Colonization Pressures Research Articles

Air dispersal of multi-drug-resistant organisms including meticillin-resistant Staphylococcus aureus, carbapenem-resistant Acinetobacter baumannii and carbapenemase-producing Enterobacterales in general wards: surveillance culture of air grilles

The environmental surveillance of air grilles in clinical areas has not been systematically analysed. Samples were collected from frequently touched items (N= 529), air supply (N= 295) and exhaust (N= 184) grilles in six medical and 11 surgical wards for the cultures of multi-drug-resistant organisms (MDROs): meticillin-resistant Staphylococcus aureus (MRSA), carbapenem-resistant Acinetobacter baumannii (CRAB) and carbapenemase-producing Enterobacterales (CPE), and isolates were selected for whole-genome sequencing (WGS). The contamination rates were correlated with the colonization pressures of the respective MDROs. From 3rd October to 21st November 2023, 9.8% (99/1008) of the samples tested positive, with MRSA (24.2%, 24/99), CRAB (59.6%, 59/99) and CPE (2.0%, 2/99), being the only detected MDROs. The contamination rate in air exhaust grilles (26.6%, 49/184) was significantly higher than in air supply grilles (5.8%, 17/295; P<0.001). The contamination rate of air exhaust grilles with any MDRO in acute medical wards (73.7%, 14/19) was significantly higher than in surgical wards (12.5%, 4/32; P<0.001). However, there was no difference in the contamination rate of air exhaust grilles between those located inside and outside the cohort cubicles for MDROs (27.1%, 13/48 vs 28.8%, 30/104; P=0.823). Nevertheless, the weekly CRAB colonization pressure showed a significant correlation with the overall environmental contamination rate (r= 0.878; 95% confidence interval (CI): 0.136-0.986; P=0.004), as well as with the contamination rate in air supply grilles (r= 0.960; 95% CI: 0.375-0.999; P<0.001) and air exhaust grilles (r= 0.850; 95% CI: 0.401-0.980; P=0.008). WGS demonstrated clonal relatedness of isolates collected from patients and air exhaust grilles. Air grilles may serve as MDRO reservoirs. Cohort nursing in open cubicles may not completely prevent MDRO transmission through air dispersal, prompting the consideration of future hospital design.

Quantifying global colonization pressures of alien vertebrates from wildlife trade

The global trade in live wildlife elevates the risk of biological invasions by increasing colonization pressure (the number of alien species introduced to an area). Yet, our understanding of species traded as aliens remains limited. We created a comprehensive global database on live terrestrial vertebrate trade and use it to investigate the number of traded alien species, and correlates of establishment richness for aliens. We identify 7,780 species involved in this trade globally. Approximately 85.7% of these species are traded as aliens, and 12.2% of aliens establish populations. Countries with greater trading power, higher incomes, and larger human populations import more alien species. These countries, along with island nations, emerge as hotspots for establishment richness of aliens. Colonization pressure and insularity consistently promote establishment richness across countries, while socio-economic factors impact specific taxa. Governments must prioritize policies to mitigate the release or escape of traded animals and protect global biosecurity.

Does non‐native diversity mirror Earth's biodiversity?

AbstractAimHuman activities have introduced numerous non‐native species (NNS) worldwide. Understanding and predicting large‐scale NNS establishment patterns remain fundamental scientific challenges. Here, we evaluate if NNS composition represents a proportional subset of the total species pool available to invade (i.e. total global biodiversity), or, conversely, certain taxa are disproportionately pre‐disposed to establish in non‐native areas.LocationGlobal.Time periodPresent day.Major taxa studiedGlobal diversity.MethodsWe compiled one of the most comprehensive global databases of NNS (36,822 established species) to determine if NNS diversity is a representative proportional subset of global biodiversity.ResultsOur study revealed that, while NNS diversity mirrors global biodiversity to a certain extent, due to significant deviance from the null model it is not always a representative proportional subset of global biodiversity. The strength of global biodiversity as a predictor depended on the taxonomic scale, with successive lower taxonomic levels less predictive than the one above it. Consequently, on average, 58%, 42% and 28% of variability in NNS numbers were explained by global biodiversity for phylum, class and family respectively. Moreover, global biodiversity was a similarly strong explanatory variable for NNS diversity among regions, but not habitats (i.e. terrestrial, freshwater and marine), where it better predicted NNS diversity for terrestrial than for freshwater and marine habitats. Freshwater and marine habitats were also greatly understudied relative to invasions in the terrestrial habitats. Over‐represented NNS relative to global biodiversity tended to be those intentionally introduced and/or ‘hitchhikers’ associated with deliberate introductions. Finally, randomness is likely an important factor in the establishment success of NNS.Main conclusionsBesides global biodiversity, other important explanatory variables for large‐scale patterns of NNS diversity likely include propagule and colonization pressures, environmental similarity between native and non‐native regions, biased selection of intentionally introduced species and disparate research efforts of habitats and taxa.

