Re: [Aroid-l] Anthurium blight

From: Jay Vannini <heloderma5 at hotmail.com> on 2010.01.16 at 18:37:58 One final clarification on control of =3Baroid blight =3Bfor those who did not catch this =3Bat the end of =3Bmy first response...even at approved rates and concentrations Agri-mycin can be briefly but extremely phytotoxic to some ornamental aroids=2C esp. some specific anthurium spp. and cut flower types (the reason why it is not =3Blabeled for use on this genus =3Bin this region) and =3Bcan burn =3Bleaves severely. For commercial growers this =3Bcan be =3Ba deal-breaker for obvious reasons=2C but for hobbyists and BGs =3Bit is infinitely preferable to have burned leaves on your prized giant Anthurium superbum or A. veitchii for a year or so than to watch it succumb to aroid blight.  =3B An old paper=2C but =3Bauthoritative source: http://facultystaff.vwc.edu/~presslar/CultivatedAnthurium/PDF-Lib/BacterialBlightControl-No14.pdf =3BThe heads-up on not making this an everyday =3Bstandby echos Surawit's earlier cautionary note about breeding blight resistance to antibiotics. I agree.  =3B J =3B Date: Fri=2C 15 Jan 2010 13:35:09 -0600 From: Steve@exoticrainforest.com To: aroid-l@gizmoworks.com Subject: [Aroid-l] Anthurium blight Thanks Jay. =3B My knowledge of this stuff is very limited but it did concern me once I began to read some of the info on the internet. =3B We see lots of poorly grown ornamental Anthurium in some of our local stores=2C often showing signs of what may be disease. =3B I have a relative that is a district manager for a large retailer and he says they throw away lots of plants as a result. =3B I just wouldn't want anyone to get the stuff in a prized collection. Thanks again for the info. Steve www.ExoticRainforest.com Jay Vannini wrote: Steve:  =3B Anthurium blight has been with us forever and affects a wide range of aroid genera. Breeders=2C including me=2C often select for plants that show apparent tolerance to it but generally have learned to live with it lurking in the wings. I am not sure that there are any Anthurium spp. nor hybrids =3Bthat are truly 100% blight-resistant=2C although the riparians antioquiense and amnicola are known to transmit their tolerance to andraeanum hybrid (the so-called andraecolas) =3Boffspring. Conversely=2C there are a number of old andraeanum =3Band crystallinum hybrids and quite a few montane spp. that are exquisitely susceptible to blight. =3BWhether or not we are seeing more aggressive strains emerging in the trade is another matter entirely=3B =3BI have not imported stock =3Bfrom the 'States since 2006 so would not be the right individual to address this possibility. =3BIt would be interesting to hear from Denis Rotolante=2C who would certainly know whether they are seeing new antibiotic-resistant strains=2C and with whom I exchanged info on Xanthomonas management in greenhouses in 2000-2001.  =3B I completely disagree with the notion that =3Bsmall scale growers cannot effectively control =3Bthis blight and should not be buying =3Banthuriums now because of it (!!!). While the last time I actually had a lab make a positive pathogen determination for me was almost 10 years back=2C I think =3Bmany of us know it when we see it=2C and I certainly no longer have the dread that I used to have for it when I first started growing anthurium in the late 90s. I suffered a number of severe outbreaks stemming from imported plants early in the last decade but=2C frankly=2C =3BI have not had a serious problem with it for years in spite of growing more than "just a few" plants for cut flower ('Tropic Fire' and my own hoffmannii based hybrids) and 0000s of foliage-type collector goodies.  =3B Basically=2C what makes anthurium blight control =3Bespecially difficult for commercial growers is that the pathogen is rapidly spread=2C not only by mechanical means such as non-disinfected cutting tools=2C employees' hands=2C clothes=2C =3Betc. - DR mentioned once that Cuban treefrogs clambering from plant to plant in his greenhouses were a suspected vector! - =3B but also by splashing water and leaves banging against each other (this is a bad thing generally for all anthuriums!). Anyone who has this problem =3Bshould be extremely careful =3Bto avoid "hard" overhead watering or exposure to rain. While this seems counterintuitive to a tropical aroid fan=2C bestest and fastest =3Bcontrol is gained when foliage is kept dry=2C well-ventilated but =3Bnearly motionless in order =3Bto minimize mechanical damage to the leaves that facilitates entry for the bacteria.  =3B - My frontline treatment for foliar infection =3Bis =3BAgrimycin (streptomycin sulfate 17%) AFTER removing =3Ball visibly infected plant tissue to a point =3Bwell beyond the =3Bclassic yellow =3Bhalo line circumscribing =3Bnecrotic tissue. I would need to check my notes to see at what concentrations I usually apply=2C but I do seem to =3Brecall that I make three apps about 5-8 days apart. =3BI often rotate or follow-up with copper-based ag-chem although it is contra-indicated in the literature...some have recommended systemic copper but I have found it unnecessary=2C expensive and quite phytotoxic.  =3B - While I occasionally use concentrated =3Bquat ammonium dips for disinfecting my pruners (at least three in the greenhouse=2C used in rotation)=2C I definitely favor flaming tools between cuts to all my =3Bplants to red hot. If you do not consistently disinfect tools between plants=2C IMO=2C you will never gain good blight control once it is firmly established =3Bin your collection. =3B  =3B - It is VERY important to remove infected leaves once they are visibly blighted to avoid the blight becoming systemic. I will say that my experience has =3Bbeen that if one permits a severe blight to extend from the lamina down the petiole (which will often mush at the geniculum and the base) to the main stem=2C the plant is generally going to hand in its lunch pail in very short order. If this occurs=2C toss these critters asap.  =3B - It seems that many growers-gardeners love to fondle their plants when they're in =3Btheir grow spaces. =3BI cannot emphasize enough that any handling of =3Baroids that are known or suspected of being blighted should be kept to an absolute =3Bminimum=2C and hands disinfected between this kind of manipulation.  =3B Note: IME=2C Agrimycin =3Bwill invariably burn/disfigure leaves of Anthurium veitchii and its hybrids=2C usually quite severely=2C as well as some old andraeanum primary hybrids and few others. =3BIt can also be extremely hard on seedlings.  =3B J  =3B  =3B Date: Mon=2C 11 Jan 2010 13:54:00 -0600 From: Steve@exoticrainforest.com To: aroid-l@gizmoworks.com Subject: [Aroid-l] Anthurium blight A warning from our friend Leland Miyano from information originating from botanist David Scherberich. There is now a very bad Anthurium blight which may be spreading. =3B At least two gardens in France have had to deal with this one which has no cure. =3B The one that is really bad is Xanthomonas campestris pv. dieffenbachiae which causes the leaf margins to turn yellow and all the leaves to drop. =3B I would suggest you be very careful about buying new Anthurium right now! =3B This has the potential to kill an entire collection. =3B Some species appear resistant but others spread it quickly. =3B Some commercial growers in Hawaii lost almost entire crops of ornamental Anthurium (the kind you buy in the store) so be very careful about buying any Anthurium in a local nursery or discount store! http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1392979/ Any of you that are knowledgeable about this blight please pass along what you know. Steve www.ExoticRainforest.com Windows Live: Friends get your Flickr=2C Yelp=2C and Digg updates when they e-mail you. _______________________________________________Aroid-L mailing listAroid-L@www.gizmoworks.comhttp://www.gizmoworks.com/mailman/listinfo/aroid-l Windows Live Hotmail: Your friends can get your Facebook updates=2C right from Hotmail=AE.--_47b61fe6-6853-4377-9bba-b439a76d2c22_----===============2413183279815617187==

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