Mary Lou Gripshover, Ohio

an alternate to HWT?

June 17, 2008

Categories: Bulb Information, Diseases and Pests, Growing Daffodils

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Has anyone tried putting bulbs in your car, closing the windows, and letting the car sit in the sun all day as an alternative to HWT?  It gets hot enough inside to kill a child (as we unfortunately had locally last year), so would it kill the bad stuff in the bulbs?
I’ve been cleaning bulbs and will have to do some HWT on bulbs from one suspect bed.  I only put bulbs in that bed when I have no where else to put them, and then dig them the next year.  Bulbs from that bed have some dark “goop,” for lack of a better term, around the neck.  Scraping further has disclosed some small grubs, possibly bulb fly grubs.  One bulb had many grubs, which surprised me as I thought the lesser bulb fly only attacked sick bulbs.
I won’t try the car method, since I can give HWT to small quantities of bulbs without difficulty, but I’m curious.
Mary Lou

16 responses to “an alternate to HWT?”

  1. Deborah Holland says:

    Hi, I think that heat treating your bulbs in a sealed and overheated car is an interesting idea. It certainly could prevent virus transmission and you could treat a lot of bulbs at a time. Regulating temperature so that it doesn’t rise above 130F. could be a problem. Maybe you could stick a thermometer on the dashboard and open and close a door. If you try the car treatment, please report on how it turns out. Also…has anyone tried microwaving the bulbs?
    Bulb flies, both greater and lesser, are pretty well established in Oregon. I treat all of my cultivars each summer. Each cultivar gets 12 private minutes in a well washed stainless steel pan at 122F. If it’s raining or there is any sign of fungus, some bleach is added. It’s tiresome, but it works.
    Most of the big bulb flies eclose here in June. They were all over the garden today. Sometimes in the very early spring I wonder about the other bumblebee-mimic flies in my garden. Are they bulb flies out of season or just harmless flower flies? I have found half grown maggots of the big fly in June. I suppose that a very early fly in this mild maritime climate could lay an egg or two in March. The big bulb fly maggots have an opaque appearance…they look pretty white. But the lessor bulb fly maggots are more transparent. You can less some loopy innards through their skin.
    Hope it goes well. Sun yesterday with temperature in the low 60’s.

    Deb Holland Newport, Oregon

  2. Clay Higgins says:

    I assumed that Mary Lou was having a big laugh with her “Car” treatment as an alternative to Hot Water Treatment AKA HWT.
    Not sure if HWT will do in virus’s on daffodils.
    However, history records that HWT treatment with a little Formaldehyde added saved the Daffodil Bulb industry in the USA back in the 1930’s or so, when nematodes were destroying whole crops.  It may not kill 100% but it kills enough that the daffodil bulbs have survived “cultivation” over the years.
    I don’t argue with anything you said, otherwise.

    Clay Higgins


  3. John Beck says:

    OK, I will chime in with a few observations An automobile is great if you do not have to worry about how hot it gets- I have dried insect collections and had the insects dry perfectly but they can get so hot they start to melt- I think that chitin melts at the same temperature that it ignites…. I have seen plans for a solar lumber kiln that would probably do the trick- automatic doors to let the hot air out at a certain temperature(I could have used one of those in my car!)but the bulbs probably deteriorate if you keep the temperature up for too long. I was of the impression that the water was used in order to get a controlled temperature to all of the bulbs and to relieve the heat quickly by exposure to air. I have heard that the nematodes need to be chemicaly killed primarily beacuse they swim everywhere and there will always be cooler ares where they can survive- the mites and especially the fly larvae have much less mobility. We grew flies in college- the only way to kill them in the microwave is to put a large enough drop of water in their bottle to create a steam heat- well a dab of grease would do the same thing! But if an insect gets into the wrong place in the microwave for a few seconds I expect that one would go rather spectacularily? The fungi that attack daffodils seem to grow rather slowly- more so than the ones on roses I would guess. If you have a susceptible fungus the rate of reproduction ought to predict the development of resistance to the poison- of course the same idea implies if you do not use enough fungicide you will cause resistance in the fungus. I would like to hear John Hunter’s thoughts on hot water, as he has been well read and coherent (would that I could be coherent) on so much about the little yellow flower in the past. Two other things- I do not see the plants as being carbon dioxide breathers- they need oxygen! And the line between killing animals and killing plants is not fine so much as black and white- you kill the bugs or the bulb goes bad or you kill the bugs and go too far and the bulbs go bad, the idea is to keep the bulbs alive so you draw a definite line where you could see a broad gradation of things that might actually work? Secondly “solarizing” can work very very well if you can retain and concentrate the heat- but seems to work best when the soil has a good amount of moisture. The moisture carries off the heat and allows it to diffuse. I do not know what it takes to get the mosture level up and still retain the heat. John Beck

  4. George Dorner says:

    This is the type of ongoing conversation that deserves to be archived information which is not readily available. I hope that the eventual replacement for the current daffnet will facilitate that.
    George Dorner  title=
    +=+=+=+=+=+=+= Anagram for Today +=+=+=+=+=+=+=+=+=+=+=
    THE ASSASSINATION OF PRESIDENT ABRAHAM LINCOLN: A pistol in rebel actor’s hands; a fine man is shot.