Reservoir of Carbapenem-Resistant Acinetobacter baumannii in the Hospital Environment and Colonization Pressure: A Surveillance-Based Study in Indian Intensive Care Unit.

The endemicity of Acinetobacter baumannii in intensive care units (ICUs) is a serious concern. We studied the reservoirs of A. baumannii in the ICU and their effects on colonization pressure and transmission. A prospective surveillance (6 months) was conducted. Screening culture (rectal and axillary) swabs were collected within 48 hours admission and in 120 hours. Surveillance cultures from patients' surroundings, health care workers (HCWs), and hospital sewage were collected. A. baumannii was identified by phenotypic and genotypic methods. Carbapenem resistance and insertion sequence element were detected. Typing was done by repetitive extragenic palindromic-polymerase chain reaction and multilocus sequence typing. Colonization pressure was calculated and compared with environment colonizers. Of the 87 patients, 21.83% (19) were colonized with A. baumannii, 73.68% (14/19) were imported, and 26.31% (5/19) acquired carriers. Axilla was the commonest site. From the environment (15), bed rails 33.33% (5/15) and suction tubes 26.66% (4/15) were the common sites. HCWs showed 7.5% (3/40) carriage. Carbapenem resistance with blaOXA-51, blaOXA-23, and ISAba1 were 91.89% (34/37). Strong correlation between colonization pressures and environmental colonizers was seen (r2 = 0.719, p = 0.032). Carbapenem and polymyxin B were (p ≤ 0.05) significant exposures. Sequence type 623 was the predominant cluster with isolates from carriers, HCWs, and environment. Colonization pressure of carbapenem-resistant A. baumannii depends on their presence in the hospital. Hands of HCWs were an important vehicle for transmission. Infection control measure should consider reducing the environmental reservoir.

Rapid recovery of native habitat-builders following physical disturbance on pier pilings offsets colonization of cryptogenic and non-indigenous species in a Chilean port

Examining the effects of disturbances within marine urban communities can shed light on their assembly rules and invasion processes. The effects of physical disturbance, through the removal of dominant native habitat-builders, were investigated in the recolonization of disturbed patches and colonization of plates on pier pilings, in a Chilean port. On pilings, disturbance substantially affected community structure after 3 months, although it slowly converged across treatments after 10 months. On plates, cryptogenic and non-indigenous species richness increased with removal severity, which was not observed in natives. Opportunistic taxa took advantage of colonizing at an early successional stage, illustrating a competition-colonization trade-off, although indirect effects might be at play (e.g. trophic competition or selective predation). Recovery of the habitat-builders then occurred at the expense of cryptogenic and non-indigenous taxa. Whether natives could continue winning against increasing propagule and colonization pressures in marine urban habitats deserves further attention. The interactions between disturbance and biological invasions herein experimentally shown in situ contribute to our understanding of multiple changes imposed by marine urbanization in a growing propagule transport network.

Highly Local Clostridioides difficile Infection (CDI) Pressure as Risk Factors for CDI

