STATO ATTUALE DELLA DIFESA FITOSANITARIA DEL NOCCIOLO
Among deseases, the bacterial blight, Xanthomonas campestris pv. corylina (Miller et al.) Dye, is considered the most serious in some countries which account the bulk of the hazelnut production (Turkey, Italy, and USA). Other pathogenic agents can cause locally economic damage.
In Europe the major pests are Phytoptus avellanae Nal. (Hazelnut Bud Mite) and Curculio nucum L. (Hazelnut Weevil), but locally severe damages can be caused by a number of species as: several bugs, Corylobium avellanae (Schrank), Myzocallis coryli (Goeze), Quadraspidiotus ostreaeformis (Curtis), Archips rosanus (L.), Operophtera brumata (L.), Zeuzera pyrina L. Anomala juni Duft, Melolontha spp, Agrilus viridis L. etc. Minor pests are also the red mite, Panonychus ulmi (Koch), and the yellow mite, Eotetranychus carpini (Oud.).
In United States the key pest is Cydia (=Melissopus) latiferreana (Wals.) (Filbertworm). Other major pests are: Myzocallis coryli (Goeze) (Filbert aphid), Archips rosanus (L.) (Filbert leafroller) and Choristoneura rosaceana (Harris) (Obliquebanded leafroller). The infestations of at least two of them (M. coryli and C. rosaceana) seem to be partially induced by the excessive use of insecticides.
The hazelnut agroecosystem includes several groups of beneficial organisms which need to be protected.
A rather limited number of agrochemicals have been registered to be used in hazelnut orchards. Some of them are very destructive of the beneficial organisms and should be avoided or used with much caution.
The general and specific criteria to manage the control of hazelnut deseases and pests are discussed.