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Dryocosmus kuriphilus is a new chestnut pest that is causing a serious problem worldwide. This gall wasp causes severe infestations of Italian Castanea sativa stands, which lowers their productivity. The most effective method for controlling gall wasp infestations is to introduce the parasitoid, Torymus sinensis, although experience shows that it can be 6-18 years before it is effective in reducing the infestation to acceptable levels. From a silvicultural point of view, it is important to reduce the damage as rapidly as possible to maintain plant vigour and fruit production, thereby avoiding chestnut stand degradation and abandonment before biological control is effective. This study analyzed the damage caused by Dryocosmus kuriphilus during normal plant development and detected differences in plant susceptibility, irrespective of genetic factors. Data were collected from a young Castanea sativa coppice stand in Tuscany (Italy) where damage was evaluated during the 2010 growing season. The study consisted of two phases: (1) classification of the damages caused by galls; and (2) studying the galls and damage distribution effects on different vigour chestnut sprouts to determine whether there were preferred oviposition sites or different degrees of susceptibility to gall wasp attack depending on a plant's physiological state. The D. kuriphilus damage classification scale was based on two factors: damage position (the vegetative organ attacked) and damage effect (abnormal organ development caused by galls). This classification included damage types that had not been previously described in literature. The statistical analysis identified differences in damage susceptibility in terms of: axis (stem or branches), plant organs (shoots, leaves, or buds), position of the attacked node (high or low region of the axis), and sprout vigour. Information on the D. kuriphilus damage distribution and its effect on plants with different levels vigour can be used to develop suitable cultural practices that could reduce the negative impact of this insect on fruit and wood production.

Peat, a non-sustainable resource, is still predominately used in forest nurseries. Coconut coir might provide an alternative, renewable, and reliable growing media but few studies have evaluated this media type in forest nurseries. We assessed the influence of pure coir, in combination with various fertilization regimes, on the growth and physiology of three ecologically diverse Quercus species seedlings (Q. robur, Q. pubescens, and Q. ilex) during nursery cultivation. Seedlings were grown using peat and pure coir in combination with three fertilization treatments (standard, K-enriched, and P-enriched). Data were collected for: (1) growth and physiological traits; (2) detailed above- and below-ground morphological traits by destructive analysis; and (3) NPK content in leaves, shoot and roots, and in the growing media, following cultivation. Peat and coir in combination with the various fertilization treatments affected above- and below-ground morphology and, to a lesser extent, the physiological traits of Quercus seedlings. Large effects of the substrate occurred for most morphological variables, with peat being more effective than coir in all studied species. Fertilization also produced significant differences. The effect of K-enriched fertilization on plant growth was clear across the three species and the two growing media. P-enriched fertilization in peat was the only combination that promoted a higher amount of this element in the tissues at the end of cultivation. Despite their smaller size, seedlings produced in coir were compatible with standard Quercus forest stocktype size, and showed a proportionally higher root system development and fibrosity. Our results suggest that coir can be used as an alternative substrate to grow Quercus species seedlings, and that fertilization can offset coir deficiencies in chemical properties. As several functional traits drive planting performance under varying environmental conditions. according to the Target Plant Concept, coir might thus serve as an acceptable material for seedling cultivation in some cases.