Nitrogen fertilization and abundance of the cereal aphis Metopolophium dirhodum and Sitobion avenae (Homoptera, Aphididae)
1992
Honek, A. (Research Institute of Plant Production, Praha (CSFR))
The effect of mineral nitrogen fertilization in winter wheat and winter barley (doses 0,40, 80, 120, and 160 kg x ha(-1) on abundance of the cereal aphids Metopolophium dirhodum (Walker) and Sitobion avenae (F.) were investigated in 1989 and 1990. Abundance of M. dirhodum increased with nitrogen dose but the numbers of S. avenae were little affected. The variation in aphid abundance correlated with plant response to nitrogen fertilization. High N doses enhanced dry mass (energy) allocation to above ground parts and increased the relative size of leaves. M. dirhodum, a leaf-colonizing species, may profit from better leaf quality. The relative size of chaff was not correlated with increasing N doses. This fact may cause the lack of N dose-related variation in abundance of S. avenae, a species which colonizes ears and relies on their quality. The effects of fertilization on aphid abundance were proportionate to the magnitude of changes in relative size and quality of host plant organs on which the aphids live
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