Juglans Cinerea Research Articles

Improving disease resistance of butternut (Juglans cinerea), a threatened fine hardwood: a case for single-tree selection through genetic improvement and deployment

Approaches for the development of disease-resistant butternut (Juglans cinerea L.) are reviewed. Butternut is a threatened fine hardwood throughout its natural range in eastern North America because of the invasion of the exotic fungus, Sirococcus clavigignenti-juglandacearum Nair, Kostichka and Kuntz, which causes butternut canker. Early efforts were made to identify and collect putatively resistant germ plasm, identify vectors and to characterize the disease. More recently, molecular techniques have been employed to genetically characterize both the pathogen and the resistant germ plasm. Much of the host resistance may originate from hybridization with a close Asian relative, Japanese walnut (Juglans ailanthifolia Carr.), and from a few natural phenotypic variants. Further genetic characterization is needed before classical breeding or genetic modification can be used to produce canker-resistant trees.

Sirococcus clavigignenti‐juglandacearum

<i>Sirococcus clavigignenti‐juglandacearum</i>

Efficacy of ArmicarbTM 100 Against Sirococcus clavaganti – Juglandacearum (A Butternut Canker Pathogen)

The genus Juglans (Juglandaceae) consists of 20 tree species referred to as walnuts and it is sub-divided into four taxonomic sections. The section Trichycaryon in which buttermut is the only member. The fungus, Sirococcus clavaganti – juglandacearum is an important pathogen causing considerable losses in butternut plantations. The butternut trees with age groups were found susceptible to this disease. In the present paper, an attempt has been made to see the safer fungicides, ArmicarbTM 100 against the pathogen Sirococcus clavaganti – juglandacearum. The result exhibits that ArmicarbTM 100, 0.3 per cent was found best and inhibited completely the growth of Sirococcus as compared to other treatment in vitro.

Viability of Sirococcus clavigignenti-juglandacearum Conidia on Exoskeletons of Three Coleopteran Species.

Butternut canker, caused by Sirococcus clavigignenti-juglandacearum, is the primary cause of decline of butternut (Juglans cinerea). Conidia of the fungus have been isolated from several insect species. The vector potential of three species of Coleoptera, Astylopsis macula, Eubulus parochus, and Glischrochilus sanguinolentus, was studied during 2001 and 2002. Beetles were collected, rinsed, and artificially inoculated with conidia. All three species carried viable conidia up to 16 days. The mean number of conidia carried per beetle in 2001 was as follows: 3.21 million at 0 h to 11,371 at 384 h for A. macula; 3.91 million at 0 h to 57 at 384 h for E. parochus; and 355,742 at 0 h to 314 at 384 h for G. sanguinolentus. In 2002, the numbers were: 1.42 million at 0 h to 2,814 at 384 h for A. macula; 1.29 million at 0 h to 85 at 384 h for E. parochus; and 72,342 at 0 h to 0 at 192 h for G. sanguinolentus. Using scanning electron microscopy, conidia were observed on the abdomen, thorax, and legs of artificially inoculated individuals of each species and on the thorax and abdomen of field-collected A. macula and E. parochus. These data suggest that all three species are potential vectors of S. clavigignenti-juglandacearum; however, A. macula and E. parochus may be more effective vectors.

Vegetation Change in a Former Chestnut Stand on the Cumberland Plateau of Tennessee during an 80-year Period (1921–2000)

Abstract A former chestnut stand on the Cumberland Plateau of Tennessee was sampled in 1952/53, 1979, and 2000. The site was clear-cut in 1921/22, and has remained unburnt and relatively undisturbed. Chestnut stumps are present, but sprouts are not. Liriodendron tulipifera remained important in the canopy since 1952/53. Acer rubrum and A. saccharum increased in the canopy, but only A. rubrum did so in the subcanopy. Quercus rubra/velutina increased in the canopy, and decreased in the subcanopy. Shade-intolerant (Juglans nigra, Liquidambar styraciflua, Ulmus rubra, Fraxinus americana) and shade-tolerant (Tilia americana, Aesculus flava) species declined, perhaps due to absence of large-scale disturbance needed for regeneration. Juglans cinerea and Cornus florida were impacted by fungal pathogens. Although J. cinerea was an important replacement species, no individuals are currently present. Cornus florida is present in the canopy, but not in the subcanopy. Lindera benzoin and Viburnum acerifolium increased...

