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The role of pollinators, pests and different yield components for organic and conventional white clover seed yields

Lundin, Ola LU ; Svensson, Glenn P. LU ; Larsson, Mattias C. LU ; Birgersson, Göran LU ; Hederström, Veronica; Lankinen, Åsa LU ; Anderbrant, Olle LU and Rundlöf, Maj LU (2017) In Field Crops Research 210. p.1-8
Abstract

A high and stable seed production of both organic and conventional white clover (Trifolium repens L.) is needed to meet market requirements. Seed yields of white clover are, however, known to vary greatly, and organic yields are often considerably lower than conventional yields. Our aim in this study was to estimate the roles of pollinators, pests and different yield components for organic and conventional white clover seed yields. We surveyed pollinators (honey bees, bumble bees and solitary bees), reared the main insect pests (Protapion fulvipes Geoffroy and Hypera spp. weevils) from flowers and measured the yield components (inflorescences per area, flowers per inflorescence, seeds per flower and weight per seed) in organic,... (More)

A high and stable seed production of both organic and conventional white clover (Trifolium repens L.) is needed to meet market requirements. Seed yields of white clover are, however, known to vary greatly, and organic yields are often considerably lower than conventional yields. Our aim in this study was to estimate the roles of pollinators, pests and different yield components for organic and conventional white clover seed yields. We surveyed pollinators (honey bees, bumble bees and solitary bees), reared the main insect pests (Protapion fulvipes Geoffroy and Hypera spp. weevils) from flowers and measured the yield components (inflorescences per area, flowers per inflorescence, seeds per flower and weight per seed) in organic, conventional untreated and conventional insecticide treated plots in 27 white clover seed fields over two years in southernmost Sweden. Unexpectedly, densities of bees other than honey bees were higher in insecticide treated plots compared to organic plots, but pollinator densities were not related to seed set. The lower pollinator visitation in organic plots might have been caused by pest damage to the flowers, as P. fulvipes and Hypera spp. weevils were more common in organic plots than in conventional insecticide treated plots. The abundances of both P. fulvipes and Hypera spp. weevils were negatively related to seed set, with P. fulvipes being most damaging for seed set. Seed yield was considerably lower (42%) in organic plots compared to conventional insecticide treated plots, and this was driven by a lower (36%) seed set. Taken together, our results indicate that pollinator densities are not limiting yields in either conventional or organic white clover seed production, whereas P. fulvipes crop damage is an important factor limiting organic yields via negative effects on seed set. Research efforts to raise white clover seed yield with minimized environmental impacts should include a focus on integrated pest management of P. fulvipes, including the development of control methods accepted in organic farming.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Apis mellifera, Integrated pest management, Protapion fulvipes, Trifolium repens
in
Field Crops Research
volume
210
pages
8 pages
publisher
Elsevier
external identifiers
  • scopus:85019942130
  • wos:000405251300001
ISSN
0378-4290
DOI
10.1016/j.fcr.2017.05.014
language
English
LU publication?
yes
id
4848df4c-3f7f-4259-a64c-4e6c9b7d2cb4
date added to LUP
2017-06-14 11:35:08
date last changed
2017-09-18 11:41:02
@article{4848df4c-3f7f-4259-a64c-4e6c9b7d2cb4,
  abstract     = {<p>A high and stable seed production of both organic and conventional white clover (Trifolium repens L.) is needed to meet market requirements. Seed yields of white clover are, however, known to vary greatly, and organic yields are often considerably lower than conventional yields. Our aim in this study was to estimate the roles of pollinators, pests and different yield components for organic and conventional white clover seed yields. We surveyed pollinators (honey bees, bumble bees and solitary bees), reared the main insect pests (Protapion fulvipes Geoffroy and Hypera spp. weevils) from flowers and measured the yield components (inflorescences per area, flowers per inflorescence, seeds per flower and weight per seed) in organic, conventional untreated and conventional insecticide treated plots in 27 white clover seed fields over two years in southernmost Sweden. Unexpectedly, densities of bees other than honey bees were higher in insecticide treated plots compared to organic plots, but pollinator densities were not related to seed set. The lower pollinator visitation in organic plots might have been caused by pest damage to the flowers, as P. fulvipes and Hypera spp. weevils were more common in organic plots than in conventional insecticide treated plots. The abundances of both P. fulvipes and Hypera spp. weevils were negatively related to seed set, with P. fulvipes being most damaging for seed set. Seed yield was considerably lower (42%) in organic plots compared to conventional insecticide treated plots, and this was driven by a lower (36%) seed set. Taken together, our results indicate that pollinator densities are not limiting yields in either conventional or organic white clover seed production, whereas P. fulvipes crop damage is an important factor limiting organic yields via negative effects on seed set. Research efforts to raise white clover seed yield with minimized environmental impacts should include a focus on integrated pest management of P. fulvipes, including the development of control methods accepted in organic farming.</p>},
  author       = {Lundin, Ola and Svensson, Glenn P. and Larsson, Mattias C. and Birgersson, Göran and Hederström, Veronica and Lankinen, Åsa and Anderbrant, Olle and Rundlöf, Maj},
  issn         = {0378-4290},
  keyword      = {Apis mellifera,Integrated pest management,Protapion fulvipes,Trifolium repens},
  language     = {eng},
  month        = {08},
  pages        = {1--8},
  publisher    = {Elsevier},
  series       = {Field Crops Research},
  title        = {The role of pollinators, pests and different yield components for organic and conventional white clover seed yields},
  url          = {http://dx.doi.org/10.1016/j.fcr.2017.05.014},
  volume       = {210},
  year         = {2017},
}