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Heat treatment of actively growing Hippeastrum

Posted by SavannaMan none (My Page) on
Wed, Mar 13, 13 at 4:27

Hi All,
From what I have read, heat treatment is usually recommended when bulbs are dormant to control tarsonemid mites or red blotch,Does anyone have experience with this treatment when bulbs are fully leafed? Does it do damage to the plant?

Sincerely,

Bill


Follow-Up Postings:

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RE: Heat treatment of actively growing Hippeastrum

Jaapm did a hot air treatment of the bulbs at 50C for 2h the plants stayed in their pots with the soil. I am not sure about the details though. I just stumbled upon some messages from him mentionign something along these lines this morning. Perhaps he would read our messages and come back and help.


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RE: Heat treatment of actively growing Hippeastrum

To evenly heat to the center core of the bulband kill mites and other larvae takes 2 hours for30 cm. bulbs with straight hot water (no cold) from the spigot in a styrofoam drink box with the lid on. For larger bulbs empty it out and refill with fresh straight hot water from the spigot and put the lid back on for another 2 hours. Do not cut the leaves or roots and you can replant in a pot or the ground immediately. The critters will be cooked and your bulb will grow. Use hot water from the spigot. Do not heat water in a pot and then add the bulb or pour the heated water over the bulb. Bill


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RE: Heat treatment of actively growing Hippeastrum

I tried this recently with active bulbs that were in rather sorry shape. I was not sure if I had Tarsonemid mites or just red blotch. Three had recently flowered, but the one on the left had not. The first photo shows the bulbs after I removed all dead and dying parts.

I used a submersible heating element and a temperature controller to maintain water temperature at 46 degrees C for 4 hours with only the bulbs and necks submerged. One of the bulbs tolerated it very well, and I think the leaves will survive. Two of the other bulbs had younger leaves, but these are senescing. The second photo is 2 weeks after the treatment.


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RE: Heat treatment of actively growing Hippeastrum

Just an update on the outcome of the treatment. Heating killed the roots on the three smaller bulbs. They all had thick basal plates, so I sliced them (as I learned from this forum). When I had heated them, they all had healthy roots, so I did not want to slice them then. Now that they were in a rootless condition, the time seemed right. After cutting, I left them to dry for a couple of days and applied Captan before setting them on soil again. I hope they have some fight left in them.


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RE: Heat treatment of actively growing Hippeastrum

I'll bet they still have the will to live! I've been really surprised to see just how hardy many amaryllis are!


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RE: Heat treatment of actively growing Hippeastrum

Are your bulbs still ok?


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RE: Heat treatment of actively growing Hippeastrum

The bulbs themselves appear to be quite firm but have not yet shown signs of new leaves.


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RE: Heat treatment of actively growing Hippeastrum

someone suggested bottom heat all the time during winter just to avoid such damage.


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RE: Heat treatment of actively growing Hippeastrum

Hi Bill,
Everyone seems a little hung up on whether you use dry heat on actively growing bulbs and hot water on bulbs in dry bulb state or after prechilling.

My technique is based on the history of hot water treatment which you can find references to on bulbs and roses or in International Bulb Society. around 1900 a woman who was well known for nursing sick [disease,infestation,etc.] bulbs back to health primarily used
hot water hydration and replanting in fresh soil mixes. Many early 20th century researchers in the U.S.. Holland,
India, and England used temperatures from 90F to 124F for periods of 10 minutes to over an hour. My assumptions
for temperature and time were based on the process used in the flower markets during a very bad outbreak of larvae
requiring treatment of every bulb by immersing bulbs in water of 159F for 24 hours. Large stainless steel vats were built with recirculating pumps and filters and... thermostatic controlled heaters to process thousands of approximately 28/30cm amaryllis bulbs in a batch. This was a lot of overkill since basically they were cooking tiny insect larvae which only had to have body temperatures of 123F or so for about 20 minutes to be ready for the butter. (yum?]

So we must raise the core temperatures of the bulbs to at least 130F for 10-20 minutes. In tests of different temperatures it was found that 2 hours at 130F the core temperature of 28/30cm bulbs routinely reach 130F. So based on this data I thought most amaryllis lovers are like me = they only have a small number of bulbs to treat. So we can use a small insulated container- hmmm a stryrofoam drink box with a styrofoam lid [you know the part that breaks first] OK what about hot water? U.S. standards for hot water heaters are settings for 112F to 148F. Go look at the little information plate on yours. So I figured homes, apartments and businesses would be good unless they have boilers for heating which sometimes send overheated water into pipes. So I unplanted my bulbs and layed them with leaves then covered with straight hot water in a styrofoam drink box with a tight lid for 2 hours. If the bulbs were larger than 28/30 cm, I dumped out the water and refilled with water for another 2 hours. I have put in 8 bulbs at a time not cooking any of the bulbs. and not seeing any spread of infestation from adult insects. All were immediately replanted in different soil. Water is a more efficient and even transfer medium of temp. than hot air. less likely to scorch your bulb. Bill Warren