Inhibition of human pathogenic fungi by ethnobotanically selected plant extracts.

In this study, 36 extracts derived from 29 plant species selected using an ethnobotanical approach were tested for antifungal activity against a taxonomically diverse group of 13 human pathogenic fungi. We compared the inhibitory characteristics of these plant extracts with those of the commonly used antifungals, amphotericin B and ketoconazole, and the plant-derived antifungal, berberine. Several plant extracts, notably those from Zingiber officinale (ginger) and Juglans cinerea (butternut), had pronounced antifungal activity against a wide variety of fungi, including strains that were highly resistant to amphotericin B and ketoconazole. Further exploration of Z. officinale as an antifungal is warranted as this species is generally regarded as safe for human consumption.

Early Season Softwood Cuttings Effective for Vegetative Propagation of Juglans cinerea

Juglans cinerea L. (butternut) is a hardwood species valued for its wood and edible nuts. Information on the vegetative propagation of this species is currently unavailable. Our objective was to determine the conditions necessary for successful stem-cutting propagation of butternut. In 1999 and 2000, 10 trees (each year) were randomly selected from a 5- and 6-year-old butternut plantation located in Rosemount, Minn. Hardwood stem cuttings were collected in March, April, and May. Softwood cuttings were collected in June and July. K-IBA at 0, 29, or 62 mm in water and IBA at 0, 34, or 74 mm in 70% ethanol were tested for root induction on cuttings. The basal end of cuttings were dipped in a treatment solution for 10 to 15 seconds, potted in a peat: perlite mixture, and placed in a mist bed for 5 to 8 weeks. Rooted cuttings were gradually hardened off from the mist bed, allowed to initiate new growth, over-wintered in a controlled cold-storage environment, and then outplanted to the field. For hardwood cuttings, rooting was greatest for those taken in mid-May (branches flushed out), 22% with 62 mm K-IBA and 28% with 74 mm IBA. Softwood cuttings rooted best when taken in June (current season's first flush of new growth or softwood growth 40 cm or greater) and treated with 62 mm K-IBA (77%) or 74 mm IBA (88%). For 1999, 31 out of 51 rooted softwood cuttings (60.8%) survived overwintering in cold storage and acclimatization to the field. For 2000, 173 out of 186 rooted softwood cuttings (93%) survived overwintering and acclimatization to the field. Chemical names used: indole-3-butyric acid-potassium salt (K-IBA); indole-3-butyric acid (IBA).

Potential Beetle Vectors of Sirococcus clavigignenti-juglandacearum on Butternut.

To identify potential beetle (Coleoptera) vectors of the butternut canker fungus (Sirococcus clavigignenti-juglandacearum), beetles were collected from butternut (Juglans cinerea) trees and freshly cut logs and branches in Vermont from 1997 through 1999. At least 17 species of beetles, representing eight families, were found to carry conidia of the pathogen. Species most commonly collected and most frequently carrying the fungus were Acoptus suturalis (Curculionidae), Astylopsis macula (Cerambycidae), Eubulus parochus (Curculionidae), and Hyperplatys maculata (Cerambycidae). In 1999, 64, 74, 37, and 52% of these species, respectively, were carrying conidia. These beetles were often collected from dead butternut stems and branches upon which the fungus was fruiting and were less frequently found in crowns of living butternut trees. The butternut curculio (Conotrachelus juglandis) (Curculionidae) was found creating feeding and oviposition wounds on new shoots in crowns of butternut trees. Six to eleven percent of curculios collected carried the fungus. Species of Nitidulidae were observed crawling on logs or burrowing into cankers and curculio wounds. Six to seven percent of the nitidulids, Cryptarcha ampla and Glischrochilus sanguinolentus, carried conidia in 1999, and 31% of G. vittatus carried the fungus in 1998. Additional study is necessary to learn how consistently any of these beetles move from diseased to healthy tissue of butternut and vector conidia of S. clavigignenti-juglandacearum.

