Philip Koehler

Dr. Philip Koehler


Research Focus & Metrics

Academic Career Length

31Years (1996-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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JFJodi M. Fiorenzano
Jodi M. Fiorenzano
PKPhilip Koehler
Philip Koehler
RXRui-De Xue
Rui-De Xue
Mosquito abatement programs contend with mosquito-borne diseases, insecticidal resistance, and environmental impacts to non-target organisms. However, chemical resources are limited to a few chemical classes with similar modes of action, which has led to insecticide resistance in mosquito populations. To develop a new tool for mosquito abatement programs that control mosquitoes while combating the issues of insecticidal resistance, and has low impacts of non-target organisms, novel methods of mosquito control, such as attractive toxic sugar baits (ATSBs), are being developed. Whereas insect baiting to dissuade a behavior, or induce mortality, is not a novel concept, as it was first introduced in writings from 77 AD, mosquito baiting through toxic sugar baits (TSBs) had been quickly developing over the last 60 years. This review addresses the current body of research of ATSB by providing an overview of active ingredients (toxins) include in TSBs, attractants combined in ATSB, lethal effects on mosquito adults and larvae, impact on non-target insects, and prospects for the use of ATSB.

29 June 2016 in Parasites & Vectors
Verified
Journal Article
Open access
PDF file
MSMohamed Sallam
Mohamed Sallam
RXRui-De Xue
Rui-De Xue
RPRoberto Pereira
Roberto Pereira
PKPhilip Koehler
Philip Koehler
The lack of available vaccines and consistent sporadic transmission of WNV justify the need for mosquito vector control and prediction of their geographic distribution. However, the distribution of WNV transmission is dependent on the mosquito vector and the ecological requirements, which vary from one place to another. Presence/density data of two WNV mosquito vectors, Culex nigripalpus and Cx. quinquefasciatus, was extracted within 5 km buffer zones around seropositive records of sentinel chickens in order to delineate their predicting variables and model the habitat suitability of probable infective mosquito using MaxEnt software. Different correlations between density data of the extracted mosquito vectors and 27 climate, land use-land cover, and land surface terrain variables were analyzed using linear regression analysis. Accordingly, the correlated predicting variables were used in building up habitat suitability model for the occurrence records of both mosquito vectors using MaxEnt. The density of both WNV mosquito vectors showed variation in their ecological requirements. Eight predicting variables, out of 27, had significant influence on density of Cx. nigripalpus. Precipitation of driest months was shown to be the best predicting variable for the density of this vector (R 2 = 41.70). Whereas, two variables were proven to predict the distribution of Cx. quinquefasciatus density. Vegetation showed the maximum predicting gain to the density of this mosquito vector (R 2 = 15.74), where nestling birds, in particular exotics, are found. Moreover, Jackknife analysis in MaxEnt demonstrated that urbanization and vegetation data layers significantly contribute in predicting habitat suitability of Cx. nigripalpus and Cx. quinquefasciatus occurrence, respectively, which justifies the contribution of the former in urban and the latter in epizootic transmission cycles of WNV. In addition, habitat suitability risk maps were produced for both vectors in response to their predicting variables. For the first time in the study area, a quantitative relationship between 27 predicting variables and two WNV mosquito vectors within their foraging habitats was highlighted at the local scale. Accordingly, the predicting variables were used to produce a practical distribution map of probable infective mosquito vectors. This substantially helps in determining where suitable habitats are found. This will potentially help in designing target surveillance and control programmes, saving money, time and man-power. However, the suitability risk maps should be updated when serological and entomological data updates are available.

1 September 2016 in Florida Entomologist
Verified
Journal Article
Open access
BCBrittany Campbell
Brittany Campbell
PKPhilip Koehler
Philip Koehler
LBLyle J. Buss
Lyle J. Buss
RBRebecca Baldwin
Rebecca Baldwin
Summary This is the first report of the tropical bed bug in Florida in over 6 decades. The tropical bed bug had previously been documented in Florida in the 1930s and 1940s. Sumario Este es el primer informe de la chinche de cama tropical en la Florida en más de 6 décadas. La chinche de cama tropical ya había sido documentada en la Florida en los años 1930 y 1940.

