Can intercrop control aphid populations and their ability to spread non-persistently transmitted virus ?

Insects, in particular aphids, can cause important damage to crops. Until now, chemicals are the most efficient, and widely used method to reduced infestation. Yet, new regulations require good environmental practices, to protect soil and human health. To comply with these, the introduction of higher crop diversity within one field might be a solution. Intercrops (i.e. association in time and space of different crops in a field) have mostly been studied for its agronomic advantages (increase in yield, enhancement of soil properties, economic benefits). However, only a few studies have focussed on the impact of intercrops towards pests. In the present study, implemented in the SRUC-Aberdeen campus, field and greenhouses experiment were carried out on the ability of intercrop to either reduce aphid infestation or non-persistent virus transmission. Barley-legume intercrops were compared to a barley sole crop. The system tested both plant species (bean or pea) and arrangement (row or mix) toward Sitobion avenae. All intercrops showed a 30% reduction in aphid numbers during the whole experiment. Intercrops with pea were more efficient to reduce S. avenae numbers at the development of the colonies. However, no distinction between the intercrops was observed at the peak of the colonies. Although a higher number of beneficial was found in the barley sole crop, intercrops seem to be efficient to control aphid development in the field. PVY transmission from Myzus persicae in a potato-barley intercrop showed no differences compare to sole potatoes. In this system intercrop was not efficient to reduce virus spreading. ; Les insectes, en particulier les pucerons, sont responsables d’importants dégâts dans les cultures. Jusqu'à maintenant, les insecticides sont le moyen de lutte le plus efficace et le plus utilisé. Cependant, des réglementations récentes imposent de bonnes pratiques pour préserver la santé humaine et celle des sols. Pour y répondre, l’introduction d’une plus grande diversité culturale au champ pourrait être ...