Studies on population dynamics of Balaninus nucum L. (Col., Curculionidae) noxious to the hazel (Corylus avellana L.) in Northern Latium (Central Italy)¹

Abstract

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.

Early nut development as a resistance factor to the attacks of Curculio nucum (Coleoptera: Curculionidae)

“…The maturation of the eggs in the ovarioles is strictly correlated to climatic conditions; in 2005, females showed mature eggs starting from late June, when the temperature exceeded 18°C. In northwestern Italy, oviposition generally starts in mid‐June, later than in central Italy and in Turkey (Paparatti, 1990; Pucci, 1992; Akça & Tuncer, 2005). In particular, in investigations carried out from 1987 to 1990, in central Italy the first mature eggs in the ovarioles were detected from 29 May to 18 June with mean temperatures of about 18°C (Paparatti, 1990; Pucci, 1992).…”

“…In Italy, C. nucum is reported as the key insect pest in the central‐southern regions, such as Latium (Paparatti & Speranza, 2005) and Campania (Viggiani, 1984); in fact, to define an economic threshold for treatment and implement integrated control strategies, biology and population dynamics of the nut weevil were investigated in hazelnut orchards of central Italy (Paparatti, 1990; Pucci, 1992). By contrast, in northwestern Italy, the main pests of hazelnut are the bud mite Phytoptus avellanae (Nalepa) and several true bugs, such as Gonocerus acuteangulatus (Goeze) and Palomena prasina (L.) (Minetti et al , 1986; Michelatti et al , 1994; Tavella et al , 1997, 2001).…”

Nut and kernel growth and shell hardening in eighteen hazelnut cultivars (Corylus avellana L.)

“…Studies conducted in other growing areas showed differences in cultivar susceptibility to blanks indicating some genetic control of this defect (Mehlenbacher et al 1993), which may also be related to particular environmental conditions (Solar, Stampar 2011). The involvement of nut weevil in the production of blanks and aborted nuts was also hypothesized by several authors in relation to the adult feeding activity on female flowers and developing nuts (Tabamaĭshvili 1988;Paparatti 1990;Pucci 1992) or as consequence of the transmission of pathogens that follows insect feeding (Akça, Tuncer 2005). However, in our research, percentages of blanks at harvest were not correlated with any other recorded parameter, including nut weevil damage at harvest.…”

Biological Control of Hazelnut Weevil (Curculio Nucum L., Coleoptera, Curculionidae) Using the Entomopathogenic Fungus Beauveria Bassiana (Balsamo) Vuill. (Deuteromycotina, Hyphomycetes)

“…Earlier research identified the biological cycle of the weevil and established a preliminary treatment threshold (Paparatti, 1990;Pucci, 1991Pucci, , 1992. More recently the adoption of this threshold, as part of guided and integrated pest control (IPM) strategies, 408 has made it possible to considerably reduce the number of insecticide treatments against weevils.…”