Presence of aphid predators in common wheat (Triticum aestivum L.) in organic and conventional agroecosystems of Tuscany

The aim of this study is to compare the presence and evolution of aphid predator populations in common wheat in three agro-ecosystems of different management, two organic of diverse age and a conventional one, in relation to field margins. The study was carried out in the Montepaldi Long Term Experiment in Tuscany, in 2008. Insect predators belonging to the families of Coccinellidae; Syrphidae and Chrysopidae were assessed. The presence of eggs, larvae, pupae and adults in the ecological infrastructures of the field margins as well as inside wheat crop at three different distance from the field’s margin (0 m, 15 m, 30 m) was estimated. Results show that ladybirds are more affected by agroecosystem management and field margin type than the other insect predators. In fact they are present in greater numbers in organic farming systems than in conventional one and in the more complex and rich ecological infrastructure. The number of insect predators within the wheat crop was not affected by the distance from the field’s margin.