Effects of nitrogen fertilization and vegetative growth on the population dynamics of the aphid,Myzus persicae, in the peach tree,Prunus persica

Abstract

The green peach aphid, myzus persicae , is a major pest in peach orchards. In order to find alternatives to the use of chemicals for aphid control, it is crucial to better understand the interactions between aphid population dynamics and tree status, i.e. growth and nutrient composition of the plant tissues. M. persicae acts as a flush feeder on peach tree. Aphid abundance is expected to be maximized on vigorous non-stressed plants, in concordance with the plant vigour hypothesis. How far cultural practices could be used to control plant vigour and in turn aphid population was tested on potted trees submitted to 2 levels of nitrogen supply (N+/N-), and artificially infested. We described shoot growth, leaf nitrogen concentration and aphid population levels during the entire infestation period (two months). When separately considering shoot growth and nitrogen treatment, we evidenced a positive effect of both factors on aphid population dynamics. However, when testing for the concurrent effects of both shoot growth and nitrogen treatment, only shoot growth had significant positive effect over aphid population dynamics. These results suggest that the observed effect of nitrogen treatment on aphid population dynamics may be an indirect one, mediated by a modification of plant growth.