An outbreak of stick insects, Ramulus mikado, as forest pests in South Korea has become a topic of concern. While other countries have reported these insects being severely affected by the entomopathogenic fungus Metarhizium spp., comprehensive research in South Korea remains limited on this topic. In our two-year investigation, we investigated the infection rate and mortality of R. mikado caused by Metarhizium anisopliae. In 2022, specimens were collected from Cheonggyesan, and in 2023 from Geumamsan. Although no infections were confirmed in the specimens collected in June of both years. Beginning in July, mortality and infection rates were greatly increased. In conclusion, the summer monsoon appears to create hot and humid conditions in the forest, contributing to reduced survival rates for these insects due to infection by M. anisopliae.

Females of adzuki bean beetle (ABB), Callosobruchus chinensis (L.), a cosmopolitan field-to-storage pest of legumes, release sex pheromone consisting of two isomeric components, 2Z-homofarnesal and 2E-homofarnesal. Two day old virgin ABB adults were exposed to sub-lethal fumigation doses (LC25=0.0056 and LC50=0.0076 mgL-1) of phosphine (PH3) to evaluate the effects on adult longevity, fertility and sex pheromone production. Longevity (female; P < 0.001, male; P < 0.001), fecundity (P < 0.001) and sterility (P < 0.001) were significantly affected. The GC-MS for solid phase micro extraction exhibited the significant reduction of release of both of the pheromone components; 2Z-homofarnesal (P < 0.0038) and 2E-homofarnesal (P = 0.0009) when the females were exposed to LC25 dose of PH3. This study unveils the detrimental effects of PH3 fumigation on some of the biological parameters of ABB.

본 연구에서는 피식자의 flash display와 크기에 따른 생존율을 확인하였다. Flash display는 생물체가 가지는 방어 기작 중의 하나로, 피식자가 포식자로부터 도망을 갈 때, 예를 들어, 개구리 다리 안쪽의 색이 몸 색과 다른 경우나, 속날개의 색이 겉날개의 색과 다른 경우(ex. 뒷날개나방) 포식자에게 시각적으로 큰 혼란을 주어 생존율을 높이는 방어 기작 이다. 이를 연구하기 위해 visual studio enterprise 6.0프로그램으로 피식자의 크기와 색을 변경 가능 하게한 시뮬레이션을 만든 후 사람을 포식자로 설정하여 일반인 총 120명, 연령대는 10~50대 중 후반을 대상으로 실험 하였다. 실험 결과로 flash display를 사용하는 피식자의 생존율이 그렇지 않은 피식자 보다 높을 것으로 예상 하였고, 크기는 작을수록 더욱 유리 할 것으로 예측 하였다. 조사 결과 피식자의 크기와 색이 생존율과 상관관계에 있다는 것과 flash display 효과가 피식자의 생존율을 더욱 높여주었음을 발견하였다. 또한 flash display의 색이 주변 환경(이번 실험에서는 녹색 계통의 풀숲을 사용하였다.)과 확실하게 다른 색(녹색 계통의 색이 아닌 색)을 띄는 개체의 생존율이 flash display를 사용하지 않은 개체 보다 월등히 높았음을 확인하였다. 이는 Flash display가 피식자의 생존율을 높이는 요인이라는 것을 시사하고 있다.

The soybean bug, Riptortus pedestris, is a polyphagous species and an important pest of soybean. We investigated the development periods and survivorship of R. pedestris egg and nymph stage. The study was conducted at eleven constant temperatures of 12, 14, 16, 18, 20, 24, 28, 32, 34, 35, and 36℃, respectively. Egg could not hatch under 14℃. Nymph could not develop to adult at 16℃. The lower developmental threshold (LDT) and thermal constant (K) of R. pedestris nymph stage were estimated by linear regression. Higher temperature threshold (TH) and lower temperature threshold (TL) were calculated by two nonlinear functions (Performance and SSI model). The adult emergence frequency of R. pedestris over full range of constant temperatures was simulated using developmental rate functions and Weibull function.

