Nitrogen fertilization effects on Myzus persicae aphid dynamics on peach: vegetative growth allocation or chemical defence?

Abstract

Plant nitrogen (N) fertilization is a common cropping practice that is expected to serve as a pest management tool. Its effects on the dynamics of the aphid Myzus persicae (Sulzer) (Hemiptera: Aphididae) were examined on young peach [Prunus persica (L.) Batsch (Rosaceae)] trees grown under five N treatments, ranging from N shortage to supra‐optimal supply for growth. Aphid population increased over time at the three intermediate N levels. It remained stable at the lowest N level and decreased at the highest N level. Four weeks after the start of infestation, the number of aphids displayed a parabolic response to N level. The relationships between N status and parameters of plant vegetative growth (stem diameter) or biomass allocation (lateral‐total leaf area and root‐shoot ratio) were consistent with responses proposed by models of adaptive plasticity in resource allocation patterns. However, the variation in plant growth predicted aphid population dynamics only partially. Whereas aphid number was positively correlated with plant N status and vegetative growth up to the intermediate N level, it was negatively correlated with plant N status above this level, but not with vegetative growth. The concentrations of primary and secondary (plant defence‐related) metabolites in the plant shoots were modified by N treatments: amino acids (main nutritional resource of aphids) and prunasin increased, whereas chlorogenic acid decreased with increasing N availability. Constitutive changes in plant chemistry in response to N fertilization could not directly explain the reduced aphid performance for the highest N level. Nevertheless, the indirect effect of N on the induction of plant defence compounds by aphid feeding warrants further investigation. The study focuses on the feasibility of handling N fertilization to control M. persicae in orchards, but findings may also be relevant for our understanding of the physiological relationships between the host’s nutritional status and the requirements of the insect.

Wheat Nitrogen Fertilisation Effects on the Performance of the Cereal Aphid Metopolophium dirhodum

“…However, in a study with Mysus persicae on grafted one-year-old peach plants and five levels of nitrogen fertilisation (0.05, 3, 6, 10 and 15 mM N from NO 3 ) [59], it was found that populations which had developed from initially placed apterous aphids, remained stable at the lowest N level, increased over time at the three intermediate levels and decreased at the highest level. Another study with populations of Aphis nerii, begun from apterae placed on milkweed (Asclepisa syriaca) and three rates of nitrogen fertiliser (0, 0.071 and 0.143g NH 4 NO 3 ) [42], found that the highest populations were on plants with the intermediate levels of fertilisation.…”

QualiTree, a virtual fruit tree to study the management of fruit quality. I. Model development

“…QualiTree, which can react to pruning, would be a good framework for future tree-aphid studies. Of course, this also calls for future consideration of nitrogen in the model because of its effect on aphid dynamics in trees (Sauge et al 2010) and more generally its implication in the trade-off between defence and growth in plant-pest interactions (Le Bot et al 2009). …”

Differential accumulation of leucine and methionine in red and green pea aphids leads to different fecundity in response to nitrogen fertilization

“…These positive effects are often attributed to improvements in nitrogenous nutrition. Neutral or negative effects of nitrogen fertilization on herbivorous insect performance, however, have also been reported . Researchers have therefore proposed that there is an optimal nitrogen level in plants for herbivorous insects, and concentrations that exceed this level reduce insect fitness .…”

“…Neutral or negative effects of nitrogen fertilization on herbivorous insect performance, however, have also been reported . Researchers have therefore proposed that there is an optimal nitrogen level in plants for herbivorous insects, and concentrations that exceed this level reduce insect fitness . The optimal nitrogen concentration in plants differs among insect species or even among genotypes of the same species .…”