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Blight
I pulled up my tomato plants yesterday (growing outside) as blight hit
them with a vengeance, taking only a couple of days to spread. The interesting thing is that this blight hadn't read the books stating that it is supposed to spread most readily in warm and humid weather. Or, again, is that correct? Wikipedia says it is favoured by cool, moist environments: "The pathogen is favored by moist, cool environments: sporulation is optimal at 12–18 °C in water-saturated or nearly saturated environments, and zoospore production is favored at temperatures below 15 °C. Lesion growth rates are typically optimal at a slightly warmer temperature range of 20 to 24 °C". But I guess it depends on what you think is "cool". Down here in south central Hampshire it has been a bit warmer the past few days (around 20 - 21 deg C or so), but it has also been very dry, with no rain for at least a fortnight, and precious little for a few months before that. At the time of posting this, RH is apparently 45/ 55% outside (depending on which humidity meter you believe). So have the books got it wrong? Is it all down to luck and wind direction? Out of interest, Phytophthora infestans is always associated with potatoes and tomatoes, but does it have much effect on other, particularly solanaceous, plants? There is some very limited information he https://www.cabi.org/isc/datasheet/40970#tohostsOrSpeciesAffected, but that's all I've been able to find (and I don't have access to the reference quoted). -- Jeff |
Blight
On 18 Sep 2019 16:18, Jeff Layman wrote:
I pulled up my tomato plants yesterday (growing outside) as blight hit them with a vengeance, taking only a couple of days to spread. The interesting thing is that this blight hadn't read the books stating that it is supposed to spread most readily in warm and humid weather. Or, again, is that correct? Wikipedia says it is favoured by cool, moist environments: "The pathogen is favored by moist, cool environments: sporulation is optimal at 12-18 °C in water-saturated or nearly saturated environments, and zoospore production is favored at temperatures below 15 °C. Lesion growth rates are typically optimal at a slightly warmer temperature range of 20 to 24 °C". But I guess it depends on what you think is "cool". Down here in south central Hampshire it has been a bit warmer the past few days (around 20 - 21 deg C or so), but it has also been very dry, with no rain for at least a fortnight, and precious little for a few months before that. At the time of posting this, RH is apparently 45/ 55% outside (depending on which humidity meter you believe). So have the books got it wrong? Is it all down to luck and wind direction? Out of interest, Phytophthora infestans is always associated with potatoes and tomatoes, but does it have much effect on other, particularly solanaceous, plants? There is some very limited information he https://www.cabi.org/isc/datasheet/40970#tohostsOrSpeciesAffected, but that's all I've been able to find (and I don't have access to the reference quoted). We have had some heavy dews over the last week or so, could that be it coupled with the cooler nights. I sprayed mine with Bordeaux Mixture and not had any rain to wash it off. -- Regards Bob Hobden |
Blight
On 18/09/19 18:18, Bob Hobden wrote:
On 18 Sep 2019 16:18, Jeff Layman wrote: I pulled up my tomato plants yesterday (growing outside) as blight hit them with a vengeance, taking only a couple of days to spread. The interesting thing is that this blight hadn't read the books stating that it is supposed to spread most readily in warm and humid weather. Or, again, is that correct? Wikipedia says it is favoured by cool, moist environments: "The pathogen is favored by moist, cool environments: sporulation is optimal at 12-18 °C in water-saturated or nearly saturated environments, and zoospore production is favored at temperatures below 15 °C. Lesion growth rates are typically optimal at a slightly warmer temperature range of 20 to 24 °C". But I guess it depends on what you think is "cool". Down here in south central Hampshire it has been a bit warmer the past few days (around 20 - 21 deg C or so), but it has also been very dry, with no rain for at least a fortnight, and precious little for a few months before that. At the time of posting this, RH is apparently 45/ 55% outside (depending on which humidity meter you believe). So have the books got it wrong? Is it all down to luck and wind direction? Out of interest, Phytophthora infestans is always associated with potatoes and tomatoes, but does it have much effect on other, particularly solanaceous, plants? There is some very limited information he https://www.cabi.org/isc/datasheet/40970#tohostsOrSpeciesAffected, but that's all I've been able to find (and I don't have access to the reference quoted). We have had some heavy dews over the last week or so, could that be it coupled with the cooler nights. I sprayed mine with Bordeaux Mixture