From F.vd.Laan@inter.nl.net Sun Jun 20 22:26:59 1999 Date: Fri, 18 Jun 1999 22:08:37 +1 From: Frits v/d Laan To: sanet-mg@ces.ncsu.edu Subject: mildew question I would like to know anyone who tried something like this before. To prevent mildew I use some organic extractions and I would like to add mildew itself as a spray. because most plants have different types of mildew I would like to use mildew from one of the very sensitive weeds that grow and allready are white from the fungus and make a thea or spray from this. Then spray the cultivated plants with this and wait for the natural reaction from the plants or from other fungi that protect the plants by destroing the mildew. (Vaccination principle) Does someone know something about this. Frits v/d Laan Organic horticulture. Gouda - Netherlands http://web.inter.nl.net/users/F.vd.Laan/ mail f.vd.laan@inter.nl.net To Unsubscribe: Email majordomo@ces.ncsu.edu with the command "unsubscribe sanet-mg". If you receive the digest format, use the command "unsubscribe sanet-mg-digest". To Subscribe to Digest: Email majordomo@ces.ncsu.edu with the command "subscribe sanet-mg-digest". All messages to sanet-mg are archived at: http://www.sare.org/san/htdocs/hypermail From lrbulluc@unity.ncsu.edu Sun Jun 20 22:27:20 1999 Date: Sat, 19 Jun 1999 10:27:04 -0400 From: Russ Bulluck To: F.vd.Laan@inter.nl.net, Sustainable Ag Subject: Re: mildew question Mildews (both powdery and downy) are _highly_ specific. If you have weeds with a mildew, spraying the mildew will possibly cause the other weeds of that species to become infested. However, little or no reaction will occur on planted crops (unless closely related to the weed). Also, powdery and downy mildew conidia (reproductive structures) are highly hydrophobic and therefore difficult to get into solution. this would be a good idea. No harm will come to your crop, and the sensitive weed may succumb to mildew. . .Russ Frits v/d Laan wrote: > I would like to know anyone who tried something like this before. > To prevent mildew I use some organic extractions and I would like to > add mildew itself as a spray. > because most plants have different types of mildew I would like to > use mildew from one of the very sensitive weeds that grow and > allready are white from the fungus and make a thea or spray from > this. > Then spray the cultivated plants with this and wait for the natural > reaction from the plants or from other fungi that protect the plants > by destroing the mildew. > (Vaccination principle) > Does someone know something about this. > > Frits v/d Laan > Organic horticulture. Gouda - Netherlands > http://web.inter.nl.net/users/F.vd.Laan/ > mail f.vd.laan@inter.nl.net > > To Unsubscribe: Email majordomo@ces.ncsu.edu with the command > "unsubscribe sanet-mg". If you receive the digest format, use the command > "unsubscribe sanet-mg-digest". > To Subscribe to Digest: Email majordomo@ces.ncsu.edu with the command > "subscribe sanet-mg-digest". > > All messages to sanet-mg are archived at: > http://www.sare.org/san/htdocs/hypermail -- Russ Bulluck Ph.D. Candidate Department of Plant Pathology North Carolina State University PO Box 7616 Raleigh, NC 27695-7616 http://www.cals.ncsu.edu/plantpath/Personnel/Students/webpage.htm ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The soil population is so complex that it manifestly cannot be dealt with as a whole with any detail by any one person, and at the same time it plays so important a part in the soil economy that it must be studied. --Sir E. John Russell The Micro-organisms of the Soil, 1923 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ To Unsubscribe: Email majordomo@ces.ncsu.edu with the command "unsubscribe sanet-mg". If you receive the digest format, use the command "unsubscribe sanet-mg-digest". To Subscribe to Digest: Email majordomo@ces.ncsu.edu with the command "subscribe sanet-mg-digest". All messages to sanet-mg are archived at: http://www.sare.org/san/htdocs/hypermail From WILSONDO@phibred.com Sun Jun 20 22:27:50 1999 Date: Sat, 19 Jun 1999 19:14:17 -0500 From: "Wilson, Dale" To: Sustainable Ag Subject: RE: mildew question [ The following text is in the "iso-8859-1" character set. ] [ Your display is set for the "US-ASCII" character set. ] [ Some characters may be displayed incorrectly. ] Russ, Frits wrote: >> Then spray the cultivated plants with this and wait for the natural >> reaction from the plants or from other fungi that protect the plants >> by destroing the mildew. You wrote: > this would be a good idea. No harm will come to your crop, > and the sensitive weed may succumb to mildew. . .Russ That is