Background. Colonization pressure at the unit level is known to be a risk factor for Clostridioides difficile infections in hospitals. Because C. difficile colonization is not routinely detected in clinical practice, only patients identified as having C. difficile infection (CDI) are included in these pressure calculations. We used data from the University of Iowa Hospitals and Clinics (UIHC) to determine whether highly local CDI pressure, due to patients in nearby rooms, is more strongly correlated with CDI than unit-level CDI pressure. Methods: We designed a base logistic regression model using variables known to be risk factors for CDI: age, antibiotic/gastric acid suppressor use, low albumin, prior hospitalization, comorbidities. To the base model, we add 2 measures, mean colonization pressure (MCP) and sum colonization pressure (SCP) of CDI at the unit level to obtain new models. To the base model, we also added CDI colonization pressure by considering CDI cases at different distance thresholds from the focal patient. Distances between patient rooms were extracted from hospital floor plans. Results: Adding unit-level CDI colonization pressures to the base model improved performance. However, adding CDI colonization pressures due to roommates and due to patients at different distances improved the model much more (Table 1). The top (resp. bottom) row shows in-sample (resp. out-of-sample) C-statistics for the base model, the base model with unit-level MCP, the base model with roommate MCP, and the base model with MCP from patients are different distances added as separate features. C-statistics for the base model and the base model with unit CDI pressure (SCP and MCP) are compared in Fig. 1 with C-statistics from the base model with CDI pressure from patients at distances D = 0, 1, 2, 3, 4, 5, 10, 15, 20 hops (1 hop = 5–6 meters). Conclusions: Our results support the hypothesis that unit CDI colonization pressure is a risk factor for CDI. However, by incorporating spatially granular notions of distances between patients in our analysis, we were able to demonstrate that the true source of CDI pressure at the UIHC is almost exclusively attributable to roommates and patients in adjacent rooms.Funding: NoneDisclosures: None

Vancomycin-Resistant Enterococcus Acquisition in a Tertiary Care Hospital: Testing the Roles of Antibiotic Use, Proton Pump Inhibitor Use, and Colonization Pressure.

BackgroundVancomycin-resistant Enterococcus (VRE) is a leading cause of healthcare-associated infections, and asymptomatic colonization precedes infection. VRE continues to spread despite widespread application of pathogen-specific control guidelines. A better understanding of the risk factors for transmission is needed.MethodsA retrospective matched case-control study was performed from June 2013 through December 2016 in a single institution. Patients in 6 intensive care units, 1 hematology and oncology unit, and 1 bone marrow transplant unit were screened by means of rectal swab sampling on admission and weekly thereafter. Case patients had a negative swab sample followed by a positive sample >3 days after admission. Controls were closely matched to case patients based on time from admission to the second swab sample, unit in which the second sample was obtained, and date of admission. Comorbidity data, procedures, healthcare settings and exposures, culture data, and duration of antibiotic and proton pump inhibitor (PPI) therapy were abstracted from the electronic medical record. A multivariable risk factor model for conversion was generated using purposeful selection.ResultsA total of 551 case patients were matched with controls. The largest modifiable effects on VRE acquisition were ≥1 day of vancomycin therapy (odd ratio, 1.98; P < .001), ≥1 day of aerobic antibiotic therapy (1.90; P < .001), and a dose-dependent effect of PPI therapy (odds ratio per day of therapy, 1.09; P < .001). Colonization pressures from patients identified to be carriers and placed in contact precautions did not confer increased risk.ConclusionsDecreasing PPI use and preventing the inappropriate initiation of antibiotic therapy are modifiable targets to decrease VRE transmission in the hospital.

Landsat study of deforestation in the Amazon region of Colombia: Departments of Caquetá and Putumayo

The Amazon rainforest, the largest in the world in terms of size and diversity, is recognized as a source of ecological services for both local and worldwide communities. Ten percent of its territory belongs to Colombia, covering approximately 35% of the country's total area. In spite of global efforts, it continues to be vulnerable to deforestation pressures. In the departments of Caquetá and Putumayo, human activities such as logging and cattle ranching are the main causes of deforestation, which is increasing the department's vulnerability to climate change and natural hazards. However, there is a lack of consistent quantitative monitoring in the Colombian Amazon region, not only of total deforestation rates but also of specific locations and causes of deforestation, despite its high rates of deforestation compared to neighboring Ecuador. In this study, Landsat 7 ETM+ and Landsat 8 images over a sixteen-year period were used to map recent changes in land cover in the departments affected by deforestation. Supervised classifications were made using the Maximum Likelihood Classifier (MLC) and expert classification system, using False Color IR composites which were effective for identifying vegetation land cover. Over sixteen years, the Tropical Rainforest land cover in the study region lost 5.2% of its area, corresponding to 3020.56 square kilometers. Overall, the study region shows an annual rate of deforestation of 0.46%, and for Caquetá alone that rate is 0.77% - about twice as high as estimates from previous studies of between 0.38% and 0.4% loss rates for tropical South America. No single factor driving deforestation was found; rather, different regions within the study area displayed different rates and causes. The particularly rapid deforestation in the department of Caquetá and the encroachment of agricultural activities into national park reserves may be explained by higher colonization pressures and intensification of illegal coca cultivation.

