1983년 대학 2학년 때 ‘식물분류학 및 실험’ 과목을 수강하면서 우리나라 곤충상을 제대로 밝혀 보겠다는 포부를 가지고 곤충분류연구실에 문을 두드렸던 기억이 여전히 생생합니다. 그를 계기로 다듬이벌레목 및 딱정벌레목의 바구미상과를 연구대상으로 곤충분류학에 입문하였습니다. 그 결과물로 한국산 바구미류에 대하여 2000년에는 373종, 2001년에는 150종에 대한 ‘원색도감’을 발간하게 되었으며, 2011～2014년에는 대한민국생물지 ‘한국의 곤충 - 바구미류 Ⅰ～Ⅴ권’을 발간함으로써 한반도 바구미상과 곤충상에 대한 이해의 폭을 넓힐 수 있었습니다. 1990년부터 농업해충 연구를 시작, 가옥해충 관리 분야에 관심을 가지게 되면서 1996년에 ‘저장곡물해충의 유충검색 및 생태’ 책자 및 2017년에 ‘저장곡물해충 및 위생해충(파리류) 도감’을 발간하였으며, 이 저장곡물해충으로부터 식품에서 문제를 일으킬 곰팡이독소 생성 병원균을 분리․동정(2018)하여 저장식품 관리의 기초를 제공하는 한편, 2008년에는 ‘박물관과 유해생물 관리’ 책자를 발간하여 문화재 관리에서 해충의 중요성을 일깨웠습니다. 1999년부터는 식물검역업무와 인연을 맺게 되면서 검역현장에서 필요로 하는 검역해충의 동정기술을 개발하여 식물검역관 교육에 힘쓰는 한편, 세계적으로 이슈화 되고 있는 침입외래해충에 대한 생물안보 분야 연구에 집중하게 되었습니다. 그 결과로 ‘외래해충의 검출 및 유입현황 분석(2012～2019)’과 ‘주요 침입해충종의 유입경로 파악(잔디왕 바구미(2009), 미국선녀벌레(2015, 2016), 꽃매미(2013), 블루베리혹파리(2015), 유럽좁쌀바구미(2018))’을 통해 생물안 보 업무에 되먹임(feedback) 및 과학적인 도구로 활용될 수 있도록 하였습니다. 2013년부터는 대학에서 친환경 해충관리 분야 연구를 집중하고 있습니다. 그 결과로 ‘노린재류 및 씨살이좀벌, 알락하늘소류 해충에 대한 효과적인 천적 탐색(2015～2018)’ 및 ‘인공알을 이용한 천적의 대량증식 기술(2018)’을 개발하여 종합적 해충관리의 학문적 발전을 유도하고 있습니다. 또한 산림청으로부터 수목진단센터를 유치하여 운영하는 한편, 나무의사제도의 안정적인 정착을 위해 생활권 수목에서 문제시 되는 해충을 올바르게 진단하고 효과적으로 관리할 수 있도록 산림해충 연구에 집중하고 있으며, 2019년 3월에는 ‘수목해충학’ 책자를 교재로 발간하였습니다. 오늘 송정곤충학상을 수상하게 됨을 계기로 제 자신을 뒤돌아보면서 농림해충관리 및 생물안보 분야에 있어서 농민 및 관계자 분들에게 조금이나마 유용한 정보 및 기술을 제공할 수 있도록 알찬 연구 및 후학양성에 더욱 매진할 것을 다짐해 봅니다. 우리나라 응용곤충학 분야의 권위 있는 송정곤충학상을 수상하게 되어 개인적으로 큰 기쁨이고 영광이라 생각하면서 한편으론 송구스럽기도 합니다. 저 자신의 노력보다는 연구방향을 지도편달해주신 많은 선생님 및 선배님, 같이 연구해온 많은 동료 및 후배님들 덕분에 이러한 영광을 누릴 수 있음을 밝히면서 한국응용곤충학회 모든 회원님들께 깊이 감사를 드립니다.

