The alfalfa weevil (Hypera postica) is an important pest that causes significant damages to alfalfa crops, reducing yield and quality, but there’s a solution. This research had two main goals to evaluate the efficacy of insecticides available in Korea for alfalfa weevil control and to provide data for pest management studies. The experiment, conducted from 2023 to 2024 at the National Institute of Animal Science in Cheonan, Republic of Korea, included four treatment plots: control (CON), early-occurrence (EAR), mid-occurrence (MID), and late-occurrence (LAT). It also included two frequency plots with primary and secondary insecticide using 50% fenitrothion emulsion, which made it truly comprehensive study. The primary insecticide was applied at the first observation of the alfalfa weevil larvae, with subsequent secondary applications at specified intervals. The results showed that two-times insecticide applications significantly reduced larvae populations and increased yield and nutrient content compared to a single application. Specifically, control rates ranged from 94 to 94.7% on the third day after treatment and from 72.2 to 93.4% on the seventh day. Plots with two applications had higher yields and crude protein content. The study concluded that the timing and frequency of insecticide applications are critical to maximizing alfalfa yield and quality, emphasizing the importance of optimized application strategies for effective pest control.

기후변화는 곤충의 성장, 발육, 생존, 생식력, 분포범위 등 생활사의 변수들에 영향을 준다. 특히 외래곤충의 경우 생태계 정착 및 확산이 빨라 지고 있으며, 생태계 교란, 토착종 감소 등 생물다양성을 감소시키는 직접적인 원인 중 하나이다. 알팔파바구미는 1990년대 제주도에서 처음 발견 후 남부지방에 대량 발생하여 농업해충으로 인식되었다. 최근 하면처로 이동하는 개체에 의한 밭작물의 피해와 여러 시군에서 서식이 확인되며 확산의 우려되고 있다. 본 연구에서는 기후변화가 알팔파바구미에 미치는 영향에 대해 파악하였다. 미래의 기후 시나리오 RCP 4.5와 RCP 8.5에서 알팔파바구미의 잠재적 분포를 추정하기 위해 MaxEnt 모델을 적용하였다. 모형의 변수는 2015~2017년까지 알팔파바구미의 서식이 확인된 66개 지점과 종의 생태특성 및 예측변수간 상관성을 고려한 6개(bio3, bio6, bio10, bio12, bio14, bio16)의 생물기후를 사용하였다. 예측된 모형의 적합 도는 평균 0.765로 잠재력이 의미 있는 값이며, 최고 따뜻한 분기의 평균기온(bio10)이 60~70%로 높은 기여도를 나타냈다. 2050년과 2070년의 시나리오(RCP 4.5, RCP 8.5)에 대한 모형의 결과는 한반도 전역에서 알팔파바구미의 분포 변화를 보여 주었으며, 기온상승에 따른 전국적 확산이 예측되었다.

Alfalfa weevil (Hypera postica Gyllenhal) belongs to the family Curculionidae, Order Coleoptera and it is one of invasive alien species in Korea. In Korea environment, this species was found in 2000 first time through the Korean quarantine inspections. Although various researches have been studied in the Europe, US, China and Japan, only few research has been performed in Korea. In this study, the life cycle, morphology and the host plants of Alfalfa weevil were investigated in the natural environment. Nine plants of total 28 host plant species known as the host plants were characterized as their wild host plants in Korea (6 and 3 of 9 were naturalized and native plants in Korea, respectively). The geographical distribution was very wide from south (Jeju) to north (Yeoncheon) area of the peninsula and the favorite habitats were park, cultivated and grass land. This species has been found easily anywhere because it takes common leguminous plants such as clover, chinese milk vetch and alfalfa. These results suggest that Alfalfa Weevil can be one of the most-damaging insect pests of leguminous crops when it adapts to Korean climate.

Alfalfa weevil is an invasive pest of several leguminous plants. In the world preservative, there is a lack of information about the level of differentiation among separate populations. We ran a comparative molecular and ecological analysis to assess diversity, phylogenetic relationship and also simplify the taxonomic decisions. By analyzing a total of 147 specimens from Middle East, Europe and America plus a few sequences in GenBank we improved our current knowledge of world phylogeography of Hypera postica. The result of mitochondrial genes (Summation of COI and CytB) revealed a deep divergence between two previously defined clades (5.6 – 6.7% nucleotide divergence) within sympatric distribution. The Eastern lineage comprised 60 haplotypes in Iran and 3 haplotypes in Italy with respectively 0.07 – 2.2% and 0.2 – 3.4% sequence divergence range. On the other hand, the Western lineage which was detected in Poland, Czech and Western America had relatively lower haplotype diversity presenting a total of 11 haplotypes and 0.1%-1.1% sequence divergence. The coexistence of two lineages in some regions led to the huge overlap in their fundamental nich, but also a certain level of divergence can be detected via ecological nich modeling analysis.

