Pezicula Malicorticis Research Articles

Abstracts, British Columbia Regional Meeting, The Canadian Phytopathological Society, 1997

Ustilago hordei; use of RAPD and AFLP technology for tagging and fingerprinting in smuts and other fungi. G. Bakkeren, D. Lin, N. Lee, M. Abdennabher, D. Gaudet, P. Thomas, D. Mills, C. A. Lévesque, and J. Kronstad. (G.B. and C.A.L.) Pacific Agri-Food Research Centre, Agriculture & Agri- Food Canada, Summerland, B.C. VOH 1Z0, (G.B., D.L., N.L., and J.K.) Biotechnology Laboratory, Departments of Microbiology and Immunology, and Plant Science, University of British Columbia, Vancouver, B.C. V6T 1Z3, (M.A. and D.M.) Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA 97331, (D.G.) Research Station, Agriculture & Agri-Food Canada, Lethbridge, Alberta, TIJ 4B1, (P.T.)Agriculture & Agri- Food Canada, Research Station Winnipeg, Manitoba, R3T 2M9. Tomato ringspot nepovirus protease demonstrates different level of tolerance to amino acid substitution at two polyprotein cleavage sites. K. Carrier and H. Sanfacon. Pacific Agri-Food Research Centre, Agriculture and Agri-Food Canada, Summerland, B.C. VOH 1Z0. Development of PCR primers specific for Pezicula malicorticis and P. perennans, fungal species associated with anthracnose and perennial cankers of apple and bull's eye rot of apple fruit. S. N. de Jong, C. A. L&vesque, and J. E. Rahe. Centre for Pest Management, Department of Biological Sciences, Simon Fraser University, Burnaby, B.C. V5A 1S6, (C.A.L.) Pacific Agri-Food Research Centre, Agriculture and Agri- Food Canada, Summerland, B.C. VOH 1Z0. First record of Pythium paddicum isolated from turfgrass roots collected from a British Columbia golfcourse. R. C. Descalzo, I. W. Geere, G. Geere, and C.A. L&vesque. I.G. MicroMed Environmental Inc., 190-12860 Clarke Place, Richmond, B.C., V6V 2H1, (C.A.L.) Pacific Agri-Food Research Centre, Agriculture and Agri-Food Canada, Summerland, B.C. VOH 1Z0. Control of the root lesion nematode Pratylenchus penetrans with antagonistic rhizobacteria. C. Hackenberg, T. Forge, A. Muehlchen, and T. Vrain. Pacific Agri-Food Research Centre, Agriculture and Agri-Food Canada, Summerland, B.C. VOH 120. A novel host-based identification and detection system using cranberry pathogens as a model. C. E. Harlton, Y. Ahn, and C. A. L&vesque. Pacific Agri-Food Research Centre, Agriculture and Agri-Food Canada, Summerland, B.C. VOH IZ The sexual stage of Pezicula malicorticis on anthracnose cankers. K. Jurkemikova and J. E. Rahe. Centre for Pest Management, Department of Biological Sciences, Simon Fraser University, Burnaby, B.C. V5A 1S6. Development of commercial biocontrol products; synergy in action, "Mickey" a case study. M. Leggett. Philom Bios Inc., 318-111 Research Drive, Innovation Place, Saskatoon, Saskatchewan S7N 3R2. A survey of blueberry fruit rot in British Columbia — implications for management. L. Macdonald. B.C. Ministry of Agriculture, Fisheries and Food, 1767 Angus Campbell Road, Abbotsford, B.C. V3G2M3. Microbiological aspects of apple replant disease and the potential for control through the use of integrated management Strategies. M. Mazzola. USDA-ARS, Tree Fruit Research Lab, 1104 N. Western Ave., Wenatchee, WA 98801. Abiotic considerations for overcoming replant problems in high density orchard systems. G. H. Neilsen, E. J. Hogue, D. Neilsen, and B. J. Zebarth. Pacific Agri-Food Research Centre, Agriculture and Agri-Food Canada, Summerland, B.C. VOH Molecular approach to monitor a beneficial Penicillium species. D. O'Gorman, M. Leggett, and C. A. Lévesque Pacific Agri-Food Research Centre, Agriculture and Agri-Food Canada, Summerland, B.C. VOH IZO; (M.L.) Philom Bios Inc., 318-111 Research Drive, Innovation Place. Saskatoon, Saskatchewan S7N 3R2. Development of fusarium crown and root rot, a new disease on greenhouse cucumbers in British Columbia. Z. K. Punja and K. Ng. Department of Biological Sciences, Centre for Pest Management, Simon Fraser University, Burnaby, B.C. V5A 1S6, and (K.N.), B.C. Ministry of Agriculture, Fisheries and Food, Abbotsford, B.C. V3G 2M3. Revisiting Pythium taxonomy, identification and ecology. A. Quail, C. Mayes, and C. A. Lévesque. Pacific Agri-Food Research Centre, Agriculture and Agri-Food Canada, Summer/and, B.C VOH1Z0. Geographic variation in the mitochondrial DNA of Chondrostereum purpureum . T. D. Ramsfield, Z. K. Punja, S. F. Shamoun, and W. E. Hintz. Centre for Pest Management, Department of Biological Sciences, Simon Fraser University, Burnaby, B.C., V5A 1S6, (S.F.S.) Canadian Forest Service, Pacific Forestry Centre, 506 West Burnside Road, Victoria, B.C., V8Z 1M5, (W.E.H.) Biology Department, University of Victoria, Victoria, B.C. V8W3N5. Binding of cucumber necrosis virus to zoospores of its fungal vector in vitro. M. Robbins and D. Rochon. Department of Plant Science, University of British Columbia, Vancouver, B.C., V6T 2A2, and Agriculture and Agri-Food Canada, Pacific Agri-Food Research Centre, Summerland, B.C. VOH IZ0. Latent infection of apples and stone fruit in British Columbia in 1997. P. Sholberg, K. Bedford, L. Lashuk, and P. Haag. Agriculture and Agri-Food Canada, Pacific Agri-Food Research Centre, Summerland, B.C., VOH 1Z0.