not what Frits was getting at. He wants to induce resistance to pathogenic strains of mildew by spraying with nonpathogenic strains. That is a neat idea, maybe it can work. There are chemicals that induce systemic resistance when sprayed on plants. This is a hot topic in the ag chemical industry, and we are trying out an inducer to control rust and other diseases in corn seed production. Jasmonate and salicylic acid are inducers, and I have heard (but not tried) that aspirin does interesting things on plants (including killing at sufficient dose). Dale To Unsubscribe: Email majordomo@ces.ncsu.edu with the command "unsubscribe sanet-mg". If you receive the digest format, use the command "unsubscribe sanet-mg-digest". To Subscribe to Digest: Email majordomo@ces.ncsu.edu with the command "subscribe sanet-mg-digest". All messages to sanet-mg are archived at: http://www.sare.org/san/htdocs/hypermail From lrbulluc@unity.ncsu.edu Sun Jun 20 22:28:06 1999 Date: Sun, 20 Jun 1999 12:36:43 -0400 From: Russ Bulluck To: "Wilson, Dale" , Sustainable Ag Subject: Re: mildew question Dale, Fritz, and others, It would work if a related plant were sprayed with a mildew from a closely related species. Most fungi don't cause disease on most plants. In fact, most fungi don't react to most plants at all (and vice versa). In order for the mildew to cause a reaction (induced systemic resistance, or systemic acquired resistance) on a plant, it must recognize "something" on the leaf surface (usually a protein, or cuticular component) and germinate, then the plant would react to the mildew. There are (as Dale points out) certain chemicals that cause plants to turn on these universal defenses (Actiguard, by Novartis, is one. Salicylic acid is another component, phosphoric acid is a third). Also, physical damage to plant can induce some plant protective compounds. Mildews are just too specific. The important thing to remember is that most plant pathogens don't cause plant disease on most plants. Disease is always the exception. Reactions to pathogens go from none to resistant reactions to susceptible reactions (disease). These, while definable, are arbitrary labels, and a continuum exists. There is also a range of disease causing organisms. Mildews and rusts are known as biotrophs. They require a living host to provide nutrients, and cannot be grown on artificial media. Mildews usually (and there are always exceptions) have a race-cultivar type of interaction. That is, a race of one species of mildew will grow on a specific cultivar of host, and not another cultivar of the same host species. (this is a generalization, since there are all sorts of this type of interaction, including species-species, species-genus, etc.) Rusts are usually the same way. Sclerotium rolfsii, on the other hand is a necrotroph, deriving it's nutrient from the dead host cells. Sclerotium rolfsii has more than 500 host species. These are extremes for generalizations. The world isn't so simple. One genus (Phytophthora) has several species that can attack a large number of plant species (P. cinnamomi, P. parasitica, P. cactorum, and P. nicotianae) and one species that attacks only two species (P. infestans, causes late blight of potato and tomato). Wow, that was a lot longer than I thought it was. For those that are still reading, I apologise for the impromptu lecture on plant pathology, and thank you for your attention. I'll step down from my soapbox now. . .Russ "Wilson, Dale" wrote: > Russ, > > Frits wrote: > >> Then spray the cultivated plants with this and wait for the natural > >> reaction from the plants or from other fungi that protect the plants > >> by destroing the mildew. > > You wrote: > > this would be a good idea. No harm will come to your crop, > > and the sensitive weed may succumb to mildew. . .Russ > > That is not what Frits was getting at. He wants to induce resistance to > pathogenic strains of mildew by spraying with nonpathogenic strains. That > is a neat idea, maybe it can work. There are chemicals that induce systemic > resistance when sprayed on plants. This is a hot topic in the ag chemical > industry, and we are trying out an inducer to control rust and other > diseases in corn seed production. Jasmonate and salicylic acid are > inducers, and I have heard (but not tried) that aspirin does interesting > things on plants (including killing at sufficient dose). > > Dale -- Russ Bulluck Ph.D. Candidate Department of Plant Pathology North Carolina State University PO Box 7616 Raleigh, NC 27695-7616 http://www.cals.ncsu.edu/plantpath/Personnel/Students/webpage.htm ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The