Effectiveness of predator odors as gray squirrel repellents

The ability of gray squirrels (Sciurus carolinensis) to discriminate between different predator odors and the use of predator odors to deter gray squirrels from foraging on plants have not been previously investigated. To test the hypothesis that predator scent decreases foraging, I investigated the effect of such scent on consumption of butternuts (Juglans cinerea) in the field. Results showed that (i) red fox (Vulpes vulpes) scent was significantly more effective than either a control or human scent; (ii) raccoon (Procyon lotor) scent was significantly more effective than white-tailed deer (Odocoileus virginianus) scent (but only after 7–9 h); (iii) red fox scent was not significantly more effective than raccoon scent; and (iv) human scent was not significantly more effective than the control. The utility of predator odors in controlling damage by gray squirrels should be explored.

Antimicrobial activity of extracts of eastern North American hardwood trees and relation to traditional medicine

Wood and bark extracts of 14 eastern North American hardwood tree species which were used traditionally as medicine by First Nation's people were screened for antimicrobial activities with eight strains of bacteria and six strains of fungi. Eighty-six percent of the bark extracts were active against methicillin sensitive Staphylococcus aureus; 71% against Bacillus subtilus and 79% against Mycobacterium phlei. The bark extract of Juglans cinerea was active against Pseudomonas aeruginosa 187, Salmonella typhiumurium, and Klebsiella pneumoniae. The wood extracts were less active: 72% were active against S. aureus (methicillin-sensitive), 36% against B. subtilus and 43% against M. phlei. Results from antifungal tests indicated that 36% of the extracts were active against at least one fungal strain and that bark extracts were more active than wood extracts. The bark extract from Juglans cinerea had the broadest spectrum of activities against Candida albicans, Saccharomyces cerevisiae, Cryptococcus neoformans, Trichophyton mentagrophytes, Microsporum gypseum, and Aspergillus fumigatus. In general, the extracts were more active against gram positive bacteria than gram negative bacteria and against filamentous fungi than yeast-like fungi. The study also demonstrated a correlation between frequency of traditional medicinal use by the First Nations people and antimicrobial activity of extracts indicating that the traditional knowledge encompasses an understanding of aspects of chemical ecology.

Ex situconservation of American chestnut (Castanea dentata(Marsh.) Borkh.) and butternut (Juglans cinereaL.), a review

Two tree species native to North America, American chestnut (Castanea dentata (Marsh.) Borkh.) and butternut (Juglans cinerea L.), which have experienced rapid declines in their populations due to similar stressors (disease and changes in land use), are used as examples of how these species would benefit from ex situ conservation efforts. Current and past ex situ and in situ conservation efforts for these species are discussed and the focus of this review is on two key research areas: 1) what needs to be preserved (genetic information) and 2) how to preserve these trees or germplasm. Key words: butternut, American chestnut, Cryphonectria parasitica, Sirococcus clavigignenti-juglandacearum, ex situ conservation

Low genetic diversity at allozyme loci inJuglans cinerea

Butternut (Juglans cinerea L.) is a minor component of the temperate deciduous forest region of northeastern North America, but it is severely affected by the butternut canker (Sirococcus clavigignenti-juglandacearum Nair, Kostichka, and Kuntz) in the southern part of its natural range. Genetic diversity and population structure in as-yet unaffected or only slightly affected natural populations were evaluated at 12 isozyme loci. The genetic diversity estimates were low with values much below those estimated in other species of the same genus or in boreal tree species, with 25 and 13.9% polymorphic loci at the species and population levels, respectively; 1.3 and 2.3 alleles per locus and per polymorphic locus, respectively, at the species level; and an average observed heterozygosity of 0.028. Population differentiation was low, with the exception of one unique population. The implications for advanced conservation are discussed.Key words: butternut, isozymes, Sirococcus, canker, population structure.

Butternut: An Underused Resource in North America

Butternut (Juglans cinerea L.) has many fine qualities as a nut species, however, it has never been commercially important. Although the nut is very edible, only a few cultivars have been selected that have desirable nut size and cracking qualities. In the last 20 years there has been a dramatic decline in the number of butternut in native stands caused to a large extent by the lack of natural reproduction and a damaging canker disease. Evidence suggests that superior, disease resistant trees can be propagated and if isolated from areas where the disease is prevalent, may remain disease-free. It is important that the remaining genetic diversity within the species is maintained. Various butternut conservation practices and research projects to restore butternut populations are underway in the United States and Canada.

