Stagonospora infection - collected threads

[Maggi Young]

Growing onions or garlic between rows of carrots protects the carrots against carrot root fly, but I think for protection  against a fungal attack the garlicky "essence" would need to be physically applied.

[johnw]

Suppose you just grow garlic in amongst your snowdrops?  It's probably not going to yield the right conditions for a bumper crop of garlic but that's not the point, is it?

Fine until someone orders a Flocon de Neige on eBay (or worse a forumist) and then gets a very nasty surprise when it flowers.  

No offence to the genus as I'm a garlic devotee.


johnw

Or worse your E.A Bowles stuffed in a roast beef...

johnw

[Alan_b]

You might well be right, Maggie, but perhaps a snowdrop bulb growing in proximity to a garlic bulb would get a continuous small dose of "garlicky essence" that could be equivalent to one large dose applied every so often?

Did I read the original recipe correctly in saying you should not heat the garlic above 60C?  If so, boiling for 5 minutes might not be a good idea.

[Maggi Young]

I think Alan, that while a carrot fly might be deterred by a general garlicky "whiff" in the area, a fungus would need to be repelled by contact with the garlicky stuff.... since it is surely a component of that which acts to deter the fungus, because I don't think fungus have a sense of smell. I would really be very surprised if a actual barrier is not needed for protection.

[Hagen Engelmann]

A few of my autumn galanthus scapes stop to grow. I fear Stago is on the way. Here is a view into the bulb.

[johnw]

Last weekend we cooked up a pot of garlic water to combat stag.  Three garlic heads chopped finely in about 5 litres of water, we held it around 54 -56c for 35 minutes checking regularly with a digital meat thermometer so we did not exceed 60c as recommended in the aforementioned study.  We are tending 25 big Hippeastrums purchased last year for a nursing home, they came with stag and after spending a very cool wet summer in the ground outdoors the stag has gone beserk.  We cut off all the leaves and dunked the huge bulbs in the full strength garlic water and will spray them regularly with this.  Will report back in a few months time. I wonder if this garlic water is stable or if a fresh batch should be made with every treatment.

The garlic pieces turned a very unusual colour of turqoise in the process.

I will give my Galanthus a dose this weekend as a safeguard, probably again when shoots appear.

johnw - close to freezing here this morning but not cold enough to have knocked the huge Canna grandes flat.

[Alan_b]

johnw, I was thinking of trying something similar myself.  Have you noticed any ill-effects of your treatment?

[johnw]

johnw, I was thinking of trying something similar myself.  Have you noticed any ill-effects of your treatment?

Alan - There have been no ill effects to date.

About half the Galanthus are already showing noses.  The Hippeastrums look a bit cleaner than before the dranching and will get sprayed with the garlic mix shortly.

I will drench the Galanthus again in a week or so as the decreasing daylight may be good for stag. Also the ventiliation dilemma here during the cold of January and February will require drenching every few weeks.

johnw

[ChrisD]

Just read through this thread and I think there are several factors involved here.

First I have always assumed carrot fly couldn't detect carrots if garlic was planted close by, presumably because of some volatile compond (smell). As Maggie says this is unlikely to affect a fungus! (Though it might be worth a try as a precaution against Narcissus fly?)

Secondly the abstract of the paper talks about a garlic homogenate, without looking at the full paper I cant be sure but I would assume this has not been heated in any way. They are investigating the growth of Stag on an agar plate (I think PDA is potato dextrose agar - dextrose is glucose) and find that a 1% homogenate (1gram of garlic in 100mls of water and blended?) killed (fungicidal) the fungus. However these microbes are almost always much easier to kill on these plates than in living organisms. We have to get the equivalent of a 1% homogenate into all the affected tissues. I guess putting an infected bulb in a plastic bag with say 10 mls of a 20% garlic homogenate and leaving for 8 hours might work it is certainly an idea of a place to start. Sorry have just reread this paragraph mls = millilitres.
I would still recommend that any obviously diseased tissue is cut off and then the "clean" remains are given this treatment.

