Chestnut Orchards Research Articles

Design, Development, and Evaluation of a Single-Stage Combined Chestnut Harvesting and Material Separation Concept

<abstract><title><italic>Abstract. </italic></title> A harvesting technique applicable for small chestnut orchards was designed and tested. The originality of the technique was a single-stage vacuum and separation process. A harvesting system was designed with inline airflow obstructions and manipulations that facilitate single-stage separation of chestnuts from orchard debris. The inline airflow modifications influenced the chestnuts’ momentum and provided an alternative pathway from the moving air flow. The chestnuts were sorted into a deposit chamber while debris and waste were discharged to the environment. Tests were made to determine chestnut harvesting performance as affected by the proportion of chestnuts to debris and the feed rate of material into the system. The validation of the harvesting process was characterized by chestnut loss and debris separation efficiency. The quantity of chestnuts and the feed rate interaction significantly affected the harvesting performance parameters. Overall chestnut loss was minimized when a large number of chestnuts entered the system, averaging 5%. Chestnut losses were as low as 1.3% while the separation efficiency was as high as 80%.

Invasion by the chestnut gall wasp in Italy causes significant yield loss inCastanea sativanut production

The Asian chestnut gall wasp Dryocosmus kuriphilus Yasumatsu (Hymenoptera Cynipidae) is an invasive species in chestnut forests and orchards in many parts of the world. 2 Nuts produced by the European chestnut (Castanea sativa Miller) are important in human food and culture, and as a component in food webs in forest ecosystems. 3 Severe infestations are reported to reduce nut yield, although precise data are lacking because of large natural year-to-year variability in yield. 4 The recent colonization of chestnut orchards in north-eastern Italy, where nut yield has been continuously and precisely recorded for several years, offered an opportunity to calculate the impact of gall wasp infestation level on yield. 5 The nut yield of C.sativa chestnut trees was negatively related to the gall wasp infestation level, with losses as high as 80% being reported when the number of current-year galls was above six galls per 50-cm twig. 6 Yield losses can be explained by direct and indirect factors related to gall formation, and a fuller understanding of the mechanisms involved could identify possible mitigation measures.

Effects of Heavy Metal Pollution of Apple Orchard Surface Soils Associated with Past Use of Metal-Based Pesticides on Soil Microbial Biomass and Microbial Communities

Apple orchard surface soils in Japan are polluted with copper (Cu), lead (Pb), and arsenic (As) due to long-term use of metal-based pesticides. We investigated the effects of heavy metals accumulated in the surface soils in apple orchards on the microbial biomass and the microbial communities. Soil samples were taken from a chestnut orchard (unpolluted control) and five apple orchards with different degrees of heavy metal pollution. Total concentrations of Cu, Pb, and As in soil ranged from 29 to 931 mg/kg, 35 to 771 mg/kg, and 11 to 198 mg/kg, respectively. The amount of microbial biomass carbon expressed on a soil organic carbon basis decreased with increasing concentrations of heavy metals. Thus, the heavy metals that accumulated in apple orchard surface soils had adverse effects on the soil microbial biomass. The analysis of phospholipid fatty acid (PLFA) composition indicated that the microbial community structure had changed because of the pesticide-derived heavy metals in soil. The relative abundance of gram-positive bacterial marker PLFAs increased and that of fungal marker PLFA decreased with increasing concentrations of heavy metals in soil. Denaturing gradient gel electrophoreses targeting the 16S ribosomal RNA gene of bacteria and the 18S ribosomal RNA gene of fungi also showed shifts in the composition of bacterial and fungal communities induced by soil pollution with heavy metals. However, the diversity of microbial communities was not significantly affected by the heavy metal pollution. This was attributable to the adaptation of the microbial communities in apple orchard surface soils to heavy metals derived from previously used pesticides.

