Monday, February 11, 2008

Mixed amaryllis messages

The two amaryllises that I potted up last month have sent out new green leaves from the top of their bulbs. That's good.

However, I've noticed something that is not good: a dark reddish area on the side of one bulb. A run through the Amaryllis/Hippeastrum Forum on Gardenweb suggests that this might be "red blotch" or "leaf scorch" (Stagonospora curtisii).

The University of Florida's Extension web-site lays it out: "red blotch" is more than not good; it's very, very bad.

The fungus and spores of red blotch are carried on the bulbs . . . Red blotch is difficult to control; disease-infected bulbs, plants or seedlings should be destroyed. Prevent disease by using sterilized potting soil when propagating and providing plants with the right growing conditions. Fungicides (like thiophanate methyl) can be applied, but they are expensive and hard to find. A hot water treatment is sometimes suggested. Dig up the bulbs, remove excess soil and soak them for 30 minutes in water kept at a constant temperature of 104-114°F (40-46°C).

I was pretty conscientious this past year about plant hygiene by bottom-watering all amaryllises and by quarantining and then destroying one bulb with mosaic virus. Dang!

GardenWeb discussants have proposed that many bulbs diseased with red blotch are being shipped into the country from the Netherlands. However, customers who discard the bulbs after blooming likely never realize that their plants carried red blotch. It's just those gardeners who season over their amaryllises that come to discover they've harbored infected plants. Double dang!

So perhaps I should not have been surprised to see small red spots nestled deep down among the dried leaves of this year's super fabulous "Royal Velvet" amaryllis. Triple dang!

1 comment:

Kylee said...

Two years ago, I got 'Susan' from a grower in Florida that had a virus. I kept it, as I do all my amaryllis bulbs, and grew it in the garden, away from the other bulbs. It didn't even bloom last year. I just recently potted it up and it's not growing yet.
I haven't recognized any red blotch on any of the bulbs. I've seen some reddish edges due to damage, but that's different. I hope you don't have it!
'Royal Velvet' is gorgeous, isn't it? It's one of those that I just can't keep my eyes off!