Detoxification of sesquiterpene phytoalexins byGibberella pulicaris (Fusarium sambucinum) and its importance for virulence on potato tubers

1992 ◽  
Vol 9 (3-4) ◽  
pp. 201-211 ◽  
Author(s):  
Anne E. Desjardins ◽  
Harold W. Gardner ◽  
Klaus-M. Weltring
2005 ◽  
Vol 78 (1) ◽  
pp. 1-10 ◽  
Author(s):  
H.W. Platt

During the 1992-1993 and 1994-1995 winter storage period for potatoes (Solarium tuberosum) in Quebec, New Brunswick, and Prince-Edward-Island, tubers were collected which had symptoms of fusarium tuber rot and silver scurf and which had been treated commercially after harvest with thiabendazole. Resistance to thiabendazole was detected in isolates of Fusarium sambucinum and Helminthosporium solani but not in isolates of F. avenaceum and F. oxysporum. However, the majority of those farms surveyed (64%) had adequate disease control with no pathogen isolated from the diseased tubers. Incidence and EC50 values of resistant isolates were lower than found elsewhere and the occurrence of farms with resistant isolates of F. sambucinum (18%) was greater than for H. solani (7%). For H. solani, EC50 values of resistant isolates were substantially less than those found in Alberta. While the study investigated commercial operations employing a wide range of thiabendazole rates (6-42 g a.i. t-1), no specifie trends were detected between the occurrence of resistant isolates and cultivar or thiabendazole application rate.


1989 ◽  
Vol 52 (12) ◽  
pp. 871-876 ◽  
Author(s):  
KURT E. RICHARDSON ◽  
GLEN E. TONEY ◽  
CAROL A. HANEY ◽  
PAT B. HAMILTON

Ethyl acetate extracts of culture filtrates from Fusarium sambucinum NRRL 13495 contained scirpentriol, triacetoxyscirpenol, 4,15-diacetoxyscirpenol, 3,4-diacetoxyscirpenol, 3,15-diacetoxyscirpenol, 15-monoacetoxyscirpenol, 4-monoacetoxyscirpenol, and 3-monoacetoxyscirpenol which are the eight possible members of the scirpentriol family of trichothecene mycotoxins. These eight mycotoxins were identified by chemical derivatization, thin layer chromatography, gas chromatography, mass spectroscopy, nuclear magnetic resonance, and comparison to standards. The total concentration of scirpenol derivatives in the culture filtrate was 426 mg/liter of which 346 mg/L was 4,15-diacetoxyscirpenol. The occurrence of a complete family of mycotoxins in a single culture implies that outbreaks of toxicity associated with Fusarium may be multiple toxicoses, and that the screening of foodstuffs for trichothecenes should be broadened, particularly potato tubers which are subject to infection by F. sambucinum.


Plant Disease ◽  
2006 ◽  
Vol 90 (11) ◽  
pp. 1460-1460 ◽  
Author(s):  
P. S. Wharton ◽  
P. Tumbalam ◽  
W. W. Kirk

Fusarium dry rot is one of the most important diseases of potato (Solanum tuberosum L.), affecting tubers in storage and whole seed or seed pieces after planting (2). Fusarium sambucinum Fuckel (teleomorph Giberella pulicaris) is the most common pathogen causing dry rot of stored tubers in North America. (4). Cut seed potato tubers of cvs. FL1879 and Pike with severe sprout rot were collected in Michigan during May 2006. As well as having rotted sprouts, all diseased tubers had dry rot. When diseased sprouts were cut in half, brown, necrotic lesions could be seen spreading down the center of the sprout in vascular tissue and at the base of the sprout in tuber tissue. Pathogen isolations were made from both infected tuber tissue and diseased sprouts on potato dextrose agar (PDA). In both cases, only F. sambucinum was isolated from diseased sprout and tuber tissue. Identification of the pathogen was based on colony and conidial morphology. This included white, fluffy mycelium on the surface and crimson coloration of the colonies viewed from the underside of PDA plates and large distinctive macroconidia (3). Identification was confirmed by comparison of ITS (internal transcribed spacer) sequence data with reference isolates. The ITS region of rDNA was amplified by polymerase chain reaction (PCR) with primers ITS1/ITS4 and sequenced. BLASTn analysis (1) of the sequence obtained showed a 100% homology with F. sambucinum Fuckel. For inoculum production, isolates were grown on PDA at 8°C for 14 days prior to inoculation. Pathogenicity was tested in potato tubers of cv. FL1879 with a single isolate collected from diseased sprouts. Whole seed tubers with 4 mm long sprouts were cut in half longitudinally with a sterile knife to ensure that seed pieces had viable sprouts. The cut surfaces of seed pieces were spray inoculated with 200 ml of conidial suspension (1 × 104 conidia ml-1) over the entire cut surface to give a final dosage of approximately 1 ml per seed piece. Care was taken to limit inoculum spray to the cut surface so that sprouts were not inoculated. Seed pieces (40 per replicate × 4 replicates) were then placed in plastic boxes (30 × 15 × 10 cm) and incubated in the dark at 18°C and 95% relative humidity for 30 days in a controlled environment chamber. As a control, cut seed pieces were spayed with sterile distilled water and incubated as above. All tubers inoculated with the pathogen developed typical Fusarium dry rot symptoms consisting of a brown, dry decay of tuber tissue with mycelial lined cavities. Sprouts on inoculated tubers developed symptoms that were observed in the initially collected seed pieces, and F. sambucinum was reisolated from all infected sprouts. The noninoculated control tubers did not develop any symptoms of dry rot. The results of the pathogenicity tests indicate that F. sambucinum caused sprout rot on potato seed pieces. Since only the cut surfaces of tubers were inoculated, it is assumed that infection of sprouts is systemic through the tuber. To our knowledge, this is the first report of F. sambucinum causing a sprout rot of developing sprouts on seed tubers in the United States. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) L. E. Hanson et al. Phytopathology 86:378, 1996. (3) P. E. Nelson et al. Pages 118–119 in: Fusarium Species: An Illustrated Manual for Identification. The Pennsylvania State University, University Park and London, 1983. (4) G. A. Secor and B. Salas. Fusarium dry rot and Fusarium wilt. Pages 23–25 in: Compendium of Potato Diseases. 2nd ed. W. R. Stevenson et al., eds. The American Phytopathological Society, St. Paul, MN, 2001.


