wide range of host crops and rapidly develops resistance to pesticides. T. urticae can be resistant to one acaricide or exhibit multiple resistances or cross resistance to various other acaricides. Acequinocyl inhibits respiration in mitochondria at the ubiquinol oxidation site (Q0) of Complex III of the electron transfer chain. Pyridaben is a METI acaricide that inhibits mitochondrial electron transport at complex I. In this study, we investigated the cross resistance to seven acaricides in acequinocyl- and pyridaben-resistant strain. Furthermore, the frequencies of the I256V and N321S mutations in mitochondrial cytochrome b (cytb) of pyridaben-resistant and fieldcollected strain was analyzed.

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 green peach aphid, Myzus persicae Sülzer, is an important sap-sucking pest of many plants, including Chinese cabbage. The objective of this study was therefore (1) to determine the effects of sublethal concentrations of afidopyropen, sulfoxaflor, and spirotetramat on adult longevity and the fecundity of M. persicae, and (2) to study the feeding behavior of M. persicae on Chinese cabbage leaves treated with various concentrations of these three insecticides. Longevity and total fecundity of M. persicae adults were decreased at concentrations higher than LC30. Feeding behavior analyses using an electrical penetration graph showed that sublethal concentrations of afidopyropen, sulfoxaflor, and spirotetramat had significant effects on the duration of phloem ingestion.

The susceptibility of Dermanyssus gallinae adults, collected from poultry farms in 5 regions, to 11 acaricides was investigated. When bifenthrin and formic acid with pyridaben were diluted 100 times, bifenthrin showed 100% acaricidal activity; however, formic acid with pyridaben showed less than 20% acaricidal activity for poultry farms in 3 regions (Gyeongju, Chilgok, and Geumsan) except Yeoncheon and Anseong. Clothianidin, thiamethoxam, fenitrothion, and formic acid with pyridaben showed differences in acaricidal activity among regions. Therefore, farmers should concentrate during the selection of these acaricides. However, carbaryl, cartap hydrochloride, dichlorvos, and bifenthrin showed high activity against D. gallinae collected from poultry farms in five regions. To control D. gallinae effectively, the alternation of acaricides is necessary, and indiscriminate pesticide use should be avoided. Therefore, this study can serve as a basis for controlling D. gallinae.

The acaricidal activity of a methanolic extract and fractions from the rhizome of Cnidium officinale against Dermanyssus gallinae adults was investigated. The C. officinale methanolic extract exhibited 100% acaricidal activity after 48 h of treatment at a dose of 4,000 ppm. Gas chromatography–mass spectrometry and nuclear magnetic resonance spectroscopy revealed (Z)-ligustilide as a constituent of C. officinale. Acaricidal activity was examined in three experimental tests (spray, fumigation and contact), with the spraying method being the most effective. The methanolic extract of C. officinale showed both contact and fumigant activities, though only fumigant activity was observed with (Z)-ligustilide. These results suggest that C. officinale derived material can be used for the development of a control agent for D. gallinae.

The effect of the ionization energy on the common house mosquito, Culex pipiens, pupa was investigated as the hatching rate, longevity and detoxification enzyme activity. The longevity of adult emerging in the pupa decreased depending on the exposure dose of Gray (Gy) in Cx. pipiens. The hatching rate of the F1 generation egg derived from Cx. pipiens pupa treated up to 70 Gy did not show any difference with the control, but the eggs did not hatch 100% at 120 Gy exposure. These results showed that Cx. pipiens was sterilized at 120 Gy. Several detoxifying enzyme (GST, non-specific esterase and MFO) activity of Cx. pipiens adult emerged from pupa irradiated with 120 Gy was investigated. The difference in activity was observed in female than in male irradiated with electron beam. As a result, electron beam irradiation seems to affect enzyme activity as well as induce infertility of Cx. pipiens.

The present study evaluated the susceptibility of field populations of Plutella xylostella and Spodoptera exigua larvae to four diamide insecticides—chlorantraniliprole, cyantraniliprole, cyclaniliprole, and flubendiamide. All the four diamide insecticides induced 100% mortality in the populations from Seongju (SJ) and Geochang (GC) when treated at a concentration recommended for P. xylostella. However, a very low insecticidal activity was observed in the population from Pyeongchang (PC) with 42.3% 3 d after treatment with chlorantraniliprole. Further, the populations of S. exigua from Cheongju (CJ), Jindo (JD), and Yeonggwang (YG) were not completely controlled by the 4 diamide insecticides. A comparison of susceptibility of S. exigua larvae to chlorantraniliprole between 2014 and 2017 showed that chlorantraniliprole induced 100% mortality in all populations in 2014, whereas a very low insecticidal activity was observed among the populations in 2017. This study can serve as a basis to control pests effectively using diamide insecticides.