지금까지 국내의 살충제 등록 및 관리는 농촌진흥청과 식품의약품안전처에 의해 이루어져 왔다. 농업해충을 방제하는 목적인 농약에 대해서는 농촌진흥청에 각 농약의 이화학적 분석자료, 약효 및 약해 시험성적서, 인축독성 시험성적서, 환경생물독성 시험성적서 및 잔류성 시험성적서 등을 구비하여 신청하며, 농촌진흥청에 등록된 농약은 농업해충의 방제를 비롯하여 검역해충(농림축산검역본부 관할) 및 산림해충(산림청 관할)의 관리 및 방제에도 사용된다. 이에 반하여, 기존 식품의약품안전처에서 ‘의약외품’이라는 명칭으로 등록 및 허가를 담당해오던 가정용 살충제(정식 명칭: 구제·방지·유인살충제) 및 방역용 살충제(정식 명칭: 감염병예방용 살충제)는 2019년 1월 기준으로 ‘살생물제’ 라는 명칭으로 환경부로 관리주체가 이관되게 되었으며, 향후 살생물제 물질 및 제품의 허가는 국립환경과학원을 통해 이루어지는 것으로 변경되었다. 관리주체 이관 및 관련법 변경과 관련한 많은 변화가 이루어졌고, 향후 더 많은 변화가 이루어 질 것으로 예상된다. 예를 들어, 기존 의약외품에서는 모기, 바퀴, 진드기, 벼룩 등 질병을 매개하는 위생해충만을 방제의 대상으로 지정하였으나, 살생물제는 가옥 또는 구조물 내 서식하는 모든 곤충 및 절지동물을 방제하는 화학제품은 살생물제로 보고 있으며, 이로 인해 기존 공산품으로 판매되며 법적인 기준이 없었던 좀벌레 방제제, 쌀벌레 방제제 및 날벌레 방제제 등의 판매를 위해서는 향후 살생물제 등록을 거쳐야만 하는 것으로 규정의 변화가 이루어지게 되었다. 이들 신규 살생물제 포함군에 대한 효력시험법 개발 등이 필요한 상황이며, 관련한 제품개발 연구인력, 허가 관련 행정인력, 사육 및 평가 전문가 등 다양한 분야의 신규 인력이 필요한 상황이다. 이러한 변화를 맞이하는 시점에서, 살충제에 대한 연구 및 규정 마련을 위해 해당학회 회원들의 역할과 책임에 대해 살펴보고자 한다.

곤충 외부 형태에 대해 그동안 정리되어 사용되고 있는 우리말 용어들 중에는 그 명칭이 지칭하는 뜻과 부위, 구조에서 혼동하기 쉬운 것들이 일부 포함되어 있다고 판단된다. 따라서 이번 기회에 곤충 가슴(thorax)에 관련된 명칭들을 체계적으로 분류하고 현재까지 사용해 왔던 우리말 명칭들을 재조정하였다. 먼저 몸통(body) 전체에서 위치와 부분을 지칭하는 명칭들을 정리하였다. 이어 가슴부위의 등판(notum), 옆판(pleuron), 가슴판(sternum) 각각에서 부위별, 구조별로 우리말 이름을 정리하였다.

Insect metabolism and the inter-species communication among insects are fascinating fields of science. The underlying chemical principles are difficult to elucidate since minute amounts of chemicals, often of unknown structures, are involved. The talk highlights recent examples of work where chemical analysis and biological research went hand in hand to unravel ecological mysteries. Focus will be on the use of modern and sensitivity improved nuclear magnetic resonance (NMR) spectroscopy serving as analytical key technology.

The red imported fire ant, Solenopsis invicta, first arrived in Texas in 1956 and quickly spread, where it now occupies more than half the state. The ecological and economic impact of this invasive ant has been well-documented in the state. Ecologically, it reduces native arthropod fauna and has a big effect on ground nesting birds. Economically, it’s estimated that this pest ant costs the state $1.2B dollars annually, affecting both urban and agricultural areas. After failed federal efforts to eradicate the fire ant, the state of Texas invested in its own research and management program, as did several other states. However, the Texas program, the Imported Fire Ant Research and Management Program, was the largest state program with $1.25 M invested annually since 1997. Several important developments arose out of this program including research on the biology and management of fire ants as well as treatment recommendations. Results of these research and management efforts will be discussed.