and not had any rain to wash it off. Having read several sources reporting the most suitable conditions for blight to spread, I really am not sure what they are! I guess it also depends somewhat on the condition of the plants, if they are stressed I would expect them to be more susceptible. I'm not a vegetable grower anyway. These were half-a-dozen plants left over from a charity plant sale I was helping with. I grew them in my compost (box about 120cm square) as at least they had a source of food and I didn't have to water every day. The plants will now add to the compost as they rot down - I have no intention of growing any tomatoes or potatoes again, and the compost will eventually be spread on the garden as a mulch. From the little I've been able to find, blight is not a concern here for plants other than tomatoes and potatoes. -- Jeff |
Blight
In article ,
Jeff Layman wrote: Out of interest, Phytophthora infestans is always associated with potatoes and tomatoes, but does it have much effect on other, particularly solanaceous, plants? There is some very limited information he https://www.cabi.org/isc/datasheet/40970#tohostsOrSpeciesAffected, but that's all I've been able to find (and I don't have access to the reference quoted). I am pretty sure that it is restricted to genus Solanum, but don't know if it can affect any of our native species or whether they can act as hosts. I have certainly not seen it on S. dulcamara and can't swear to having seen it (ot nor having seen it) on S. nigrum. Regards, Nick Maclaren. |
Blight
On 19/09/2019 09:01, Nick Maclaren wrote:
In article , Jeff Layman wrote: Out of interest, Phytophthora infestans is always associated with potatoes and tomatoes, but does it have much effect on other, particularly solanaceous, plants? There is some very limited information he https://www.cabi.org/isc/datasheet/40970#tohostsOrSpeciesAffected, but that's all I've been able to find (and I don't have access to the reference quoted). I am pretty sure that it is restricted to genus Solanum, but don't know if it can affect any of our native species or whether they can act as hosts. I have certainly not seen it on S. dulcamara and can't swear to having seen it (ot nor having seen it) on S. nigrum. Regards, Nick Maclaren. Now I'm going to ask a couple of stupid questions.#When a plant catches blight do the spors come from the ground or the air? Would covering then with fleece have any deterant effect? |
Blight
In article ,
David Hill wrote: Now I'm going to ask a couple of stupid questions.#When a plant catches blight do the spors come from the ground or the air? Would covering then with fleece have any deterant effect? Not stupid at all. The air. And I doubt it. Polythene does, hoever. Regards, Nick Maclaren. |
Blight
On Wed, 18 Sep 2019 16:18:37 +0100, Jeff Layman wrote:
I pulled up my tomato plants yesterday (growing outside) as blight hit them with a vengeance, taking only a couple of days to spread. The interesting thing is that this blight hadn't read the books stating that it is supposed to spread most readily in warm and humid weather. Or, again, is that correct? Wikipedia says it is favoured by cool, moist environments: "The pathogen is favored by moist, cool environments: sporulation is optimal at 12–18 °C in water-saturated or nearly saturated environments, and zoospore production is favored at temperatures below 15 °C. Lesion growth rates are typically optimal at a slightly warmer temperature range of 20 to 24 °C". But I guess it depends on what you think is "cool". Down here in south central Hampshire it has been a bit warmer the past few days (around 20 - 21 deg C or so), but it has also been very dry, with no rain for at least a fortnight, and precious little for a few months before that. At the time of posting this, RH is apparently 45/ 55% outside (depending on which humidity meter you believe). So have the books got it wrong? Is it all down to luck and wind direction? Out of interest, Phytophthora infestans is always associated with potatoes and tomatoes, but does it have much effect on other, particularly solanaceous, plants? There is some very limited information he https://www.cabi.org/isc/datasheet/40970#tohostsOrSpeciesAffected, but that's all I've been able to find (and I don't have access to the reference quoted). Try Googling "Hutton Period" and looking at the Bligh****ch web site. I subscribed some years ago, and get alerts such as: "A Hutton Period alert is in place today for at least one of your chosen postcode area(s). A 'Full' Hutton Period occurs when the following criteria are met on 2 consecutive days:- Minimum air temperatures are at least 10°C Relative Humidity is 90% or above for at least 6 hours Please visit the website for full details of all affected areas. " This was 25th of August, however. Cheers Dave R -- AMD FX-6300 in GA-990X-Gaming SLI-CF running Windows 7 Pro x64 --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus |
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