Control of Postharvest Pathogens and Colonization of the Apple Surface by Antagonistic Microorganisms in the Field

ABSTRACT Selected isolates of Aureobasidium pullulans, Rhodotorula glutinis, and Bacillus subtilis reduced the size and number of lesions on wounded apples caused by the postharvest pathogens Penicillium expansum, Botrytis cinerea, and Pezicula malicorticis. Combinations of the antagonistic microorganisms were applied to apple trees in the field late in the growing season of two consecutive years. The population dynamics of the introduced microorganisms and the incidence of fruit decay were determined. Population sizes of introduced antagonists on apple surfaces increased in the field following application of treatments until harvest. After transfer of the fruit from the field into cold storage, the populations of the introduced antagonists remained higher than in the control treatments. Identification of the applied isolates of A. pullulans and R. glutinis during the experiments was achieved by isolate-specific DNA probes generated from random amplified polymorphic DNA. A combination of two strains of A. pullulans and one strain of R. glutinis suppressed rotting of apple to the same extent as the commonly used fungicide Euparen. Our data demonstrate that the application of antagonistic microorganisms in the field represents a promising alternative to fungicide treatments to control post-harvest diseases of apple.

Effect of High-Carbon Dioxide and Low-Oxygen Controlled Atmospheres on Postharvest Decays of Apples

Controlled atmosphere storage with carbon dioxide concentrations above 2.8% reduced the development of lesions incited by Botrytis cinerea (causing gray mold), Penicillium expansum (causing blue mold), and Pezicula malicorticis (causing bull's-eye rot) in McIntosh, Delicious, and Golden Delicious apples (Malus domestica) kept for 61 days at 0 C. Low-oxygen atmospheres were less effective for decay control (.)

