THE REPRODUCTIVE CAPACITY OF SPIDER MITES (Acari: tetranychidae) POPULATION IN SINGLEAND MULTI-LEADER APPLE TREE CROWNS OF ELSTAR AND JONAGOLD CVS.

Abstract

The present study aimed at finding techniques alternative to chemical control, capable of reducing spider mite density. The experiment was carried out in 7 single-leader and 3 multi-leader training systems. The pest density was compared across the systems and between apple cultivars Elstar and Jonagold showing variable crown densities and trichome cover of leaves. The spider mite mobile stages were more abundant in singleleaders crowns, whereas more eggs were laid in multi-leader crowns. Nevertheless, the egg and the youngest stages survival was reduced in multi-leader crowns probably by the more intensive solar radiation reducing the air RH. The lowest pest abundance was found in the crowns of the V-Güttingen system, and in the similar, stretched Tatura trellis 2-leader system. These types of crowns should be therefore recommended for integrated and organic apple production.

Keywords

• Malus domestica
• tree architecture
• Panonychus ulmi
• Tetranychus urticae