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Pollen Beetles (pollen + beetle)

Distribution by Scientific Domains
Life Sciences66%

Selected Abstracts

Pollen beetle in the UK; the start of a resistance problem?

EPPO BULLETIN, Issue 1 2008
D. M. Richardson
In 2003, the first report of poor control of pollen beetle Meligethes aeneus at a site in South East England in the UK was investigated but resistance to pyrethroid insecticides was not confirmed in subsequent laboratory testing. Bioassays of 26 UK samples of M. aeneus collected in 2004 with the pyrethroid lambda-cyhalothrin showed little or no divergence from the response expected of a fully susceptible strain. In 2006 samples of pollen beetle from the UK were sent to Germany, and again these were shown to be fully susceptible. In 2007 using test kits supplied by Udo Heimbach, BBA, 19 samples of pollen beetle were tested, again from across the UK. Results indicated that a small number of individuals were fully resistant, surviving the highest dose of lambda-cyhalothrin tested (0.375 microg/L) after 5-h exposure at 4 sites, and after 24-h exposure at 2 of these sites. [source]

Host plant affects pollen beetle (Meligethes aeneus) egg size

PHYSIOLOGICAL ENTOMOLOGY, Issue 2 2004
Barbara Ekbom
Abstract., In some herbivorous insect species, egg size is larger on low-quality hosts than on high-quality hosts and may be related to the prospect that larger offspring are more likely to survive on a poor host. Sizes of eggs laid by pollen beetles [Meligethes aeneus Fab. (Coleoptera: Nitidulidae)] were examined with insects confined on one of two different host plants that had previously shown differences in adult preference and larval performance. Individual females were also exposed sequentially to both the low-quality host (Sinapis alba L.) and the high-quality host (Brassica napus L.) and the size of their eggs was determined. Pollen beetles laid shorter eggs on low-quality hosts both for different females on different host plants and for the same individuals on different host plants, in contrast to the prediction that low-quality hosts would receive larger eggs than high-quality hosts. Previously, egg production rate was shown to be reduced when pollen beetles are exposed to low-quality hosts and it is suggested that oogenesis is incomplete, resulting in shorter eggs. The possibility that this is related to antibiosis on S. alba is discussed. [source]

Summary of findings from a participant country pollen beetle questionnaire

EPPO BULLETIN, Issue 1 2008
D. M. Richardson
A questionnaire was sent to all participating countries to gain some background information on rape growing and on pollen beetle (Meligethes aeneus). Information was sought on the use of thresholds, the availability of active substances and on the year in which resistance, if present, had been observed. A summary of the main findings of the questionnaire are presented. In total 20 countries responded and resistance in pollen beetle was reported in 12 of those countries. Information presented shows the range of active substances and doses recommended, frequency of use of insecticides on rape, and year when resistance was reported. [source]

Pollen beetle in the UK; the start of a resistance problem?

EPPO BULLETIN, Issue 1 2008
D. M. Richardson
In 2003, the first report of poor control of pollen beetle Meligethes aeneus at a site in South East England in the UK was investigated but resistance to pyrethroid insecticides was not confirmed in subsequent laboratory testing. Bioassays of 26 UK samples of M. aeneus collected in 2004 with the pyrethroid lambda-cyhalothrin showed little or no divergence from the response expected of a fully susceptible strain. In 2006 samples of pollen beetle from the UK were sent to Germany, and again these were shown to be fully susceptible. In 2007 using test kits supplied by Udo Heimbach, BBA, 19 samples of pollen beetle were tested, again from across the UK. Results indicated that a small number of individuals were fully resistant, surviving the highest dose of lambda-cyhalothrin tested (0.375 microg/L) after 5-h exposure at 4 sites, and after 24-h exposure at 2 of these sites. [source]

Different methods of monitoring susceptibility of oilseed rape beetles to insecticides

EPPO BULLETIN, Issue 1 2008
T. Thieme
The resistance of oilseed rape pollen beetles to lambda-cyhalothrin has increased in Germany over the period 2002 to 2007. Oilseed rape pollen beetles are very good at dispersing, therefore field results should always be compared with those of laboratory experiments. The response of oilseed rape pollen beetles to active substances may not be the same as that to formulated products. Bioassays in which beetles are exposed to insecticides on either complete inflorescences or flower buds give different results. It is evident that samples of the genus Meligethes collected in the field can include several different species. Monitoring for insecticide resistance should be done using only the true oilseed rape pollen beetle. [source]