자운영 포장에서 알팔파바구미 성충의 발생양상과 1세대 성충의 밭작물 유식물에 대한 기주선호성을 조사하였다. 자운영 포장에서 포충망에 의한 알팔파바구미의 월동 성충은 3월 하순부터 발생하기 시작하여 4월 중순에 피크를 나타내었으며, 1세대 성충은 4월 하순부터 발생하기 시작하여 5월 하순에 피크를 나타내었다. 하지만 월동 성충의 발생량은 매우 적었고, 1세대 성충의 발생량은 매우 많았으나, 연차간 변이가 심하였다. 온실에서 배추 및 콩 등 11종의 유식물에 대한 알팔파바구미 1세대 성충의 7일 차 발생충수는 배추>콩>케일 순으로 유의하게 많았으며, 조, 땅콩, 기장, 가지 및 상추에서 매우 적었고, 옥수수, 쑥갓, 수수에서는 전혀 발생하지 않았다. 7일 차 유식물의 피해주율도 배추(60.0%)>콩(50.0%)>케일(30.0%)>조(16.7%), 기장(13.3%)>상추(3.3%) 순으로 유의하게 심하였다. 한편, 자운영포장에서 11종의 유식물에 대한 7일 차 피해주율은 배추(46.7%), 콩(43.3%)>케일(23.3%)>조(13.3%), 기장(13.3%) 순으로 유의하게 심하여 온실에서의 결과와 같은 경향을 나타내었다. 따라서 알팔파바구미의 기주선호성은 녹비작물포장 주변에서 밭작물의 안전한 재배를 위한 작물선택의 참고자료로 활용될 수 있을 것이다.

 ,  , This study was conducted to evaluate the scouting methods for larva and adults of the alfalfa weevil, Hypera postica Gyllenhal on Chinese milkvetch, Astragalus sinicus L. in the field. Three sampling methods, shake-bucket, shake-picking, and a sweeping net were evaluated for collecting alfalfa weevil larvae. We found significant differences among scouting methods and date in all survey fields. Sweep-net sampling was less able to detect small larvae than large larvae, which were not detected until early April whereas the shake-bucket, and shake-picking methods efficiently collected larvae from middle March. A Pitfall trap with three different baits - no bait, kidney bean seeds and sprouting kidney beans were compared for collection efficiency of alfalfa weevil adults. Collection efficiencies were significantly different by bait(p<, 0.018). Traps baited with sprouting kidney beans were the most efficient for collecting the alfalfa weevil. The number of alfalfa weevil caught was not significantly different between kidney bean seed and no bait in the pitfall trap. Therefore, the shake-bucket method for larvae and a pitfall trap baited with sprouting kidney beans for adults are recommended for scouting of the alfalfa weevil in a Chinese milkvetch field.

Alfalfa weevil, Hypera postica Gyllenhal, is regarded as one of the most important insect pests on Chinese milk vetch and hairy vetch. The insect usually feed on leaves, stems and pods of the green manure which causes severe reduction of biomass. This study was conducted to observe the occurrence of H. postica larva and adult on Chinese milk vetch in 2009 to 2010, and to evaluate host plants preference of 11 different seedlings in 2010, Milyang, Korea. Occurrence of H. postica larvae on Chinese milk vetch was observed to increase from early April clearly and its peak population was showed during middle to late April. The 1st generation of newly emerged adult of H. postica was appeared on 20th May. Newly emerged H. postica adult was fed on green manure such as Chinese milk vetch and hairy vetch as well as various seedlings located at nearby upland. And then the insects were migrated into aestivating places in middle to late of June. Thus, host plant preference of H. postica adults were evaluated with 11 different seedlings using transparent acrylcage and at Chinese milk vetch field. As a result, H. postica adult preferred on Chinese cabbage, followed by soybean, kale, foxtail millet and proso millet. The damaged rating of seedlings were shown to have the same trend with adult occurrence. In particular, few H. postica adults were occurred on eggplant, lettuce, corn, crown daisy and peanut, and thereby those crops were regarded as non-preference plants due to the absence of damage. These informations can be used by upland farmers who sowing from late May to early June for effective management of H. postica.

Laboratory tests were conducted to determine the susceptibility of the alfalfa weevil, Hypera postica to Korean entomopathogenic nematodes, Steinernema carpocapsae GSN1 strain (ScG), S. glaseri Dongrae strain (SgD), Heterorhabditis bacteriophora Hamyang strain (HbH), and Heterorhabditis sp. Gyeongsan strain (HeG) at the petri dish assay. The larval mortality of H. postica was significantly different depending on nematode species and treatment concentration. SgD and HeG strain were more effective against H. postica larva than ScG and HbH strain. When SgD and HeG strain were treated with the rate of ＞20 infective juveniles (ijs) per alfalfa weevil larva, mortality was ca. 77.5-100% at the late instars of H. postica in 3 days. The number of established nematode was significantly different depending on nematode species, whereas number of progeny was not significantly different. The mean number of established ijs of SgD strain in a host was the highest at 80 ijs by 30.2. The highest progeny number of HeG strain was 2,671.5 with 80 ijs. All nematode strains were not parasitic entirely to H. postica adults. These results show that alfalfa weevil late larva is highly susceptible to Korean entomopathogenic nematodes in the laboratory.