Insect neuropeptides are involved in most physiological processes in insects, such as diuresis, ecdysis, and pheromone biosynthesis. The peptides perform these functions as ligands for G-protein coupled receptors (GPCRs) that trigger specific biochemical functions. Our research in this area has focused on the Pheromone Biosynthesis Activating Neuropeptide (PBAN) and its GPCR in fire ants. I will show that PBAN is involved in fire ant pheromone production and interestingly, also in important functions of all colony life stages. Since many neuropeptides play critical roles in insect development and reproduction, the peptide hormones and their receptors are viewed as promising targets for novel biologically-based control. These possibilities will be illustrated. Secondly, the use of venom alkaloids, cuticular hydrocarbons, and pheromones as useful taxonomic characters will be illustrated using Solenopsis species in the USA and in South America.

The red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), is an invasive pest affecting urban and rural communities, agricultural production and wildlife. Its complex biology and genetics is reflected in the existence of two different colony forms: monogyne and polygyne. We focus our studies on the polygyne form more abundant in Texas, characterized by the presence of multiple queens that co-operate for colony success. Our conceptual framework resides in the hypothesis that understanding gene networks linking nutrition and reproduction may reveal critical signaling pathways that could be disrupted to manage fire ants. In the pre-omics era we began by systematically cloning and characterizing the expression of genes and proteins important for reproduction and signaling and that we believe participate in the fire ant ‘genetic tool kit’. Our earlier studies focused on the vitellogenin receptor (VgR) and in the application of RNAi to reduce VgR gene expression as proof of principle that gene silencing in queens could lead to impaired egg production. Signaling systems related to reproduction and nutrition were also studied, such as the insulin receptors and the sNPF receptor, a G protein-coupled receptor. We have immunolocalized the sNPF receptor in the brain of queens and workers and found correlations in its neuronal gene expression in both castes with respect to the presence or absence of brood in the colony. We have generated and compared transcriptomes of mated and virgin queen brains and ovaries and identified a few differentially expressed genes. Most recently, with the release of the new fire ant genome in the Fall of 2018, we mined the genome to compile and curate the annotation of G protein-coupled receptors. The lecture will summarize key aspects of the biology of fire ants and morphological and functional differences among colony members. Experimental approaches utilized to begin to understand regulation of colony growth at the molecular level will be presented. It is our goal to unravel the endocrinological control of the fire ant colony with the hope of identifying novel targets to impair queen maturation, ovarian development, colony nutrition and brood production.

Red imported fire ant Solenopsis invicta is one of the 100 most threatening alien species in the world. Originally distributed in parts of South America, it has invaded 24 other countries and regions now. Because of its ferocious habits, rapid reproduction and strong competitiveness, it is easy to outbreaks and cause disaster in a short period of time after the invasion, and will endanger agriculture and forestry, human health, biodiversity and public safety. The fire ant had been found in Taoyuan, Taiwan in September 2003, and Guangdong, mainland China on September 23, 2004. As a new invasive species in south China, although it was paid serious attention by the governments and the scientists, but the fire ant has kept spreading fast after its invasion. In order to delay its expansion and control its infestation, the following research on the fire ant has been carried out and completed 14 years after its invasion in China. To discover the fire ant invasion in mainland China, and reveal its spreading and expanding law, including 1) the genetic diversity, invasive sources, ways, routes, migration and expansion of the fire ant in China at different spatial scales; 2) a system of methods for estimating invasion and expansion; 3) monitor continuously for 14 years to clarify its diffusion dynamics in mainland China. Clarify the catastrophic law and mechanism of the fire ant invasion in mainland China, and include 1) The laws and mechanisms of invasive biology, behavior, population dynamics, ecological adaptation, social immunity, interspecific competition/reciprocity; 2) The disturbance of the fire ant invasion to crops, species relationship, community structure, control pest function, pollination function and soil environment in southern six ecosystems; 3) The laws and mechanisms of inhibiting invasion and restoring diversity in the diverse habitats; 4) New functions of chemosensing related genes and the regulation mechanism of light avoidance behavior. Reveal the basic theory of chemical control of the fire ant, and establish a safe and efficient technical system for emergency control and eradication, such as 1) the transmission toxicity, behavioral toxicity, reproductive disturbance, repellent activity, control effect and environmental effect of 46 insecticides; 2) pesticide-induced killing-queen behavior and its mechanism; 3) standard methods for evaluation of control effect for insecticides. Reveal the basic theory of chemical control of the fire ant, and establish a safe and efficient technical system for emergency control and eradication, such as 1) Five safe and efficient formations and their application technologies, and breakthroughs in high attractiveness, waterproofing formations and application methods, and the control effect of single use with 89% - 97%; 2) emergency prevention and control in 8 types of ecological areas eradication mode and technology system, with the breakthrough of inefficient or ineffective products and technology in rainy and low temperature seasons, and the control effect with 96% - 100%, and local eradication of 19 areas. Put forward risk management strategies, and build up an accurate, efficient and safe monitoring and quarantine technology system, and include 1) the suitability and risk management strategies and techniques based on more extensive research; 2) new monitoring technologies with the accuracy of 98% - 100%; 3) relationship among the three methods, and a monitoring and index system; 4) efficient quarantine technology for entry-exit, occurrence regions and transportation; 5) near infrared reflection ant nest detection system, and information management system; 6) construct the management, technical standards and promotion system, and apply them widely; 7) more than 40 national standards and schemes in a management/technical standard system.

