Leptosphaeria salvinii. [Descriptions of Fungi and Bacteria].

Author(s):  
M. B. Ellis

Abstract A description is provided for Leptosphaeria salvinii[Magnaporthe salvinii]. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Oryza sativa. DISEASE: Stem rot of rice (Oryza sativa). Symptoms are usually first seen at the later growth stages. Necrotic lesions begin on the outer leaf sheath near the water line; these spread gradually to the inner sheaths and the stem base. At about maturity lodging may occur and sclerotia will be found within the tissues. Partial sterility is caused and grain becomes light and chalky. Late infection can lead to small tillers but whether the pathogen caused excessive tillering, as earlier reports stated, is in doubt. Sclerotia form conidia when floating free or detached on moist substrata. Symptoms seem to vary with the growing conditions. GEOGRAPHICAL DISTRIBUTION: Widespread with host (CMI Map 448, ed. 1, 1968). Additional records not mapped are: Costa Rica, Indonesia, Laos, Panama, Peru. TRANSMISSION: Probably largely through the sclerotia; the role of the conidium and ascospore has been little studied. Viability of the sclerotium is variable, depending on temperature and substratum conditions (11: 599; 47, 182), and a period of 6 yr has been reported (20: 381). Both sclerotia and perithecia survive high summer temperatures (46, 1574).

Author(s):  
B. L. K. Brady

Abstract A description is provided for Sarocladium oryzae. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOST: Oryza sativa (rice). DISEASE: Sheath rot. This occurs in the upper leaf sheath enclosing young panicles and starts as oblong or irregular lesions with brownish margins and greyish centres, 0.5-1.5 cm long, which later enlarge and coalesce. Whitish mycelium may be seen in the centre of the lesions and occasionally inside the rotted sheaths. Severely affected panicles do not emerge, the effect being known as choking. The symptoms are evidently indistinguishable from those associated with S. attenuatum. GEOGRAPHICAL DISTRIBUTION: India, Bangladesh, Brunei, Kenya, Nigeria. Although it is not always possible when 'Acrocydndrium oryzae' is reported in the earlier literature to know whether S. oryzae or S. attenuatum is intended, the distribution of the former extends into S.E. Asia and the latter into N. America. TRANSMISSION: By conidial dispersal. Fungal attack is often associated with damage by pests - the boring beetle, Corticarina gibbosa (Amin et al.) or the mite Steneotarsonemus madecassus (Hsieh et al., 1977 with 'Acrocylindrium oryzae') and S. spinki (Chien & Huang, 1979).


2011 ◽  
Vol 24 (2) ◽  
pp. 163-171 ◽  
Author(s):  
Shigeru Tanabe ◽  
Naoko Ishii-Minami ◽  
Ken-Ichiro Saitoh ◽  
Yuko Otake ◽  
Hanae Kaku ◽  
...  

The biological role of a secretory catalase of the rice blast fungus Magnaporthe oryzae was studied. The internal amino acid sequences of the partially purified catalase in the culture filtrate enabled us to identify its encoding gene as a catalase-peroxidase gene, CPXB, among four putative genes for catalase or catalase-peroxidase in M. oryzae. Knockout of the gene drastically reduced the level of catalase activity in the culture filtrate and supernatant of conidial suspension (SCS), and increased the sensitivity to exogenously added H2O2 compared with control strains, suggesting that CPXB is the major gene encoding the secretory catalase and confers resistance to H2O2 in hyphae. In the mutant, the rate of appressoria that induced accumulation of H2O2 in epidermal cells of the leaf sheath increased and infection at early stages was delayed; however, the formation of lesions in the leaf blade was not affected compared with the control strain. These phenotypes were complimented by reintroducing the putative coding regions of CPXB driven by a constitutive promoter. These results suggest that CPXB plays a role in fungal defense against H2O2 accumulated in epidermal cells of rice at the early stage of infection but not in pathogenicity of M. oryzae.


Author(s):  
V. P. Heluta

Abstract A description is provided for Arthrocladiella mougeotii. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. DISEASE: Powdery mildew of Lycium species only. The mycelium, conidiophores, conidia and ascomata form first white, then dirty-grey patches on damaged green parts of the host. Infected parts are deformed slightly and, in cases of high infection, plants can lose their ornamental qualities. Damaged leaves can fall prematurely. HOSTS: Lycium barbarum (= L. europaeum), L. chinense, L. dasystemum, L. halimifolium, L. ovatum, L. potaninii, L. rhombifolium, L. ruthenicum. [Type host - Lycium barbarum] GEOGRAPHICAL DISTRIBUTION: Africa: Canary Islands. Asia (temperate areas only): Armenia, Azerbaijan, China, Republic of Georgia, Israel, Japan, Kazakhstan, Kirghizistan, Korea, Russia (Russian far east), Tadzhikistan, Taiwan, Turkey, Turkmenistan, Uzbekistan. Australasia: New Zealand (introduced). Europe: Austria, Belgium, Bulgaria, Czech Republic, Estonia, France, Germany, Hungary, Italy, Netherlands, Norway, Poland, Rumania, Slovakia, Sweden, Switzerland, UK, Ukraine (southern), former Yugoslavia. North America: USA (introduced). TRANSMISSION: By wind-dispersed conidia. The rôle of ascospores in disease transmission is unknown, although it has been supposed that they can cause the initial stage of the disease.