Interventi per la gestione dei castagneti invasi dal cinipide

Abstract: The rapid spread of the Chinese gall wasp (Dryocosmus kuriphilus Yasumatsu) in Italian chestnut growing areas is causing new criticisms. In this context, in addition to a clear plant suffering due to the wasp infestation, the dangerous recurrence of chestnut blight and the sudden spread of Gnomoniopsis sp., a coloniser of galls but also the etiological agent of nut brown rot, must be considered. Therefore, it is very important to increase the plants’ vigour and prevent their decline. Preliminary experiments were carried out in different Italian regions between 2010 and 2011. Organic plant fertilizers were applied to plants showing middle or high defoliation levels caused by the wasp attacks. The observations carried out during the growing season indicate a good vegetative restart in the treated plants compared to the untreated controls, in all the situations and independently of the fertilizers applied. Most of the treated plants (between the 75% and the 100%) showed an evident improvement in the canopy vegetation, while the untreated controls were always classified in the worse classes of crown condition. These preliminary results highlight the efficacy of this kind of treatments for infested chestnut stands. This strategy, which is based on the preliminary evaluation of the plant vigour (following the proposed scale of attack severity and lack of foliage), consists in a manuring treatment at vegetative restart, which can be repeated in the following years in dependence on the results obtained. Moreover, pruning may be suggested only to manage the development of plants showing a definite recovery. The gall wasp pullulation requires new management strategies aimed at preserving the chestnut orchards, in order to avoid the chestnut cultivation to be marginalized or abandoned.

GNOMONIOPSIS CASTANEA sp. nov. (GNOMONIACEAE, DIAPORTHALES) AS THE CAUSAL AGENT OF NUT ROT IN SWEET CHESTNUT

The genus Gnomoniopsis (Gnomoniaceae, Diaporthales) is currently composed of 13 species which are endophytic and/or parasitic to plants in the families Fagaceae, Onagraceae and Rosaceae. Species definition is based on a combination of morphological traits, association with specific plant hosts, and phylogeny. In this paper a new species, Gnomoniopsis castanea sp. nov., is described based on the association with Castanea sativa (a plant species never reported to be infected by fungi the genus Gnomoniopsis), morphology and phylogenetic analysis of the ITS region of ribosomal DNA and on the EF1-a locus. The fungus is consistently associated with nut rot and caused the disease when artificially inoculated to fruits or flowers. Infection incidence varied depending on the orchard and the year and attained up to 83% of the nuts in some areas of north-western Italy. The fungus was also consistently isolated from the bark of symptomless branches in naturally infected chestnut orchards.

Pruning methods to restore Castanea sativa stands attacked by Dryocosmus kuriphilus

Dryocosmus kuriphilus Yasumatsu, an invasive gall wasp originating from Asia, is the latest serious pest attacking Castanea sativa Mill. in Europe; the negative effects on fruit and wood production are considerable. The most effective defense strategy is biological control, but parasitoid effectiveness requires at least 6–10 years to reduce damage to acceptable levels. In Italy, prolonged productivity losses could adversely affect human activity in chestnut orchard stands, resulting in negative socio-economic and hydrogeologic consequences. Thus, it is necessary to quickly reduce the impacts of the infestation to avoid degradation of chestnut stands during the time delay required for parasitoid efficiency. We examined green pruning as a means to reduce negative impacts of gall wasps and stimulate healthy shoots in a young chestnut coppice in Central Italy. Two different pruning cuts (Long- and Short-cut) on growing shoots and four timings of application were tested. The development and phytosanitary status of nodes was observed over 2 years on pruned and control sprouts. Pruning was effective in reducing gall wasp damage though responses varied among pruning techniques and application times. Long-cut pruning made in spring during the full growth phase induced a higher number of new and better-developed shoots. Pruning during the end of the egg-laying period of the gall wasps promoted development of only healthy new shoots. Our results indicate that is possible, by choosing the best combination of time and technique, to identify a pruning method useful to maintain growth and development of C. sativa stands threatened by D. kuriphilus.

Spread and population structure of Cryphonectria parasitica in a young chestnut orchard in Slovakia

Abstract The chestnut blight pathogen Cryphonectria parasitica was studied in a chestnut collection composed of both seedlings and grafts derived from selected Castanea sativa and C. sativa × C. crenata trees located in south-east Slovakia, near village Príbelce on an area of approximately 3.5 ha. The study was conducted during eight years (2003–2010). During this period 133 trees were infected, which represents 59.82% of chestnut trees of all chestnut accessions. Based on the phenotype of the fungus culture and the type of cankers in the field, all isolates were determined to be virulent. No hypovirulent strains were found. No vegetative compatibility (vc) type diversity was observed. More than 130 isolates were analyzed for vc and all were in single vc type, which was identical with EU 12. All isolates assayed for mating type were MAT-1. No perithecia were observed. No significant differences were found between the proportion of cankered and dead cankered trees in seedlings and grafts of hybrid origin (C. sativa × C. crenata) and of C. sativa origin. However, particular seedlings and grafts of hybrid origin seemed to exhibit certain resistance to chestnut blight.