  5. Mary Lou Gripshover, Ohio Mary Lou Gripshover says:

    Actually, Clay, I was serious.  Thanks to all who commented.  I know that HWT won’t kill virus (nothing does as far as I know).
    In the March 2003 Daffodil Journal, David Adams wrote an article saying that he has had success letting his bulbs “cure” in the sunshine to control basal rot and asked if anyone else had tried it.  Tony James (see March 2006 Daffodil Journal) said he had and that he has now cut his losses from basal rot from 95% to about 1%.  So I wondered whether some time in a hot car would do it, too.  Several people commented about the temperature getting too hot in the car, and that’s probably the limiting factor.  I just may let my car sit out, measure the temperature, and also put a pot of water in the car and measure that temperature as well. 
    Someone, I think maybe Ian Tyler, has experimented with treating bulbs in the microwave.  Ian, if it was you, chime in here.
    Interesting discussion.  Thanks, All.
    Mary Lou

  6. Deborah Holland says:

    —- Keith Kridler < title=> wrote: virus’s the Water are bulbs. the inside with of separate a eggs is our off plant! Dear Keith,
    I was not suggesting that the heat within a sealed car would kill virus. A cultivar with virus would still have the virus. I was thinking that virus is more likely to float off to infect other bulbs in water then in the air of a closed car. Sealing the bulbs in plastic bags could help. I was only addressing the problem of bulb fly. Nothing else.
    I live on a small lot…6,000 square feet. Families with small children live around me. I avoid pesticides, herbicides and strong chemicals whenever possible. I’m looking for GREEN solutions. Sunny and mild weather here. Good for weeding.

    Deb Holland Newport, Oregon

  7. Ian Tyler says:

    Thanks for the invitation Mary Lou!
    I did my microwave tests a few year back until the money ran out! ( lost my job and income) Now back on track!
    But still have the Weight x Wattage x Time table to help anyone who wishes to try with a microwave!
    My conclusions were:
    You can kill all bulb pests no problem!
    But Large Fly Larva remain in the bulb dead and start the to rot down, and small fly arrive fast if left in side the bulb.
    If, and I’m told it is possible you could “nuck” the larvae crisp it would poke out with a pin, but I have never managed this yet!
    Bulbs with small fly are to far gone for any treatment.
    Bulb mite is just fine 3 secs on full power with rid any bulb.
    Virus and Nematodes
    There was a small sign or two that it retarded virus but not conclusive enought to say ya or na
    And I was not brave enough to bring nematodes into my garden to find out if it could be treated, of course not many people will admit to having it anyway, let at all send it to you knowingly. 
    If you have any other questions just ask!
    Best wishes to All
    Ian :o)

  8. Clay Higgins says:

    Mary Lou,
    Having done HWT on a regular basis, the science of it is that you have to hold a high temperature for a long period of time, without getting too hot.  Getting too hot destroys the bulb (cooks it), and not being hot enough doesn’t cook the nematodes.  My problem with using the car to heat the bulbs is the controlling of the heat.  I’d like to see the adjustment nob on the sun (LOL) to make sure it doesnt’ get to hot.
    Poach eggs yes. LOL.
    Yes, I use the method of leaving my bulbs in the sun after digging, every since he put it on daffnet.  Works like a charm.  I have significantly reduced my loss as well.  Down to about 2%.  I leave them out there until I “get around tuit” before I bag them and take them in – week to 10 days.  I’ve noted that bulbs that are missed in the digging, and that stay out in the sun all summer, blooms it’s head off the next year.  So, I’m sold on the sun drying as not hurting the bulbs.

    Clay Higgins


  9. Donna Dietsch says:
    Hi Denise,
    Here in Ohio we don’t have much problem with eelworm because it gets cold enough in the winter that they don’t survive.  We do have plenty of problems with fungus.  It gorws anywhere and especialy loves sugar.  You should see how much I go through  to clean the hummingbird feeders!  So I guess no molasses for us.
  10. Denise and Neil McQuarrie says:

    Some years ago I read an article about the use of a heavy drenching molasses and other sugar products to kill nematodes in the ground, not specific to daffodils but vegetable crops.  There is a lot of information on the internet if you Google it.  Molasses is apparently a good plant food, too.
    The article I read surmised that the nematodes died through osmosis but recent papers have questioned that theory. 
    So maybe instead of poisonous chemicals we should be experimenting with using molasses or sugar  in the HWT and ground to kill eelworm.  Doesn’t solve the fungus problem – maybe ordinary household bleach?
    Regards to all

    Denise and Neil McQuarrie
    New Zealand 7161
    Phone (03) 526 8847
    National Daffodil Society of NZ Inc.
    The website for all daffodil enthusiasts – visit us often!

