Gibberella pulicaris. [Descriptions of Fungi and Bacteria].

Author(s):  
C. Booth

Abstract A description is provided for Gibberella pulicaris. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Cereals, flax, hops, lupin, strawberry, tomato, potato. DISEASE: This fungus has a threefold expression in terms of economic importance; canker and dieback, root rots, storage rots. As a canker form it can be a serious disease of hops (Burgess, 1964); as a root rot it attacks a wide variety of hosts especially cereals in Eastern Europe, but also flax (49, 1044), lupin (47, 2190), strawberry (43, 1091), tomato (46, 61c) and numerous other hosts; as a storage rot it is of considerable importance on potato. Although this fungus may be important as a root rotting organism or as a storage rot, the perithecia are usually found only in association with its third role, that of a canker forming or dieback organism of woody hosts. GEOGRAPHICAL DISTRIBUTION: Common in N. temperate and Mediterranean regions; Asia, Europe, N. Africa and N. America. In the southern hemisphere it probably represents an introduction. Dingley (36, 127) states the early records for NZ are misidentifications although it has since been recorded there on passion fruit (49, 2943). In Australia it can be a serious problem in stored potatoes. TRANSMISSION: By conidial splash or by ascospores; canker of hops becomes progressively more severe if infected material is allowed to remain in the hop garden.

1969 ◽  
Vol 55 (2) ◽  
pp. 139-146
Author(s):  
Lii-Jang Liu ◽  
José Adsuar ◽  
Enrique Pérez

A sugarcane disease survey was conducted over different mill zones of Puerto Rico during the fall of 1969 and the spring of 1970. It covered the plantations of 10 sugar mills. The results obtained to date indicate that the diseases of major importance are ratoon stunting, chlorotic streak, pineapple disease, and root rot caused by a complex of Pythium, Fusarium and nematodes. The specific disease problems are identified in each area. Special attention was given to disease distribution, economic importance, and possible methods of control. Although in general low incidence of ratoon stunting was observed in commercial plantings, data obtained from previous variety tests indicate this malady to be potentially dangerous. Hot water treatment of seedpieces should be conducted to prevent its further spread. The significance of chlorotic streak disease as a factor in yield decline in Puerto Rico has not yet been completely evaluated. The high incidence of this disease, under present conditions, has given rise to concern. Pineapple disease caused by Thielaviopsis paradoxa greatly affects the germination of P.R. 980, especially in areas with poor drainage. Root rots caused by Pythium, Fusarium and nematodes reduced germination of P.O.J. 2878 and H. 328560 by as much as 40 percent in poorly-drained areas.


Author(s):  
E. Punithalingam

Abstract A description is provided for Wojnowicia hirta. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Cereals and grasses (Agropyron, Avena, Bromus, Calamagrostis, Calamovilfa, Dacrylis, Distichlis, Elymus, Festuca, Hordeum, Koeleria, Phleum, Poa, Secale, Sorghastrum, Sorghum, Spartina, Stipa, Triticum). DISEASE: Secondary foot rot or root rot of cereals and grasses. Also referred to as rot of mature straw. Rot of cereals and grasses is very common (5, 223; 6, 272; 7, 370; 11, 503; 12, 685; 16, 242; 48, 120; 1602) and considered to be of definite economic importance (Sprague, 1950). In France infected wheat plants have been reported to become etiolated and progressively shrivelled without producing lesions (4, 662). As the disease progresses, cells at the base of the culms were claimed to collapse resulting in the breaking of the stems and general lodging of plants in infected areas (5, 223; 12, 685). Subsequently pycnidia were reported appearing on lower leaf-sheaths above and below the soil line (1, 288). Sometimes affected wheat plants have been found to show discolouration of culm bases and roots (5, 223), or dark brown to black spots and streaks on the stem which are partly superficial (7, 370, Sprague, 1935). GEOGRAPHICAL DISTRIBUTION: Africa (Morocco, South Africa, Tunisia); Asia (Turkey); Australasia and Oceania (Australia, New South Wales, South Australia, Victoria, Western Australia); Europe (Belgium, Bulgaria, Czechoslovakia, Finland, France, Germany, Irish Republic, Italy, Netherlands, Poland, Rumania, Spain, Switzerland, UK, USSR); North America (Canada, Alberta, Saskatchewan; USA, Arkansas, California, Colorado, Dakota, Idaho, Kansas, Montana, Oregon, Washington, Wyoming). TRANSMISSION: Infected soil has been found to be the chief mode of transmission where stubble has been ploughed under (3, 191). It has also been reported that W. hirta occurs on culms overwintered in the field usually at the 2nd node (9, 639-641).


Author(s):  
D. J. Stamps

Abstract A description is provided for Phytophthora palmivora. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: A wide range; 138 species of economic, ornamental, shade and hedge plants were listed (48, 337-344). DISEASE: Black pod and canker of cacao; patch canker, black stripe and leaf fall of Hevea rubber; bud rot of coconut and other palms; fruit and stem rot of pawpaw; root rots and damping-off of seedlings. GEOGRAPHICAL DISTRIBUTION: World-wide in tropical and warm temperature regions with high rainfall. TRANSMISSION: In cacao by direct contact between diseased and healthy pods, by rain splash from diseased pods, leaves and infested soil, and by insect vectors and ant tents. In rubber by rain. Soil as a source of inoculum for pawpaw root rot.