The small brown planthopper, Laodelphax striatellus, and the white backed planthopper, Sogatella furcifera, are important agricultural pests. L. striatellus could overwinter in Korean peninsula as nymph stage but S. furcifera could not. We investigated the survivorship and fecundity of two species for comparing population growth. The longevity and fecundity of two species were investigated at temperatures of 12.5, 15.0, 17.5, 20.0, 22.5, 25.0, 27.5, 30.0, 32.5, and 35.0℃. Adult longevity and fecundity of two species were significantly influenced by temperature. Longevities of L. striatellus were longer than those of S. furcifera at different temperatures. Specially, oviposition period of L. striatellus was twice as long as that of S. furcifera. Total fecundity per female of L. striatellus were also more than those of S. furcifera. The oviposition model of each species was consisted of three components - age specific survival rate, age specific oviposition rate and total fecundity per female. The relationship between adult developmental rate and temperatures was described by exponential function. The age specific survival rate and the age specific cumulative oviposition rate were explained by two parameter inversed-Weibull function and Weibull function. Temperature dependent fecundity was estimated using three parameter Gaussian function. Daily egg production of two species in relation to adult age and temperature was estimated.

In order to establish an indoor-rearing system for A. Alcinous, the effect of temperature and pupal diapause was investigated. Temperature has been suggested as an important factor in determining the developmental rate, Lifespan and mortality in invertebrates. As temperature increase, the developmental period was gradually reduced. The developmental period of A. alcinous larvae was 12.9 days and 25.8 days at 30℃ and 20℃, respectively. And we investigated the effect of different chilling days on diapause termination. Under longday condition(LD 16:8h, 20℃) oxygen consumption gradually increase. But oxygen consumption on the first day of pupa was the highest and rapidly fell down the next day and attained lowest point after 7days, with average value of 1.92mol/min/g under shortday condition(LD 8:16h). Diapause pupae were chilled for 60, 75, 90, 105 days at 8℃ and thereafter subjected to LD 16:8h at 25℃. And emergence rate at 60~90days was 57.1~80.7%.

This study was performed to compare the host preference, survivorship and feeding behavior using EPG against ggot-mae-mi, Lycorma delicatula against seven plants such as Ailanthus altissima, Vitis vinifera, Malus pumila, Pyrus calleryana, Hibiscus syriacus, and Pinus densiflora. In host preference. L. delicatula was most preferred the Ailanthus altissima, Vitis vinifera and was not preferred the other plants. Survival rate of 3rd Nymph was recorded from Ailanthus altissima, Vitis vinifera as 15.0, and 15.4 days, respectively, it showed longest period. However, Malus pumila, Pyrus calleryana, Hibiscus syriacus, were survived within 6 days and Pinus densiflora was within 5 days. Moreover, L. delicatula was survived within 2 days to the three kinds of fruits. Ecdysis rate from 3rd to 4th nymph also high from Ailanthus altissima, Vitis vinifera as 63.3, 63.0 % and the order was followed as Malus pumila(17.7%) > Pyrus calleryana(9.3%) > Hibiscus syriacus(7.8%) > Pinus densiflora(5.9%). Especially, ecdysis rate was recorded 0% to the three kinds of fruits. Feeding behavior was analyzed using EPG and compared the differences their waveform from seven kinds of plants and three kinds of fruits. Non-probing time was short in host plants, reversely, Phloem-feeding time was recorded longer in Ailanthus altissima, Vitis vinifera as 45.7 and 13.7 min, respectively. And other plants and fruits were not showed feeding behavior.

To isolate plant insecticidal factors, a series of survivorship tests were conducted using artificial diets mixed with seed extract of a mungbean variety (Vigna radiata), which gave a high mortality to the bean bug, Riptortus clavatus. Seed flour was extracted with methanol and ethanol solutions, and then the crude extract was first fractionated with layers of ether, n-butanol and water in solvent/solvent partition. Layers of ether and n-butanol fractions showed insecticidal effects to the bean bug, respectively. The n-butanol fraction was further isolated with several fractions on a reversed-phase column chromatography, and its 100% methanol fraction showed a high insecticidal effect. The fraction was further isolated on a normal-phase column chromatography, and the 70% methanol fraction showed the highest insecticidal effect. The final fraction was analyzed and fractionated on a reversed-phase HPLC. The active isolates were almost insoluble in any organic solvents and did not show any absorption in ultra-violet and visible light wavelength range. On the other hand, the ether fraction of crude extract was isolated on a normal phase column chromatography, and its hexane fraction showed the activity. The hexane fraction was further isolated on a reversed-phase HPLC and tested for the survivorship of the bean bug.