The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), is one of the most important pest species devastating many horticultural and ornamental crops and fruit trees. In the present study, a field strain was collected in January 2001 and has been selected for sixteen years with acequinocyl. The resistance ratio calculated from the LC50 of eggs and adults was 191- and 4,237-fold, respectively. The laboratory-selected acequinocyl resistance (LSAR16) strain was screened with 11 acaricides for cross-resistance. The detoxifying enzyme activities and quantitative real-time PCR analysis were performed in the LSAR16 strain. Crossing experiments revealed that LSAR16 strain was inherited maternally, incompletely dominant and monogenic. Most importantly, we identified two new point-mutations at mitochondrial cytb from acequinocyl resistant T. urticae.

The susceptibility of the Frankliniella occidentalis and Frankliniella intonsa was evaluated using 46 commercial insecticides. There were 10 kinds of insecticides as benfuracarb, chlorfenapyr, spinetoram, spinosad, abamectin + chlorfenapyr, abamectin + emamectin benzoate, chlorfenapyr + clothianidin, chlorfenapyr + imidacloprid, clothianidin + spinetoram and dinotefuran + spinetoram, which showed more than 90% mortality against both thrips, F. occidentalis and F. intonsa. Since the F. intonsa is more susceptible than F. occidentalis, it is considered that both thrips can be controlled by insecticides that show insecticidal activity on the F. occidentalis. The effect by the elapsed time after treatment of 10 kinds of insecticides was analyzed as LT50 and LT95 values. Benfuracarb was the fastest in 4.3 h (LT50) and 14 h (LT95), and spinetoram showed the most late time at 13.5 h (LT50) and 62.3 h (LT95), respectively.

Fumigation activity of Frankliniella occidentalis, western flower thrips, and phytotoxicity were evaluated with phosphine(PH3) and ethyl formate (EF) in the asparagus. Fumigation activity of PH3 and EF showed in the order of egg (64.7 mg·h/Land 132.9 mg·h/L), nymph (5.5 mg·h/L and 14.8 mg·h/L), and adult (3.8 mg·h/L and 14.7 mg·h/L) respectively at 5˚C in12 L desiccator. The adsorption of PH3 was 24% at 5˚C. However, the adsorption of EF increased sharply to 98% at 5˚C.PH3 showed 100% control for all development stage of F. occidentalis with 4g/m3 in 0.65m3 at 2˚C for 48h exposure. Thephytotoxicity was not found. The results revealed that the EF is highly absorbable in asparagus, so it is not suitable as afumigant, but PH3 is considered to be suitable as an alternative MB fumigant for control of the F. occidentalis in asparagus.

Pseudococcus orchidicola and Pseudococcus longispinus, a notorious cosmopolitan pest species of mealybugs, known to be distributed indoors in Korea. The effect of temperature on the development of P. orchidicola and P. longispinus was studied. The duration of nymphal period of the two mealybugs at 24 and 28℃ have been recorded. Developmental duration of P. longispinus was longer than P. orchidicola in both females and males. The adult longevity was estimated to 74.9 and 91.1 days at 24℃ for P. orchidicola and P. longispinus, respectively. The average fecundity per female was greater at 28℃. The survival of P. orchidicola and P. longispinus during winter at outdoor was failed.

Ethyl formate (EF) and phosphine (PH3) is an alternative fumigant to methyl bromide (MB). For applying import sweet pumpkins in Korea, the efficacy of EF and PH3 was evaluated on Tetranychus urticae adult and egg stage which is pest in sweet pumpkins. The eggs of T. urticae were more tolerance than adults in both EF and PH3. When T. urticae eggs were treated with EF for 4 hrs, LCT99=107.63 mg/L and LCT99=45.37 mg/L at 5°C and 20°C, respectively. PH3 treatment at 5°C and 20°C for 24 hrs, eggs were controlled LCT99=49.44 mg/L and LCT99=17.23 mg/L, respectively. The mixed treatment of EF and PH3 showed no significant synergistic effect on T. urticae. However, EF (80 mg/L) and PH3 (4 mg/L) treatment did not cause any external phytotoxicity damages in sweet pumpkin even when treated with the maximum amount of fumigant at 5℃ and 20℃ for 24hrs.