There is a dilemma here - whether to heat or boil or not. All plants contain a huge variety of different compounds some of which will be decomposed by heating and some of which will be converted by heating into something else (and some of which wont be affected at all). If it is this something else which is needed then obviously the heating step is needed. In an ideal world we would compare heated against boiled against not heated. My guess would be it probably doesn't matter but as the abstract doesn't mention heating then probably not heating is the place to start.

Finally the garlic preparations used to deter slugs may not be effective in treating Stag, in fact I would rather doubt it.

Hope this all makes sense 

Chris



 

[ChrisD]

John - sorry I missed your comment/question about a fresh batch for every treatment. No rules about this but your heat treatment will not have sterilised the garlic soup and I would expect microbes to start growing in it. If it goes "cloudy" throw it away. As ever the most work - making up a fresh batch for each treatment - is the safest and best way.

Another thought, you are treating your Hippeastrums to cure them of Stag, but you are applying this mixture to the drops to prevent them getting the infection. Generally the prevention is easier than the treatment but also more difficult to "interpret". If you cure the infection you will be fairly sure it was the garlic treatment, if your drops don't get Stag will it be the garlic treatment or not - you will never know. Very frustrating.

Chris

[johnw]

Chris - I still have the batch made on 5 November in a refrigerated tight jar, it's clear.

However I intend to make a new batch for every treatment.

I'm not really expecting a cure, if I can keep spores at bay that would be a plus.  As you say I may never know if the garlic worked or not.  The Hippeastrums in a different location do not appear to be getting any worse so I'll spray them periodically as mentioned to see what happens. Actually I was out and checked them this evening, they look pretty good, many of the reddish blotches on the bulbs have dried and turned brown - however that could be due to the drier atmosphere in that greenhouse - they spent a desperately wet summer outdoors.

johnw

[Giles]

Regarding the above - there is a stable preparation of garlic extract freely available called 'Garlic Wonder'.
With botrytis (wasn't there a thread on this? I can't find it) it may be worth trying 'Serenade'. It is only licenced for use on protected strawberries with Botrytis cinerea, in the UK, but is used for a wider range of crops (and diseases) elsewhere. (It works, I've tried it.)

[Alan_b]

there is a stable preparation of garlic extract freely available called 'Garlic Wonder'.

Thank, Giles, I thought this tip was worth pursuing and my Garlic Wonder arrived in the post today.  Now I just have to work out the dosage.

... botrytis (wasn't there a thread on this? I can't find it)

It's here http://www.srgc.org.uk/forum/index.php?topic=6697.0 ; something called "Trichoderma" is being touted as the answer to botrytis.

[kentish_lass]

I am just catching up on older posts and was drawn to this product called 'Garlic Wonder' and have ordered some from Amazon.
I used to bubble up my own concoction but the smell in the kitchen was just too much! I generally use it to deter slugs from the early growth on my daylilies but recently growers have been recommending it for deterring daylily gall midge which is a real pest.

I am wondering if it would be worth spraying the snowdrops once the flowers are over and just as the Narcissus Fly are around - which I gather will be earlier this year?  The trouble is - once it rains it gets washed off.

Alan - did you work out a dilution rate and what are you using yours to prevent (hopefully) ? 

Jennie

[Alan_b]

A few years ago I had a problem with Stagonospora curtisii which spread quite rapidly through a densely-planted snowdrop bed so that two years after I first noticed a few infected plants I had to rescue the remaining snowdrops into pots.  I also have a problem with swift moth larvae which added to the number of fatalities. 

I still have a few isolated pots with bulbs that have a low-grade infection.  I have attached a photograph (taken in haste so not very good quality) which shows unpleasant brown marks on the bulb, the top of the outer scales missing and somewhat reduced root growth.  But the bulb still manages to produce leaves from one year to the next so I am looking for something that will cure the bulb completely and might be used to combat any future infections.  In the end I just followed the instructions on the Garlic Wonder bottle and diluted it 10:1.  In this instance I sprayed the leaves, bulb and roots before repotting in fresh compost.  Since I had made up 500 ml, I also tried spraying the leaves of some of my other healthy snowdrops as a preventative precaution.