The red imported fire ant (RIFA, Solenopsis invicta), an exotic species, detected in Taiwan in 2003 was originally from USA. A program was launched immediately under Bureau of Animal and Plant Health Inspection and Quarantine Council of Agriculture (BAPHIQ) in 2004 for RIFA management. The National Red Imported Fire Ant Control Center (NRIFACC) helps the BAPHIQ to integrate/coordinate the RIFA eradication program which involves every governmental department, however the actual implementation of prevention and control work is the local government. It has made a significant progress in public education, since our general public can recognize RIFA accurately now and succeed to localize RIFA in Northern Taiwan. However, nationwide RIFA eradication is still far from success, the major constraints of the eradication program in Taiwan include (1) RIFA had likely been in Taiwan longer than reported, (2) difficulty to detect incipient infestation, (3) mass reproductive queens that can spread over 10-20 km after nuptial flight, (4) movement control is not easy to perform, (5) man power or company for chemical treatment is not enough, (6) funding is insufficient to allow success, (7) meteorological condition disfavors the control practice. Fortunately, we have developed humidity resistant baits that could enhance the control efficiency of RIFA in humid or wet conditions and resolve the weather constraints of RIFA and other invasive ants control in wet tropical and subtropical habitats. For the success of NRIFACC eradication efforts, participation of all stakeholders would remain a very important strategy in the future. In particular, a centralized team would further facilitate the management of RIFA. Moreover, due to the increasing in international trades and the recent detection of RIFA in Japan and Korea, an international efforts and cooperation on RIFA management is a key issue to control global movements of RIFA.

Two infamous ant species, red imported fire ant (RIFA, Solenopsis invicta) and tropical fire ant (TFA, S. geminata), originated from South America are invading and harming many countries around the world. Among them, RIFA, known as one of the 100 world’s worst invasive alien species, has been discovered in South Korea; in Busan (Gamman CT) in 2017, and subsequently in Busan (Hutchison CT), Pyongtaek, Incheon and Daegu in 2018. With these relentless introduction of RIFA, South Korea is not safe no more from these ants and faces a risk of settlement. Our research goal is tracing the country origin of invasive populations of RIFA and TFA based on molecular epidemiological approach. We are conducting both microsatellite and genome-wide SNP analyses in order to derive a complementary interpretation. These two methodologies are expected to result in improved resolution in population genetics analysis. Nevertheless, this work needs collaboration of many countries belonging to the range of origin and invasion of RIFA and TFA. We will briefly introduce our research project and progress of collaboration research.

The red imported fire ant (RIFA, Solenopsis invicta Buren) is defined as invasive species and one of 100 most threaten alien species in world by IUCN. In Korea, RIFA has been first detected at September 28th, 2017 in Busan Port during surveillance by Animal and Plant Quarantine Agency (APQA). The RIFA colony was revealed as a polygyne and H5 type through epidemiological analysis on Gp-9 gene and mt-DNA haplotype. APQA has developed eradication program for RIFA with enhanced surveillance in all nationwide Ports and Internal Container Depots. There are subsequently 7 times more invasions of RIFA in Ports (Busan, Pyongeaek, and Incheon) including 2 times of inlands (Daegu and Ansan) and completely eradicated so far. International trade and climate change increases possibility of establishment and spreading of RIFA in Korea. Therefore, it must be required an international cooperation for prevention of global spreading of RIFA between countries.

