Fertilizing and disease control on Hippeastrum
Hans-Werner Hammen (Wed, 26 Oct 2005 12:58:03 PDT)

bulbs raised from seeds I found out:
A control against diseases is not necessary.

The main fungal disease in gardener's amaryllis is red blotch.
My carefull observation revealed that this fatal event never occurs by
itself but originates from a superinfection of plant material damaged by the
bulb scale mite Steneotarsonemus laticeps.

The other potentially fatal disease is basal plate soft rotting.
It only occurs after prolonged overwatering.
But.. it might originate from nematode infection, too!
I speculate on this suite of reason and effect...

So for my part I always worry ONLY about little critters which might attack
my amaryllogene treasures
http://forums2.gardenweb.com/forums/bulbs/…
but never reflect on remedial actions against fungal diseases.
A fungal disease "("only")" reveals that something behind the observed
disorder is wrong and that has to be checked out.

On the other hand, I experienced that the bulb scale mites perform the
maximum damage particularly on WELL-husbanded plants (if they are allowed
to).

So as I care for my plants very intensively I have to undertake thorough
prophylactic (and sometimes remedial) actions against these mites, too. That
includes acaricidal sprayings onto the surface of the substrate and the
visible part of the bulbs, too, and I NEVER let these parts get wet.

(Instead) I administer water only from below; every second day - for
practical reasons; daily watering would be still better - thus following
the example of the nature which delivers the water from the underground (on
a REGULAR basis) - but only irregularly from above by rainfalls.
The uppermost centimeters of the suibstrate should remain completely
bone-dry with this method!

And, as regards to the question of fertilizing, I follow the example of the
nature, too, and I deliver minerals by EVERY water administration into the
soucoupe; generally 1000 ppm of a 6-3-6 with micronutrients, into lukewarm
water with a total Ca++ and Mg++ content of 2.7 mmol/L equivalent to 15
German hardyness degrees.

Hans-Werner