Preface to “Invasive Species” Topical Collection

making valuable contributions to basic ecology and conservation biology. Invasion ecology is a rather young field, and much effort is still needed to develop generalized principles and to transform the discipline into a predictive science. The majority of studies on invasive species have focused on terrestrial habitats. However, marine and coastal systems worldwide are being invaded at extraordinary rates owing to shipping, opening and construction of seaways and canals, fisheries, aquarium trade, habitat modification, and climate change (Williams et al. 2013). In particular, shipping vectors such as ballast water and hull fouling, which are responsible for 65–70 % of aquatic invasions (Ricciardi 2006; Molnar et al. 2008), are capable of translocating almost entire aquatic communities during a single introduction event (Sylvester et al. 2011; Briski et al. 2012) and have no equivalent in the terrestrial environment. Therefore, work addressing key transport vectors in aquatic systems such as those that quantify the number of transported species and their abundances (i.e., propagule and colonization pressures), those that examine community dynamics of entrained assemblages during the transport process, and those that investigate genetic diversity and phenotypic plasticity of introduced species in relation to vector type is urgently needed. Further, studies identifying predictors of invasion success, forecasting impact of invasive species on invaded communities, and testing of hypotheses, such as the importance of hybridization, invasion meltdown, and enemy release, are essential for understanding mechanisms underlying invasion success in marine and coastal environments as well as abilities of invasive species to adapt rapidly during the invasion process. This ‘Topical Collection’ addresses many tenets of invasion ecology and sheds new light on this important part of marine biology. It provides a venue for the exchange of information on various aspects about aquatic invasion ecology and an opportunity Marine Biology introduces a new feature called ‘Topical Collections’, which promotes current and emergent areas of research. The electronic ‘Topical Collections’ are continuations of the former printed ‘Special Issues’, with an advantage of being publicly available with the very first article accepted. In addition to the online publication in the ‘Topical Collection’, all articles are published electronically and in print in regular volumes. The first Marine Biology ‘Topical Collection’ focuses on “Invasive Species”. Human population growth and increased global trade have significantly expanded our collective ecological ‘footprint’, with the introduction of nonindigenous species, particularly the invasive ones, being recognized as one of the dominant environmental stressors (Sala et al. 2000). Invasive species may act as predators, parasites, pathogens, or competitors of native species; their introductions and spread can result in dramatic changes in recipient ecosystems, including significant negative impact on local biodiversity as well as ecosystem functions and services to human society (Simberloff et al. 2013). The ability to predict and/or identify future invaders, the responsible transport vectors and pathways (i.e., transport means and routes), and potential impact would allow managers and policy makers to develop strategies to prevent new invasions and manage existing ones, while also

Variation in propagule and colonization pressures following rapid human‐mediated transport: Implications for a universal assemblage‐based management model

Recent studies have recognized the importance of propagule pressure (number of individuals) and colonization pressure (number of species) for explaining establishment success of nonindigenous species. However, the International Ballast Water Management Convention, when ratified, will require ships to satisfy a numeric discharge standard that focuses only on cumulative propagule pressure of all individuals released. Because of practical constraints, the standard does not differentiate between discharges of single vs. multiple species. The assemblage‐based approach, which uses rank‐abundance gradients to quantify and manage introduction risk, may compensate for this limitation (e.g., even gradient [relatively consistent propagule pressures among n transported species] or uneven gradient [uneven propagule pressures among n transported species]). Here we explore species abundance distributions of zooplankton during transportation in ballast water to assess variability in the structure of assemblages, with implications for the potential development of an assemblage‐based management model. Specifically, we explored species abundance distributions for voyages that lasted &lt; 24 h, those from 24 to 48 h, and those from 48 to 72 h (i.e., three time scales). Species abundance distributions within and across transit time scales were highly variable. As transport time increased, we observed a shift from uneven to even rank‐abundance gradients. Owing to variation in assemblage structure, the number of organisms necessary to quantify colonization pressure exhibited similarly strong variation within and across time scales. Our study indicates that assemblage‐based approaches to estimate introduction risk are warranted, yet the variation inherent in transported assemblages will induce substantial uncertainty within management models.