soil population is so complex that it manifestly cannot be dealt with as a whole with any detail by any one person, and at the same time it plays so important a part in the soil economy that it must be studied. --Sir E. John Russell The Micro-organisms of the Soil, 1923 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ To Unsubscribe: Email majordomo@ces.ncsu.edu with the command "unsubscribe sanet-mg". If you receive the digest format, use the command "unsubscribe sanet-mg-digest". To Subscribe to Digest: Email majordomo@ces.ncsu.edu with the command "subscribe sanet-mg-digest". All messages to sanet-mg are archived at: http://www.sare.org/san/htdocs/hypermail From timj@mainmin.co.nz Sun Jun 20 22:29:51 1999 Date: Mon, 21 Jun 1999 11:26:53 +1200 From: Tim Jenkins To: sanet-mg@ces.ncsu.edu Subject: Re: mildew question [ The following text is in the "iso-8859-1" character set. ] [ Your display is set for the "US-ASCII" character set. ] [ Some characters may be displayed incorrectly. ] The idea of collecting spores (conidia) from one species and spraying them on a crop to give protection from the crop's own form or species of powdery mildew is an interesting one. If it worked, it would probably be through what's called "induced resistance" - the promotion of the crop's plants resistance to infection. This has been seen with some rust fungi and is certainly possible with powdery mildew. Examples with rust fungi usually involve a strain of rust to which the host plant has some resistance; inoculation with this strain may reduce the infection caused by subsequent inoculation with a strain to which the plant is not resistant. I have certainly seen resistance reactions of some plants to powdery mildew which is not suited to that species. The resistance reactions can involve plant cells dying rather than being parasitised by the fungus. There is likely to also be some production of "secondary chemicals" (a handy term for often complex molecules formed by organisms where the molecule is not of direct metabolic use but is often involved in warding off pathogen and pest damage etc). The production of any anti-fungal compounds would be induced resistance and may reduce the infection from the proper form of mildew. One of the many problems with taking advantage of this phenomenom would be that you may need to find a powdery mildew form that is closely related to one that attacks your crop plant. Generally this would be a powdery mildew form that you've collected from a plant reasonably closely related to your plant. E.g. for lettuce powdery mildew you could collect Erysiphe cichoracearum spores off Calendula (same species of powdery mildew on both lettuce and Calendula but very likely different forms i.e. formae speciales). Erysiphe cichoracearum is reported on members of over 15 plant families but depending on definition true members may be only present on members of the daisy family and within this family there are many formae speciales which to varying extents will only infect 1,2, 3 or more species to any extent. As Russ wrote, conidia are difficult to get in solution. It is better with some surfactant or soap. Spores could either be collected by soaking infected leaves (leaves can be dried first and with some species, dry leaves can be left in a paper bag for several months and the powdery mildew spores will be alright for use when they are needed. Spores could also be collected dry by brushing them off infected plants. One of the best ways to control powdery mildew without chemicals is to regularly wet the plant surface especially with soapy water. This is because powdery mildew although needing moisture at first for spore germintation but thereafter the powdery mildew mycelium grows on the outer surface of the plant and is inhibited by too much moisture. This is the reason why powdery mildew is favoured by dry weather in contrast to other fungal diseases e.g. downy mildews/rusts and general rots. Because of the effect of just water and soap on reducing powdery mildews, you should try out how effective a powdery mildew "vaccination" spray was compared to just soap and water. Any induced resistance would be temporary. A better way perhaps of inducing resistance is to use a plant extract. Some plants if dried, ground and soaked in water will provide the sort of response you are looking for, reducing powdery mildew and other diseases. Try Reynoutria (used to be Polygonum) sacchalinensis (giant knotweed). I would be interested to hear of any results (or lack of) with the mildew spray. Tim Dr Tim Jenkins SoilTech P.O. Box 558 CHRISTCHURCH NEW ZEALAND > >Mildews (both powdery and downy) are _highly_ specific. If you have weeds >with a mildew, spraying the mildew will possibly cause the other weeds of that >species to become infested. However, little or no reaction will occur on >planted crops (unless closely related to the weed). Also, powdery and downy >mildew conidia (reproductive structures) are highly hydrophobic and therefore >difficult to get into solution. > >this would be a good idea. No harm will come to your crop, and the sensitive >weed may succumb to mildew. . .Russ > >Frits v/d Laan wrote: > >> I would like to know anyone who tried something like this before. >> To prevent mildew I use some organic extractions and I would like to >> add mildew itself as a spray. >> because most plants have different types of mildew I would like to >> use mildew from one of the very sensitive weeds that grow and >> allready are white from the fungus and make a thea or spray from >> this. >> Then spray the cultivated plants with this and wait for the natural >> reaction from the plants or from other fungi that protect the plants >> by destroing the mildew. >> (Vaccination principle) >> Does someone know something about this. >> >> Frits v/d Laan >> Organic horticulture. Gouda - Netherlands >> http://web.inter.nl.net/users/F.vd.Laan/ >> mail f.vd.laan@inter.nl.net >> >> To Unsubscribe: Email majordomo@ces.ncsu.edu with the command >> "unsubscribe sanet-mg". If you receive the digest format, use the command >> "unsubscribe sanet-mg-digest". >> To Subscribe to Digest: Email majordomo@ces.ncsu.edu with the command >> "subscribe sanet-mg-digest". >> >> All messages to sanet-mg are archived at: >> http://www.sare.org/san/htdocs/hypermail > >- -- >Russ Bulluck >Ph.D. Candidate >Department of Plant Pathology >North Carolina State University >PO Box 7616 >Raleigh, NC 27695-7616 > >http://www.cals.ncsu.edu/plantpath/Personnel/Students/webpage.htm > To Unsubscribe: Email majordomo@ces.ncsu.edu with the command "unsubscribe sanet-mg". If you receive the digest format, use the command "unsubscribe sanet-mg-digest". To Subscribe to Digest: Email majordomo@ces.ncsu.edu with the command "subscribe sanet-mg-digest". All messages to sanet-mg are archived at: http://www.sare.org/san/htdocs/hypermail From WILSONDO@phibred.com Mon Jun 21 11:14:27 1999 Date: Mon, 21 Jun 1999 04:49:39 -0500 From: "Wilson, Dale" To: 'Russ Bulluck' , Sustainable Ag Subject: RE: mildew question [ The following text is in the "iso-8859-1" character set. ] [ Your display is set for the "US-ASCII" character set. ] [ Some characters may be displayed incorrectly. ] Russ, > I apologise for the impromptu lecture on plant pathology, > and thank you for your attention. Don't apologize, plant pathology is very interesting. > There are (as Dale points out) certain chemicals that > cause plants to turn on these universal defenses (Actiguard, > by Novartis, is one. Salicylic acid is another component, It would be nice if organic growers could turn on systemic acquired resistance (SAR) using non-synthetic chemicals. Can salicylic acid do this in a practical sense? > Mildews are just too specific. Since SAR is a fairly generalized response, it might be possible to turn it on in a plant using a non-specific, sub-virulent pathogenic assault. Are their less fastidious pathogens that one could brew up and spray on to trigger SAR, or would that be playing with fire? I am thinking of facultative saprophytes that will germinate and "attempt" to infect almost anything. > The important thing to remember is that most plant pathogens > don't cause plant disease on most plants. Disease is always > the exception. Reactions to pathogens go from none to resistant > reactions to susceptible reactions (disease). Don't certain bacteria colonize the leaf surface? It is amazing to me how seed-borne Xanthomonads and Pseudomonads can survive and propagate in plant canopies, causing disease even under arid conditions. They must have a very intimate relationship with the leaf surface. Of course, in the grand scheme of things fungi are much more important pathogens Could fungal triggers of SAR be put into leaf-surface bacteria to get generic SAR triggers? Dale To Unsubscribe: Email majordomo@ces.ncsu.edu with the command "unsubscribe sanet-mg". If you receive the digest format, use the command "unsubscribe sanet-mg-digest". To Subscribe to Digest: Email majordomo@ces.ncsu.edu with the command "subscribe sanet-mg-digest". All messages to sanet-mg are archived at: http://www.sare.org/san/htdocs/hypermail From lrbulluc@unity.ncsu.edu Mon Jun 21 11:16:40 1999 Date: Mon, 21 Jun 1999 09:10:16 -0400 From: Russ Bulluck To: "Wilson, Dale" Cc: Sustainable Ag Subject: Re: mildew question "Wilson, Dale" wrote: > Russ, > > > I apologise for the impromptu lecture on plant pathology, > > and thank you for your attention. > > Don't apologize, plant pathology is very interesting. > > > There are (as Dale points out) certain chemicals that > > cause plants to turn on these universal defenses (Actiguard, > > by Novartis, is one. Salicylic acid is another component, > > It would be nice if organic growers could turn on systemic acquired > resistance (SAR) using non-synthetic chemicals. Can salicylic acid do this > in a practical sense? > It would be nice. Salicylic acid is very difficult to get into plants, and I don't think it is UV stable. It is a signalling molecule in the SAR pathway, and can be found in the Xylem and intracellular matrix (I think). Phosphoric acid (found in Coca Cola) is better at turning on the SAR. I think that it is one of the major ingredients in Alloette (sp). One problem with turning on the SAR pathway is that the plant devotes a _large_ amount of energy producing compounds to prevent infection, and not on fruit production. > > > Mildews are just too specific. > > Since SAR is a fairly generalized response, it might be possible to turn it > on in a plant using a non-specific, sub-virulent pathogenic assault. Are > their less fastidious pathogens that one could brew up and spray on to > trigger SAR, or would that be playing with fire? I am thinking of > facultative saprophytes that will germinate and "attempt" to infect almost > anything. > In theory, yes. Are you playing with fire? Yes. The best thing to do might be to brew up a batch of _highly_ pathogenic bugs, and then boil the batch, and use the extract to spray. The extract may contain materials that could induce SAR. Of course, the extract could also contain heat-stabile enzymes that would kill your plants! I would do this with fungi, but not bacteria, and with _great_ caution. Better yet, I would let a university experiment station do this, and watch to see what happens to their fields! > > > The important thing to remember is that most plant pathogens > > don't cause plant disease on most plants. Disease is always > > the exception. Reactions to pathogens go from none to resistant > > reactions to susceptible reactions (disease). > > Don't certain bacteria colonize the leaf surface? It is amazing to me how > seed-borne Xanthomonads and Pseudomonads can survive and propagate in plant > canopies, causing disease even under arid conditions. They must have a very > intimate relationship with the leaf surface. Of course, in the grand scheme > of things fungi are much more important pathogens Could fungal triggers of > SAR be put into leaf-surface bacteria to get generic SAR triggers? > > Dale Sorry, I didn't mention bacteria or nematodes (or viruses for that matter) . Both of which can cause disease, and induce SAR (in fact the SAR phenomenon was first observed in TMV infection and subsequent TMV challenging to different leaves on the same plant). Most plant pathogenic bacteria (except for most of the Erwinia spp.) do tend to survive epiphitically, and will cause SAR to occur. Most often hypersensitive responses occur (a different phenomenon all together), and are usually caused by a direct genetic response. Once SAR is induced (by fungi, virus, herbivory, or bacteria) it can be effective against all pathogens. -- Russ Bulluck Ph.D. Candidate Department of Plant Pathology North Carolina State University PO Box 7616 Raleigh, NC 27695-7616 http://www.cals.ncsu.edu/plantpath/Personnel/Students/webpage.htm ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The soil population is so complex that it manifestly cannot be dealt with as a whole with any detail by any one person, and at the same time it plays so important a part in the soil economy that it must be studied. --Sir E. John Russell The Micro-organisms of the Soil, 1923 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ To Unsubscribe: Email majordomo@ces.ncsu.edu with the command "unsubscribe sanet-mg". If you receive the digest format, use the command "unsubscribe sanet-mg-digest". To Subscribe to Digest: Email majordomo@ces.ncsu.edu with the command "subscribe sanet-mg-digest". All messages to sanet-mg are archived at: http://www.sare.org/san/htdocs/hypermail From bluestem@webserf.net Mon Jun 21 11:18:04 1999 Date: Mon, 21 Jun 1999 13:06:16 +0100 From: Bluestem Associates To: "sanet-mg@ces.ncsu.edu" Subject: Mildew, etc. Time to pop in with a brief observation from a soil chemist's point of view. You can accomplish a lot by way of increasing