Joint International Conference on Long-term Experiments ...

Table 1. The density of harmful pest species in wheat crops from Oradea in the 2005
– 2006 agricultural year
Species Date of control Density
Zabrus tenebrioides October 8 2.7 larvae/ m²
Eurygaster maura May 11 6.2 adults / m²
Eurygaster integriceps May 11 3.1 adults / m²
Aelia rostrata May 11 4.1 adults / m²
Oulema melanopus April 9 12 adults / m²
Oulema melanopus May 13 220 larvae / m²
Schyzaphis graminum June 24 56 aphids / plant
Haplotrips tritici June 16 27 adults and larvae / ear
Anisoplia spp June 29 9 adults / m²
Oscinella frit October 22 11.3% attacked plants
Cephus pygmaeus June 29 3.4% attacked plants
Macrosteles laevis October 28 11 adults / m²
Agriotes spp April 5 6 larvae / m²
Naturally, some of these species hold a minor economic importance in the area, partly
as a result of the fact that plants rebuild their vegetative mass, thus no production losses
due exclusively to pests are registered.
Of the total number of pests collected in cereal ecosystems, the dominant species were
the ones whose frequency is presented in table 2. The numbers represent the average
values of mowings at different dates.
Table 2. The frequency of pest fauna (%) in cereal crops
Crop Wheat Barley Oats Triticale
Species % % % %
Phyllotreta spp 29.7 22.7 26.7 42.9
Eurygaster maura 4.5 2.8 0.7 0.2
Aelia acuminata 1.9 1.4 0.7 0.5
Oulema melanopus 58.9 11.8 77.8 10.7
Cephus pygmaeus 12.4 6.7 2.9 16.5
Haplotrips tritici 71.0 41.6 - 0.2
Schyzaphis graminum 46.2 44.4 45.7 2.9
Anisoplia spp 4.9 2.6 - 1.5
Agromyza nigra 18.0 2.3 - -
As to maize crops, taking into account the fact that the majority of soils in the area have
an acid or weak acid reaction, particular difficulties are caused by the larvae of Agriotes
spp, which populate these soils. Their density fluctuates from one year to another,
depending on the quantity of rainfall during autumn – spring and on the humidity of the
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