MSMohamed Sallam
Mohamed Sallam
SMSarah R. Michaels
Sarah R. Michaels
CRClaudia Riegel
Claudia Riegel
RPRoberto Pereira
Roberto Pereira
WZWayne Zipperer
Wayne Zipperer
PKPhilip Koehler
Philip Koehler
The consistent sporadic transmission of West Nile Virus (WNV) in the city of New Orleans justifies the need for distribution risk maps highlighting human risk of mosquito bites. We modeled the influence of biophysical and socioeconomic metrics on the spatio-temporal distributions of presence/vector-host contact (VHC) ratios of WNV vector, Culex quinquefasciatus, within their flight range. Biophysical and socioeconomic data were extracted within 5-km buffer radii around sampling localities of gravid female Culex quinquefasciatus. The spatio-temporal correlations between VHC data and 33 variables, including climate, land use-land cover (LULC), socioeconomic, and land surface terrain were analyzed using stepwise linear regression models (RM). Using MaxEnt, we developed a distribution model using the correlated predicting variables. Only 12 factors showed significant correlations with spatial distribution of VHC ratios (R2 = 81.62, p < 0.01). Non-forested wetland (NFWL), tree density (TD) and residential-urban (RU) settings demonstrated the strongest relationship. The VHC ratios showed monthly environmental resilience in terms of number and type of influential factors. The highest prediction power of RU and other urban and built up land (OUBL), was demonstrated during May–August. This association was positively correlated with the onset of the mosquito WNV infection rate during June. These findings were confirmed by the Jackknife analysis in MaxEnt and independently collected field validation points. The spatial and temporal correlations of VHC ratios and their response to the predicting variables are discussed.

1 March 2009 in Journal of Medical Entomology
Verified
Journal Article
Open access
PDF file
ACAlexandra Chaskopoulou
Alexandra Chaskopoulou
SNSam Nguyen
Sam Nguyen
RPRoberto Pereira
Roberto Pereira
MSMichael E. Scharf
Michael E. Scharf
PKPhilip Koehler
Philip Koehler
This research studied 31 volatile compounds for indoor control of the medically important mosquitoes Aedes aegypti L. and Culex quinquefasciatus Say. Only adult female mosquitoes were tested. The test compounds were from six families that included five heterobicyclics, eight formate esters, formic acid (a hydrolyzed metabolite of formate esters), eight acetate esters, four propionate esters, three butyrate esters, and two valerate esters. Also, the organophosphate compound dichlorvos (DDVP) was tested as a positive control. Cx. quinquefasciatus was generally more susceptible than Ae. aegypti. Cx. quinquefasciatus was most susceptible to a subset of heterobicyclics and formate esters (rank: n-butyl formate > hexyl formate = dihydrobenzofuran = menthofuran = heptyl formate = ethyl formate). Ae. aegypti was most susceptible to a subset of formate esters (rank: methyl > n-butyl > propyl = ethyl = hexyl). The most active materials against both species had LC50s of 0.4–1 mg active ingredient per 0.5 liter of air volume (0.8–2 mg/liter), which is 50- to 60-fold less toxic than dichlorvos (an organophosphate insecticide that is being phased out from indoor use). In relation to Drosophila melanogaster Meigen, both mosquito species were generally more susceptible to formate esters but more tolerant of heterobicyclics. Generally, the most toxic compound against all dipterans tested to date is n-butyl formate, whereas menthofuran is additionally toxic against Cx. quinquefasciatus and D. melanogaster. Finally, the toxicity differences between species point to the potential for differential toxicity among mosquito genera/species, suggesting that further studies of a number of mosquito species might be warranted.

25 April 2016 in Journal of Medical Entomology
Verified
Journal Article
Closed access
PDF file
CMCorraine A. McNeill
Corraine A. McNeill
RPRoberto Pereira
Roberto Pereira
PKPhilip Koehler
Philip Koehler
SMSeth A. McNeill
Seth A. McNeill
RBRebecca Baldwin
Rebecca Baldwin
Behavioral bioassays were conducted to determine whether bed bug adults and nymphs prefer specific colored harborages. Two-choice and seven-choice behavioral color assays indicate that red (28.5%) and black (23.4%) harborages are optimal harborage choices for bed bugs. Yellow and green harborages appear to repel bed bugs. Harborage color preferences change according to gender, nutritional status, aggregation, and life stage. Female bed bugs prefer harborages with shorter wavelengths (lilac—14.5% and violet—11.5%) compared to males, whereas males prefer harborages with longer wavelengths (red—37.5% and black—32%) compared with females. The preference for orange and violet harborages is stronger when bed bugs are fed as opposed to when they are starved. Lone bed bugs (30%) prefer to be in black harborages while red harborages appear to be the optimum harborage color for bed bugs in more natural mixed aggregations (35.5%). Bed bug nymphs preferred different colored harborages at each stage of development, which is indicative of their developing eye structures and pigments. First instars showed no significant preference for any colored harborage soon after hatching. However, by the fifth instar, 27.5% of nymphs significantly preferred red and black harborages (which was a similar preference to adult bed bugs). The proportion of oviposited eggs was significantly greater under blue, red, and black harborages compared to other colored harborages tested. The use of visual cues such as specific colors offers great potential for improving bed bug monitoring tools by increasing trap captures.