Plant Disease ◽  
1997 ◽  
Vol 81 (10) ◽  
pp. 1216-1216 ◽  
Author(s):  
M. E. Sánchez-Hernández ◽  
A. Ruiz-Dávila ◽  
A. Trapero-Casas

Several species of the genus Phytophthora are associated with root rot and trunk cankers in olive trees (Olea europaea L.). Among them, Phytophthora megasperma has been cited as being associated with olive root rots in Greece (1). Unidentified species of Pythium and Phytophthora have also been associated with olive tree root rots in the United States. However, the status of P. megasperma and Pythium spp. as olive tree root pathogens has remained unclear. Following a 5-year period of severe drought in southern Spain, autumn-winter rainfall rates in 1996 to 1997 steadily increased in both quantity and frequency. Under these unusually wet conditions, olive trees remained waterlogged for several months. During this period, we observed foliar wilting, dieback, and death of young trees, and later found extensive root necrosis. In 46 of 49 affected plantations surveyed, P. megasperma was consistently isolated from the rotted rootlets, particularly in young (<1- to 10-year-old trees) plantations. This fungus was not detected on plant material affected by damping-off from several Spanish olive tree nurseries. The opposite situation occurred with P. irregulare. This species was not associated with rotted rootlets in the field. In contrast, it was consistently isolated from necrotic rootlets from young olive plants affected by damping-off. These plants were grown in a sand-lime-peat soil mixture under greenhouse conditions and showed foliar wilting and extensive necrosis of the root systems. Pathogenicity tests were conducted with several isolates of P. megasperma and P. irregulare on 6-month-old rooted cuttings of olive, under both weekly watering and waterlogged conditions. Under waterlogged conditions, both fungal species produced extensive root necrosis 2 weeks after inoculation that resulted in wilting of the aerial parts and rapid plant death. Waterlogged control plants remained without foliar symptoms but a low degree of root necrosis was recorded. In addition, under weekly watering conditions, plants inoculated with either species showed some degree of root rot but foliar symptoms were not evident. No differences in pathogenicity were observed within the Phytophthora or Pythium isolates. Reference: (1) H. Kouyeas and A. Chitzanidis. Ann. Inst. Phytopathol. Benaki 8:175, 1968.


Author(s):  
B. L. K. Brady

Abstract A description is provided for Ascosphaera apis. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Apis mellifera and Megachile spp. DISEASE: Chalkbrood of the honey bee (Apis mellifera) with a few poorly documented records on leaf cutting bees Megachile spp. (Melville & Dade, 1944) and M. internis (Baker & Torchio, 1968). The spores are ingested by young larvae and germinate in the gut, breaking out of the hind end when larvae are sealed in their cells prior to pupation. If one strain only is present this forms the typical chalkbrood. If both strains are present a layer of grey cysts forms on the surface of the larva. Larvae are most susceptible at 3-4 days old and are then chilled briefly immediately after sealing. Although fatal to the larvae, this rarely destroys a whole colony and individual dead larvae are ejected by the bees. Ascospores persist many years providing periodic trouble in adverse conditions. GEOGRAPHICAL DISTRIBUTION: Europe; USA. Until 1968 chalkbrood was considered to be a European disease and it was only in 1971 that it became recognised as of economic importance in USA (Hitchcock & Christensen, 1972). TRANSMISSION: By ascospores within the cells of the comb to young larvae. From hive to hive probably by robber bees. More prevalent in cold, wet summers.


Author(s):  
G. M. Waterhouse

Abstract A description is provided for Pythium intermedium. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On a wide range of hosts represented by the following families: Begoniaceae, Bromeliaceae, Chenopodiaceae, Compositae, Coniferae, Cruciferae, Euphorbiaceae, Geraniaceae, Gramineae, Leguminosae, Liliaceae, Linaceae, Moraceae, Onagraceae, Ranunculaceae, Rosaceae, Solanaceae, Ulmaceae, Violaceae; also in the Equisetales and Filicales. DISEASES: Damping-off of seedlings, foot rot and root rot of ornamentals, occasionally of crop plants and trees. GEOGRAPHICAL DISTRIBUTION: Asia (China); Australia & Oceania (Hawaii); Europe (England, Belgium, France, Germany, Holland, Sweden, U.S.S.R.); North America (U.S.A.); South America (Argentina). TRANSMISSION: A common soil inhabitant.