Low genetic diversity at allozyme loci in &lt;i&gt;Juglans cinerea&lt;/i&gt;

Butternut (Juglans cinerea L.) is a minor component of the temperate deciduous forest region of northeastern North America, but it is severely affected by the butternut canker (Sirococcus clavigignenti-juglandacearum Nair, Kostichka, and Kuntz) in the southern part of its natural range. Genetic diversity and population structure in as-yet unaffected or only slightly affected natural populations were evaluated at 12 isozyme loci. The genetic diversity estimates were low with values much below those estimated in other species of the same genus or in boreal tree species, with 25 and 13.9% polymorphic loci at the species and population levels, respectively; 1.3 and 2.3 alleles per locus and per polymorphic locus, respectively, at the species level; and an average observed heterozygosity of 0.028. Population differentiation was low, with the exception of one unique population. The implications for advanced conservation are discussed.Key words: butternut, isozymes, Sirococcus, canker, population structure.

Genetic evidence that butternut canker was recently introduced into North America

Butternut (Juglans cinerea) is seriously threatened by a canker disease caused by Sirococcus clavigignenti-juglandacearum, a fungus with no known sexual stage. This pathogen was first reported in 1967 and is now found throughout the native range of butternut, suggesting that it was introduced into North America. We used randomly amplified polymorphic DNA (RAPD) markers to examine genetic variation in S. clavigignenti-juglandacearum over a large portion of the native range of butternut. The 55 RAPD fragments were all found in all 86 isolates of the fungus. This complete monomorphism is consistent with the fungus having been introduced into North America as a single isolate and suggests that if resistant butternut genotypes are found, the pathogen will not likely be able to rapidly evolve genotypes that can attack them.Key words: Sirococcus clavigignenti-juglandacearum, Juglans cinerea, RAPD, randomly amplified polymorphic DNA.

101 Propagation of Juglans cinerea L. (Butternut)

Butternut trees are becoming endangered as a result of butternut canker disease; thus, it is desirable to propagate disease-resistant trees for screening and provenance tests. The objective of this study was to determine the conditions necessary for successful cutting propagation. In 1998, 10 trees were selected from a 4-year-old butternut plantation located in Rosemount, Minn. Hardwood cuttings were collected 30 Mar., 21 Apr., and 6 May. The auxins, indole-3-butyric acid-potassium salt (KIBA) in water at 0, 29, or 74 mmol·L-1 were tested for root induction. The basal end of cuttings were dipped in treatment solutions for 10 to 15 s and placed in a 1 peat: 1 perlite mixture in Deepots™ (D40) in a mist bed. Mist was applied for 5 s every 15 min. Greenhouse conditions were: 12-h photoperiod provided by high-pressure sodium lamps (60 μmol·m-2·s-1), 22 °C, and bottom heat of 27 °C (heating pads). Softwood cuttings were collected 20 May, 18 June, 30 June, and 23 July. Rooting treatment solutions and greenhouse conditions were the same as for the hardwood cuttings, except no heating pads were used. Rooted cuttings were planted in Treepots™ (10 × 10 × 36 cm) and gradually hardened off from the mist bed. Hardwood cuttings from the first two collection dates did not initiate roots. Best rooting (12.5%) was achieved on hardwood cuttings collected 6 May using 29 mmol·L-1 KIBA. Softwood cuttings rooted to some degree at all concentrations of rooting solution and at every collection date. The greatest rooting (70%) was achieved using 74 mmol·L-1 IBA. In general, best rooting percentages were achieved with softwood cuttings collected 18 June and 23 July and treated with 62 mmol·L-1 KIBA or 74 mmol·L-1 IBA. Both rooted hardwood and softwood cuttings were successfully acclimatized from the mist bed and many have initiated new growth.

