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Hazelnut is one of the most important orchards in central Italy (Viterbo province). More than eighty phytophagous insect pests adversely affect hazelnut orchards, but only a few of these, such as Anisandrus dispar F. (Coleoptera, Scolytidae), induce severe damage. A bacterial disease (called moria) constitutes one of the main phytopathological problems of hazelnut plants in central Italy. Two years ago, the Lazio Regional Government and local hazelnut cooperatives supported a research into the bio-ethology of A. dispar and its possible association with moria disease on hazelnut plants in Viterbo. In 2003 and 2004 two experimental hazelnut areas were selected in the Capranica and Caprarola districts (Viterbo), where eighteen chemio-chromotrophic traps were installed to study the dynamic population of A. dispar and to catch live Scolytidae females. Representative samples of live A. dispar females were used to isolate and identify the bacterial populations present both outside and inside the insects. After two years 5,726 A. dispar females had been caught. Of more than 1,400 live A. dispar females, 10% were submitted to microbiological analyses by morphological, physiological, biochemical and molecular techniques. The populations of the main bacteria (by outside and inside) associated with the phytophagous were identified as Erwinia billingae, Brenneria quercina, Pantoea cedenensis and Pseudomonas spp. Studies are currently in progress to: i) clarify the biological cycle of A. dispar; ii) identify the role (direct and/or indirect) of the insect respect to the epidemiology of moria disease; iii) carry on pathogenicity tests on bacterial isolates to prove their involvement in bacteriosis; iv) develop specific primers to identify the presence of these bacteria when associated with the insect and with asymptomatic hazelnut plants; v) verify the influence of environmental parameters on the biology of both the insect and the disease.

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The author reports on the results of a study concerning basis research carried out with the aim of defining guided and integrated methods for the control of the key insect of the hazel-grove agroecosystem, Balaninus nucum L. (Col., Curculionidae).The researches carried out in a hazel grove typical for Northern Latium (Central Italy) allowed to investigate a number of aspects of the population dynamics of adults and of preimaginal instars, to define the duration of embryonal and post-embryonal development and to ascertain the extent of damages.Moreover, highly significant correlations were found between the number of e g bearing females and percentage of oviposition detected in the fruits, and between the average n u m t i of egg-bearing females and percentage of hazel-nuts with eggs. The information reported in this paper will be verified in other hazel-growing environments, so as to formulate an economic threshold for treatment calling for the use of more suitable chemicals, less detrimental for the equilibria of the biotic community.( 1972, 1977, 1984), VIGGIANI et al. (1979) and PUCCI (1991). However only few among these species are detrimental to such an extent as to justify chemical treatment; in spite of this, in the Latium hazel-growing environment, farmers administer an average of four treatments per year on a calendar basis, mainly against the hazel bugs (Gonocerus acuteangulatus G., Palomena prusina L. and Nezura viridulu L.) and the coleopter Balaninus nucum L.The results however are often disappointing because the treatments are carried out in unsuitable times and without taking into account the dynamics of population density and of the resulting damages which the pests are able to produce.