Pherocon AM trapping and the "whole plant count" method - A comparison of two sampling techniques to estimate the WCR adult densities in Central Europe

R. Bažok, I. Sivčev, T. Kos, J. Igrc Barčić, J. Kiss, S. Jankovič

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Pherocon AM (PhAM) trapping and visual counting are two commonly used methods for identifying maize fields in the USA that contain a sufficient number of adult western corn rootworms (WCR), Diabrotica virgifera virgifera LeConte to cause economic root damage by larvae the following year. Therefore, the estimation of adult WCR population plays an important role in management decisions (rotation or treatment). The goals of this study were (1) to compare adult WCR data obtained by PhAM trapping to "whole plant count" data in different maize developmental stages, (2) to determine the period in which the data obtained by both methods show the highest correlation, (3) to determine the regression curve between capture of WCR on PhAM as an independent variable and number of WCR observed by visual plant count, and (4) to determine if the "whole plant count" method can serve as a substitution for PhAM trapping under European conditions. Three samplings were conducted in 2006 in 38 fields in Croatia and one sampling was conducted in 22 fields in Serbia. Sampling in Croatia was conducted when maize plants were in the R 65-69, R 73-77 and R 79-85 developmental stages according to BBCH identification keys of maize. Sampling in Serbia was conducted when maize plants reached R 69-71 developmental stages. Three to six PhAM traps were placed in each 0.5 to 4 ha maize field seven days prior to sampling. Visual counts were conducted on the same day as trap inspections. Adult WCR densities in the PhAM traps were correlated to adult densities on whole plants. Statistical analyses comparing the results of PhAM trapping with the visual "whole plant count" method showed that there is a significant medium to strong correlation between them. Correlation coefficients varied depending on the data used in the analysis. When sampling was conducted in the first half of August (maize developmental stages R 69-77), the correlation coefficients were the highest (r(R 6971) = 0.8677 and r(R 73-77) = 0.706). Coefficients of determination were the highest as well [r2(R 69-71) = 0.753; r2(R 73-77) = 0.4984]. Therefore, the most appropriate period for sampling is during the first half of August. At that time, the majority of the maize plants were between the R 69 and R 77 developmental stages. According to the results, 0.5-1 visually determined adult/plant corresponds to 40 adults/trap/week. This shows that both methods are equally useful for estimating the population densities of WCR in the Central European region.

Original languageEnglish
Pages (from-to)298-305
Number of pages8
JournalCereal Research Communications
Volume39
Issue number2
DOIs
Publication statusPublished - Jun 1 2011

Fingerprint

Diabrotica virgifera virgifera
Central European region
Zea mays
trapping
corn
developmental stages
traps
sampling
Serbia
Croatia
methodology
taxonomic keys
mature plants
population density
economics
larvae
Population Density

Keywords

  • Central Europe
  • correlations
  • Pherocon AM traps
  • sampling techniques
  • western corn rootworm
  • whole plant counts

ASJC Scopus subject areas

  • Agronomy and Crop Science
  • Genetics
  • Physiology

Cite this

Pherocon AM trapping and the "whole plant count" method - A comparison of two sampling techniques to estimate the WCR adult densities in Central Europe. / Bažok, R.; Sivčev, I.; Kos, T.; Igrc Barčić, J.; Kiss, J.; Jankovič, S.

In: Cereal Research Communications, Vol. 39, No. 2, 01.06.2011, p. 298-305.

Research output: Contribution to journalArticle

@article{bc1fbb2762ee4af5acf8f89668ea34e6,
title = "Pherocon AM trapping and the {"}whole plant count{"} method - A comparison of two sampling techniques to estimate the WCR adult densities in Central Europe",
abstract = "Pherocon AM (PhAM) trapping and visual counting are two commonly used methods for identifying maize fields in the USA that contain a sufficient number of adult western corn rootworms (WCR), Diabrotica virgifera virgifera LeConte to cause economic root damage by larvae the following year. Therefore, the estimation of adult WCR population plays an important role in management decisions (rotation or treatment). The goals of this study were (1) to compare adult WCR data obtained by PhAM trapping to {"}whole plant count{"} data in different maize developmental stages, (2) to determine the period in which the data obtained by both methods show the highest correlation, (3) to determine the regression curve between capture of WCR on PhAM as an independent variable and number of WCR observed by visual plant count, and (4) to determine if the {"}whole plant count{"} method can serve as a substitution for PhAM trapping under European conditions. Three samplings were conducted in 2006 in 38 fields in Croatia and one sampling was conducted in 22 fields in Serbia. Sampling in Croatia was conducted when maize plants were in the R 65-69, R 73-77 and R 79-85 developmental stages according to BBCH identification keys of maize. Sampling in Serbia was conducted when maize plants reached R 69-71 developmental stages. Three to six PhAM traps were placed in each 0.5 to 4 ha maize field seven days prior to sampling. Visual counts were conducted on the same day as trap inspections. Adult WCR densities in the PhAM traps were correlated to adult densities on whole plants. Statistical analyses comparing the results of PhAM trapping with the visual {"}whole plant count{"} method showed that there is a significant medium to strong correlation between them. Correlation coefficients varied depending on the data used in the analysis. When sampling was conducted in the first half of August (maize developmental stages R 69-77), the correlation coefficients were the highest (r(R 6971) = 0.8677 and r(R 73-77) = 0.706). Coefficients of determination were the highest as well [r2(R 69-71) = 0.753; r2(R 73-77) = 0.4984]. Therefore, the most appropriate period for sampling is during the first half of August. At that time, the majority of the maize plants were between the R 69 and R 77 developmental stages. According to the results, 0.5-1 visually determined adult/plant corresponds to 40 adults/trap/week. This shows that both methods are equally useful for estimating the population densities of WCR in the Central European region.",
keywords = "Central Europe, correlations, Pherocon AM traps, sampling techniques, western corn rootworm, whole plant counts",
author = "R. Bažok and I. Sivčev and T. Kos and {Igrc Barčić}, J. and J. Kiss and S. Jankovič",
year = "2011",
month = "6",
day = "1",
doi = "10.1556/CRC.39.2011.2.14",
language = "English",
volume = "39",
pages = "298--305",
journal = "Cereal Research Communications",
issn = "0133-3720",
publisher = "Cereal Research Non-Profit Company",
number = "2",

}

TY - JOUR

T1 - Pherocon AM trapping and the "whole plant count" method - A comparison of two sampling techniques to estimate the WCR adult densities in Central Europe

AU - Bažok, R.

