A native minute pirate bug, Orius minutus (L.), is a generalist predator of small insect pests such as thrips, mites, scale, etc. By comparing with Tetranychus urticae Koch in choice test, we evaluated the prey preference by counting number of prey killed for 4 hours on Amphitetranychus vienensis (Zacher), Frankliniella intonsa (Trybom), Stephanitis pyrioides Scott, and Eriococcus sp. nymph. Among them F. intonsa was the only one killed more than T. urticae by O. minutus. In no choice test, mean number of prey killed was highest in F. intonsa (7.2) followed by T. urticae (3.0), A. vienensis (2.4), Eriococcus sp. (2.0), and S. pyrioides (0.0) for 4 hours. This experiment shows that O. minutus could be a good predator for F. intonsa and T. urticae.

Orius spp. (Heteroptera: Anthocoridae) prey on small arthropods such as aphids, thrips, whitefly, and mites both in greenhouse and field. Use of chemical attractants to natural enemies can improve the efficacy of biological control through push-pull strategy. We compared attractiveness of three synthetic herbivore-induced plant volatiles (HIPVs), i.e., nonanal, methyl anthranilate, and methyl salicylate for thrips natural enemies, O. laevigatus (Fieber) and O. minutus (L.), in Y-tube olfactometer. Mated unfed adult females of O. laevigatus showed higher choice rate to methyl anthranilate or methyl salicylate than nonanal. Orius minutus showed higher choice rate to methyl anthranilate than methyl salicylate or nonanal. These results suggest that, among the three HIPVs, methyl anthranilate can be used for the attractant of both O. laevigatus and O. minutus.

The hawthorn spider mite, Amphitetranychus viennensis (Zacher), is an important tetranychid causing damage on fruittrees and woody ornamental plants. We investigated the effect of a mycoinsecticide BotaniGard® ES at different humiditylevels on the eggs and adults mortality of A. viennensis. In a laboratory condition, egg mortality was significantly influencedby the conidial concentration and RHs. Highest mortality of eggs was observed at 1×108 conidia/ml with 95% RH thanother conditions. In 1×108 conidia/ml, LT50 at 95 and 75% RH were significantly different from 55% RH. In BotaniGard®spray in cherry plants, mites decreased on day 6 at all the concentrations, but the mite populations rebounded exceptin 1×109 conidia/ml where it maintained 0 until 9 days after spraying. It is therefore concluded that B. bassiana hasa potential to be used against A. viennensis

As a broad-spectrum insecticide azadirachtin may cause acute toxicity and alter behavior of natural enemies. We evaluatedthe toxicity of azadirachtin on two egg parasitoids of Riptortus pedestris (Fabricius) (Hemiptera: Alydidae), Ooencyrtusnezarae Ishii (Hymenoptera: Encyrtidae) and Gryon japonicum (Ashmead) (Hymenoptera: Platygastridae), by pre-treatinghost eggs with five concentrations, i.e., 15, 10, 7.5, 5, and 2.5 mL/L. Azadirachtin significantly reduced parasitism byG. japonicum in 15 and 10 mL/L concentrations than other lower concentrations. Similar effect was also observed inO. nezarae. The parasitism reduction capacity (R) for G. japonicum was 40.8 and 33.1% in 15 and 10 mL/L concentrations,but it was 81.6 and 71.4% in O. nezarae, respectively. Based on the IOBC guideline, azadirachtin can be slightly ormoderately harmful to O. nezarae and slightly harmful or harmless to G. japonicum.

Frankliniella intonsa (Trybom) (Thysanoptera: Thripidae) is an important pest in protected culture. We assessed fourrepellents (carvacrol, cis-jasmone, methyl jasmonate, and methyl salicylate) of Frankliniella occidentalis (Pergande)(Thysanoptera: Thripidae) known from literatures to develop a behavioral management tactic against F. intonsa. We measuredthe repellency of F. intonsa that exposed to 100 times diluted repellents on leaf disc. Repellency was 2.60 times higherin methyl jasmonate followed by methyl salicylate (2.16 times), cis-jasmone (2.15 times) and carvacrol (2.08 times) comparedto control. These results suggest that methyl jasmonate can be incorporated as a component of integrated managementof F. intonsa.

