>
>I'm looking for any information on "organic"-approved fungicides
>and/or cultural practices which will work against the following fungi:
>
>Mycena citricolor
The disease is called 'Ojo de gallo' --- cock's eye --- in Spanish. M.
citricolor is the perfect phase of the causal organism, Omphalia
flavida, most easily identified in the field by the small yellow
structures overgrowing lesions when the weather is rainy or otherwise
quite humid. Organic control is all cases is the same --- management of
ventilation, and particularly shade management. Keep shade in the
35-45% range. Ojo de gallo is rarely a problem in *well-maintained*
diverse polyculture stands dominated by coffee. Cost (and impact) of
bordeaux mix and other "organic" fungicides is rarely justified by the
level of tissue damage to be found when cultural techniques are in
order.
>Hemileia vastarix
The disease is called 'Roya' --- rust --- is Spanish. In most of the
areas where I have worked the control is quite simple. Plant coffee
above 1400 metres ideally, 1200 metres for sure. Diverse polycultures
minimize disease pressure above 1200 metres, but really don't help at
all below that altitude.
The folks growing 'cafe tecnificado' below 1200 metres have a
significant fungicide bill. I am unaware of a single certified organic
coffee planting below 1200 metres anywhere in the Americas, save
Hawai'i. It doesn't mean that there absolutely aren't any, just that
they're awfully rare.
Coffee below 1200 metres in many areas also gets hammered by 'la Broca'
--- coffee berry borer --- Hypothenemus hampei (a snout beetle with a
face only its mother could love) --- so there is a double incentive to
plant at higher elevations. Broca can still be a problem at higher
elevations, but there are several good organic controls, mainly a
parasitic wasp and the entomopathogenic fungus Beauveria bassiana.
That's not what you asked, however, so I'll leave it at that.
Bart Hall
Lawrence, Kansas
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