Risk factors for Pseudomonas aeruginosa acquisition in intensive care units: a prospective multicentre study

Pseudomonas aeruginosa is a major nosocomial pathogen in intensive care units (ICUs); however, endogenous versus exogenous origin of contamination remains unclear. To identify individual and environmental ICU risk factors for P. aeruginosa acquisition. A five-month prospective multicentric study was performed in ten French ICUs. Adult patients hospitalized in ICU for ≥ 24 h were included and screened for P. aeruginosa colonization on admission, weekly and before discharge. P. aeruginosa acquisition was defined by a subsequent colonization or infection if screening swabs on admission were negative. Water samples were obtained weekly on water taps of the ICUs. Data on patient characteristics, invasive devices exposure, antimicrobial therapy, P. aeruginosa water and patient colonization pressures, and ICU characteristics were collected. Hazard ratios (HRs) were estimated using multivariate Cox model. Among the 1314 patients without P. aeruginosa on admission, 201 (15%) acquired P. aeruginosa during their ICU stay. Individual characteristics significantly associated with P. aeruginosa acquisition were history of previous P. aeruginosa infection or colonization, cumulative duration of mechanical ventilation and cumulative days of antibiotics not active against P. aeruginosa. Environmental risk factors for P. aeruginosa acquisition were cumulative daily ward 'nine equivalents of nursing manpower use score' (NEMS) [hazard ratio (HR): 1.47 for ≥ 30 points; 95% confidence interval (CI): 1.06-2.03] and contaminated tap water in patient's room (HR: 1.76; CI: 1.09-2.84). Individual risk factors and environmental factors for which intervention is possible were identified for P. aeruginosa acquisition.

A conceptual model of community dynamics during the transport stage of the invasion process: a case study of ships’ ballast

AbstractAimAfter J. L. Lockwood, P. Cassey and T. Blackburn (2009, Diversity and Distributions, 15, 904–910) first described a theoretical relationship between propagule pressure and colonization pressure, two empirical studies demonstrated that the transport stage of the invasion process can profoundly influence the strength of the relationship among multiple events, as well as predictions of introduction risk. However, studies exploring dynamics of transported communities are rare, as repeated‐measures sampling during transportation by any vector is logistically difficult. We constructed a conceptual model of community dynamics during transportation and supported it by empirical data for propagule pressure and colonization pressure of plankton.LocationGlobal.MethodsA conceptual model of community dynamics was developed based on lognormal species abundance distribution and the simulation model of J. L. Lockwood, P. Cassey and T. Blackburn (2009, Diversity and Distributions, 15, 904–910). We considered four cases: case ‘A’ – no reduction in propagule nor colonization pressure; case ‘B’ – strong reduction in propagule and mild reduction in colonization pressure; case ‘C’ – mild reduction in propagule and strong reduction in colonization pressure; and case ‘D’ – strong reduction in both propagule and colonization pressures.ResultsThe cases ‘B’, ‘C’ and ‘D’ were supported by empirical data for invertebrates, dinoflagellates and diatoms from ships’ ballast tanks, respectively. Propagule pressure of invertebrates, dinoflagellates and diatoms decreased 99.95%, 80% and 94% in 25 days, respectively, while colonization pressure decreased 34%, 57% and 64%.Main conclusionsTransport affects both propagule pressure and colonization pressure of taxa, with the magnitude of change dependent on length of transport and taxon‐specific survival and reproduction. Our model demonstrates that introduction risk varies substantially across and within taxa depending on the occurrence and severity of selection pressures during transportation which serve to change species abundance distributions.

Study on the relationship between colonization pressure and MRSA cross transmission among hospitalized patients

Objective Based on active monitoring MRSA carriage for hospitalized patients, the relationship between colonization pressure and MRSA cross transmission in wards without rigorous contactisolation measures was analyzed, and the role of colonization pressure in predicting MRSA cross transmission was further evaluated. Methods From March to December 2009, active MRSA colonization screening was performed for 240 hospitalized patients in emergency ward and 94 cases in RICU in our hospital. rep-PCR method was employed to do homology analysis on MRSA strains obtained in this study. MRSA weekly colonization pressure, threshold colonization pressure ,cross transmission rate were calculated respectively. RR of MRSA cross transmission under higher level of colonization pressure and lower level of colonization pressure was analyzed. Results MRSA carriage rates on admission for patients in emergency wards and RICU were 6. 25% (15/2A0) and 13. 83 % (13/94) ,and MRSA cross transmission occurred in 13 weeks and 14 weeks in above two units, respectively. Threshold colonization pressures for above two units were 6. 49%and 17. 66%, respectively. For emergency ward, the MRSA cross transmission rate under higher level of colonization pressure was significantly higher than that under lower level of colonization pressure (x2 = 7. 10,P＜0. 01), the RR of MRSA transmission was 9. 61 (95% CI:1. 25-74.00). For RICU, the MRSA cross transmission rate under higher level of colonization pressure was significantly higher than that under lower level of colonization pressure(x2 = 12. 60, P＜0. 01 ), the RR of MRSA transmission was 15.87 (95% CI:2. 06-122. 10). Conclusions Higher level of colonization pressure is an important risk factor for MRSA transmission, and average colonization pressure can be used as a prediction index for MRSA transmission and strengthening prevention and control measures. Key words: Methicillin resistance; Staphylococcus aureus; Staphylococcal infections; Cross infection