resistance to fungal pathogens by making sure that the crop has abundant *available* calcium. Calcium plays a key role in strengthening plant pectins, and these pectins (in turn) often provide the most important barrier to the polygalcturonase used by many (most???) fungi to exploit an infection court when germinating. Anyone who has ever made a low-sugar jam using low-methoxy pectin (e.g. Pomona) has exploited this phenomenon to stiffen the pectin by adding small amounts of soluble calcium. There is also some benefit to be had from ensuring abundant manganese availability to the crop. This can be tricky because at low pH Mn is toxic, and in alkaline conditions is often unavailable. Manganese is polyvalent with a vengence (largely pH dependent), but high levels of the non-toxic forms will allow the plant to be somewhat more resistant to attack. Copper nutrition is also a potentially interesting element of plant health, though the information is rather more anecdotal than in the case of manganese. Increasing soil copper levels has been effective in greatly reducing white mould damage to edible beans in some areas of Michigan. Many Chilean grapes grow in high copper soils and rarely need a fungicide treatment, in spite of significant pressure. Warrants further study, in any case. What is interesting to note (a bit sad, even) is the extent to which the conventional research establishment has dismissed calcium, manganese, and copper, almoste entirely because they *don't increase yields.* We don't need *more* crops, we need HEALTHIER crops. It's easier and more profitable to let the crops get sick and subsequently treat them with something out of a bag. Add to good nutrient management some of the newer fungal antagonists (Trichoderma harzianum and some others) and you have the makings of a reasonably sound preventative program. It all begins in the soil. Bart Hall Lawrence, Kansas To Unsubscribe: Email majordomo@ces.ncsu.edu with the command "unsubscribe sanet-mg". If you receive the digest format, use the command "unsubscribe sanet-mg-digest". To Subscribe to Digest: Email majordomo@ces.ncsu.edu with the command "subscribe sanet-mg-digest". All messages to sanet-mg are archived at: http://www.sare.org/san/htdocs/hypermail From WILSONDO@phibred.com Mon Jun 21 11:19:24 1999 Date: Mon, 21 Jun 1999 09:05:14 -0500 From: "Wilson, Dale" To: 'Russ Bulluck' Cc: Sustainable Ag Subject: RE: mildew question [ The following text is in the "iso-8859-1" character set. ] [ Your display is set for the "US-ASCII" character set. ] [ Some characters may be displayed incorrectly. ] Hi Russ, > Phosphoric acid (found in Coca Cola) is better at turning on > the SAR. I think that it is one of the major ingredients in > Alloette (sp). I believe it is salts of phosphorOUS acid (H3PO3) rather than PhosphorIC acid (H3PO4). This is confusing, since phosphorous acid is also called phosphonic acid. Rumor has it that spraying off-the-shelf phosphonate is almost as good as Aliette (aluminum ethyl phosphonate). Dale To Unsubscribe: Email majordomo@ces.ncsu.edu with the command "unsubscribe sanet-mg". If you receive the digest format, use the command "unsubscribe sanet-mg-digest". To Subscribe to Digest: Email majordomo@ces.ncsu.edu with the command "subscribe sanet-mg-digest". All messages to sanet-mg are archived at: http://www.sare.org/san/htdocs/hypermail "Wilson, Dale" wrote: > Hi Russ, > > > Phosphoric acid (found in Coca Cola) is better at turning on > > the SAR. I think that it is one of the major ingredients in > > Alloette (sp). > > I believe it is salts of phosphorOUS acid (H3PO3) rather than PhosphorIC > acid (H3PO4). This is confusing, since phosphorous acid is also called > phosphonic acid. Rumor has it that spraying off-the-shelf phosphonate is > almost as good as Aliette (aluminum ethyl phosphonate). > Okay, I'm not a chemist. But I suspect you are right. I'm under the impression that Rhone-Poulenc has a "use-patent" on phosphonate. That you can't legally just spray phosphonate. Not sure. . . just what I've heard. . .Russ -- Russ Bulluck Ph.D. Candidate Department of Plant Pathology North Carolina State University PO Box 7616 Raleigh, NC 27695-7616 http://www.cals.ncsu.edu/plantpath/Personnel/Students/webpage.htm ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The soil population is so complex that it manifestly cannot be dealt with as a whole with any detail by any one person, and at the same time it plays so important a part in the soil economy that it must be studied. --Sir E. John Russell The Micro-organisms of the Soil, 1923 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~