here - First Legume Society Conference (LSC1)

Book of Abstracts First Legume Society Conference 2013: A Legume Odyssey Novi Sad, Serbia, 9-11 May 2013
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Spatial and temporal relationships between pea aphids (Acyrthosiphon pisum Harris,
1776) and their natural enemies in the course of field peas (Pisum sativum L.) occupation
Marek Seidenglanz, Igor Huňady, Vojta Hlavjenka
AGRITEC Plant Research L.t.d., Šumperk, Czech Republic
Spatial distributions of pea aphid (Acyrthospihon pisum) and its natural enemies in field peas
(assessed in large field trials in the Czech Republic during 2008 - 2012, project NAZV:
QH82027) were influenced by the way of growing the crop. In field pea monocultures the aphids
tended to aggregate into clusters significantly more (Spatial Analysis by Distance IndEces was
used; SADIEShell version 1.22). Especially that was well apparent when insecticides were applied
into the crop some time (mostly 14 days) before the beginning of pea aphid fly activity. There
was easy to localize patch clusters (they were indicated by the values of aggregation Indices I a and
J a, p < 0,05), usually more than one per field, with differently large areas and with different
distances one another. In patch clusters (focuses) the infestation of plants were increasing
intensively in time and the infestation extended across the whole crop from them. The
distributions of aphids in field peas intercropping with spring cereals were more uniform (Indices
of aggregation, I a, were usually smaller than unity), aphids had weaker tendency to create
significant clusters and clear focuses of infestation in the crop and their population growth were
less dramatic. The distributions of pea aphids and their natural enemies (especially Syrphid´s
larvae and other predators and parasitoid A. ervi) were significantly associated only in field peas
intercropped with spring cereals. Field pea growing in monocultures and also using of insecticides
had clear negative effects on spatial and temporal associations (expressed by Indices of
associations I m) between distributions of pea aphids and their natural enemies in crops. Pea
aphid´s predators and parasitoids were able to find their host significantly earlier (temporal view)
and more effectively (spatial view) in field peas intercropping with spring cereals compared to
field peas monocultures (with or without insecticides). That fact explains earlier decline of pea
aphid populations in ecological mixtures compared to monocultures.
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