COLONIALISM, AMERICANIZATION, AND INDIGENOUS IDENTITY: A RESEARCH NOTE ON CHAMORRO IDENTITY IN GUAM

ABSTRACT This study explores baseline dimensions of identity among Chamorros in Guam, as a case in point of indigenous identity consciousness, in the context of U.S. colonialism, territorial relations, and Americanization. Despite the adverse effects of colonization and Americanization pressures, ethnographic findings suggest that Chamorros are conscious of their indigenous identity with respect to reference-group interaction, political awareness, cultural attitudes, and self-identification. Implications of these preliminary findings for future research on this understudied topic and population are discussed.

Resistance in an Amazonian community: Huaorani organizing against the global economy

...a good book ...clearly written ...that raises a number of important general issues relevant to the contemporary political, and economic struggles of indigenous peoples of the Amazon and elsewhere. - Terence Turner, Cornell University Like many other indigenous groups, the Huaorani of eastern Ecuador are facing many challenges as they attempt to confront the globalization of capitalism in the 21st century. In 1991, they formed a political organization as a direct response to the growing threat to Huaorani territory posed by oil exploitation, colonization, and other pressures. The author explores the structures and practices of the organization, as well as the contradictions created by the imposition of an alien and hierarchical organizational form on a traditionally egalitarian society. This study has broad implications for those who work toward cultural survival or try to save the rainforest. A native of Pennsylvania, Lawrence Ziegler-Otero teaches in the Department of Anthropology at SUNY Plattsburgh. After a first career as a trade union organizer in the United States, he became an anthroplogist in order to study political, labor and indigenous organizations. He has also lived and worked in Ecuador and Puerto Rico.

Satellite change detection analysis of deforestation rates and patterns along the Colombia-Ecuador border.

This study uses Landsat satellite data to document the rates and patterns of land-cover change along a portion of the Colombia-Ecuador border during a 23-yr period (1973-1996). Human colonization has resulted in extensive deforestation in both countries. Satellite change detection analysis showed that the annual rates of deforestation were considerably higher for the Colombian side of the border. In addition, loss of forest cover on the Colombian side for the study period was almost 43%, while only 22% on the Ecuadorian side. The study found that there is no single factor driving deforestation on either side of the border, but concluded that the higher rates on the Colombian side may be due to higher colonization pressures and intensification of illegal coca cultivation. On the Ecuador side of the border the satellite images documented patterns of deforestation that reflected road networks associated with oil exploration and development.

Site-Specific Integrated Pest Management for High-Value Crops: Impact on Potato Pest Management

Site-specific agriculture optimizes agricultural inputs by varying application rates to match within-field requirements. Two years of trials were conducted in rotated commercial potato fields to compare traditional whole-field integrated pest management with site-specific management for Colorado potato beetle, Leptinotarsa decemlineata (Say), green peach aphid, Myzus persicae (Sulzer), and potato leafllopper, Empoasca fabae (Harris). Additionally, the spatial dynamics of Colorado potato beetle populations subjected to whole-field integrated pest management were studied. Colorado potato beetle infestations mostly remained near field edges throughout the season. Highest densities for each life stage remained near the locations of the initial colonizing adults. Even if management thresholds were as low as the 3rd density decile, between 60 and 95% of the field area could be left untreated when the mean density exceeded the threshold. Site-specific management reduced insecticide inputs for the green peach aphid but not for potato leafhopper. Initial Colorado potato beetle colonization pressure, measured as egg mass density ≈7 d after crop emergence, was a significant covariable in determining season-long insecticide requirements. Analysis of covariance demonstrated that after accounting for this variable, site-specific management significantly reduced insecticide inputs compared with whole-field integrated pest management. Cumulative season-long Colorado potato beetle insecticide savings of 30-40% across a broad range of colonization pressures were observed.