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.
The key to invasive pest management lies in preemptive action. However, most current research using species distribution models is conducted after an invasion has occurred. This study modeled the potential distribution of the globally notorious sweet potato pest, the sweet potato weevil (Cylas formicarius), that has not yet invaded Korea using MaxEnt. Using global occurrence data, bioclimatic variables, and topsoil characteristics, MaxEnt showed high explanatory power as both the training and test areas under the curve exceeded 0.9. Among the environmental variables used in this study, minimum temperature in the coldest month (BIO06), precipitation in the driest month (BIO14), mean diurnal range (BIO02), and bulk density (BDOD) were identified as key variables. The predicted global distribution showed high values in most countries where the species is currently present, with a significant potential invasion risk in most South American countries where C. formicarius is not yet present. In Korea, Jeju Island and the southwestern coasts of Jeollanam-do showed very high probabilities. The impact of climate change under shared socioeconomic pathway (SSP) scenarios indicated an expansion along coasts as climate change progresses. By applying the 10th percentile minimum training presence rule, the potential area of occurrence was estimated at 1,439 km2 under current climate conditions and could expand up to 9,485 km2 under the SSP585 scenario. However, the model predicted that an inland invasion would not be serious. The results of this study suggest a need to focus on the risk of invasion in islands and coastal areas.
2020년 7월 하순에 전남 해남의 무화과 농장에서 Aclees속에 속하는 바구미가 발견되었다. 이 바구미는 무화과곰보바구미(신칭), Aclees taiwanensis Kôno, 1933로 동정되었다. 아마도 아열대 및 열대 아시아가 원산인 이 외래종 바구미는 이탈리아와 프랑스에도 침입되어 무화과나무 에 심각한 피해를 일으키고 있다. 이 논문이 한국에서 보고되는 Aclees속 바구미에 대한 첫 보고이다.
We sequenced 15,803 bp of the leaf-rolling-weevil, Apoderus jekelii (Coleoptera: Attelabidae) mitochondrial genome (mitogenome) that lacked ~8,000 bp of the A+T-rich region for the completion of the genomic sequence. The A. jekelii mitogenome, which includes 1,169 bp of A+T-rich region, possesses typical sets of genes [13 protein-coding genes (PCGs), 22 tRNA genes, and 2 rRNA genes]. Phylogenetic analyses using the eight concatenated PCG sequences, which are commonly available for the mitogenome sequences of Curculionoidea, revealed Attelabidae as monophyletic, as well as the sister relationship between current A. jekelii and congeneric species A. coryli in Attelabidae, with the highest nodal supports both in Bayesian inference and maximum likelihood methods. In order to gain a more comprehensive picture of the phylogenetic relationships among the lineages of Attelabidae, an extended analysis with more taxonomic sampling will be necessary. †These authors contributed equally to this paper.
The greater rice weevils, Sitophilus zeamais, are one of the devastating insect pests of stored cereals. Since they reside in stored product, mainly food, synthetic insecticides are not favorable choice to control them, as which botanical pesticides can be alternatives in this particular situation. In the present study, contact and fumigant activity of twenty-three plant essential oils against the adults S. zeamais were examined. To identify the chemical compositions of potent essential oils, Gas chromatography-mass spectrometry was performed. Interestingly, essential oils which showed great contact toxicity did not always produce fumigant toxicity accordingly. Among the twenty-three oils assessed, seventeen oils displayed acute contact toxicity and only six oils exhibited fumigant effect. Cinnamon oil was the most toxic in both fumigant and contact assays (LC50 = 10.02 μL/L air, 0.04 μL/cm2, respectively). Cinnamaldehyde in cinnamon oil and terpinen-4-ol in tea tree and majoram oils were identified as the most abundant components, respectively.