Bulb Scale Mite on Hippeastrum

Carol Jensen jorna@mobilixnet.dk
Tue, 31 May 2005 09:58:44 PDT
At 03:32 30-05-2005, Hans-Werner Hammen wrote:
>Hello Jim;
>
>I live and I grow my hippeastrums in Germany.
>
>I regret that I can not offer anything for the GROWING crop (nota bene) which is fully endorsed by legality for the private gardener:
>
>Dicofol ( in Kethane) is no more allowed in Germany and Avermectines (in Abamectin) is not accessible for the private gardener.
>
>Oxydemeton-methyl (a phosphorous-organic pesticide; in Metasystox-Spezial, from  Bayer) works and its use is principally legal for ornamentals outdoors but it has to be used at the at less two- better 4-fold concentration compared to the recommended. AND it has to be sprayed repeatedly BECAUSE you can not eradicate these mites with it - although it is a systemic pesticide. You can never obtain a sufficient agent concentrations in the older bulb scale parts where the bulk of mites live and from where they emerge to seek for new life space. But you can sufficiently protect the new growth by spraying into the heart of the plant.
>
>In autumn when I harvest my bulbs I treat them mechanically against these 8 legged critters. I first cut the leaves at a rather high level, then remove all loose parts on the substrate surface and all dry and loose matter of the bulbs, then I make the final clean cut to keep only a rather short bulb neck and immediately spray with 10 % non drying oil in isopropanol. I use JoJoba oil, medium light mineral oil works, too.
>
>I spray on the wound and on the cleaned bulb and the substrate surface (My bulbs stay in the grow boxes, keeping the roots undisturbed, during the winter reposal. There is no hope that removing the soil has any curing effect on the bulbs The spraying procedure has to be repeated several times during the winter reposal because new spaces open between the leaf bases as the bulbs dry. Spraying must be thorough but still so superficially that the bulk of roots does  not get affected.
>
>The only eradicative means is the Hot Water Treatment. It is a well known and simple procedure but depends on precise laboratory (or technical) equipment. It is only performed on bulbs after the growth season. It removes red blotch, eelworms and mites (but not virus). A disadvantage is that the roots have to be removed before or are killed during the HWT. The bud initials are usually not killed after 46 degC / 2 h treatment.
>
>Reinfection from the environment is to be expected with high probability, yes, sorry; I had my experiences in that, too...
>
>Seedlings of amaryllid plants should be raised as far away as possible from adult plants in order to stay completely free from this pest as long as possible.
>
>All the world is worrying about the red blotch: I never experienced red blotch to develop on uninfested gardener's amaryllis bulbs. Red blotch is "solely" a secondary infestation by the opportunistic Stagonospora although it can become deadly for amaryllis bulbs particularly in cold wet weather in autumn.
>
>It seems that all knight star bulbs from commercial sources are infested with mites. My experience, sorry. I worry about the mite, not about red blotch.
>
>Hans-Werner
Hi Hans-Werner,

I keep my bulbs indoors all year, though they could be planted outdoors. I have lost amaryllis which died down before I knew it in autumn.

I have had red blotch and it is not so bad, but I cure it by cutting off the infected part and drying the bulb for a month or so. Never had any mites or other problems, and I have loads and loads of amaryllis, also sidebulbs, also bulbs from San Diego.

I plant every indoor plant in my own compost and they grow wonderfully and are healthy. I hibernate amaryllis, 2 at a time, from September or October or until they are all in hibernation, and take them out after 2 months to flower.

Carol from Denmark 



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