Influence of the introduced parasitoid Torymus sinensis (Hymenoptera: Torymidae) on T. koreanus and T. beneficus as indigenous parasitoids of the chestnut gall wasp Dryocosmus kuriphilus (Hymenoptera: Cynipidae) on chestnut trees in Nagano Prefecture, Japan

We describe here the parasitoid wasps Torymus sinensis Kamijo and T. beneficus Yasumatsu & Kamijo (early-spring and late-spring strains), which are introduced and indigenous natural enemies of the chestnut gall wasp Dryocosmus kuriphilus Yasumatsu, an invasive chestnut pest in Japan. We recently discovered specimens of T. koreanus Kamijo, endemic in Korea, among Torymus parasitoids collected from D. kuriphilus galls in a Japanese chestnut orchard. In this study we compare the composition of Torymus parasitoids emerging from D. kuriphilus galls before and after the release of T. sinensis. Before the release of T. sinensis, early-spring and late-spring strains of T. beneficus predominated (58.3 and 20.8% of specimens collected). However, a few years after the release, both T. beneficus strains had been almost completely displaced by T. sinensis. In contrast to the rapid decrease in T. beneficus, T. koreanus did not decrease drastically before and even after the release of T. sinensis (approximately 10–20% of specimens collected). These results suggest that not a few T. koreanus were present in the Japanese chestnut orchard investigated at least several years after the release of T. sinensis, although both the T. beneficus strains were rapidly displaced by T. sinensis during this period.

경상남도 산청군 밤나무 재배지의 조성 기간에 따른 토양 및 잎 양분 특성

higher (p 0.05) between both establishment periods. Leaf area, leaf mass, and nutrient (N, P, K, Ca, Mg) concentration of green leaves were also not significantly different (p>0.05) between both establishment periods. The results indicate that soil bulk density in chestnut orchards is dependent on the establishment periods, while soil chemical property and leaf nutrient concentration may be little influenced by the establishment periods.

N and P resorption efficiency and proficiency from leaves under different forest management systems of deciduous woody species

Leaf N and P resorption efficiency and proficiency were explored in three permanent (non–tiled) and unfertilised plots: a Castanea sativa mill. paraclimax coppice (CC), a chestnut orchard (CO), and Quercus pyrenaica Wild. climax forest (Oak), adjacent to the CO plot, all located in central western Spain. To estimate the seasonal variation of the nutrients contained in the leaves, 9, 3 and 3 trees with different diameters were selected at the three plots respectively. Over three years (2001 to 2003), three annual samplings of leaf nutrients were made (June, September and October) at different heights of the trees (low, middle and high). The evolution of foliar N concentration along the growing period of both species was found to be similar and independent of year and the height of the tree at which the leaves developed. No significant differences were observed between evolution of foliar N concentration along the growing period in either chestnut or Oak. As in the case of the N resorption efficiency measurement in which no significant differences among plots were found for N resorption efficiency and proficiency. The levels of P in leaves were inversely proportional to the concentrations of this element in the soil, which decreased in the order Oak plot, Chestnut coppice and Chestnut orchard, although differences were only significant between the former and the latter. Key words: Castanea sativa, efficiency, forest management, N and P resorption, proficiency, Quercus pyrenaica.

BORON APPLICATION ON A CHESTNUT ORCHARD: EFFECT ON YIELD AND QUALITY OF NUTS

Although boron (B) deficiency in chestnuts (Castanea sativa Mill.) has been identified in Portugal and B fertilization was carried out in some orchards, the post-treatment evaluations have not been made to date. So the objective of this trial was to confirm the B deficiency and to quantify the effect of B applications to the soil on nut yield and quality. In October 2006, a fertilizer trial was established in a 15 year-old orchard in a very acid soil derived from siliceous schists. Soil liming and a basal fertilization were carried out in 16 trees and two levels of sodium tetraborate (Granubor, 14.6% B) were applied to eight trees: control (B0) and 100 g of Granubor per tree (B1). In the beginning of September chestnut leaves were collected from five trees and analyzed for macro- and micronutrients. Nut productivity was measured per tree and some nut quality parameters were evaluated, including the chemical composition of the kernel (soluble sugars, starch, total fiber, crude protein, and crude fat) in 2007, and dry matter, nut caliber, and fruit damage in 2007 and 2008. Boron fertilization of chestnuts significantly increased nut production: 75% in the first year (8 kg and 14 kg per tree, respectively, in the B0 and B1) and, in the second year, was over four times higher (4 kg and 17 kg per tree, respectively, in the B0 and B1). No significant differences were found in dry matter, nut caliber, nut damage and chemical composition of the kernel in the first year, but in the second year lower fruit damage by chestnut tortrix (P<0.0089) was observed. Foliar analyses exhibit relatively low B concentrations in the control trees (average value of 8 mg kg−1) in both years, while in the fertilized trees the foliar B concentration were in average 61 mg kg−1 in the first year, and 34 mg kg−1 in the second year. The large drop in the foliar B concentration in the second year suggests the need to monitoring the nutrient status of chestnut orchards or more frequent of B application than usual practice.