Author(s):  
C. Booth

Abstract A description is provided for Fusarium sulphureum[Gibberella cyanogena]. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Solanum tuberosum; also isolated from the following hosts: Arachis, Citrus, Cocos, Cupressus, Elasis, Fragaria, Gleditsia, Hibiscus, various Leguminosae, Lycopersicon, Linus, Phaseolus, Picea, Pinus, Pisum, Solanum, Sorghum, Trifolium, Triticum, Zea and also from animal and poultry feed and from soil. DISEASE: Fusarium sulphureum[Gibberella cyanogena] is often reported under the name Fusarium sambucinum[Gibberella pulicaris] f. 6; economically it is most important as the cause of potato tuber dry rot (54, 536; 56, 3195). GEOGRAPHICAL DISTRIBUTION: Probably world wide. It has been reported on potato tubers from Australia, Canada, Cyprus, East and West Germany, Iran, New Zealand, UK and USA. TRANSMISSION: By soil, water and planting material.


2014 ◽  
Vol 25 (3-4) ◽  
pp. 69-76
Author(s):  
G. A. Mustafayeva

Scales (Hemiptera, Diaspididae) are the dangerous crop and park-ornamental plant pests. They reproduce very quickly and cause great harm to plants, sometimes even lead to their complete destruction. Scales suck juices from plants, cause premature drying, dying and falling off leaves, dry branches, deformation of leaves, fruits and shoots, reducing annual growth of plants. Therefore the fight with these pests is rather topical in the agriculture. In this connection in this work the analysis of bioecological peculiarities of oleander scale on the territory of Azerbaijan, and also the detection of species content of parasites and predators, which regulate their number is conducted. We will mark that oleander scales in the wild there are the entomophages are vermin and predators that reduce their quantity. For realization of biological fight against people we studied the bioenvironmental features of wreckers, and also educed specific composition of vermin and predators that regulate their quantity. In a biological fight against these wreckers, one of basic questions is study of specific composition of these entomophages. The faunistic material on entomophages of this pest was collected from different biocenosis; the researched works were conducted in the laboratory and field conditions in Azerbaijan. The advanced and research studies that we conducted gave an opportunity to educe entomophages oleander scale that inflicts an enormous damage to the agricultural cultures and park-decorative plants. The method of breeding of effective types of entomophages is studied in laboratory terms. Firstly the biology of oleander scale on Apsheron peninsula and in Guba Khachmazskii area was studied. The results of long-term studies showed that oleander scale, having distributed on Apsheron peninsula, on olive trees gives 3 generations. Only adult female animals and maggots of I and II age spend winter. Awakening of the scales on olives takes place in March-April. In II and III decade of April the male animals begin their flight. In Guba Khachmazskii area the biology of this scale, dwelling on oleander bush was studied. On this plant the scale gives 3 generations. Young female animals, and also maggots of I and II age winter. As a result of the works conducted the following entomophages of oleander scale were detected: predator Rhyzobius lophanthae Blaisd, Chilocorus bipustulatus L., Chilocorus renupustulatus L; parasites: Aphytis chilensis Howаrd, Aspidiotiphagus citrinus Graw, Encarsia aurantii (Howard). The habitat of Rhyzobius lophanthae is Australia. At the end of the last century of this predatory beetle left to California, from there left to Italy and in other Mediterranean countries. In 1947 by chance was left to Georgia (Abkhazia). Maybe these useful predators in Azerbaijan were from Georgia. For diluting the entomophages from the local indigenous fauna the potato tubers were used, on which firstly the oleander scales, and then road-beetles Rhyzobius lophanthae, Chilocorus bipustulatus reproduced themselves. In the laboratory conditions the methods of diluting of these Coccinellidae was developed. Thus, firstly the way of diluting parasites of oleander scale was studied and developed – Aphytis chilensis Howard, Aspidiotiphagus citrinus Graw и Encarsia antantii (Howard). It was detected that predatory entomophage-chilocor in the natural conditions is ineffective, as their maggots and chrysalises are affected by other local parasites. In the laboratory conditions this beetle produce itself very well on the potato tubers, infected by oleander scale. However, we should note that among entomophage parasites Aphytis chilensis plays the huge role in destruction of scales. In dependence on the weather conditions this macrophage in the nature can give 3–4 generations. Also it was proved that beetle Rhyzobius lophanthae in the biological fight can be applied against all round scales. This predator is effective entomophage of oleander, olive scale, black pine-leaf scale, white peach scale, European fruit scale and cactus scale. In connection with this, Rhyzobius lophanthae can be applied in the biological fight against oleander scale and presently is irreplaceable and perspective entomophage. 


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