To investigate the temperature-dependent development of Spodoptera litura, experiments were conducted at five constant temperatures: 15, 20, 25, 30, and 35±1°C, with 60±5% relative humidity and a light/dark cycle of 16L : 8D. Daily observations were made of the egg, larval, pupal, and adult stages. The total developmental periods recorded were 182.0 days at 15°C, 78.2 days at 20°C, 46.2 days at 25°C, 34.3 days at 30°C, and 30.0 days at 35°C, indicating that higher temperatures accelerate development across the egg, larval, and pupal stages. Linear model analysis estimated the lower developmental threshold and thermal constant for the total immature period to be 11.0°C and 714.3 degree-days (DD), respectively. Nonlinear models provided estimates for the optimal developmental temperatures for the total period: 35.3°C for the Briere 1 model, 35.4°C for the Briere 2 model, 34.5°C for the Lactin 1 model, 33.8°C for the Lactin 2 model, 35.3°C for the Taylor model, and 34.2°C for the Logan6 model. Additionally, the developmental completion distribution was effectively described by a 3-parameter Weibull function, achieving a goodness of fit (R 2) of 0.81. Adult longevity was longest at 20°C, averaging 23.5 days for males and 21.0 days for females, while the shortest longevity was observed at 30°C, with males living an average of 10.2 days and females 9.7 days.

The present study was undertaken to ascertain the temperature development characteristics of Phthorimaea operculella (Lepidoptera: Gelechiidae) across its various developmental stages. To this end, the insect was subjected to six constant temperature conditions (13, 17, 25, 27, 32, 34±1°C), relative humidity (RH) levels of 65±5%, and photoperiods of 16 : 8 h light/dark. The developmental time of larvae was longest at 13°C, and as the temperature increased up to 35°C, the developmental time tended to become shorter. At the pupal stage, all individuals developing at 13°C perished and were excluded from the calculation of the development period for the development model. To ascertain the relationship between temperature and development, a regression model was employed for analysis. The lower threshold temperature of the total immature stage was determined to be 9.4°C, and the thermal constant was found to be 454.5DD. In the analysis of the temperature-development experiment, the Lactin 2 model exhibited an optimal fit (R 2=0.90-0.98) for the total immature stage of P. operculella.

Dysmicoccus brevipes (Cockerell), Dysmicoccus neobrevipes Beardsley and Pseudococcus longispinus (Targioni-Tozzetti) are widely-distributed pests that feeds on many economically important hosts, particularly tropical fruits and ornamentals. The potential distribution of these mealybug pests into South Korea remains a primary concern because of their high incidence in interceptions screened during inspection. Hence, these species prompted a modelling effort to assess their potential risk of introduction. Potential risk maps were developed for these pests with the CLIMEX model based on occurrence records under environmental data. The potential distribution of these pests in South Korea in the 2020s, 2050s and 2090s was projected based on the RCP 8.5 climate change scenario. Results show that D. brevipes, D. neobrevipes and P. longispinus have little potential for invasion in the exterior environment of South Korea due to high cold stress in the 2020s. However, for D. brevipes and P. longispinus, 3 and 86 locations in Jejudo, were predicted to be marginally suitable for this pest under future climate factors, respectively. In that respect, the results of these model predictions could be used to prepare a risk-based surveying program that improves the probability of detecting early D. brevipe, D. neobrevipes and P. longispinus populations.

미국선녀벌레는 2009년 발견이후 현재 131개 시군에 15,730ha가 발생되고 있다. 주로 단감 등 10여종 이상의 작물을 흡즙하여 피해를 준다. 2017년 이탈리아 파도바 대학에서 천적인 선녀벌레집게벌(Neodryinus typhlocybae)을 도입하여 국립농업과학원에서 생태특성 조사, 대량사육 기술개발 및 미국선녀벌레 발생 현장에 방사하고 있다. 선녀벌레집게벌은 미국선녀벌레 어린약충(1~3령)에 기생하면 암컷의 비율이 낮고 수컷은 2화 성 개체가 많아져 생산이 비효율적이다. 본 연구에서 어린약충에 기생할 때 보다 노숙약충에 기생할 경우 3배정 도 암컷생산의 비율이 높아졌고, 월동하고 있는 고치들을 5월 중순 무렵에 20℃의 서늘한 곳에 보관하면 우화시 기를 상온에 놓아둔 것에 비해 10일 이상 늦추는 결과를 얻었다.

During the larval development process of insects, juvenile hormone (JH) is essential for regulating various aspects of larval life, including growth, reproduction, and behavior, throughout their larval stage. The larval stage of Spodoptera frugiperda, when it consumes plant-derived metabolites, develops into pupae, but these pupae are unable to molt successfully. In this way, plant-derived metabolites contain or produce inhibitors of juvenile hormone, thereby disrupting the development of insect larvae and making them vulnerable to harm. Therefore, in this study, we established an in vitro screening system using yeast cells transformed with the Met-SRC juvenile hormone receptor of S. frugiperda. Through this system, we were able to identify juvenile hormone disruptors from plant-derived metabolites and confirm their developmental inhibitory effects on the larvae of S. frugiperda.