  11. Lina Burton says:

    For anyone who wants to try it, one way to keep track of the temperature in the car is to put a meat thermometer  with a remote sensor in the car, in the shade, and set the alarm to 118. This would give you a few minutes to get to the car and open the doors to cool things down a bit before the temperature rose to 121. A battery-powered portable fan might be useful too.

    Lina Burton

  12. Denise and Neil McQuarrie says:

    that gives me another idea Donna, if the winter is so cold that eelworm doesn’t survive, maybe we could try freezing the bulbs – but would it kill the plant tissue as well?  What would the temperature have to be and how long would they have to be frozen for?
    Regards, Denise.

  13. Mary Lou Gripshover, Ohio Mary Lou Gripshover says:

    I live in Ohio, too, and I’ve had eelworm.  Had the soil treated with Basamid and gave HWT to all my bulbs.  Don’t want to do that again.  🙁
    Mary Lou

  14. Donna Dietsch says:
    Mary Lou,
    I’ve never had them.  Then again, just that you are 100 miles south makes your climate zone a bit warmer than here in Columbus.  Don’t know if that is the reason, but it could be.  I don’t remember if you ever had them when you lived here in Columbus.  Did you?
    I understood that teasel was an intermediate host to the eelworm. Dr. Steven Still, former dean of horticulture at Ohio State Univ told me about that.
    So, no teasel around me, I am on top of a hill facing northwest which is the direction of the prevailing winds, and  colder for that reason.  I think I will just worry about fly and fungus.
  15. Bob Spotts says:


    I trust you meant "chill" not "freeze."

    Here in mild-Winter oakley, I always chill new bulbs obtained from the UK, Holland, Michigan, or even Oregon before planting them in the Fall. That way, their emergence is hastened in the Spring and they get a complete growing season before our mid-Spring warm spell puts them into dormancy. The length of chilling – two to six weeks – depends upon the climate from whence the new bulbs come.

    One year my old fridge malfunctioned and unnoticed the temperature dropped below freezing. I had placed my new bulbs from Brian Duncan in the fridge and didn’t check on them for the four weeks I planned to chill them. All seemed well when I took the bulbs out to plant them – they were firm, indeed hard! I planted half of the bulbs that day and left the rest for the next day. When I started to plant the rest on the second day, they weren’t hard any more – they were grey balls of putty! Every bulb was lost. I learned that freezing bulbs kills them!

    But, of course any eelworm that, improbably might have been there, was there was killed as well!


    At 05:08 PM 6/19/2008, Denise and Neil McQuarrie wrote:

    that gives me another idea Donna, if the winter is so cold that eelworm doesn’t survive, maybe we could try freezing the bulbs – but would it kill the plant tissue as well?  What would the temperature have to be and how long would they have to be frozen for?
    Regards, Denise.

  16. Donna Dietsch says:
    That isn’t going to work, either.  I remember the year, a while ago, when it stayed warm here until the day before Christmas.  Then, that night, the temperature plumeted to 15 below zeroF,  The bubs all died.  There is something that the cell walls do that prepare them for freezing temperatures.  It involves the cell walls getting tough and then the fluid inside the cells freeze and with the freezing, expand the cell and the tough, maybe even leathery, cell walls will expand as the fluid expands.  But that year, since the weather had stayed warm, the cells never did that preparation and so the fluid inside the cells froze and expanded, breaking the cell walls open.  The next spring, all of us dug the slime out of the ground, which had been daffodil bulbs.  I remember that year I visited Peggy MacNeale in Cincinnati and wept with her as we looked at the beds that had held all her precious miniatures.  The beds were empty ground.  There was one small clump of Tete A Tete out in back of the house.  The others, many of them one of a kind and irreplaceable, were all gone.  There were several hundred clumps that had gone.  I found that I had lost everything that had been planted next to a concerete drive or walkway, as Peggy’s precious miniatures had been.  The ones I still had left were in a bed that I had ammended heavily with leaf mold.  The heat from the decomposition of the leaves had kept the bed from freezing rapidly and so saved the bulbs in it.
    So, the moral to the story is that you cannot freeze bulbs to kill the fly.

    Denise and Neil McQuarrie < title=> wrote:

    that gives me another idea Donna, if the winter is so cold that eelworm doesn’t survive, maybe we could try freezing the bulbs – but would it kill the plant tissue as well?  What would the temperature have to be and how long would they have to be frozen for?
    Regards, Denise.