Orius minutus (L.) (Hemiptera: Anthocoridae) is a native predators of soft body insects such as mites, thrips, and aphids.We compared 24 h consumption rate of O. minutus with that of a commercialized O. laevigatus (Fieber) on egg andadult stage of Tetranychus urticae Koch (Acari: Tetranychidae). Orius minutus predated 1.4 times more adult T. urticae(58 mites) in 24 h than O. laevigatus. Similarly, O. minutus consumed 128 eggs while O. laevigatus consumed 98 eggsin 24 h without statistical difference. These results suggest that native O. minutus can be applied for the augmentativebiological control after the development of mass-rearing method.

Oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae), is an important pest for both stone and pomefruits. In a previous study, we selected four best plant extracts [Nicotiana tabacum L., Allium sativum L., Zanthoxylumpiperitum (L.) DC., and Sapindus mukorossi Gaertn.] against first instar larva, and here we evaluated them against adultstage (<5 d old) in laboratory. N. tabacum applied at 2 mg/ml showed highest corrected mortality of 85 and 100% infemale and male, respectively, within 168 h of exposure. Combined spray of N. tabacum and A. sativum showed LT50of 103.5 and 63.9 h on female and male, respectively. We also evaluated the deterrent effect of the plant extracts onovipositioning, and found that female laid less egg (29) on N. tabacum treated twigs at the concentration of 4 mg/twig.Thus N. tabacum can be a potential botanical insecticide against G. molesta.

Frankliniella intonsa (Trybom) (Thysanoptera: Thripididae) is an important pest of field and greenhouse crops such as pepper and strawberry. Chemical attractants are commonly used for monitoring thrips, but few are available for F. intonsa. Thus, we evaluated three attractants of Frankliniella occidentalis known from literatures for their attraction of F. intonsa in Y-tube olfactometer. Fed unmated adult females of F. intonsa showed higher initial response to (S)-(−)-verbenone than other attractants, i.e. aggregation pheromone of F. occidentalis and methyl isonicotinate. Unfed mated adult females of F. intonsa showed similar initial response. These results suggest that (S)-(−)-verbenone also can be used for monitoring and further in behavioral control tactics of F. intonsa.

Spodoptera exigua (Hübner) is an important pest with wide host range including cabbage, beans, potato etc. We evaluate the virulence of Beauveria bassiana ARP14, B. bassiana GHA, and Isaria japonica with concentration of 1×108 conidia/mL against larval stage of S. exigua using glass scintillation vial. Lethal median time (LT50) of these three fungi was not found significantly different in both fourth and second instar. Infection rate was higher in fourth instar than second instar. Infection rate was highest by B. bassiana ARP14 (84.0%) followed by B. bassiana GHA (63.6%) and I. japonica (45.8%) in fourth instars of S. exigua. Our results suggest that B. bassiana ARP14 can be a new component of integrated pest management of S. exigua.

Negative effects of insecticides on non-target organism can be reduced by using selective and less toxic insecticides. We assessed the effect of subsequent application of flonicamid and Beauveria bassiana GHA on pests and natural enemies in soybean fields by recording their density in 6-8 d interval. Flonicamid controlled Aphis glycines Matsumura in 6 day after spray (DAS). Nymphs of Riptortus pedestris (F.) were also reduced by 46 and 48% in 12 and 19 DAS, respectively. Application of B. bassiana reduced R. pedestris nymph 50% in 16 DAS whereas adult R. pedestris, Medythia nigrobilineata Motschulsky and A. glycines were not significantly reduced in treated fields. Ladybird beetles, syrphid flies, hymenopteran wasps, and parasitism rate of R. pedestris eggs were not different between the treatment and control. These results suggest that flonicamid and B. bassiana showed less negative effect on the natural enemies and effective against aphids and nymphs stage of R. pedestris.

An entomopathogenic fungus, Beauveria bassiana ARP14, was isolated from field collected Riptortus pedestris (F.). Lethal concentration of ARP14 was compared with commercialized GHA strain against R. pedestris and its egg parasitoids Ooencyrtus nezarae Ishii and Gryon japonicum (Ashmead). Mortality and infection rate were evaluated in five concentrations, i.e., 1×10 9 , 1×10 8 , 1×10 7 , 1×10 6 , and 1×10 5 conidia/mL using glass scintillation vial. The LC50 of 2nd, 4th instar, and adult stage of R. pedestris was not different between the two strains. The infection rate of ARP14 was higher than that of GHA in 4th instar and adult stage in 1×10 8 conidia/mL. The infection rate was low in ARP14 than GHA in both egg parasitoids. Therefore, our results suggest that the ARP14 strain can be used against R. pedestris with less negative effect on egg parasitoids than GHA strain.