Correlation among soil enzyme activities under different forest system management practices

Soil enzyme activities were performed in three permanent no-till and unfertilised plots located in the South of Salamanca province (Spain), the first in a Castanea sativa Mill. paraclimax coppice (CC), the second in a chestnut orchard (CO) and the third in a Quercus pyrenaica Wild. climax forest (Oak), adjacent to the CO plot.We hypothesized that the activities of dehydrogenases, ureases, acid phosphatases, arylsulphatases and β-glucosidases in different forest ecosystems are involved in the carbon, nitrogen and phosphorus cycling and we report their relationship with each other and with physical, chemical and general biochemical parameters of the soils. The main aim of the study was to detect biological criteria for sustainable development in natural degenerate forests of Mediterranean Europe. For this, we used sweet Chestnut (C. sativa Mill) and Oak Q. pyrenaica Wild as models to better define the ecological conditions of these natural resources in terms of nutrient balance, physiology and biological diversity of their communities, to relate them to the conditions of exploitation and land-use changes, for the characterization of sustainable ecological systems.Furthermore, soil respiration was high and significantly different in the chestnut coppice stand than the other two stands, chestnut orchard and oak.Correlations between soil biochemical and soil microbiological variables showed that the three different forest management practices had also a strong effect on soil function conditions. In a discriminate analysis, CC and Oak were discriminated clearly, while CO was in the middle of the biplot sharing some properties with each of the two different groups. Thus, we proposed a soil property transition from the best soil structure and function properties at one chestnut management properties with low tree densities (CC and CO) to other with the worst ones at highest tree density conditions (Oak). According to natural soil conditions in Oak, we assumed that most of the enzyme activities reached their highest levels at highest C and N soil contents but at lowest soil base saturation percentage while they were not at all associated with P soil availability.

The Effect of Cow Dung and Red Bean Straw Dosage on Soil Nutrients and Microbial Biomass in Chestnut Orchards

Abstract This research study on the effect of cow dung and straw Red Bean Dosage on soil nutrients and microbial biomass in Chestnut orchards. The results indicate that: red bean straw and cow dung facilities can significantly increase soil nitrogen, phosphorus, and effective Potassium content and microbial biomass, and times the amount of cow dung fertilizer increase soil nitrogen, phosphorus, and effective Potassium content and microbial biomass significantly, times the amount of the red bean straw fertilizer can increase soil available K, but there is no significant difference to improve nitrogen and phosphorus and microbial biomass. In the application of less, the effect of the Red Bean on soil fertility, straw is better than cow dung, but in the situation of organic farming, require a lot of organic manure, the nutrient supply of cow dung on the chestnut tree's is better than red bean straw.

Response of bat species to sylvo-pastoral abandonment

We assessed the effect of abandonment of sylvo-pastoral practices in chestnut orchards (Castanea sativa) on bats in southern Switzerland to determine practical recommendations for bat conservation. We compared bat species richness and foraging activities between traditionally managed and unmanaged chestnut orchards, testing the hypothesis that managed orchards provide better foraging opportunities and harbour more bat species. Echolocation calls of foraging bats were sampled simultaneously at paired sites of managed and unmanaged orchards using custom made recorders. Vegetation structure and aerial insect availability were sampled at the recording sites and used as explanatory variables in the model. In a paired sampling design, we found twice the number of bat species (12) and five times higher total foraging activity in the managed chestnut orchards compared to the unmanaged ones. Bat species with low flight manoeuvrability were 14 times more common in managed orchards, whereas bats with medium to high manoeuvrability were only 5 times more common than in abandoned orchards. The vegetation structure was less dense in managed orchards. However, management did not affect relative insect abundance. Bats primarily visited the most open orchards, free of undergrowth. As a result of restricted access into the overgrown forests, the abandonment of chestnut orchards leads to a decline in bat species richness and foraging activities. Continued management of chestnut orchards to maintain an open structure is important for the conservation of endangered bat species in the southern Swiss Alps.

