Asian chestnut gall wasp in Tuscany: gall characteristics, egg distribution and chestnut cultivar susceptibility

Abstract

1 Preliminary investigations were carried out on Dryocosmus kuriphilus Yasumatsu on Castanea sativa Miller in Tuscany to assess variations in gall characteristics in coppice and high forest at two crown heights (height < 2 or 2-6 m), influence of bud size and bud position on oviposition rates and susceptibility of three cultivars. 2 Gall size may depend on various factors, including wasp population density. In the present study area, small galls (with one or two cells) were the most numerous in 2008, whereas larger galls (with more than three cells) prevailed in 2009. 3 Dryocosmus kuriphilus oviposition occurrence was influenced by both bud size and bud position. Buds with eggs tended to be larger in size compared with bud without eggs, suggesting that D. kuriphilus females prefer to lay eggs in larger buds (approximately 6 mm 3 ) compared with smaller buds (approximately 3 mm 3 ). The mean number of eggs per bud tended to decrease from the apical bud toward the basal bud. 4 Three C. sativa cultivars, Carpinese, Fusca and Cesurone, were examined. Fusca grafts had significantly more galls compared with Carpinese and Cesurone, whereas Cesurone grafts had more larvae per bud compared with Carpinese and Fusca.Overall, the Carpinese cultivar may be less susceptible to D. kuriphilus galling compared with the Fusca and Cesurone cultivars.

Plant genotype and the preference and performance of herbivores: cultivar affects apple resistance to the florivorous weevil Anthonomus pomorum

“…Besides chemical plant characteristics, the physical properties of plant organs may also play an important role for plant resistance (McCall & Irwin, ; Carmona et al ., ). The flower buds may, for example, differ in size, the physical strength of bud scales and in the hairiness of the bud (Bandeili & Müller, ; Panzavolta et al ., ). Because we do not have information on physical properties such as strength or hairiness, the potential role of those characteristics for apple resistance to florivores is to be addressed by future studies.…”

Assessing the impact of Dryocosmus kuriphilus on the chestnut tree: branch architecture matters

“…has focused on various aspects. These include insect biology (Viggiani and Nugnes 2010;Bernardo et al 2013), host-gall wasp interactions (Germinara et al 2011;Panzavolta et al 2012), biological (Quacchia et al 2008) and mechanical control (Maltoni et al 2012b;Turchetti et al 2012), identification of less susceptible C. sativa genotypes (Dini et al 2012;Sartor et al 2015), visual crown damage assessment (Guyot et al 2015), damage description and classification (Maltoni et al 2012a). In this context, and based on the experience of prior Japanese research, a number of different methods for the assessment of infestation degree (MAID) have been implemented and used (Kotobuki et al 1985;Matošević et al 2010;Sartor et al 2015) (Table 1).…”

Biology and monitoring of Dryocosmus kuriphilus on Castanea sativa in Southern Italy

“…In 2002, it was introduced into Europe and colonized the European chestnut Castanea sativa Miller (Aebi et al , 2007; Graziosi & Santi, 2008; Zhang et al , 2009). The level of damage on this new ‘host’ plant appears to depend on the cultivar (Botta et al , 2006; Panzavolta et al , 2012).…”