thanks Vincent, for the link to RIMpro - I look forward to investigating more when I'm not so tired -
David - On Apr 21, 2011, at 12:10 PM, Vincent Philion wrote: > Hi! I agree with both Dave and Daniel, but let me add a grain of salt: > > All infection events are not equal. > > Plain infection models tell you nothing about ascospore availability & > discharge. Conditions may be right for spores to infect... but infection only > occurs IF spores are both mature and ejected! Then, as Daniel underlines, the > question of dry hours comes up. Does a short break during the infection kill > all spores? A portion? > > Because there are many processes going on: Maturation, discharge, infection > and each process has it's own rules (effect of light, temperature, drying, > etc), none of the models included in these machines are a good reflection of > what's actually going on. > > The only model I'm aware of that addresses each of these issues in a rational > approach is RIMpro: > > (http://www.biofruitadvies.nl/RIMpro/rimpro_e.htm) > > It's been used in Europe for over 20 years and it integrates all the > knowledge on spore maturation (Gadoury & MacHardy), infection (revised > Mill's), effect of light, drying, etc. > > It was actually developed by an entomologist that was fed-up with the never > ending discussions of pathologist on each separate aspect, without a clear > image of the "big picture". (Me included!) > > The software was validated over many years and many countries. Nonetheless, > development is still ongoing because some pathologists still argue and find > small areas needing improvement. (pathologists are a feisty bunch... Me > included) > > > Vincent > > > Le 2011-04-21 à 11:32, Daniel Cooley a écrit : > >> Dave's right, the Mills model is Al Jones from about 1980. The WA model is >> actually the original Bill Mills model from the 40's, and the Cornell model >> is Gadoury, Stensvand and Seem's 1994 revision. Nice overview, Dave. I >> haven't checked, but there may be differences between the Cornell model and >> the other two in terms of split wetting periods, and that may be what's >> beyond the strange predictions in David D.'s wetting event. Two hours isn't >> very long, but may be enough for the WA model to call them distinct events, >> while the Cornell model did not. >> >> In general, I have found the black box approach used by Spectrum with their >> implementation of disease models to be less than satisfying at times. Their >> manual is pretty sketchy, and sometimes just wrong about what the published >> models say and what the SpecWare model does. More information about the way >> the models work would be very helpful. >> >> On Apr 21, 2011, at 11:13 AM, Dave Rosenberger wrote: >> >>> Hello, David -- >>> I really don't know how the Spectrum instruments are programmed, and I >>> don't know what they are using for the Washington scab model. Thus, this >>> response may be of limited usefulness. >>> I suspect that that the differences between the Cornell and the Mills >>> (MI) models relate to two key differences among these models. Again, I >>> don't know this for a fact because I don't know how Spectrum programmed >>> their unit, but I would guess that the Mills (MI) model uses the modified >>> Mills Table that was published by Al Jones and he put into the original >>> Reuter-Stokes scab caster. If so, that program will not discount wetting >>> periods that start after dark, and it will use slightly longer wetting >>> requirements for light infections than those used by the Cornell model. >>> The Cornell model presumably does not count wetting periods that start >>> after dark because relatively few ascospores are released in the absence of >>> light. In a high inoculum block, those few that do discharge at night can >>> still create problems, but in most commercial blocks night-time discharge >>> will not be significant, especially early in the season. In my opinion, >>> ignoring night time discharge is a bit more risky by the time one gets to >>> pink bud (when most ascospores are maturing), and it is absolutely >>> foolhardy to ignore night time discharges between pink and petal fall if >>> the rains in question come at the end of a relatively long warm dry period. >>> In this latter situation, the swelling ascospores cause the pseudothecia >>> to explode and the light-triggered release mechanism may be by-passed. >>> The Cornell model was based on lab trials that showed ascospores can >>> infect in the same relatively short periods that Bill Mills had initially >>> described for secondary infections. Thus, the Cornell model will trigger >>> 'infected' before the Mill's MI model. Although NY has adopted the 'Cornell >>> model' because it is technically more correct, I still prefer the modified >>> Mill's table that was developed by Jones (although I do believe in >>> discounting night-time wetting, especially early in the season). >>> Bill Mills developed his scab model by actually looking at what >>> happened to trees outdoors. As a result, his model and the modified Mill's >>> table from Al Jones actually represent an integration of minimum infection >>> conditions AND spore numbers. Conidia are always produced in much greater >>> quantities than ascospores under conditions in commercial orchards. Thus, >>> with conidia, large quantities arrive and infect leaves within 6 hr at >>> optimum temperatures. If you artificially put large quantities of >>> ascospores on leaves, you also get infections within 6 hr at optimum >>> temperatures. In reality, however, it takes some time for an economically >>> significant dose of ascospores to arrive on leaves in a commercial orchard >>> because there are relatively few of them. Mills and Al Jones therefore used >>> 9 hr as the minimal wetting period at optimum temperatures to account for >>> the fact that their data suggested it would require an extra three hours to >>> accumulate an economically significant >> dose of ascospore as compared to conidia. (Some of my plant pathology >> colleagues my wish to quibble with these broad generalizations because I've >> skipped a lot of details