Host plant affects pollen beetle (Meligethes aeneus) egg size

PHYSIOLOGICAL ENTOMOLOGY, Issue 2 2004
Barbara Ekbom
Abstract., In some herbivorous insect species, egg size is larger on low-quality hosts than on high-quality hosts and may be related to the prospect that larger offspring are more likely to survive on a poor host. Sizes of eggs laid by pollen beetles [Meligethes aeneus Fab. (Coleoptera: Nitidulidae)] were examined with insects confined on one of two different host plants that had previously shown differences in adult preference and larval performance. Individual females were also exposed sequentially to both the low-quality host (Sinapis alba L.) and the high-quality host (Brassica napus L.) and the size of their eggs was determined. Pollen beetles laid shorter eggs on low-quality hosts both for different females on different host plants and for the same individuals on different host plants, in contrast to the prediction that low-quality hosts would receive larger eggs than high-quality hosts. Previously, egg production rate was shown to be reduced when pollen beetles are exposed to low-quality hosts and it is suggested that oogenesis is incomplete, resulting in shorter eggs. The possibility that this is related to antibiosis on S. alba is discussed. [source]

Different methods of monitoring susceptibility of oilseed rape beetles to insecticides

EPPO BULLETIN, Issue 1 2008
T. Thieme
The resistance of oilseed rape pollen beetles to lambda-cyhalothrin has increased in Germany over the period 2002 to 2007. Oilseed rape pollen beetles are very good at dispersing, therefore field results should always be compared with those of laboratory experiments. The response of oilseed rape pollen beetles to active substances may not be the same as that to formulated products. Bioassays in which beetles are exposed to insecticides on either complete inflorescences or flower buds give different results. It is evident that samples of the genus Meligethes collected in the field can include several different species. Monitoring for insecticide resistance should be done using only the true oilseed rape pollen beetle. [source]

Genetic diversity in pollen beetles (Meligethes aeneus) in Sweden: role of spatial, temporal and insecticide resistance factors

AGRICULTURAL AND FOREST ENTOMOLOGY, Issue 4 2007
Nadiya Kazachkova
Abstract 1,Pollen beetles Meligethes aeneus are pests of oilseed Brassica crops that are subject to intensive chemical control. Resistance to pyrethroids has been reported. Although this insect is of great economic importance, little is known about its genetic properties and population structure. 2,Amplified fragment length polymorphism (AFLP) analysis with the restriction endonuclease combination EcoRI and PstI was performed on 133 samples of groups of three pollen beetles collected during 2001,04 from five different provinces of Sweden. Both susceptible and resistant insects were studied. Using one primer combination, more than 450 polymorphic DNA fragments were obtained and, in total, four primer combinations were used for analysis. A subsample of 59 single beetles was analysed using one primer combination. 3,AFLP profiles were analysed by similarity measures using the Nei and Li coefficient and Neighbour-joining dendrograms were generated. The dendrogram built using 133 samples showed three distinct groups, each containing beetles representing one generation. Statistical analysis using analysis of molecular variance of single beetle samples showed no evidence of significant genetic difference between resistant and susceptible beetles. Instead, a clear difference between samples, depending on time of collection and generation, was observed. 4,The expected regional population structure, although statistically significant, explained little of the variation. The levels of genetic variation within populations were very high. There appears to be a high rate of gene flow between pollen beetle populations. The implications of this in the context of insecticide resistance are discussed. [source]

Insecticide-resistant pollen beetles (Meligethes aeneus F) found in Danish oilseed rape (Brassica napus L) fields

PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 9 2003
Lars Monrad Hansen
Abstract The pollen beetle is the most important pest in Danish oilseed rape fields. In 2001, we screened a broad range of pollen beetle populations for pyrethroid and dimethoate resistance. A standard dip-test was used to test insecticide resistance in 18 populations collected from oilseed winter and spring rape fields. The beetles were treated with four different insecticides: the pyrethroids tau-fluvalinate, lambda-cyhalothrin and esfenvalerate, and the organophosphate dimethoate. The results show that up to 99% of the pollen beetles survived Danish standard doses of pyrethroids and up to 36% of the beetles survived standard doses of dimethoate. Copyright © 2003 Society of Chemical Industry [source]

Host plant affects pollen beetle (Meligethes aeneus) egg size

PHYSIOLOGICAL ENTOMOLOGY, Issue 2 2004
Barbara Ekbom
Abstract., In some herbivorous insect species, egg size is larger on low-quality hosts than on high-quality hosts and may be related to the prospect that larger offspring are more likely to survive on a poor host. Sizes of eggs laid by pollen beetles [Meligethes aeneus Fab. (Coleoptera: Nitidulidae)] were examined with insects confined on one of two different host plants that had previously shown differences in adult preference and larval performance. Individual females were also exposed sequentially to both the low-quality host (Sinapis alba L.) and the high-quality host (Brassica napus L.) and the size of their eggs was determined. Pollen beetles laid shorter eggs on low-quality hosts both for different females on different host plants and for the same individuals on different host plants, in contrast to the prediction that low-quality hosts would receive larger eggs than high-quality hosts. Previously, egg production rate was shown to be reduced when pollen beetles are exposed to low-quality hosts and it is suggested that oogenesis is incomplete, resulting in shorter eggs. The possibility that this is related to antibiosis on S. alba is discussed. [source]