Riptortus pedestris (Fabricius) is one of major soybean pests in Korea. Its feeding during pod formation period significantly reduces the yield of soybean. Management tactics commonly used include insecticide such as etofenprox and aggregation pheromone trap, but they have been often found ineffective. As an alternative methods, parasitoids such as Gryon japonicum (Ashmead) and Ooencyrtus nezarae Ishii could be conserved by directly releasing non-viable host eggs in the field, by incorporating the non-viable host eggs into aggregation pheromone trap, by planting a trap crop of natural enemies, or by combining selective insecticides with a trap crop of natural enemies. I present study results of these tactics with discussion here.

Virulence of six entomopathogenic fungi was assessed against the 1st instar larva (<5 h old) of oriental fruit moth Grapholita molesta (Busck) in laboratory which is considered as an important pest for stone fruits. Three strains of Beauveria bassiana and each strain of Metarhizium robertsii, Metarhizium bruneum, and Isaria farinosa were evaluated with the concentration of 1×108 conidia/mL at 95.9% RH and 25.4°C by glass scintillation vial assay. Among all, two strains of B. bassiana, ARP14 (87.5%) and A (unpublished) (72.7%), showed highest virulence with 9.8 and 12.6 h of LT50 within 16 h of exposure. However, B. bassiana A showed highest infection rate of 90.0% compare to ARP14 (70.0%) after 14 days. From these results, the two strains of B. bassiana, ARP14 and A, can be used for the control of G. molesta.

Oriental fruit moth Grapholita molesta (Busck) (Lepidoptera: Tortricidae) is an important pest for stone fruits like apple, peach, pear etc. Growers usually depend on chemical insecticides to control this pest, but it causes problems like resistance, pest resurgence, and health hazard. Although various plant extracts have been known to be potential against other lepidopterans, their effectiveness against oriental fruit moth has rarely been studied. So, we evaluated toxicity of 28 methanolic plant extracts known from previous literatures in the laboratory condition. Residual toxicity against 1st instar larvae (<5 h old) were examined using glass scintillation vial method at the concentration of 2 mg/ml. Among the tested botanicals Nicotiana tabacum L. was most effective and showed 92% mortality within 20 h and LT50 value was 12.9 h followed by Allium sativum L., Zanthoxylum piperitum (L.), and Sapindus mukorossi Gaerten. which showed 88, 70, and 65% mortality within 20 h, respectively. Rhododendron micranthum Turcz., Humulus japonicus Seibold & Zucc., Nerium indicum Mill., and other extracts showed least effectiveness on 1st instar larvae of oriental fruit moth. Hence, we suggest N. tabacum, A. sativum, Z. piperitum, and S, mukorossi as botanicals to be used against oriental fruit moth.

Information on spatial distribution and peak occurrence is important for site and time specific pest management. So, we investigated seasonal occurrence and edge distribution of major soybean pests by visual count in six commercial fields located in Andong from July 16 to October 23 in 2015. We found a total of 19 species in 10 families. The major pest during vegetative stage was Medythia nigrobilineata (Motschulsky) while Riptortus pedestris (Fabricius) and Halyomorpha halys (Stal) showed peak occurrence during reproductive stage of soybean. Aphis glycines Matsumura was found throughout the season. Seasonal density of M. nigrobilineata was 0.20 and 0.38/plant in edge and interior without significance, respectively. The infestation of A. glycine was also found similar between edge and interior. Immatures of R. pedestris and H. halys distributed more in edge (0.21 and 0.36/plant) than interior (0.12 and 0.12/plant), respectively. The application of these informations on spatial distribution pattern of soybean pest was discussed.

A mycoinsecticide, Beauveria bassiana (strain GHA) marketed as BotaniGard® ES, was evaluated as a biological control agent against Riptortus pedestris (Fabricius) (Hemiptera: Alydidae) a major soybean pest. It was tested on commercial soybean fields with one time spray of both high (1×109) and medium (1×108spore/ml) concentration and double spray of the medium concentration. Nymph population decreased in all treated fields regardless of dose and frequency of spray. But, adult and egg populations were not affected. Alive nymphs collected from the fields and kept in laboratory showed infection rate ranging 35-68% in treated plots while 0% in control plots. It also reduced damage on soybean pods and seeds by 17.7-21.2 and 18.0-22.5% compare to control, respectively. Additionally, B. bassiana reduced other pests found in soybean fields including brown marmorated stink bug Halyomorpha halys (Stål) and two striped leaf beetle Medythia nigrobilineata Motschulsky. Also there was no negative effect on the parasitism of released non-viable eggs of R. pedestris. These results suggest that, in field condition, one time spraying of B. bassiana in the concentration of 1×108spore/ml can help reducing crop damage as well as R. pedestris nymph population.

