From r4do.sitorus at gmail.com Sun Jan 6 00:58:28 2008 From: r4do.sitorus at gmail.com (r4do.sitorus@gmail.com) Date: Sun Jan 6 00:58:30 2008 Subject: Ganoderma Message-ID: <6647b626-2b65-424c-8f46-80cc4e57f954@d4g2000prg.googlegroups.com> Dear all, Would you please give me any information about ganoderma in palm oi? From jgarciadelarosa at prodigy.net.mx Sat Jan 12 00:44:58 2008 From: jgarciadelarosa at prodigy.net.mx (Jose Garcia de la Rosa) Date: Sat Jan 12 00:45:02 2008 Subject: PRO/PL> Potato purple top disease - USA (WA, OR) Message-ID: <8_73sC.A.imB.nPqhHB@sol01.ashbva.gweep.ca> INCORRECT DIAGNOSIS OF THE POTATO PURPLE TOP Ing. Josi Garcma de la Rosa jgarciadelarosa@prodigy.net.mx Before 1967, many plant diseases were erroneously diagnosed as "virus", due to ignorance of the existence of phytoplasmas that were discovered that year by Doi et al in Japan. Besides, in the case of the potato purple top was reported as a micro nutrients deficiency and, occasionally, as a symptom of Phytophthora infestans or Fusarium. Remission of symptoms in potato with purple top, after several oxytetracyclin applications, 1987, Toluca Valley. Remission of "rayado fino" symptoms in corn after the antibiotic application. A few years later, potato purple top was proven to be caused by phytoplasma following the steps of the scientific method, the fulfillment of Koch Postulates, and the remission of symptoms when oxytetracyclin was applied. Psyllids and leafhoppers were proven to be insect vectors of this disease. Remission of symptoms in pawpaw, with symptoms of "virus disease" in the lower leaves. 2002, Cuautla, Morelos. Mixico. In 1989, Academic Press published the book The Mycoplasmas, Volume V, and in the Appendix there is a list of approximately 800 diseases caused by phytoplasmas, which had formerly been diagnosed as "virus". Nevertheless, during the last 10-15 years there have been, repeated incorrect diagnoses that consider the following factors as causal agents of some symptoms of the potato purple top: TOXINS. Without isolating the toxin, to prove its existence and without making toxicity tests, some researchers assert that the nymphs of Bactericera(Paratrioza)cockerelli transmit a toxin that causes some symptoms of purple top. The argument continues, that in order to avoid this damage caused by a sucking insect, the most effective method is the chemical control of the vectors. However, it is accepted that spraying insecticides is very expensive and the control is unsatisfactory. Potato psyllids toxins stunt the growth and cause upward curling of potato leaves. Photo by Bill Callison. FUNGI. Other investigators have isolate Fusarium sp., Verticillium sp., or Phytophthora infestans from tubers of damaged plants and concluded that these diseases can be the causal agent of the spotty appearance of fried products. These researchers have ignored that it is not possible to deduce cause and effects, without fulfillment of Koch Postulates. Are, the micro- organisms isolated from a damaged tissue the causal agent of the symptom present in the field? In many cases the micro- organism could be saprophytic. The same error can be committed when diagnosis is based only on PCR, DNA, ELISA, etc., which can detect the presence of a specific micro- organism, but that does not prove that it is the causal agent. VIRUS. After 1967, substantial literature was published proving that many symptoms attributed to "virus" up until 1967 were in fact caused by phytoplasmas. Moreover, as the "virus" cannot be multiplied in a synthetic culture media, because they need living cells to replicate, this step prevented the fulfillment of Koch Postulates. That is why, some scientists view that the diagnose of phytopathogenic "virus" doesn't have a scientific base. However, some researchers still consider the "virus" as phytopathogens agents, when actually they may only be phytotoxic. XILELLA FASTIDIOSA. Recently, it has been reported that this bacteria could cause some symptoms of the potato purple top with no proof pathogenesis. This bacteria have been diagnosed as the causal agent of several diseases in some fruit trees and is considered as a Fastidious Xylem-Limited Bacteria(XLB), without injuring the foliage. Koch Postulates have not been fulfilled in any of these diseases, perhaps, because it is not the causal agent of the field