Melon thrips, Thrips palmi Karny (Thysanoptera: Thripidae) is a worldwide polyphagous pest. The management of this pest have mainly relied on chemical agents. However, the overuse is harmful to the environment and results in insects resistance. Therefore, alternative eco-friendly control methods that have different mode of action, such as biological control, are necessary to overcome the current issue. In this study, we isolated entomopathogenic fungi from Korean soil, and characterized them via morphological and molecular techniques and pathogenicity assay against Tenebrio molitor larvae. The isolated fungi were screened for virulence against T. palmi under laboratory conditions and the results were used to establish a thrips-pathogenic fungal library. The highly virulent isolates were selected and further characterized for optimum culture conditions and application as biopesticide in the field.

A residual contact vial plus water (RCVpW) bioassay method was established to monitor insectiside resistance in field populations of the melon thrips, Thrips palmi. Resistance level against six major insecticides were evalutated in five regions to test applicability of RCVpW as an on-site resistance monitoring tool. Reduced mortality in response to six test insecticides were exhibited compared to the RDA susceptable strain showing 100 % mortality, indicating different degree of resistance. An apparently reduced mortality to emamectin benzoate and chlofenapyr was observed in some field populations, suggesting uneven distribution of resistance to these insecticides in field populations. In addition, spinosad resistance was high and widely distributed in the test regions. Synergistic bioassay revealed that cytochrome P450-mediated metabolic factor is involved in spinosad resistance in the Korean population.

From simple niche models to machine learning methods, there have been intensive efforts to understand the potentialdistribution of species in last two decades. Especially in the agricultural sector, recent SDM, Species Distribution Models,studies highly enthused to predict the potential distribution of invasive species under Climate Change. Beyond the distribution,efforts are needed to assess potential risk caused by the target pest. The Shared Socio-Economic Pathways (SSPs) are scenariosfor climate change impacts and adaptation measures. We used MaxEnt model to predict potential distribution of melonthrips with two RCPs (4.5, 8.5) and three SSPs (SSP1, SSP2, SSP3) scenarios. In agricultural land, the potential distributionof melon thrips increases under climate change, but the impact is reduced with the development-oriented scenario, SSP3.

Thrips palmi Karny was introduced and first recorded in 1993 in Korea. This species has become a serious pest of vegetable and ornamental crops. CLIMEX simulation was applied to T. palmi to predict the potential geographic distribution in Korea under the Representative Concentration Pathway (RCP) 8.5 climate change scenario. In the CLIMEX simulation, ecoclimatic index (EI) was calculated, and compared in each simulated year and each simulated location. The map comparisons showed a good agreement between simulated and present distributions of T. palmi, indicating that the CLIMEX model was well explained and appropriate for prediction of future distributions of this species in Korea. In near future, until a year of 2020, all the western and eastern parts of Korea showed favorable to marginal suitability for T. palmi populations in fields. After the year of 2040, the potential distributions are shifted from no persistent to favorable for establishment and persistence from coastal to interior of the Korean peninsula except a north-eastern interior region which is the northernmost part of high mountains (Baekdu-Daegan) area in South Korea. Based on simulation results, T. palmi would overcome its weather restriction in near future under a severe climate change scenario, thus, pest management measures and strategies should be re-constructed in Korea, with further studies including interspecific competition and understanding ecosystem change due to climate change.