and also done some "reading between the lines." >> Nevertheless, I think my general conclusions in comparing the two models are >> valid.) >>> The Cornell model also provides only a yes/no response to infection, >>> whereas the original Mills table and the Jones version of the Mills table >>> still provides gradations of light, moderate, or heavy infection based on >>> duration of the wetting periods at various temperatures. Again, because >>> ascospores are relatively limited in number in most orchards, it makes >>> sense to parse out the severity of infection for ascospores whereas just >>> the minimal wetting/temperature requirements are enough to trigger conidial >>> infections if conidia are present because conidia are either present in >>> large numbers or not at all. >>> By having information on light-moderate-heavy infection, one can adjust >>> one's on-site risk factors based on other details of the specific orchard >>> situation. For example, in a clean orchard with trees just at green tip, I >>> would ignore the "light" Mills period and begin to worry only after >>> triggering at least a "moderate" Mill's period because there are so few >>> spores at green tip that the marginal conditions for a light infection >>> period will be unlikely to result in noticeable scab. However, even in a >>> clean orchard, I would NOT ignore a light Mills period when trees are at >>> tight cluster or pink. >>> I hope others will chime in on what differences may be incorporated >>> into the Washington model. >>> >>>> Is anyone else on this list using Spectrum instruments to monitor weather >>>> and model disease? - I've had a 'Watchdog' for several years now, and >>>> yesterday had an anomaly, with complete disagreement and inconsistencies >>>> between the three scab models - >>>> >>>> The software uses models from Cornell, Washington State, and Mills (MI) - >>>> I'm used to Cornell being very conservative and WA being the opposite - >>>> this event, Cornell indicated 'infected', WA 'none', and Mills 'heavy' - >>>> I've never modeled an event with Mills being 'heavy' and WA 'none' - >>>> >>>> circumstances were such that we were cruising along in the lower 40'sF >>>> monday and then an overnight rain till 7AM tues morning - a two hour dry >>>> period, followed by a rain, followed by the violent front (no damage here, >>>> but tremendous light show) - while that front was moving thru, >>>> temperatures rose above 50*F for about 6 hours, peaking at 56*, before >>>> declining back to the lower 40's again - >>>> >>>> to add to the mystery, if I model tuesday, from the two hour dry thru the >>>> end of the event, I get the 'infected', 'none', 'heavy' analysis from the >>>> program - if I run the model from the start of the rainy event monday so >>>> to include the rainy monday night/early tues thru the end of the event >>>> wednesday morning, the Mills model indicates 'light' infection (Cornell >>>> indicates 'infected', WA 'none) - >>>> >>>> as a practical matter, at our stage of development, these temperatures, >>>> and specific schedule of the wet periods, I normally wouldn't worry much >>>> about scab infection - but seeing that 'heavy' infection indicated from >>>> the Mills model is disconcerting - >>>> >>>> dunno - any thoughts? >>>> >>>> thanks, >>>> David Doud >>>> grower, IN >>>> _______________________________________________ >>>> apple-crop mailing list >>>> apple-crop@virtualorchard.net >>>> http://virtualorchard.net/mailman/listinfo/apple-crop >>> >>> >>> -- >>> ************************************************************** Dave >>> Rosenberger >>> Professor of Plant Pathology Office: 845-691-7231 >>> Cornell University's Hudson Valley Lab Fax: 845-691-2719 >>> P.O. Box 727, Highland, NY 12528 Cell: 845-594-3060 >>> http://www.nysaes.cornell.edu/pp/faculty/rosenberger/ >>> >>> _______________________________________________ >>> apple-crop mailing list >>> apple-crop@virtualorchard.net >>> http://virtualorchard.net/mailman/listinfo/apple-crop >> >> _______________________________________________ >> apple-crop mailing list >> apple-crop@virtualorchard.net >> http://virtualorchard.net/mailman/listinfo/apple-crop > > Vincent Philion, agr., M.Sc. > Phytopathologiste > Laboratoire de production fruitière intégrée > Institut de recherche et de développement en agroenvironnement > > 335, Rang des vingt-cinq Est > Case postale 24 > Saint-Bruno-de-Montarville (Québec) J3V 4P8 > Tél. bureau: 450 653-7368 poste 224 > Tél. laboratoire: 450 653-7368 poste 229 > Cellulaire: 514-623-8275 > Télécopie: 450 653-1927 > > Verger du parc national du Mont-Saint-Bruno > 330, Rang des vingt-cinq Est > Case postale 24 > Saint-Bruno-de-Montarville (Québec) J3V 4P8 > Téléphone et télécopieur : 450 653-8375 > Courriel: vincent.phil...@irda.qc.ca > Site Internet:www.irda.qc.ca > > Pour nous trouver: > Laboratoire: > http://maps.google.ca/maps/place?cid=9609486867104665866&q=irda+pfi&hl=fr&sll=45.557814,-73.360476&sspn=8.87586,1.961403&ie=UTF8&ll=45.557814,-73.360476&spn=0,0&z=16 > > Verger: > http://maps.google.ca/maps/place?cid=11405391288824931904&q=verger+irda&hl=fr&sll=45.54961,-73.350585&sspn=0.012504,0.018389&ie=UTF8&ll=45.54961,-73.350585&spn=0,0&z=16 > > > Un expert est une personne qui a fait toutes les erreurs qui peuvent être > faites dans un domaine très étroit. > Niels Bohr > > Avez-vous réellement besoin d'imprimer ce courriel? Si oui, imprimez-le > recto-verso! > > AVIS DE CONFIDENTIALITÉ > Ce message peut contenir de l'information de nature privilégiée et > confidentielle. Si vous n'êtes pas le destinataire visé ou croyez l'avoir > reçu par erreur, nous vous saurions gré d'en aviser l'émetteur. Si ce message > vous a été transmis par erreur, veuillez le détruire sans en communiquer le > contenu à d'autres personnes ou le reproduire. > > _______________________________________________ > apple-crop mailing list > apple-crop@virtualorchard.net > http://virtualorchard.net/mailman/listinfo/apple-crop _______________________________________________ apple-crop mailing list apple-crop@virtualorchard.net http://virtualorchard.net/mailman/listinfo/apple-crop