symptoms. Also, these bacteria require polysaccharose, enzymes, proteins and other organic compounds in order to multiply in a culture media. Yet in the xylem vessels only mineral salts and water circulate, so wouldn't X. fastidiosa be only a saprophyte? Other evidence that this bacterium is not phytopathogen is because the diseases that it supposedly it causes, can not be controlled with streptomycin sulphate. Streptomycin sulphate has been used as an excellent bactericide on all crops since 1950 Pierce's disease of grapevine, supposedly caused by Xylella fastidiosa INSECT VECTORS AND PHYTOPLASMAS. In most universities, insect, taxonomy, biology, population dynamic and control with insecticides are studied in great detail. In a very few cases the research is focused to the direct control of phytoplasmas with oxytetracyclin. That is why, potato producers have limited information on the use of antibiotics to control effectively potato purple top at low cost. This is true in spite of proven effectiveness during the last 30 years. The poor results obtain with insecticides, are due to some of the following factors: 1. - The leafhoppers and psyllids have a great mobility, and one insect can infect 100 plants per day. 2. - They can fly up to 30km. in 24 hours, depending on the wind speed. 3. - Once they insert the stylet in the phloem, the phytoplasma is transmitted regardless of whether the insect dies afterwards. 4. - When they suck the sap of plants sprayed with oxytetracyclin, the phytoplasma that could be carried in the salivary glands are destroyed and it stops being an infective vector. 5. - Nobody has determined the economic threshold to justify their control as sucking insects in potatoes. . SYMTOMATOLOGY. The diversity of symptoms cause by phytoplasmas, has produced confusion to the extent that potato purple top is often considered a "syndrome or a pathogenic complex". Recently, based on a symptom named Zibra chip (Zc), but without knowledge of either the causal agent or the vector, it is diagnosed as a "new potato disease", which affects mainly the tubers quality. In my opinion, the symptoms diversity caused by phytoplasmas, is due to the fact that the symptoms are not produced directly by these micro- organisms, but indirectly by altering the sap circulation. My HYPOTHESIS in this respect is as follows: "In the autumn, when the temperature drops, the callose (polysaccharose) is formed in the phloem of some trees, which cut off the sap circulation and causes the fall of leaves in winter. In spring, when the temperature raises the callose is dissolved and the sap circulation is restored and begins the sprout. In the annual crops, something similar happens: when a strange body (phytoplasma) enters the phloem, the plants, as a defense mechanism produces small quantities of polysaccharose, which partially block the sap circulation, and that impede the normal movement of nutriments, hormones, enzymes, etc., causing the symptoms which now we know are typical of the phytoplasma damage. When oxytetracyclin is properly applied, the phytoplasma is destroyed, the polysaccharose disappears, the normal sap circulation is restored resulting in the remission of symptoms. In other words, the symptoms are the result of the deficient sap circulation, and they can be quite different according to the plant age, variety, moment of the infection, weather, insect vector, etc. Therefore, the remission of symptoms is the most accurate, quick and inexpensive method to diagnose and control the damage cause by phytoplasmas. BIBLIOGRAPHY Fletcher, J. and A. Wayadande. 2000. Fastidious vascular-colonizing bacteria . The Plant Health Instructor. Flores Nava, A. and Garcma de la Rosa, J. 2002. Potato Purple Top. Pfizer, Mixico Garcma de la Rosa, J. 2003. The Kingdom Fungi. Pfizer, Mixico. Munyaneza, J. 2005. Purple Top Disease in Potatoes of Pacific Northwest of the US. Yakima Agricultural Research Lab, USDA-ARS. USA Secor, G. 2005. A new purple top like disease causing losses in potato crops in North America. Department of Plant Pathology, North Dakota State University, Fargo, ND USA Whitcomb and Tully, J. G. 1989. Editors, The Mycoplasma, Spiroplasma, Acholeplasma and Mycoplasma of Plants . Academic Press. New York, EUA [demime 1.01d removed an attachment of type application/ms-tnef which had a name of winmail.dat]