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----- Original Message -----
From: Jay Vannini
To: aroid-l@gizmoworks.com
Sent: Saturday, January 16, 2010 5:54 PM
Subject: Re: [Aroid-l] Anthurium blight
Steve:
Glad to have been of service.
Several clarifications appear in order.
- IMO, it is EXTREMELY unlikely that anthurium blight is not already in everyone's exotic aroid collection who is reading this, either manifest or latent.
- From old lab work I know that I have had at least three separate introductions into my own, from South Florida nurseries (1999-2000), from a domestic anthurium cut flower source (1998-2000), and from a commercial supplier in South America (this was diagnosed from tissue collected at port of entry by our Ag Ministry lab in 2003...at that time Xanthomonas campestris-positive did not require destruction of the plants so they were waived. Needless to say, I quarantined the blazes out of this and all subsequent commercial imports through 2006. Following ratification of DR-CAFTA we are now under the regional one size fits all rule...these plants would be incinerated if this import occurred today).
- Based on the protocol I outlined earlier, I grow many flawless, very blight-sensitive Anthurium spp. in close proximity to other plants with minor blight halos evident on leaf edges and have images to prove it.
- For George Yao's benefit, what I outlined in response to your initial posting IS an IPM-inspired protocol for control of this blight in private and public collections.
- Commercial growers have a vastly different set of challenges and require a very different protocol for blight management and require a somewhat different approach (see below).
- I have the short form product data sheet for Agri-mycin formulation that I use (manufactured at Pfizer's Toluca plant in México) before me. A correction to an earlier statement I made...it is in fact 15% streptomycin sulfate and 1.5% oxytetracycline + inert balance, not 17% streptomycin as I wrote. In any event, in free translation the sheet reads that the product is "recommended" for "control of the following diseases": "...bacterias caused by the genera Xanthomonas, Erwinia and Pseudomonas" in the "following crops": "Ornamentals"...Philodendron, Dieffenbachia, Aglaonema."
- At yesterday's market close, Pfizer, Inc. market cap was almost US$ 160 BILLION.
- If, say, it were revealed that Pfizer, Inc.'s ag-chem division was making manifestly false claims regarding the efficacy of one of their mainstream products then, say, a well-heeled large ornamental plant grower might be tempted to sue their pants (and big pants they are!) off.
- Agri-mycin can provide very effective suppression (not cure) of anthurium blight in COLLECTIONS OF ORNAMENTALS when used properly in conjunction with a broader IPM-inspired protocol. It is NOT a panacea nor a silver bullet to eradicate anthurium blight and neither I (nor Pfizer) would ever claim that it is. However, it certainly can provide suppression to a point where healthy, well-grown plants can prosper with it latent in their environments. My own fairly large blight-susceptible aroid collection, plus several published sources, proves it.
- IMO, and as diplomatically-put as possible; anyone who claims otherwise doesn't know what he/she doesn't know.
- If a given grower blithely continues to challenge their blight-susceptible tropical aroids with environmental (note: IME, lousy water quality aggravates anthurium blight in delicate plants for certain) or management issues, this critter will ultimately (often in short order) decimate all those vulnerable plants and nothing short of Divine Intervention will save them. Don't waste your money on ag-chem if you are not willing to practice clean culture - it won't really help.
Thus, from a hobbyists' perspective, successful management of this nasty pathogen requires a certain mindset and quite a bit of discipline with regard to handling and triage of visibly-affected plants. Believe me, it works. Conversely, commercial growers have, in the past, been faced with no other economically viable option other than having to destroy their entire blight-susceptible inventory and start afresh with new cultivation protocols and blight-resistant stock from micropropagation. This also works, but at a very steep price.
All those here who are willing to properly dispose of the entirety of their exotic aroid collections just because they contain some suspicious-looking or blight-diagnosed rare plants and start all over with those handsome (the colors!!!) tissue-cultured, mass-produced, PATENTED (no unauthorized asexual propagation, folks) anthuriums, aglaonemas, alocasias and philodendrons, please hold up your hands.
Didin't think so...
J
Date: Fri, 15 Jan 2010 13:35:09 -0600
From: Steve@exoticrainforest.com
To: aroid-l@gizmoworks.com
Subject: [Aroid-l] Anthurium blight
Thanks Jay. 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. We see lots of poorly grown ornamental Anthurium in some of our local stores, often showing signs of what may be disease. 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. 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:
Anthurium blight has been with us forever and affects a wide range of aroid genera. Breeders, including me, 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 that are truly 100% blight-resistant, although the riparians antioquiense and amnicola are known to transmit their tolerance to andraeanum hybrid (the so-called andraecolas) offspring. Conversely, there are a number of old andraeanum and crystallinum hybrids and quite a few montane spp. that are exquisitely susceptible to blight. Whether or not we are seeing more aggressive strains emerging in the trade is another matter entirely; I have not imported stock from the 'States since 2006 so would not be the right individual to address this possibility. It would be interesting to hear from Denis Rotolante, who would certainly know whether they are seeing new antibiotic-resistant strains, and with whom I exchanged info on Xanthomonas management in greenhouses in 2000-2001.
I completely disagree with the notion that small scale growers cannot effectively control this blight and should not be buying anthuriums 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, I think many of us know it when we see it, 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, frankly, I 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.
Basically, what makes anthurium blight control especially difficult for commercial growers is that the pathogen is rapidly spread, not only by mechanical means such as non-disinfected cutting tools, employees' hands, clothes, etc. - DR mentioned once that Cuban treefrogs clambering from plant to plant in his greenhouses were a suspected vector! - 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 should be extremely careful to avoid "hard" overhead watering or exposure to rain. While this seems counterintuitive to a tropical aroid fan, bestest and fastest control is gained when foliage is kept dry, well-ventilated but nearly motionless in order to minimize mechanical damage to the leaves that facilitates entry for the bacteria.
- My frontline treatment for foliar infection is Agrimycin (streptomycin sulfate 17%) AFTER removing all visibly infected plant tissue to a point well beyond the classic yellow halo line circumscribing necrotic tissue. I would need to check my notes to see at what concentrations I usually apply, but I do seem to recall that I make three apps about 5-8 days apart. I 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, expensive and quite phytotoxic.
- While I occasionally use concentrated quat ammonium dips for disinfecting my pruners (at least three in the greenhouse, used in rotation), I definitely favor flaming tools between cuts to all my plants to red hot. If you do not consistently disinfect tools between plants, IMO, you will never gain good blight control once it is firmly established in your collection.
- 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 been 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, the plant is generally going to hand in its lunch pail in very short order. If this occurs, toss these critters asap.
- It seems that many growers-gardeners love to fondle their plants when they're in their grow spaces. I cannot emphasize enough that any handling of aroids that are known or suspected of being blighted should be kept to an absolute minimum, and hands disinfected between this kind of manipulation.
Note: IME, Agrimycin will invariably burn/disfigure leaves of Anthurium veitchii and its hybrids, usually quite severely, as well as some old andraeanum primary hybrids and few others. It can also be extremely hard on seedlings.
J
Date: Mon, 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. At least two gardens in France have had to deal with this one which has no cure. 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. I would suggest you be very careful about buying new Anthurium right now! This has the potential to kill an entire collection.
Some species appear resistant but others spread it quickly. 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
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