Articles
SUSCEPTIBILITY OF HAZELNUT TO THE ATTACKS OF THE NUT WEEVIL AND OTHER PESTS
Article number
845_69
Pages
445 – 450
Language
English
Abstract
Pest attacks are responsible for the highest losses in hazelnut yield worldwide; in particular, the nut weevil Curculio nucum (Coleoptera: Curculionidae) is the most widespread and harmful species in Europe and Turkey.
The resistance of hazelnut varieties to the nut weevil, as well as to other hazelnut pests, is known but it has been poorly investigated so far.
Therefore, in 2004-2005 research was carried out to investigate factors affecting C. nucum attacks on two cultivars (TGL, Ennis) and four selections (Daria, 101, B6, L35) in a 15-year-old orchard of northwestern Italy.
In both years nut weevil adults were sampled from May to July on all cultivars and selections, but in greater quantities on TGL and Daria, and in smaller quantities on 101 and B6. By contrast, at harvest time the damage rate varied from 2.6% in TGL to 51.8% in 101, independently of the numbers of the collected adult weevils.
However, TGL and 101 were the earliest and latest in kernel development and shell hardening, respectively.
In particular, when nut weevil females bore mature eggs (generally when mean temperatures exceeded 18°C), TGL showed a more advanced kernel development and shell hardening compared to the other cultivars.
Therefore, the susceptibility to nut weevil attacks was strictly related to shell hardening; indeed, a rapid hardening of the shell can hamper the oviposition of C. nucum females.
By contrast, no correlation was found between shell thickness and damage at harvest time.
Moreover, in 2004-2005, the susceptibility of hazelnut to bugs, in particular Gonocerus acuteangulatus (Heteroptera: Coreidae), was also investigated to assess the incidence of damage in relation to the nut variety, the attack period and the adult behaviour.
The resistance of hazelnut varieties to the nut weevil, as well as to other hazelnut pests, is known but it has been poorly investigated so far.
Therefore, in 2004-2005 research was carried out to investigate factors affecting C. nucum attacks on two cultivars (TGL, Ennis) and four selections (Daria, 101, B6, L35) in a 15-year-old orchard of northwestern Italy.
In both years nut weevil adults were sampled from May to July on all cultivars and selections, but in greater quantities on TGL and Daria, and in smaller quantities on 101 and B6. By contrast, at harvest time the damage rate varied from 2.6% in TGL to 51.8% in 101, independently of the numbers of the collected adult weevils.
However, TGL and 101 were the earliest and latest in kernel development and shell hardening, respectively.
In particular, when nut weevil females bore mature eggs (generally when mean temperatures exceeded 18°C), TGL showed a more advanced kernel development and shell hardening compared to the other cultivars.
Therefore, the susceptibility to nut weevil attacks was strictly related to shell hardening; indeed, a rapid hardening of the shell can hamper the oviposition of C. nucum females.
By contrast, no correlation was found between shell thickness and damage at harvest time.
Moreover, in 2004-2005, the susceptibility of hazelnut to bugs, in particular Gonocerus acuteangulatus (Heteroptera: Coreidae), was also investigated to assess the incidence of damage in relation to the nut variety, the attack period and the adult behaviour.
Publication
Authors
S. Moraglio, L. Guidone, L. Tavella, N. Valentini, G. Me
Keywords
hazelnut variety, Curculio nucum, Gonocerus acuteangulatus, damage incidence, nut developmental stages
Online Articles (125)