>The most
>important disease for this area is "requeima" (phytophthora
>infestans). The principal pest is "broca pequena" (Neoleucinodes
>elegantalis), for which there is no control (including no registered
>toxic).
P. infestans is known here as late blight. Less common than early blight
(alternaria), but devastating when it occurs. I like the Portuguese name.
It's definitely requiem for the tomatoes when late blight strikes. It's the
same blight that caused the Irish potato famine.
There are no really good remedies for it here, either. Late blight is a
major problem for tomato and potato growers in some areas, regardless of
what chemicals they use. We deal with it on our farm by using long
rotations (five years) and strict field sanitation (all residues
incorporated immediately after last harvest).
Can't help you with the pest. My insect references don't list Neoleucinodes
elegantalis. From the Portuguese, it sounds like a borer (broca pequeña
translates to "little drill bit", I think).
>A second expirament will look at the effect
>of two foliar applications on requiema: 1) is "Calda de Vicosa" - a
>solution of copper sulfate, magnesuim sulfate, zinc sulfate, boric
>acid, Cal, and water. 2) is sulfer calcium - solution of sulfer,
>hidrated Cal. These solutions are being used as alternatives to the
>toxic fungicides available. My question is: Are these really
>alternatives? I do not have the chemistry background or information
>available as to their toxicity.
The two foliar sprays that you mention would likely be accepted under
organic certification regimens, but they are not harmless. Lime sulfur
(sulfur and hydrated calcium) is highly corrosive and must be handled and
applied with care.
Cass Peterson
cpete@nb.net
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