"biocontrol" is one method that one can try for blackspot. The following may be useful in putting the concept of biocontrol into layman terms: "Disease-suppressive soil microorganisms have been found in many places. In monoculture wheat the severity of "take all" disease often decreases within three to five years. This phenomenon is known as "take all decline," and is considered an effective natural control. Although the mechanisms are not completely understood, the decline is associated with changes in soil microorganisms that compete with and prey on the fungus. Melon plants grown in the Chateaurenard region of France do not show Fusarium wilt symptoms even though the fungus is present in the soil. Soils with suppressive characteristics tend to develop slowly and are usually found in fields where perennial crops or monocultures have been grown for many years. Suppressiveness may be lost if the monoculture is interrupted even for one year, or if pesticides are applied. For example, researchers first recognized soils suppressive to cereal-cyst nematode when nematode numbers increased after application of a broad-spectrum biocide. Many species of fungi and bacteria in the genera Trichoderma, Streptomyces, Bacillus and Pseudomonas suppress diseases, but at this time only a few strains are commercially available. Additional commercial products may be available soon, however, as this is currently an active research area." The quote was taken from: Http://www.cals.ncsu.edu/sustainable/peet/IPM/diseases/org_cert.html ---------------------------------------------- The following article from the Maine Rose Society web page ( http://www.mainerosesociety.com/articles/control.html ) was written by by DR. LAKSHMI SRIDHARAN, who should be familar with those of you that are members of the American Rose Society. ----------------------------------- Examples that friendly fungi do exist: Http://taylorandfrancis.metapress.com/app/home/contribution.asp?wasp=59ghxnlylp03feg2dr2p&referrer=parent&backto=issue,1,10;journal,2,54;linkingpublicationresults,1:100635,1 Http://taylorandfrancis.metapress.com/app/home/contribution.asp?wasp=4g1ltlxhtr3ya223recn&referrer=parent&backto=issue,8,10;journal,4,54;linkingpublicationresults,1:100635,1; Http://taylorandfrancis.metapress.com/app/home/contribution.asp?wasp=8000375kwm5qnk5e7y47&referrer=parent&backto=issue,1,10;journal,6,54;linkingpublicationresults,1:100635,1; Http://taylorandfrancis.metapress.com/app/home/contribution.asp?wasp=07wckmqrxr3jqg6kducy&referrer=parent&backto=issue,9,10;journal,7,54;linkingpublicationresults,1:100635,1; ------------------------------------------------ Blackspot on roses is scientifically called "diplocarpon rosae". The link below reports that trichoderma harzianum is a promising control - see their exact wording (the document is a PDF document. The applicable section is easily found by typing diplocarpon into the PDF find command - the binoculars). Http://www.gtz.de/ecosan/download/Bangalore03-Ramanujam.PDF ------------------------------------------------------ Title: The Abundance and Structure of the Root-Associated Microbial Complexes of Two Greenhouse Rose Cultivars. Authors: Polyanskaya, L. M.; Ozerskaya, S. M.; Kochkina, G. A.; Ivanushkina, N. E.; Golovchenko, A. V.; Zvyagintsev, D. G. Authors affiliation: Faculty of Soil Science, Moscow State University, Vorob'evy gory, Moscow, Russia. Published in: Microbiology (Moscow, Russian Federation)(Translation of Mikrobiologiya), volumn 72, pages 496-502, (2003). Abstract: "The study of the root-assocd. microbial complexes of affected and healthy rose plants of two cultivars (Grand gala and Royal velvet) grown in a greenhouse showed that the biomass of eukaryotic microorganisms in the rhizoplane and rhizosphere of healthy rose plants and in the surrounding soil was considerably lower than in the same loci of affected plants. In contrast, the biomass of root-assocd. prokaryotic microorganisms was higher in the case of healthy than in the case of affected rose plants. The root-assocd. bacterial complexes of both affected and healthy rose plants were dominated by the genera Arthrobacter, Rhodococcus, and Myxobacterium and did not contain phytopathogenic bacteria. The root-assocd. fungal complex of healthy roses was dominated by fungi of the genus Trichoderma, whereas that of the affected rose plants was dominated by the species Aureobasidium microstictum. The affected cane cuttings and cankers occurring on affected canes were found to contain Coniothyrium fu-ckelii (the causal fungus of rose stem canker) and sclerotia of Botrytis cinerea (the causal fungus of gray rot). The micromycete complex of healthy rose plants was not so diverse as was the micromycete complex of affected rose plants." ---------------------------------------------- Title: Biological control of black spot of rose caused by Dipocarpon rosae . Authors: Prasad, R. D.; Rangeshwaran, R.; Sunanda, C. R.; Vinita, J. Authors affiliation: Project Directorate of Biological Control, Post Bag No. 2491, H.A. Farm Post, Bellary Road, Hebbal, Bangalore 560 024, India. Published in: Annals of Plant Protection Sciences,volumn 10, pages 256-259, (2002). Abstract: "Fungal biological control agents (Trichoderma harzianum , T. viride and Chaetomium globosum ) were used either alone or in combination with fungicides (chlorothalonil and mancozeb) to manage black spot of rose caused by D. rosae under greenhouse conditions. Black spot incidence in biological control agent and/or fungicide treatments was significantly low (disease ratings from 0.33 to 3.33) compared to the control at all observation dates. After 100 days of spraying, defoliation was lowest with chiorothalonil, Trichoderma harzianum +chlorothalonil, C. globosum +chlorothalonil and T. harzianum +mancozeb treatments. The highest mean vigour index was recorded in T. harzianum treatment. The highest flower production was recorded in C. globosum +chlorothalonil treatment (4.33) followed by T. harzianum alone and T. harzianum +chlorothalonil treatment (4.00)." -------------------------------------------------- Cornmeal is considered to be a good food for the friendly fungus "trichoderma harzianum". The fungus is available commercially, see: http://www.ipmofalaska.com/files/trichoderma.html There may be another benefit to this fungus as there is a report that it helps root growth: Title: Effect of Trichoderma Colonization on Auxin-Mediated Regulation of Root Elongation. Author: Bjoerkman, Thomas. Department of Horticultural Sciences, Cornell University, Geneva, NY, USA. Published in: Plant Growth Regulation, volumn 43, pages 89-92, (2004). Abstract: "The biocontrol fungus Trichoderma harzianum 1295-22 increases root growth in addn. to roles in suppressing disease. Its agricultural use could be expanded if the mechanism of growth enhancement were known. Among the proposed mechanisms of growth enhancement is that the fungus counteracts auxin inhibition of root-cell elongation. We tested whether there was evidence for a secreted auxin inhibitor, for enhanced auxin degrdn., or for altered auxin sensitivity. Our results provide no support for any of these mechanisms. Trichoderma secretions inhibited growth, whereas an auxin inhibitor would increase growth. Auxin inhibited growth to the same extent in colonized and uncolonized roots, indicating no change in auxin sensitivity. Endogenous auxin levels maintained growth closer to the max. in uncolonized roots, indicating stronger auxin limitation of growth in colonized roots. These tests indicated that Trichoderma-colonized roots had a faster max. growth rate, but an unchanged response to auxin." -------------------------------------------- Even if naturally occurring trichoderma harzianum only reduces the amount of blackspot fungus by 10 to 20 % (the numbers are just a guess), there are probably going to be a number of different "friendly" fungi in an organic garden. For example, the following paper reports that 2 fungi that are now recognized as biocontrol potential have increased levels on blackspot infected leaves: ------------------------------------ Title: PHYLLOPLANE MICROORGANISMS OF ROSA CULTIVAR PICADILLY FOLLOWING INFECTION BY DIPLOCARPON-ROSAE Author: HAYES A J Author Affiliation: DEP OF FORESTRY AND NATURAL RESOURCES, UNIV OF EDINBURGH, UK. Published in: Transactions of the British Mycological Society, volumn 79, pages 311-320, (1982). Abstract: "The phylloplane microflora of the hybrid tea rose cultivar Picadilly was studied for 2 growing seasons on healthy leaves and on leaves infected by D. rosae. Large increases in numbers of yeasts and bacteria on healthy leaves were noted from the end of July until the beginning of Oct. Late in the growing season numbers of all types of microbes increased dramatically. Following infection by D. rosae numbers of microbes generally showed a marked increase, but this was not always sustained. Cryptococcus laurentii and Micrococcus sp. populations on infected leaves were 3-4 times those on correspondingly healthy leaves. The species composition and changes in numbers of phylloplane microbes are compared with descriptions of microflora isolated from leaves of other plants and possible reasons for the observed differences are discussed." -------------------------------------- The following two links are Google searches for the two fungi listed and the word biocontrol. --------------------------------------- Http://www.google.com/search?hl=en&lr=&q=%22cryptococcus+laurentii%22+biocontrol&btnG=Search ----------------------------------------------- Http://www.google.com/search?hl=en&lr=&q=micrococcus+biocontrol&btnG=Search ------------------------------------------- The science of biocontrol is still in its infancy. The use of Chitosan is one of the early results of this area of research. The following is the EPA summary: ( Http://www.epa.gov/pesticides/biopesticides/ingredients/factsheets/factsheet_128930.htm ) "SUMMARY Chitosan is used primarily as a plant growth enhancer, and as a substance that boosts the ability of plants to defend against fungal infections. It is approved for use outdoors and indoors on many plants grown commercially and by consumers. The active ingredient is found in the shells of crustaceans, such as lobsters, crabs, and shrimp, and in certain other organisms. Given its low potential for toxicity and its abundance in the natural environment, chitosan is not expected to harm people, pets, wildlife, or the environment when used according to label directions." -------------------------------------------- There is a scientific literature report of 10 - 20 % effectiveness against blackspot. Title: Chitosan as the biocontrol agent of fungal pathogens; activity and mode of action. Authors: Wojdyla, Adam T. Authors affiliation: Research Institute of Pomology and Floriculture, Skierniewice, Pol. Published in: Bulletin of the Polish Academy of Sciences: Biological Sciences, volumn 51, pages 159-165, (2003). Abstract: "In in vivo expts. showed that chitosan added to potato dextrose agar at 3 mg/cm3 in 50% suppressed radial growth of Colletotrichum gloeosporioides and Phytophthora cryptogea. Another tested fungi were less sensitive to chitosan. ED50 for Cylindrocladium scoparium and Myrothecium roridum was more than 5 mg/cm3. In vivo expts. showed that only 10-20% effectiveness of the compds. against Diplocarpon rosae was found, when chitosan at 0.2-0.4 mg/cm3 was used for rose spraying. Also spraying of willow 2 times at weekly intervals against Melampsora epitea decreased the mean no. of rust pustules per leaf. Spraying of dieffenbachia 24 h before inoculation with M. roridum resulted in significant decrease of necrosis spread on leaves. Five days after inoculation the compds. inhibited the development of leaf spot about 94%. Chitosan applied preventively before inoculation of leaves gave significantly better results in the control of M. roridum than used 24 h after inoculation. Spraying of chrysanthemum, naturally infected with Puccinia horiana decreased the mean no. of pustules per leaf about 95%."

I though that some may be interested in the diseases of roses through Russian eyes. https://translate.googleusercontent.com/translate_c?depth=1&hl=en&prev=search&rurl=translate.google.com&sl=ru&u=http://vsadu.ru/post/bolezni-roz-foto-opisanie-priznaki.html&usg=ALkJrhhOWrbpms67N6mMXPzVdr2setuNLQ

This was really interesting. I'm going to share this with a friend. Thanks, Henry Carol

Nature is complex. Apparently mechanical transmission is not always successful. I wonder if the mites contribute a cofactor that helps the virus overcome the immune system. The following may apply to this point: "but no consistent method of mechanical inoculation has been developed for both wheat and maize that can satisfactorily bypass the use of the wheat curl mite as a vector (Mirabile, 2001; Seifers et al., 1997; Skare et al., 2003)." http://amarillo-tamu-edu.wpengine.netdna-cdn.com/files/2010/12/A-new-eriophyid-mite-borne-membrane-enveloped-virus-like-complex-isolated-from-plants.pdf ---------------------------------------------- "We are beginning to determine what proteins are present in the mite saliva, in order to determine how the mites are suppressing the immune reactions. In collaboration with Doug Cavener and Kaori Iida, we have isolated the genes for several genes involved in honeybee immunity. Not all invaders are met with a well-defined immune response, as during disease transmission by insect vectors. Understanding the mechanisms that underlie co-evolution between the vector and disease organism is critical to understanding how the disease transmission cycle might be disrupted. Through interdisciplinary collaboration with Drs. F. Gildow (PSU) and S. Gray (Cornell), we are examining the mechanisms underlying virus/vector specificity in aphids at the accessory salivary gland, the primary site determining transmission of different species of luteoviruses. In my lab, we have identified several proteins that bind to luteovirus in a vector-specific manner and that are also recognized by antibodies that mimic the virus. We are isolating the genes encoding these proteins for studies of the evolution of these virus/vector interactions, among different aphid and viral species. This research may further understanding of mechanisms underlying the vector-specificity of mosquitoes for transmission of alphaviruses." http://ento.psu.edu/directory/dxc12