Interazioni tra cinipide galligeno e cancro della corteccia: una nuova criticità per il castagno

Abstract: The fast spread of Chinese gall wasp (Dryocosmus kuriphilus) represents a new constraint factor for chestnut stands and orchards in Italy. So far, the favourable effect of hypovirulence in Cryphonectria parasitica-Castanea sativa patho-system allowed the development of chestnut cultivation. This situation could be modified by the progressive weakening of the trees caused by intensive attacks of the new parasite. During recent surveys worrying blight damage recurrences were observed in different Italian chestnut areas (in Piemonte, Trentino and Toscana regions) which were highly infested by the Chinese wasp. While biological control treatments against the parasite are carried out, it is necessary to set up integrated protocols for the management of chestnut orchards to allow the survival of trees and their productivity.

"CASTANEA SATIVA WOODS" IN THE NORTHERN APENNINES: A PHYTOSOCIOLOGICAL ANALYSIS ALONG ECOLOGICAL GRADIENTS

Castanea sativa woods, one of the most widespread habitats of southern Europe, are included in the European Community Natura 2000 network within Sites of Community Importance (SCI). In the Northern Apennines, chestnut woods are mainly coppices derived from old chestnut orchards, and now abandoned. To describe the relationship between present chestnut structure and vegetation features, we analysed the plant diversity of chestnut woods by 143 phytosociological releves within 6 SCIs. The gradient of diversity was identified by multivariate analysis (clustering and ordination) and related to other woods such as mixed oak woods or lowest altitude Fagus sylvatica woods in order to evaluate the potential evolutionary pattern of present chestnut woods.

MONITORING OF CHESTNUT MOTHS BY INTRA- AND INTERSPECIFIC SEMIOCHEMICALS

The effectiveness of synthetic sex attractants and a compound of plant origin, ethyl-(E,Z)-2,4-decadienoate, to monitor the flight activity of the chestnut moths Pammene fasciana, Cydia fagiglandana and Cydia splendana in southern Italy was evaluated. Field trapping tests were carried out from the end of June to the end of September during 2006 and 2007 in two chestnut orchards. In both years, pagoda traps were baited with rubber septum dispensers loaded with 1 mg of synthetic sex attractants of one of the three species or with 40 mg of ethyl-(E,Z)-2,4-decadienoate. In 2007, Pherocon IIB traps baited with the sex attractant blend of P. fasciana or ethyl-(E,Z)-2,4-decadienoate were also used. In both years, pheromone traps captured a high number of P. fasciana males, a fair number of C. fagiglandana males and no male of C. splendana. The pattern of weekly catches by pheromone traps showed a peak of flight activity between the second and third decade of July and a smaller one at the end of August for P. fasciana and between the second and third decade of August for C. fagiglandana, without substantial variations among trapping sites. Traps baited with ethyl-(E,Z)-2,4-decadienoate allowed for capturing conspicuous numbers of P. fasciana males and females and the pattern of flight activity as monitored by this compound was similar to that by the sex pheromone blend. Failure to capture C. splendana males could be due to a lack of attractiveness of the sex attractant blend used but also to a low presence of this pest, as suggested by visual fruit samplings carried out at the harvest. Captures of female chestnut moths by ethyl-(E,Z)-2,4-decadienoate are of practical interest since they could be used for a more rational application of control means.