자연생태계 내에서 곤충은 식물과 다양한 관계를 맺고 살아가고 있는 중요한 분류군이라 할 수 있다. 특히, 대부분의 곤충은 식물을 먹이로 하는데 잎, 줄기 및 뿌리 등 먹이선호도에 따라 가해부위가 다르며, 가해특성에 따라 흡즙성, 저작성, 종자가해성, 혹형성 및 잠엽성과 같은 다양한 기능군으로 나누어 볼 수 있다. 최근에는 곤충에 의한 화분매개의 중요성이 재조명됨에 따라 이를 증진시킬 수 있는 방안에 대한 논의가 활발하게 이루어지고 있다. 이외에도 중요 식물종의 보존과 곤충의 연관성에 초점을 두고 보전의 효율을 증대할 수 있는 방안도 시도될 필요성이 있다. 본 연구에서는 우리나라에서의 곤충과 식물과의 상호관계에 대해 폭넓게 살펴보고 향후 연구가 필요한 분야를 제시하고자 한다.

The Hemiptera are a large and diverse order of insects with mouth parts specially modified for piercing and sucking soluble contents in vascular bundles. Many hemipterans (aphids, whiteflies, psyllids, stinkbugs, leafhopper and planthoppers) are important pests of plants, either by direct feeding and as vectors of viral and bacterial plant diseases. Plants can alter their physiology to tolerate insect infestation and vice versa. Here we present research topics, which include the current and future advances in hemipteran-plant interactions that address the systematics, resistance, susceptibility and implications for future forest research.

Insects are directly and/or indirectly associated with plants, and interactions of them have long been studied in many countries. The suborders Heteroptera and Auchenorrhyncha, in Hemiptera which is the largest hemimetabolous insect order, are also closely associated with various plants as their hosts and habitats. In addition, some groups of Auchenorrhyncha are known as the vector to transmit pathogens such as phytoplasma and virus to the plant. However, there have been a few researches on interaction of insect groups and plants, although it is important to construct data and to understand their interaction for application in various fields. In this talk, the current research on interaction of two suborders and plants is presented. The importance and direction of future work are also discussed.

Host relationships between insects and plants are one of the major factor driving evolutionary diversification within terrestrial ecosystems. Beetles (Coleoptera) are the most diverse and species-rich group of insects, and a robust, time-calibrated phylogeny is fundamental to understanding macroevolutionary processes that underlie their diversity. Recently, many studies have been carried out about the relationships among those taxa according to the attention on co-evolution of phytophagous insects and their hosts, however, most of them focused on special taxa (family or genus level) of insects. In this presentation, we especially reviewed current trends of studies on interactions between coleopteran insects and host plant in the world and Korea for proposals of future studies.

In Europe, the cabbage stem flea beetle (Psylliodes chrysocephala) is a specialized insect feeding on Brassicaceae plants. The plants use the glucosinolate-myrosinase defense system, but P. chrysocephala can overcome this chemical defense by detoxification of the emerging ITCs by conjugation with glutathione (mercapturic acid pathway). In addition to known products of the mercapturic acid pathway, previously unreported metabolites were isolated, and their structures were elucidated by means of high resolution mass spectroscopy (HR-ESITOFMS) and nuclear magnetic resonance (NMR). The products found may represent general detoxification products of the mercapturic acid pathway.

식식성 파리류는 농업경제학적으로 매우 중요한 분류군으로 인식되어 분류, 예찰 및 방제, 생태, 생리 등 다양한 분야에서 활발한 연구가 진행되고 있다. 식식성 파리류의 습성은 leaf-miners, stem-borers, root tunnellers, fruit borers, cambium miners, seed borers, inhabitants of flowerheads 등이 대표적으로 알려져 있으며, 식물체의 다양한 부위를 공격한다. 대부분의 식식성 파리류는 한 종의 식물을 공격하는 것으로 알려져 있으나, 일부는 2종 이상의 식물체와 관련이 있다. 이들은 생태학적 습성으로 인해 비교적 크기가 작고 변이의 폭이 넓어, 분류동정이 어려운 특징이 있다. 따라서, 최근 통합분류학적 접근을 통한 계통학적 연구, 예찰 및 방제를 위한 유인물질의 개발, 잡초 방제를 위한 생태학적 연구 등이 활발히 이루어지고 있다. 본 연구를 통하여 분류군별 생물학적 특징과 세계적인 연구동향을 정리하여 소개하며, 추가적으로 연구가 필요한 분야에 대해 제안하고자 한다.

