No subject

[Arisaema Enthusiast Group (AEG) Discussion List (and other=]

hardy  Aroids)" <ARISAEMA-L at NIC.SURFNET.NL> Aroids)" <ARISAEMA-L at NIC.SURFNET.NL>
Sender: "Arisaema Enthusiast Group (AEG) Discussion List (and other=
From: Giorgio Pozzi <studio.pozzitaubert at TISCALI.IT>
Subject: Re: Decapitated Arisaema/rust
In-Reply-To: <6.0.1.1.2.20070331161456.021406d8 at postoffice.att.net>
Mime-Version: 1.0 (Apple Message framework v752.3)
Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowe=
d 
Content-Transf er-Encoding: 7bit

Il giorno 31/mar/07, alle ore 22:16, George R. Stilwell, Jr. ha scritto:

> Russell,
>
> The recommended treatment for Arisaema with the rust is to
> decapitate them, burn the leaves, and plant the tuber. It works fine.
>
> Just plant your tuber and wait.
>
> Ray

Ray,

I thought it was mandatory to destroy the whole plant....

Giorgio

from the site :

http://www.shieldsgardens.com/amaryllids/Arisaema.html

There seems to be one major pest that afflicts Arisaema, the Arisaema
Rust, Uromyces ari-triphylli. The currently recommended treatment for
Arisaema Rust is total destruction of all the afflicted plants in a
collection, according to some in the Arisaema Enthusiasts Group.

A forest perennial, Jack-in-the-Pulpit, Arisaema triphyllum,
reproduces both asexually and sexually, as either a male or a female.
Each individual possesses the ability to change gender multiple times
throughout its lifetime. Gender is correlated with size: Small plants
do not flower and reproduce clonally only, medium sized plants are
males, and large plants are females. Size and gender for a given
growing season are predetermined by the amount of photosynthate
stored over the previous growing season in an underground corm.
Infection by the systemic rust, Uromyces ari-triphylli, has the
potential to alter this reproductive strategy by affecting the size,
gender and persistence of infected plants. Disease is transmitted
horizontally and to clonal offspring, but not vertically to sexually
produced offspring. Although sexual reproduction is costly for an
already diseased-stressed plant, seed derived offspring are more fit
because they escape disease. The other reproduction option,asexual,is
not advantageous since offspring will be diseased. As part of an
ongoing demographic study investigating the effects of infection on
both individuals and populations, we censused six natural populations
of Jack-in-the-Pulpit, three healthy and three diseased. Preliminary
results revealed infected flowering individuals were smaller than
their healthy counterparts and diseased individuals were more likely
to flower than healthy individuals of the same size. In addition,
diseased populations had a higher proportion of flowering individuals
than healthy populations. These data suggest that disease may cause a
plant to invest in sexual reproduction and to do so at a smaller size
than healthy individuals.