AU - Sivčev, I.

AU - Kos, T.

AU - Igrc Barčić, J.

AU - Kiss, J.

AU - Jankovič, S.

PY - 2011/6/1

Y1 - 2011/6/1

N2 - Pherocon AM (PhAM) trapping and visual counting are two commonly used methods for identifying maize fields in the USA that contain a sufficient number of adult western corn rootworms (WCR), Diabrotica virgifera virgifera LeConte to cause economic root damage by larvae the following year. Therefore, the estimation of adult WCR population plays an important role in management decisions (rotation or treatment). The goals of this study were (1) to compare adult WCR data obtained by PhAM trapping to "whole plant count" data in different maize developmental stages, (2) to determine the period in which the data obtained by both methods show the highest correlation, (3) to determine the regression curve between capture of WCR on PhAM as an independent variable and number of WCR observed by visual plant count, and (4) to determine if the "whole plant count" method can serve as a substitution for PhAM trapping under European conditions. Three samplings were conducted in 2006 in 38 fields in Croatia and one sampling was conducted in 22 fields in Serbia. Sampling in Croatia was conducted when maize plants were in the R 65-69, R 73-77 and R 79-85 developmental stages according to BBCH identification keys of maize. Sampling in Serbia was conducted when maize plants reached R 69-71 developmental stages. Three to six PhAM traps were placed in each 0.5 to 4 ha maize field seven days prior to sampling. Visual counts were conducted on the same day as trap inspections. Adult WCR densities in the PhAM traps were correlated to adult densities on whole plants. Statistical analyses comparing the results of PhAM trapping with the visual "whole plant count" method showed that there is a significant medium to strong correlation between them. Correlation coefficients varied depending on the data used in the analysis. When sampling was conducted in the first half of August (maize developmental stages R 69-77), the correlation coefficients were the highest (r(R 6971) = 0.8677 and r(R 73-77) = 0.706). Coefficients of determination were the highest as well [r2(R 69-71) = 0.753; r2(R 73-77) = 0.4984]. Therefore, the most appropriate period for sampling is during the first half of August. At that time, the majority of the maize plants were between the R 69 and R 77 developmental stages. According to the results, 0.5-1 visually determined adult/plant corresponds to 40 adults/trap/week. This shows that both methods are equally useful for estimating the population densities of WCR in the Central European region.

AB - Pherocon AM (PhAM) trapping and visual counting are two commonly used methods for identifying maize fields in the USA that contain a sufficient number of adult western corn rootworms (WCR), Diabrotica virgifera virgifera LeConte to cause economic root damage by larvae the following year. Therefore, the estimation of adult WCR population plays an important role in management decisions (rotation or treatment). The goals of this study were (1) to compare adult WCR data obtained by PhAM trapping to "whole plant count" data in different maize developmental stages, (2) to determine the period in which the data obtained by both methods show the highest correlation, (3) to determine the regression curve between capture of WCR on PhAM as an independent variable and number of WCR observed by visual plant count, and (4) to determine if the "whole plant count" method can serve as a substitution for PhAM trapping under European conditions. Three samplings were conducted in 2006 in 38 fields in Croatia and one sampling was conducted in 22 fields in Serbia. Sampling in Croatia was conducted when maize plants were in the R 65-69, R 73-77 and R 79-85 developmental stages according to BBCH identification keys of maize. Sampling in Serbia was conducted when maize plants reached R 69-71 developmental stages. Three to six PhAM traps were placed in each 0.5 to 4 ha maize field seven days prior to sampling. Visual counts were conducted on the same day as trap inspections. Adult WCR densities in the PhAM traps were correlated to adult densities on whole plants. Statistical analyses comparing the results of PhAM trapping with the visual "whole plant count" method showed that there is a significant medium to strong correlation between them. Correlation coefficients varied depending on the data used in the analysis. When sampling was conducted in the first half of August (maize developmental stages R 69-77), the correlation coefficients were the highest (r(R 6971) = 0.8677 and r(R 73-77) = 0.706). Coefficients of determination were the highest as well [r2(R 69-71) = 0.753; r2(R 73-77) = 0.4984]. Therefore, the most appropriate period for sampling is during the first half of August. At that time, the majority of the maize plants were between the R 69 and R 77 developmental stages. According to the results, 0.5-1 visually determined adult/plant corresponds to 40 adults/trap/week. This shows that both methods are equally useful for estimating the population densities of WCR in the Central European region.

KW - Central Europe

KW - correlations

KW - Pherocon AM traps

KW - sampling techniques

KW - western corn rootworm

KW - whole plant counts

UR - http://www.scopus.com/inward/record.url?scp=79957521264&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=79957521264&partnerID=8YFLogxK

U2 - 10.1556/CRC.39.2011.2.14

DO - 10.1556/CRC.39.2011.2.14

M3 - Article

AN - SCOPUS:79957521264

VL - 39

SP - 298

EP - 305

JO - Cereal Research Communications

JF - Cereal Research Communications

SN - 0133-3720

IS - 2

ER -