미세방울 디지털 PCR(Droplet digital PCR, ddPCR) 법은 정량 PCR 법과 같이 형광물질을 사용하여 정량분석이 가능하다는 점은 유사하지만, PCR 반응액을 만든 후 이 반응액을 바로 PCR에 사용하지 않고 수 만 개의 동일한 크기의 미세방울(droplet)로 구획(partitioning)한 후에 PCR 반응을 수행하는 점이 기존의 PCR 법과 가장 큰 차이라고 볼 수 있다. 이렇게 구획된 나노리터 크기의 미세방울 중에서 형광신호가 검출되는 미세방울과 검출되지 않은 미세방울의 수를 계수하여 프아송 분포(Poisson distribution) 계산에 적용하면 표준검량선 없이 목적 유전자의 절대정량 분석이 가능하다. 곤충이 매개하는 질병 바이러스의 경우 소량의 바이러스 감염 여부를 확인하기 위해서 다수의 곤충 유전자를 확인해야 하는데, 이와 같이 미세방울 형태의 ddPCR을 이용하면 기존 Real-time PCR 법에 비해 극소량의 목적 유전자를 높은 민감도로 검출할 수 있으며, PCR 저해요소(inhibitor)에도 큰 영향을 받지 않는다는 장점이 있다. 또한 미세방울 방식의 디지털 PCR을 이용하면 다중 PCR 분석이 가능하여 1개의 시료에서 다양한 질병매개 바이러스를 검출할 수 있다.

Plants of the Salicacea genus have in common that they utilize phenolic glycosides, so called salicinoids, as protection against leaf chewing herbivores. The caterpillar Cerura vinula only feeds on poplar and willow trees that belong to the family of Salicacea. For this reason, Cerura vinula is viewed as a specialist herbivore that is adapted to the salicinoid defense. Taking advantage of chemical and biochemical techniques we want to trace the salicinoid metabolism pathway, the location of transformation and the involved enzymes. To gain insights into the salicinoid metabolism the caterpillars were put on a specially designed diet. It consisted either of one salicinoid in large excess or one 13C labelled compound, applied together with fresh poplar leaves. As a next step, we are going to identify the new compounds formed in the caterpillar by MS and NMR techniques. To determine the location and mechanism of the transformation we started with a dissection of the caterpillar and a check of the tissue pH value. Afterwards, we incubated the midgut, hindgut and salivary gland tissues with salicin as model substrate and analyzed the transformation products by LC-MS. The transformation products resulted from deglycosilation of the substrate and consecutive oxidation and conjugation of the aglycon. With the gained knowledge we then aimed to identify the enzymes, which are involved in the metabolism. We successfully proofed the existence of glucosidases in the midgut by isoelectric focusing and incubation of the gel with the model substrate 4-methylumbelliferyl β-D-glucopyranosid. Additionally, we performed RNA sequencing on the caterpillar tissue. The transcripts and enzymes involved in the salicinoid metabolism are currently analyzed. During our studies we could determine the mid gut as the place for the deglycosilaton, oxidation and conjugation of salicinoids. Further we identified a new for Cerura vinula undescribed metabolite and proofed the presence of β-glucosidases in the midgut.

One of major mechanisms of insecticide resistance is the reduced susceptibility caused by mutations on the main target sites, such as sodium channel and acetylcholinesterase. Bioassay is a useful method to diagnose insecticide resistance of mosquitoes; however, it is hard to establish regional/annual resistance database based on bioassay. Recently, various markers of mutation and copy number variation have been identified through insecticide mechanism studies. Thus, molecular detection of resistance based on the resistance marker is now feasible, which can be readily implemented as a novel resistance monitoring tool to complement or replace the conventional bioassay method. In Korea, the density of vector mosquitoes native to the subtropical areas has increased due to climate change. Therefore, it is required to establish an efficient resistance monitoring system based on molecular markers to facilitate the construction of a nation-wide resistance map for more effective control of mosquitos. In addition, alternative insecticides should be introduced to the areas where mosquitoes develop high levels of resistance to maximize control efficacy against resistant populations