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RE: Heat treatment of actively growing Hippeastrum

Bill,
Thank you for the information. I used 46 C (i.e. 115 F) based on recommendations in Veronica Read's book. That is considerably cooler than the 130 F that you recommend. Considering that 115 F killed the roots and leaves on three of the bulbs, would roots and leaves ever survive 130? Losing roots and leaves is better than the alternative (losing the bulb), but since I already had removed so many rotten layers, I had hoped to avoid further losses to the plants.

Using hot tap water sounds like a more convenient way to do it than the way I did, but then again, I had the heating element and temperature controller available, so it was not much trouble.

Bill


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RE: Heat treatment of actively growing Hippeastrum

Thanks for the information and insight, Mr. Warren! -Tina


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RE: Heat treatment of actively growing Hippeastrum

Hi Bill, the main points I wasemphasizing was dry heat is more likely to damage the outer layers before you get the bulb core to your target temp. Also if your bulb is inthesame container as the heating element you can get uneven heating of water. The large system I studied circulated the water from the heating chamber to the bulbchamber. My technique isto be available to people in most anylocation. The hot water.heater is both batch heater and temp controller with the lided styrofoam drink box as the bulb chamber. I am concerned about the loss of the roots. In the half doxen orso times I used this set.up, no roots or leaves were lost that were no yelliw or damaged before treatment. Let me caution us all to be skeptical about what we read in
text books , articles, and esoecially on the internet. I have found it very difficult to instruct orcomunicate. Not only mixing up my words, but does everyoneputthe same meaning I do. So try to put yourself in thr writers situation. How does what they do differ from what you do in eqipment, technique, goal material? My bloom extension technique was deceloped from tryingto use old hot waterhydration techniques that were used a century ago.When I have published them at Botanical Gardens seminars, in this forum, in the I.B.S. members discussion ,group. I am surprised at the people who say that can't work no oneelse has written about it. I have to laughto myself and say out loud "The hhippeastrum aren't through teaching us yet." Bill Warren


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RE: Heat treatment of actively growing Hippeastrum

Here is an update on the heat treatment. Of the three smaller bulbs, two are recovering well with new roots and leaves, while one has neither but is still firm. The largest bulb, which retained some of its leaves after the heat treatment, is doing well. The surviving leaves never recuperated well, but a couple are still hanging on.

Bill


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RE: Heat treatment of actively growing Hippeastrum

  • Posted by edie_h 5aNY (Finger Lakes) (My Page) on
    Mon, Dec 16, 13 at 19:28

When doing heat treatment, do you keep the bulb neck dry or submerge it? Do hippeastrum bulbs float? I have a foam cooler with lid, a rapid-read cooking thermometer, and a spotty Red Peacock that just aborted its scape. Do I need anything else, besides hot water and time?


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RE: Heat treatment of actively growing Hippeastrum

I submerged the whole thing. In fact, I put a strainer on top and weighted it to hold the bulb underwater. I used a big soup pot and wrapped a heating pad around the outside. Used a towel to buffer the temp a bit. Got the water to temp and held it for 24 hours just to be sure. I used the settings from the V. Read book.
K


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RE: Heat treatment of actively growing Hippeastrum

Hi , I practice the hot water treatment too as it is easy and reliable . I use a cooler with a top , I submerge totaly the bulbs and maintain them in the bottom of the cooler. As temperature should be 46 °C , I start with a higher temperature as the bulbs will refresh it quickly. I check temperature each hour and add hot water if necessary. It doesn't affect the bulb if you exceed 46°C.
Wih my first tests I was keeping the leaves but now I always cut them as they never recover. I keep the roots as with some varieties they don't suffer , it depends.
After the treatment , keep the bulbs for a few days in a heated room neck down for all the water goes out. Then replant (or stock for rest period ). hope it helps.
 photo HippeastrumHotWaterTreament1.jpg
 photo HippeastrumHotWaterTreament2.jpg


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RE: Heat treatment of actively growing Hippeastrum

  • Posted by edie_h 5aNY (Finger Lakes) (My Page) on
    Sat, Dec 21, 13 at 19:10

Yes, that does help, especially the visuals. Thank you.


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RE: Heat treatment of actively growing Hippeastrum

Hi Bill Warren

Thanks for the very informative posts!

Just one thing I don't understand - what is the function of putting the bulbs in the styrofum cup?

Can't I just place them in the water directly?

thanks


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