Author(s):  
E. Punithalingam

Abstract A description is provided for Scirrhia pini[Mycosphaerella pini]. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On pines including Pinus radiata and its hybrids, P. halepensis, P. canariensis, P. carbaea, P. ponderosa, P. nigra and others, Pseudotsuga menziesii (46, 2860), Larix decidua (49, 273). DISEASE: Dothistroma blight; red band. GEOGRAPHICAL DISTRIBUTION: North America (Canada, USA including Alaska), South America (Argentina, Brazil, Chile, Uruguay), Australasia and Oceania (New Zealand), Asia (Brunei, India, Japan), Africa (Ethiopia, Kenya, Malawi, Rhodesia, Swaziland, Tanzania, Uganda), Europe (Austria, France, Rumania, UK, USSR (Republic of Georgia), Yugoslavia) (CMI Map 419, ed. 2, 1970; record in CMI Herbarium). TRANSMISSION: By airborne conidia released and dispersed by a splash take-off mechanism for short distances. Long distance dispersal may be by transport of infected material, such as nursery stock and, under special conditions, clouds may carry sporal inoculum (43, 2100). Survival time of inoculum in the form of cast, infected foliage on the forest floor is limited to 2-6 months under moist conditions (50, 2003).


1970 ◽  
Vol 14 (1) ◽  
pp. 25-36
Author(s):  
Hosne Ara ◽  
Bushra Khan ◽  
Md. Mansur-ul-Kadir Mia

The available record of the genus Cleome L. for Bangladesh has been updated in this paper and includes C. diffusa, C. gynandra, C. hassleriana, C. rutidosperma and C. viscosa. The updating has been done in case of nomenclature with important synonyms, local names, description of the taxa along with illustrations, flowering and fruiting times, ecological notes, specimens examined and their geographical distribution. For identification of the species, a dichotomous bracketed key has been added in this paper. Information on chromosome number and economic importance have also been provided where available. Key words: Cleome, Taxonomic revision, Capparaceae, Bangladesh DOI: 10.3329/bjpt.v14i1.520 Bangladesh J. Plant Taxon. 14(1): 25-36, 2007 (June)


Plant Disease ◽  
1999 ◽  
Vol 83 (1) ◽  
pp. 51-54 ◽  
Author(s):  
D. K. Malvick ◽  
J. A. Percich

Aphanomyces root rot is a serious disease of pea (Pisum sativum), and additional sources of resistance are needed for development of disease-resistant cultivars. Accessions (n = 123) from the P. sativum Plant Introduction (PI) collection with the highest relative levels of resistance to one strain of Aphanomyces euteiches were previously identified from among approximately 2,500 accessions evaluated. The chosen 123 accessions were evaluated in this study for resistance to root rot caused by multiple strains of this pathogen. Five strains representing different US geographical locations and pathogenicity characteristics were used to evaluate pea seedlings in a greenhouse. Disease severity (DS) and percent loss of fresh biomass (inoculated vs. non-inoculated plants) were determined 15 days after inoculation. Significant differences (P = 0.05) in levels of DS and biomass loss (BL) occurred among the accessions after inoculation individually with the five strains. The relative rank of accessions based on DS and BL varied with the strain of A. euteiches used for inoculations. The 20 accessions with the lowest DS after inoculation with each strain were identified. Based on lowest DS, two accessions were among the 20 identified with all five individual strains, and four other accessions were among the 20 identified with four of the five strains. The results suggest that the P. sativum PI collection contains useful accessions for breeding programs aimed at developing pea varieties with resistance to A. euteiches.


Plant Disease ◽  
2022 ◽  
Author(s):  
Liu Yang ◽  
Tian Yuan ◽  
Xia Zhao ◽  
Yue Liang ◽  
UWAREMWE CONSTANTINE ◽  
...  

Root rot is a serious disease in plantations of A. sinensis, severely affecting yield and quality and threatening sustainable production. Fusarium isolates (n=32) were obtained from field samples of root rot tissue, leaves and infected soil. Isolates were identified by comparing the sequences of their internal transcribed spacer (ITS) region and translation elongation factor 1-ɑ (TEF-1ɑ) to sequences of known species in the NCBI-database. These Fusarium isolates include F. tricinctum (43.75%), F. equiseti (31.25%), F. solani (9.37%), F. oxysporum (6.25%), F. acuminatum (6.25%), and F. incarnatum (3.12%). For pathogenicity testing under greenhouse conditions, seven isolates were selected based on a phylogenetic analysis, including four strains of F. tricinctum and one strain each of F. solani, F. oxysporum, and F. acuminatum. The seven isolates were all pathogenic but differed in their ability to infect: the four F. tricinctum strains were capable pathogens causing root rot in A. sinensis at 100% incidence and the highly aggressive. Furthermore, the symptoms of root rot induced by those seven isolates were consistent with typical root rot cases in the field, but their disease severity varied. Observed histopathological preparations of F. tricinctum-infected seedlings and tissue-slides results showed this fungal species can penetrate epidermal cells and colonize the cortical cells where it induces necrosis and severe plasmolysis. Plate confrontation experiments showed that isolated rhizosphere bacteria inhibited the Fusarium pathogens that cause root rot in A. sinensis. Our results provide timely information for informing the use of biocontrol agents for suppression of root rot disease.


Sign in / Sign up

Export Citation Format

Share Document