Riptortus pedestris (F.) (Hemiptera: Alydidae) is an important pest of soybeans in Korea and Japan. A synthetic aggregation pheromone trap has been commercialized and used in soybean fields in Korea for both monitoring and mass-capture of this bug. As the trap’s efficacy in reducing the pest population or crop damage is unknown, in this study we evaluated the aggregation pheromone trap in experimental soybean fields located in Andong National University. Two treatments, one with traps deployed for the entire cultivation period and one with no traps, were tested in six small experimental fields. The total numbers of R. pedestris (in all life stages) in soybean field were not significantly different between the treatments until August. But, in presence of pheromone, the pest’s abundance increased significantly in September and October. Relative to the size of the bug population in the field, trap catch rate was low during the fall (when bug density was highest) and high in early summer when the field population was very low. Placement of aggregation traps in plots caused pod and seed damage from R. pedestris to increase 2.7 and 2.2 times compared to the control. In conclusion, R. pedestris populations increased significantly during the fall in the presence of the aggregation pheromone trap, which should therefore be used with great caution whether as a control measure or as a monitoring tool.

Lethal concentration of Beauveria bassiana (Strain GHA, Botanigard, Arysta LifeScience) against Riptortus pedestris (F.) (Hemiptera: Alydidae) was compared with that of its’ parasitoid Ooencyrtus nezarae Ishii (Hymenoptera: Encyrtidae). Five concentrations of the mycoinsecticide, i.e., 5×108, 1×108, 2×107, 4×106, and 8×105 conidia/ml, were used. Glass scintillation vial was coated with 100 μl solution, and insects were released and assessed up to 12 hours. The LC50 and LC20 of second instar R. pedestris were 1.8×1010 and 1.5×108 conidia/ml, and those of O. nezarae were 1.9×107 and 2.8×106 conidia/ml, respectively. The mortality of O. nezarae was observed 3.9 times higher than R. pedestris in higher concentration. This result shows that O. nezarae is more susceptible to the mycoinsecticide than R. pedestris.

The western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), has been considered as a major thrips species after its invasion in 1993 in Korea although recently F. intonsa (Trybom) was found as a dominant species locally. To explain their asymmetrical abundance in the field, we hypothesized differential insecticide susceptibility of both thrips species as an underlying mechanism. Laboratory assays were conducted to know their susceptibility to different pesticides including chlorfenapyr, chlorpyrifos, thiamethoxam, spinosad, s-metolachlor, and metalaxyl by direct spray, residue, and oral ingestion. Results showed that both thrips species were highly susceptible to chlorfenapyr and mortality reached 100% within 12 hours in F. occidentalis in all the assays while 9 hours in F. intonsa in direct spray and residual assays. The LT50[h] values of tested insecticides were significantly lower than that of herbicide or fungicide regardless of exposure methods except metalaxyl from direct spray. The insecticides tested here differed considerably in species specific toxicity, and F. intonsa is generally more susceptible to the insecticides irrespective of exposure methods.

Frankliniella occidentalis (Pergande) is an anthophilus pest of many greenhouse and field crops worldwide. We compared the influence of constant (27.3ºC) and fluctuating temperatures (23.8 to 31.5ºC, with an average of 27.3ºC) on the life table characteristics of F. occidentalis held at a 16:8 h L:D photoperiod and 45 ± 5% RH. The development times from egg to adult of F. occidentalis were significantly affected by temperature fluctuation and sex. Survival of immature life stages was higher under fluctuating than constant temperature. Total first instar larvae/female was not significantly different (58.7 at constant and 60.5 at fluctuating temperatures) but daily production of first instars was higher in constant temperature than fluctuating temperatures (3.3 at constant temperature and 3.1 at fluctuating temperatures). The off-spring sex ratio was not significantly different between constant and fluctuating temperatures. The intrinsic rate of natural increase (rm), net reproductive rate (R0), finite rate of increase (λ), mean generation time (tG), and doubling time (tD) were affected significantly by fluctuation of temperature. The intrinsic rate of natural increase of F. occidentalis was higher in constant temperature (0.1808) than did in fluctuation of temperatures (0.1733). Thus, this study show that variable temperatures influence population growth rates of F. occidentalis.