Author(s):  
Letizia Mondani ◽  
Giorgio Chiusa ◽  
Paola Battilani

Fusarium proliferatum has been reported as the main causal agent of garlic dry rot during the postharvest stage, but information on this fungus during the crop growth stage is lacking. We focused on the cropping season of garlic (Allium sativum L.) in the field, until its harvest, with the aim of clarifying the role of F. proliferatum in bulb infection as well as the impact of crop growing conditions on pathogen-plant interaction. Studies were conducted in Piacenza (northern Italy) for three seasons from 2016 to 2019. Six garlic farms were sampled. A different field was sampled every year. Soil samples were recovered at sowing time for the counting of fungal colony forming units (CFU). Plant samples were collected at three growth stages, from BBCH 15 (fifth leaf visible) to BBCH 49 (ripening), for which disease severity assessment and fungi isolations were performed. Fusarium was the most frequently isolated genus, of which F. proliferatum and F. oxysporum were the dominant species. F. proliferatum registered the highest incidence in all the farms tested, but F. oxysporum was dominant in the first year of the study. F. oxysporum incidence was correlated with dry weather, whereas F. proliferatum was correlated with rainy weather. In conclusion, our result confirms the association of F. proliferatum with garlic bulbs from the crop’s early growth stages, suggesting potential seed transmission as a source of this fungal pathogen. Further studies should investigate the link between fusaria occurrence in the field and dry rot outbreaks occurring postharvest and during storage of garlic.


Author(s):  
J. N. Kapoor

Abstract A description is provided for Podosphaera leucotricha. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Malus spp., chiefly on M. pumila (apple), peach (Prunus persica), quince (Cydonia ualgaris) and Photinia spp. also attacked (Hirata, 1966). Also reported on almond fruit (43, 2544). DISEASE: Powdery mildew of apple. GEOGRAPHICAL DISTRIBUTION: Africa (? Kenya, Rhodaia, South Africa, Tanzania); Asia (China, India, Israel, Japan, U.S.S.R.); Australia and New Zealand, Europe (widely distributed) North America (Canada and U.S.A.); South America (Argentina, Brazil, Chile, Colombia, Peru). (CMI map 118). TRANSMISSION: Overwinters on host as dormant mycdium in blossom buds. The role of deistothecia in overwintering is doubtful. Spread by wind-borne conidia (Anderson, 1956).


Author(s):  

Abstract A new distribution map is provided for Rice grassy stunt tenuivirus Viruses: Tenuivirus. Hosts: Rice (Oryza sativa). Information is given on the geographical distribution in ASIA, Bangladesh, Brunei, Darussalam, China, India, Kerala, Tamil Nadu, Indonesia, Java, Nusa, Tenggara, Sulawesi, Sumatra, Japan, Kyushu, Korea Republic, Malaysia, Philippines, Sri Lanka, Taiwan, Thailand, Vietnam, OCEANIA, Fiji, Papua New Guinea, Solomon Islands.


Author(s):  
E. Punithalingam

Abstract A description is provided for Phomopsis oryzae-sativae. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOST: Oryza saliva. DISEASE: Collar rot of rice, appearing at the end of tillering stage. Visible symptoms are small dark brown lesions at the base of the auricle of the topmost fully expanded leaf. These lesions enlarge to cover the whole auricle and in the advanced stage lesions extend to the adjacent parts of the leaf sheath and leaf blade. Within 14 days the blade joint at the top of leaf sheath turns dark brown and then rots, causing the leaf blade to drop off (Kanjanasoon, 1962). GEOGRAPHICAL DISTRIBUTION: Asia (Thailand). TRANSMISSION: No studies reported. Conidia presumably dispersed by water splash.


Author(s):  

Abstract A new distribution map is provided for Heterodera oryzicola Rao & Jayaprakash Nematoda: Heteroderidae Hosts: Mainly rice (Oryza sativa), also banana and plantain (Musa spp.). Information is given on the geographical distribution in ASIA, India, Goa, Haryana, Kerala, Madhya Pradesh, Orissa, Tamil Nadu, West Bengal.


Author(s):  
Sanjay Kumar Yadav ◽  
Subhash Babu ◽  
Gulab Singh Yadav ◽  
Raghavendra Singh ◽  
Manoj Kumar Yadav

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