Susceptibility of species of Juglans to pathovars of Xanthomonas campestris

SummaryBacterial blight is considered one of the most serious diseases affecting the genus Juglans. Artificial inoculations with Xanthomonas campestris pv. Juglandis were performed in the field by spraying seedlings of Juglans cinerea, Juglans hindsii, Juglans mandshurica, Juglans nigra, Juglans regia and Juglans sieboldiana. Juglans nigra, J. cinerea ana J. sieboldiana proved to be the most resistant. The multiplication ability of Xanthomonas campestris pv. corylina, X. c. pv. juglandis, and X. c. pv. campestris was evaluated by injecting 2‐year‐old seedling leaves of J. mandshurica, J. nigra and J. regia. The bacterial growth was monitored in the infected tissue over 12 days. Xanthomonas c. pv. juglandis exhibited a high growth rate and induced black greasy spots in J. mandshurica and J. regia; X. c. pv. campestris grew in leaf tissues without inducing symptoms, X. c. pv. corylina showed a very low growth rate. None of the tested bacterial strains multiplied in the leaves of J. nigra. This confirms the results obtained in the field tests. Juglans regia was the most susceptible among the walnut species tested.

Genetic evidence that butternut canker was recently introduced into North America

Butternut (Juglans cinerea) is seriously threatened by a canker disease caused by Sirococens clavigignenti-juglandacearum, a fungus with no known sexual stage. This pathogen was first reported in 1967 and is now found throughout the native range of butternut, suggesting that it was introduced into North America. We used randomly amplified polymorphic DNA (RAPD) markers to examine genetic variation in S. clavigignenti-juglandacearun over a large portion of the native range of butternut. The 55 RAPD fragments were all found in all 86 isolates of the fungus. This complete monomorphism is consistent with the fungus having been introduced into North America as a single isolate and suggests that if resistant butternut genotypes are found, the pathogen will not likely be able to rapidly evolve genotypes that can attack them.

First Report of Butternut Canker Caused by Sirococcus clavigignenti-juglandacearum in New Brunswick, Canada.

In June 1997, butternut canker was found for the first time in New Brunswick, Canada, at Stickney, Carleton County. A fungal isolate recovered from a young branch canker on butternut (Juglans cinerea L.), cultured on potato dextrose agar, produced spores and cultural morphology as previously described (1). This strain was retained as FSC-758 in the Fredericton Stock Culture Collection at the Atlantic Forestry Centre. The disease was also detected at four other locations in Carleton County along the Saint John River watershed within 20 km of the State of Maine. One stem canker examined at Peel, Carleton County, suggests the disease has been present at this site in New Brunswick for at least 7 years. The butternut tree is at the northeastern edge of its natural range in New Brunswick and, prior to the pathogen's detection, was believed to be far enough from infected butternut in the northeastern United States, Ontario, and Quebec to escape infection. Because planted specimens of butternut exist outside the tree's natural range in New Brunswick and in the neighboring provinces of Nova Scotia and Prince Edward Island, efforts are underway to determine how far the fungus has spread in the Maritime Provinces. Reference: (1) V. M. G. Nair et al. Mycologia 71:641, 1979.

Role of the cotyledonary tissue in improving low and ultralow temperature tolerance of butternut (Juglanscinerea) embryonic axes

Butternut (Juglans cinerea L.) survival is threatened in North America by the fungus Sirococcus clavigignenti-juglandacearum. To date, there is no control for this fungal disease and long-term seed storage, to ensure survival of the species, is not a viable option. Initially, low (0, –5, –10, –15, and –40°C) and ultralow (–196°C, cryopreservation) temperature tolerance of butternut embryonic axes isolated from the nuts collected from one tree was examined. Embryonic axes with approximately 3 mm of cotyledonary tissue attached to the hypocotyl area germinated after exposure to 0, –5, –10, –15, and –40°C for 4 h and to –196°C for 24 h. Percent germination after exposure to 0 and –5°C was 87 and 82%, respectively, and after –10 and –15°C was 29 and 27%, respectively. Thirty-two percent of axes germinated after –40°C, and 36% germinated after exposure to –196°C. Tolerance to –196°C was examined in the embryonic axes isolated from the nuts of 13 other trees. Significant tree-to-tree variation was found in the tolerance of the embryonic axes to low temperature. This variation corresponded to the water content of the embryonic axes; water contents of 4.8% and lower exhibited tolerance to –196°C. Reducing the water content of the embryonic axes by slow desiccation to 4.8% or less resulted in an increased tolerance to –196°C. These results suggest that low and ultralow temperature storage of embryonic axes may be a viable method for butternut ex situ conservation.