GENETIC DIVERSITY OF INTENSIVELY AND EXTENSIVELY MANAGED CHESTNUT (CASTANEA SATIVA) ORCHARDS IN GREECE

Chestnut (Castanea sativa) orchards in Greece can be broadly classified in two categories: intensively managed (commercial cultivars grafted on selected rootstock established on agricultural land in the vicinity of rural communities) and extensively managed (local scions grafted on wild trees demarcating areas within natural forests, away from rural communities). The genetic diversity and multilocus genetic structure of two intensively and two extensively managed orchards is reported and compared based on 17 isoenzyme loci. Results indicated that intensively managed orchards present a high number of unique genotypes (85% of the total number of individuals), while extensively managed orchards have a rather low-number of unique genotypes (21% of the total number of individuals). In one intensively managed orchard, interspecific C. sativa × C. crenata hybrids were identified in 22% of the individuals studied. Genetic diversity parameters were higher in the intensively managed orchards evidently as a result of the higher number of alleles present (mean average number of alleles per locus in the intensively and the extensively managed orchards was 2.31 versus 1.50 respectively). The genetic diversity of intensively managed orchards is comparable to that of adjacent natural populations and higher than the diversity reported in western European orchards. It is postulated that the greater number of unique genotypes in intensively managed orchards may reflect the traditional arboricultural practices of the local growers. It can present an obstacle regarding the nut uniformity for industrial processing; nevertheless it may be beneficial under climatic change scenarios. The implementation of the above results for further selection and breeding is discussed.

EVALUATION OF SIMPLE SEQUENCE REPEATS (SSR) FOR GENETIC ANALYSIS OF CHESTNUT TREES IN MICHIGAN ORCHARDS

In Michigan, non-grafted seedlings of Chinese descent commonly planted by growers predominate chestnut orchards because of the resistance to chestnut blight. In addition, grafted hybrids of European, Chinese, and Japanese descent, many with unknown pedigrees, are also present in orchards. The outcome of this genetic mixing in orchards is a chestnut product with variable size and quality. Therefore, the objective of this study is to evaluate the use of simple sequence repeats (SSRs) to genetically characterize promising chestnut trees and cultivars currently growing in Michigan orchards. In the summer of 2007, we began a series of crosses in four isolated orchards, where each orchard consisted of two cultivars. Trees of the C. sativa × C. crenata hybrid cultivar 'Colossal' were selected as the female parent for every cross due to its good yield and because it is planted in orchards throughout the state. The chestnut cultivars 'Benton Harbor' and 'Eaton', both with Asian backgrounds, and the European hybrid cultivars 'Nevada', and 'Okei' were selected as pollinizer trees. Fifty nuts per cross were randomly selected as the individuals representing the four populations. We were able to generate fingerprints using both universal and specific primers such as (GTG) 5 and CsCAT/EMCs loci, respectively. The SSRs data were analyzed using 'PeakScanner' and 'Identity' software. Complex polymorphic bands were observed among chestnut cultivars, which ranged from 1,200 to 300 base pairs in length when (GTG) 5 was used. Amplicon sizes ranged from 76 to 193 base pairs when specific SSRs were used and the number of alleles observed at a locus ranged from 4 to 6. Results obtained from this study will allow for the genetic characterization of the chestnut cultivars and seedling trees currently growing in Michigan, and subsequently will help us establish high quality chestnut plantings for food and fiber production.

AN EPIDEMIC OF GNOMONIA PASCOE ON NUTS OF CASTANEA SATIVA IN THE CUNEO AREA

Since 2005, chestnut growers have observed increasing losses in yield in some sweet chestnut orchards lying to the South of Cuneo. In 2007-2008 a health survey was carried out on branches, flowers and developing nuts. A fungus was constantly isolated from the bark, but not from the xylem, of 1 to 3-year old branches, fruit stem, burrs, and with a variable frequency from the stigmas and styles. The fungus could not be isolated from the inner layer of the hylum. It was isolated sporadically from the nuts just after the fruit setting and with frequency increasing 25-80% in 2007 and 4-84% in 2008, in completely ripened nuts. In the diseased nuts, small chalky areas originate at the ripening time from the endosperm outer layers, and develop towards the centre of the kernel; progressively their color turns brown and the endosperm mummifies; the pathogen colonizes the pellicle and the shell on which it produces 122x85 - 251 x 171 μm, globose, black, pycnidium-like acervuli, that split open along the top and release a slimy, globular mass of conidia. Conidia are pale brown, one-celled, ovoid-oblong, biguttulate, 6.1-7.32 x 2.44-2.68 μm. This fungus, being able to colonize asymptomatically the branches and the immature nuts, has an endophytic life style with a true pathological behavior only on the ripened nuts. It is likely that it is unable to colonize the endosperm through the stem. It reproduced the disease in artificially inoculated healthy nuts, and endophytically colonized artificially inoculated chestnut branches. On the basis of such characteristics, the pathogen has been identified as Discula pascoe sp. nov., the anamorphic stage of Gnomonia pascoe sp. nov., a pathogen recently reported in the rainy areas of Australia and New Zealand. The territorial distribution, the epidemiology and the systematic characterization of the pathogen through phylogenetic analyses by unilocus and multilocus markers are under investigation.