The temperature-dependent development of Poinsettia thrips, Echinothrips americanus was studied at eight constant temperatures (15.0, 17.5, 20.0, 22.5, 25.0, 27.5, 30.0, and 32.5±1°C), 65±5% RH and photoperiod of 16L : 8D conditions. The developmental stages were divided into egg, 1st instar, 2nd instar, pre-pupa, pupa, and adult. The total developmental time in the immature stage was 40.4 days at 15.0°C and 11.6 days at 30.0°C, and it decreased with increasing temperature. The lowest temperature of the whole immature period was 10.7°C, and the cumulative temperature to complete the entire immature period was 217.4 degree days. The optimal development temperature (Topt) for the whole immature stage was estimated to be in the range of 30.51-31.21°C. Topt for each immature stage was 31.64-35.47°C at egg, 30.02-33.08°C at 1st instar, 29.16- 34.43°C at 2nd instar, 27.63-29.21°C at pre-pupa, and 29.81-30.12°C at pupa. In the analysis of the six non-linear models, Logan 6 model was the most appropriate as Zi (Weighting Factors) was 0.18.

The occurrence of Laodelphax striatellus (SBPH) in Korea ranged 0.3-19.3 individuals in 2021, and 0.3-23.3 individuals in 2022 during the investigation period. Nilaparvata lugens (BPH) was not observed in 2021, but N. lugens (BPH) showed the highest number(82.0 inds.) in late September of 2022. The occurrence of Sogatella furcifera (WBPH) was not severe during the study period. Compared to Korea’s situation, N. lugens (BPH) and S. furcifera (WBPH) in Asian regions showed high occurrence in Bangladesh and Sri Lanka. The results of the field survey could be confirmed with the occurrence pattern of about once or twice in their regions. Continuous monitoring is required for the best control of planthopper species in rice production regions of Asia. We anticipate that exchange of occurrence information and establishment of a control cooperation system will improve rice productivity in Asian regions by preventing outbreak of planthopper species and reducing damages caused by the species.

기후변화로 인해 농경지의 병해충 발생 세대수가 증가하고 있으며, 노린재류 등을 포함한 일부 해충의 경우에는 발생량도 증가하는 경향을 보이고 있다. 볼록총채벌레, 붉은불개미 등 열대 및 아열대 지역 원산 외래해충의유입도 늘어나고 있는 실정이다. 따라서 우리는 이러한 외래종의 국내에서의 정확한 발생특성을 이해하고 이러한 해충의 발생지에서 기후노출지수(생육적온에 놓인 날의 횟수, 발생지역의 상대습도)와 해충의 고유생육 특성과 관련되는 민감도 지수(기주식물, 월동란밀도, 월동생존율 등) 그리고 돌발 해충의 발생시 방제할 수 있는 적응능력 등에 관한 자료를 취합하여 시군구별 이들 해충발생의 취약성(vulnerability)을 평가한다. 시군구별 이들 돌발해충의 발생 취약성 평가를 위한 실태조사(Surveillance)는 정점조사(Fixed plot survey)와 순회조사(Roving survey)를 실시하였고, 특정 지역에 특정 해충의 발생여부를 조사하는 일반실태조사(General surveillance)와 발생량 및 발생시기, 기주식물 등을 조사하는 특별실태조사(Specific survey)를 실시하였고 해충종별로 페로몬 트랩(pheromone trap), 황색끈끈이트랩(yellow stiky trap), 유아등 트랩(light trap) 등을 이용하여 발생여부 및 발생량을 조사하여 분석에 이용하였다.

농작물 해충 발생 실태조사란 조사지역에서 특정 해충의 발생시기, 발생량, 주요 기주직물의 종류 등에 관해 작물 생육기를 중심으로 주기적으로 조사하는 것을 말한다. 기후변화에 따라 새로이 발생하거나 피해도가 증가하는 병해충의 카테고리는 비래병해충, 돌발병해충, 남방계 병해충 등이 있다. 병해충 발생 ‘영향평가’라 함은 기후ꞏ기상 인자가 안정화된 현재의 농업생산시스템(적지, 생산성, 병해충, 생물다양 성 등)에 변화를 일으키는 영향값을 산출하는 것이다. 즉, 현재 상태를 기준으로 하여 기후변화에 따른 영향값 차이를 평가하는 것을 말한다. 병해충 발생 ‘취약성’ 이란 기후변동과 극한현상을 포함한 기후변화의 부정적 영향에 대해 특정 경작지나 그 경작지 내의 농작물이 민감하게 반응하거나 대처할 수 없는 정도를 말한다. 이번 연구는 영향평가 지표를 선정 및 이 기준으로 실시한 실태조사 결과를 가지고 특정 지역의 특정 해충에 대한 취약성 평가를 하는 방법에 관해 논한다.

The rice green caterpillar Naranga aenescens Moore (Lepidoptera: Noctuidae) is one of important destructive insect pests to Poaceae including rice and corn. We investigated the development periods of N. aenescens egg, larva, pupa and total immature at eight constant temperatures of 15.0, 17.5, 20.0, 22.5, 25.0, 27.5, 30.0, and 32.5°C, respectively. N. aenescens developed successfully from egg to the adult stage at all temperatures tested except 15.0°C. Developmental rate of N. aenescens increased as temperature increased from 15.0 to 30.0°C but declined at 32.5°C except pupa stage. The lower developmental threshold (LDT) and thermal constant (K) was estimated by linear regression. Higher temperature threshold (TH) and lower temperature threshold (TL) were calculated by two nonlinear functions. LDT and K from egg to adult emergence were 12.01°C and 330.84DD. The temperature range of N. aenescens from TL to TH using performance model (24.03) was wider than that from SSI model (19.77). Developmental completion of N. aenescens was described using a two-parameter Weibull distribution model. The adult emergence frequency of N. aenescens 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.