The role of benzoic acid and phenolic compounds in latency in fruits of two apple cultivars infected with Pezicula malicorticis or Nectria galligena

Pezicula malicorticis forms a latent infection of apples which develops into a bitter rot in stored fruits. Phenolic compounds do not apppear to be significant in maintaining latency in fruits of Cox's Orange Pippin or of Bramley's Seedling since (a) the concentration of neither total phenolics norofchlorogenic acid, the major phenolic constituent of apples, decreased significantly during storage and (b) chlorogenic acid is, in any case, a poor inhibitor of growth of the fungus. Benzoic acid, particularly at low pH, inhibited the growth of P. malicorticis and of N. galligena, which also causes latent infections in apple. Both fungi elicited benzoic acid production in fruits of the two apple cultivars, harvested at various times during the growing season. With fruits taken from store, however, while Bramley's were still healthy and capable of producing benzoic acid following inoculation, some Cox's were showing symptoms of natural Pezicula infections and healthy Cox's did not produce benzoic acid following inoculation. These results suggest that the accumulation of inhibitory concentrations of benzoic acid is the primary mechanism responsible for establishing and maintaining latency in bitter rot of both Cox's Orange Pippin and Bramley's Seedling and N. galligena rot of Cox's Orange Pippin. They also confirm the operation of the same mechanism in rot of Bramley's Seedling caused by N. galgena.

Pezicula malicorticis: Factors affecting spore germination and invasion of apple fruit

In aqueous suspension, conidia of Pezicula malicorticis (Jacks.) Nannf. germinated readily at the mean shade temperatures experienced in southern England in the period July to September. The percentage germination rate on cuticles detached from apple fruit, declined sharply in atmospheric humidities below 94% r.h., but conidia germinated well on intact apples stored at 93% r.h. In alternating wet and dry periods, germ-tubes were branched, with enhanced production of appressoria. Ungerminated conidia survived dry periods for up to 5 weeks, but on apples produced fewer lesions with increase in length of the period in the ungerminated state. Survival of germinated conidia depended partly on the length of the germ-tube and also on the mean ambient temperature. Extracts of apple peel containing phenolic compounds inhibited or reduced the pectolytic activity of culture filtrates of P. malicorticis . The inhibitory activity of these extracts fell as the fruit ripened both on the tree and after harvest.

Phlyctaena vagabunda Desm., Pezicula malicorticis (Jackson) Nannf., and other fungi associated with apple twigs

The apple fruit rotting fungi Phlyctaena vagabunda, Pezicula malicorticis and Botrytis cinerea were isolated from apple tree pruning stubs or cankers. This report constitutes the first record of Pezicula malicorticis in New South Wales. It is suggested that pruning stubs provide the source of infection for fruit rots caused by these fungi.

The occurrence of Pezicula alba sp.nov. and P. malicorticis, the perfect states of Gloeosporium album and G. Perennans, in England

Pezicula malicorticis (Jackson) Nannfeldt, the perfect state of Gloeosporium peremans Zeller & Childs, previously found only in the United States and Holland, is reported on apple trees at Horsmonden, Kent. The perfect state of G. album, previously unknown, is described and given the name Pezicula alba sp.nov. Both fungi were grown from ascospores and the pathogenicity of these cultures to apple was demonstrated.

Observation en Hollande de la forme parfaite du champignonGloeosporium perennans Zeller et Childs

In October 1956 apothecia, belonging toPezicula malicorticis (Jackson)Nannfeldt (=Neofabraea malicorticis (Cordley) Jackson), the perfect stage of the parasite known in plant pathology literature asGloeosporium perennans, have been found on naturally infected appletrees in Druten and near Deest (Land van Maas en Waal) and on appletrees at Wageningen, which had been inoculated with mycelium ofG. perennans in October 1955. The apothecia occurred as well on the surface of the bark as in old conidial fructifications; they were sessile, clearly convex, bright-yellow under moist conditions and brownish when old or dry. The diameter of the apothecia was 0,4–1,6 mm. As many as 100 apothecia were found on a square cm. It is put forward that the formation of the apothecia has been favoured by the very wet weather of the preceding summer.